WO2024134602A1

WO2024134602A1 - Cannula

Info

Publication number: WO2024134602A1
Application number: PCT/IB2023/063152
Authority: WO
Inventors: Manu PROSSER; Bernard Tsz Lun IP; Qun SHAO; Christian Francis FISCHER; Eu-Lee TEH; Zainab Ali A ALMADAN; Sook Min TEOH; Sam TE WHARE
Original assignee: Fisher & Paykel Healthcare Limited
Priority date: 2022-12-23
Filing date: 2023-12-22
Publication date: 2024-06-27

Abstract

A cannula for delivering fluid to a body cavity of a patient during a surgical procedure. The cannula comprises a cannula housing and a cannula shaft extending from the housing. The cannula shaft defines a first lumen and a second lumen. The first lumen is configured as a delivery lumen and comprises a delivery inlet and a delivery outlet. The delivery inlet is configured for connection to a fluid source. The delivery outlet is configured to deliver fluid flow relative to a distal end of the cannula shaft and to diffuse at least a portion of the fluid flow from the delivery lumen into the body cavity.

Description

Cannula

FIELD OF THE DISCLOSURE

[0001] The present disclosure relates to cannulas configured to deliver fluid to and/or vent fluid from a body cavity of a patient, in particular during a medical procedure. Also disclosed are systems including such cannulas.

BACKGROUND

[0002] Various medical procedures may require delivery of fluid, such as gas, to a body cavity of the patient during the procedure. A medical procedure may require venting of the fluid from the body cavity.

[0003] Examples of such medical procedures include laparoscopy and endoscopy.

Endoscopic procedures enable a medical practitioner to visualize a body cavity by inserting an endoscope, or the like, through one or more natural openings, small puncture(s), or incision(s) to generate an image of the body cavity. In laparoscopy procedures, a medical practitioner typically inserts a medical instrument through natural openings, small puncture(s), or incision(s) to perform a medical procedure in the body cavity. In some cases an initial endoscopic procedure may be carried out to assess the body cavity, and then a subsequent laparoscopy carried out to operate on the body cavity. Such procedures are widely used, for example, on the peritoneal cavity, or during a thoracoscopy, hysteroscopy, colonoscopy, gastroscopy or bronchoscopy.

[0004] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

SUMMARY

[0005] The present disclosure provides examples of a cannula configured to deliver fluid to a body cavity of a patient during a medical procedure, for example a surgical procedure. [0006] The cannula may be configured to deliver one or more types of fluid to the body cavity. For example, the cannula may be configured to deliver fluid to the body at one or more different temperatures, humidities and/or flow rates. The cannula may be configured to deliver fluid for insufflation of the body cavity. The fluid for insufflation may include relatively cold and dry gas. The cannula may be configured to deliver fluid for therapeutic purposes to the body cavity. The fluid for therapeutic purposes may include relatively warm and/or humidified gas, for example. The cannula may be configured to facilitate delivery of fluid for insufflation and/or therapeutic purposes to the body cavity.

[0007] Fluid delivered to a body cavity may, under certain conditions, be projected into the body cavity in a high-velocity stream, or a jet. The velocity of the fluid flow may be dependent on factors including, but not limited to, the temperature, humidity, fluid flow rate and/or the exit conditions at a delivery outlet. Given identical exit conditions, the risk of jetting may be exacerbated as flow rate increases. Jetting of fluid flow may impart undesirable forces within the body cavity. Jetting may result in movement of material such as sutures and/or tissues, for example. Further, in some cases, jetting may cause undesirable temperature changes within the body cavity. For example, if warmed or heated fluid is used, jetting may cause uneven or localised heating and/or burning of body tissues, which could be undesirable. One or more undesirable effects associated with jetting, such as those described above for example, may increase with increased temperature and/or flow rate of the fluid being delivered.

[0008] The present disclosure provides examples of cannulas suitable for diffusing fluid flow delivered to the body cavity. The cannula may include one or more diffusers, for example one or more diffusing apertures, configured to diffuse the fluid flow as it enters the body cavity. The diffusion of the fluid flow may reduce or substantially eliminate jetting of the fluid flow.

[0009] A medical procedure may further require venting of fluid (such as gases) from the body cavity. Venting of fluid may be provided for removal of the fluid from the body cavity. Venting of fluid may help to maintain a substantially constant pressure within the body cavity. Further, venting of fluid may advantageously vent smoke and/or other debris created during the surgical procedure (for example from electrosurgery, cauterising, laser cutting or the like) from inside the body cavity. Venting of fluid may be provided for re-circulation of the fluid back to the body cavity, for example, in connection with a recirculation circuit. The re-circulation circuit may direct the fluid through one or more filters and/or humidifiers, prior to returning the fluid to the body cavity.

[0010] The present disclosure provides examples of cannulas configured for venting of fluid from the body cavity. In particular, disclosed are example cannulas suitable for simultaneous delivery of fluid to, and venting of fluid from, the body cavity. For example, cannulas according to the present disclosure may be configured for delivery of insufflation fluid and/or delivery of fluid for therapeutic purposes and/or for venting of fluid from the body cavity. A cannula as disclosed in some examples herein may include two lumens, and may thus be considered a “dual-lumen” cannula. For example, the cannula may include a delivery lumen and a venting lumen.

[0011] It may be possible to use both lumens of a “dual-lumen” cannula as fluid delivery lumens, so as to deliver two fluids to the body cavity. In some examples, one or more lumens of the “dual-lumen” cannula may be used interchangeably for venting or for fluid delivery.

[0012] In further examples, as discussed in more detail below, a cannula may include three lumens, and may thus be considered a “tri-lumen” cannula. In such examples, the cannula may include a venting lumen and two fluid delivery lumens. However, other arrangements are also contemplated, including interchangeable use of one or more lumens for venting and delivery. In some examples, a venting lumen of the cannula may be configured for connection to one or more evacuation lines, for removal of the fluid. The cannula may be configured for connection to a re -circulation circuit.

[0013] The present disclosure provides examples of a cannula configured to receive a medical instrument therein. The medical instrument may be any appropriate instrument for use within the surgical cavity, such as an obturator, a scope, an electro-surgery tool (such as an electrocautery tool), or the like. The cannula may be configured to receive the medical instrument within a lumen of the cannula, such as a fluid delivery lumen for example.

[0014] The medical instrument may comprise a surgical scope (such as a laparoscope) including a viewing portion. Condensation may form on a surface when the temperature of a gas falls below the dew point temperature for the level of humidity the gas is carrying. This may be caused by the gas contacting a surface which is at a temperature below the dew-point temperature of the gas. The human body is a warm and humid environment and can have a temperature (such as a core body temperature, for example) of about 37 °C. Prior to being inserted into this environment, medical instruments intended for insertion into the surgical cavity, such as cameras, scopes, or other medical instruments may have a temperature, and/or can be exposed to temperatures, at or below typical room temperature and/or below a typical human body temperature. When inserted into this environment, condensation or fogging can form on a viewing portion of the medical instrument (such as a scope) or elsewhere on the medical instrument. In some cases, this condensation can coalesce into droplets. Condensation can also form elsewhere, such as within a cannula through which the medical instrument is inserted, which can coalesce into droplets and migrate down towards, and onto, the viewing portion. Further, when the instrument is removed from the body cavity, this may cause the temperature of the instrument to decrease, which can result in further fogging and/or condensation when reintroduced to the cavity. Condensation, fogging, and/or droplets on the viewing portion can impair vision of a user of the medical instrument.

[0015] Additionally and/or alternatively, during a medical procedure, various other substances can contact the viewing portion of the medical instrument, and/or come within view of the viewing portion of the medical instrument, which can impair vision. For example, the viewing portion of a scope may contact or be positioned near particles created by the procedure, such as surgical smoke. When the viewing portion becomes contaminated by particles, fluid droplets, or the like, it may be necessary to remove the medical instrument and clean the visual impairment. However, removing a medical instrument from the surgical cavity can cause it to cool, for example below the patient’s body temperature, such that when the instrument is reinserted to the body, further condensation and/or droplets can form which, again, can inhibit vision through the viewing portion. This process may need to be repeated multiple times. Past approaches to resolve this include pre-warming the medical instruments, and/or using a light or a heating source at the end of the scope to warm the viewing portion. Such interventions typically require additional steps that can negatively impact the workflow and efficiency of the procedure. Integrating or including a heating source with the scope, such as a heating element adjacent a viewing portion, can increase complexity and/or cost.

[0016] Cannulas according to some examples of the present disclosure may be configured to direct fluid relative to an end of the medical instrument. In particular, disclosed examples of cannulas may be suitable for directing fluid flow around and/or near a distal end of a medical instrument, and/or directing fluid flow towards a desired region of the body cavity. This can prevent or at least reduce condensation and/or droplets forming on the viewing portion of the medical instrument, and/or prevent or at least reduce other substances from contacting or coming within view of the viewing portion.

[0017] The present disclosure provides examples of a proximal end housing of the cannula. The proximal end housing may be configured to retain a relative positioning of one or more components of the cannula. The present disclosure provides examples of a cannula comprising a proximal end housing attachable to a housing of the cannula. The proximal end housing may be configured to clip onto the cannula housing to retain the seals between the cannula housing and the proximal end housing.

[0018] The proximal end housing may be configured to retain at least one seal at a proximal end of the cannula.

[0019] The present disclosure provides examples of a cannula configured to accommodate an obturator. During a surgical procedure, a surgeon may apply rotational and longitudinal forces when inserting an obturator and cannula into a patient cavity. This “twist and push” insertion technique may make insertion of the obturator easier and may minimise damage to the tissue during insertion. The present disclosure provides examples of a cannula in which movement of the obturator relative to the cannula is restricted or inhibited when the obturator is received in the cannula. Restriction of rotation of the obturator relative to the cannula may facilitate use of such insertion techniques.

[0020] The present disclosure provides examples of a cannula that may be configured (or configurable) to inhibit and/or prevent insertion of a medical instrument through the cannula. For example, the cannula may be configured to inhibit insertion of a medical instrument through the cannula to the body cavity. In such examples, the cannula may include a lumen capable of receiving a medical instrument. The cannula may include a proximal port capable of receiving a medical instrument. The cannula may be configured to prevent passage of the medical instrument beyond a distal end of the cannula. [0021] For example, the cannula may have a distal end which is blind. That is, the distal end of the cannula shaft may be at least partially closed and configured to inhibit or prevent a medical instrument from passing through the distal end of the cannula. For example, the delivery lumen may be capable of receiving a medical instrument but the blind distal end may block passing of the medical instrument through or beyond the distal end of the cannula.

[0022] The blind distal end may include one or more openings or apertures configured to allow fluid flow therethrough, but may be configured to inhibit passage of a medical instrument therethrough. In some examples, the blind distal end of the cannula, for example a distal tip portion, may have a pointed or tapered shape, configured to facilitate insertion of the cannula into the body cavity (for example, by functioning in the manner of an obturator tip).

[0023] According to one disclosed aspect, there is provided a cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; and a cannula shaft extending from the housing, the cannula shaft defining: first lumen; and a second lumen, wherein the first lumen is configured as a delivery lumen and comprises a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow relative to a distal end of the cannula shaft and to diffuse at least a portion of the fluid flow from the delivery lumen into the body cavity.

[0024] The delivery outlet may comprise at least one diffuser in fluid communication with the delivery lumen. The diffuser may comprise at least one diffusion aperture extending through a side wall of the cannula shaft. The at least one diffusion aperture may be located at or adjacent to the distal end of the cannula shaft. The at least one diffusion aperture may be spaced from a distal end of the cannula shaft. The delivery outlet may comprise a plurality of diffusion apertures in spaced array around the cannula shaft. The plurality of diffusion apertures may be spaced substantially evenly around the cannula shaft.

[0025] In some examples, the delivery lumen may comprise a blind distal end. In other examples, the delivery outlet may comprise an open distal end of the delivery lumen. [0026] A resistance to fluid flow through the at least one diffusion aperture may be less than a resistance to fluid flow through the open distal end of the delivery lumen, when a medical instrument is received in the cannula. The delivery outlet may be configured to deliver a greater percentage of the fluid flow through the at least one diffusion aperture than through the open distal end of the delivery lumen. The delivery outlet may be configured to deliver between about 60% and about 80% of the fluid flow through the at least one diffusion aperture, or about 70% of the fluid flow through the at least one diffusion aperture.

[0027] The at least one diffusion aperture may directs at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft. The angle may be between about 10 degrees and about 60 degrees.

[0028] The at least one diffusion aperture may taper towards a distal end. The at least one diffusion aperture may be at least partly defined by a fluid directing surface, configured to direct at least part of the fluid flow. The fluid directing surface may directs the at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft. The cannula shaft may taper inwardly in a region of the at least one diffusion aperture such that at least a portion of the at least one diffusion aperture may be angled relative to a longitudinal axis of the cannula shaft.

[0029] The cannula may comprise a tapered distal tip portion. The tapered distal tip portion may tapers towards a central longitudinal axis of the cannula shaft. The tapered distal tip portion may include a tapered inner surface. The tapered distal tip portion may include a tapered outer surface. The at least one diffusion aperture of the delivery outlet may extends through a side wall of the tapered distal tip portion. A maximum outer diameter of the tapered distal tip portion may be substantially equal to a maximum outer diameter of the cannula shaft.

[0030] The second lumen may comprise a second delivery lumen. The second delivery lumen may comprise a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow relative to a distal end of the cannula shaft.

[0031] The second lumen may comprise a venting lumen. The venting lumen may comprise a venting inlet, comprising an open distal end of the venting lumen. The venting inlet may comprise at least one venting inlet aperture extending through a side wall of the cannula shaft and in fluid communication with the venting lumen at or adjacent to a distal end of the cannula shaft. The venting inlet may comprise a plurality of venting inlet apertures in spaced array around the cannula shaft. The venting inlet may comprise a substantially annular opening. The venting inlet may comprise one or more openings extending through a side wall of the cannula shaft. The venting inlet may comprise a plurality of openings extending through a side wall of the cannula shaft. The plurality of openings may be spaced around the cannula shaft. The plurality of openings may be substantially evenly spaced around the cannula shaft.

[0032] The cannula shaft may include a delivery shaft defining the delivery lumen, and a second shaft defining a second lumen. The second shaft may be a venting shaft defining a venting lumen. The second shaft may be a second delivery shaft defining a second delivery lumen. The delivery shaft and the second shaft may be at least partially nested relative to each other. For example, the delivery shaft may be at least partially nested within the second shaft. Alternatively, the second shaft may be at least partially nested within the delivery shaft.

[0033] The delivery shaft may extend distally beyond a distal end of the second shaft. The second shaft may extend distally beyond a distal end of the delivery shaft. The delivery shaft and the second shaft may be positioned substantially concentrically with respect to each other.

[0034] The cannula may comprise at least one spacer element configured to position the delivery shaft and the second shaft relative to each other. The at least one spacer element may comprise at least one protrusion on a wall of the delivery shaft and/or on a wall of the second shaft. The at least one spacer element may comprise an inwardly directed wall portion of the cannula shaft.

[0035] The cannula may comprise at least one guide element. The at least one guide elements may be configured to position a medical instrument within the cannula, such as within the delivery lumen. The at least one guide element may hold a medical instrument shaft substantially concentrically relative to the cannula shaft. The at least one guide element may be provided in or on an inner wall of the cannula shaft. [0036] The cannula housing may comprise a first port in fluid communication with the first lumen and a second port in fluid communication with the second lumen. The first port may be a delivery port configured for connection to a fluid source. The second port may be a venting port configured for connection to a venting element.

[0037] The cannula housing may comprise a first port housing and a second port housing. The first port housing may comprise the first port. The second port housing may comprise the second port. The first port housing and the second port housing may be at least partially nested relative to each other.

[0038] The second port housing may be a venting port housing comprising a venting port. The second port housing may be a second delivery port housing comprising a second delivery port.

[0039] The delivery port may extend from the venting housing transverse to a longitudinal axis of the cannula shaft. The delivery port may extend from the venting housing transverse to a longitudinal axis of the cannula shaft.

[0040] The cannula may further comprise a port housing seal configured to provide a substantially fluid-tight seal between the venting port housing and the delivery port housing.

[0041] The port housing seal may be configured to seal the delivery lumen and/or the venting lumen at a proximal end of the cannula.

[0042] The cannula housing may comprise a proximal end port for receiving a medical instrument therethrough. The cannula may comprise an instrument seal configured to provide a substantially fluid-tight seal between the cannula housing and the medical instrument. The instrument seal may define an aperture for receiving the medical instrument therethrough.

[0043] The cannula may further comprise a proximal end port seal. The proximal end port seal may be configured to provide a substantially fluid tight seal across the proximal end port when no medical instrument is inserted into the cannula housing.

[0044] The cannula may further comprise a proximal end housing attachable to the cannula housing. The proximal end housing may be configured to secure the delivery port relative to the venting port. The proximal end housing may comprise one or more apertures configured to cooperate with one or more corresponding protrusions on the cannula housing. The proximal end housing may be configured to secure one or more seals between the proximal end housing and the cannula housing.

[0045] The instrument port may extend through the proximal end housing. The proximal end housing may comprise one or more protrusions configured to secure one or more seals between the proximal end housing and the cannula housing. The proximal end housing may comprise one or more protrusions configured as guide elements for positioning a medical instrument within the cannula.

[0046] The cannula may be configured to receive a medical instrument therein. The medical instrument to be received may comprise a surgical scope. The medical instrument to be received may comprise an obturator.

[0047] The cannula may be configured to inhibit rotational movement of the obturator relative to the cannula upon receipt of the obturator in the cannula. The cannula housing may comprise one or more obturator accommodating portions configured to engage corresponding locating elements of the obturator for restricting relative rotation between the obturator and the cannula. The obturator accommodating portions comprise one or more apertures configured to receive a corresponding one or more locking fingers of the obturator locating elements to releasably secure the obturator to the cannula.

[0048] According to another disclosed aspect, there is provided a cannula for providing fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing at a proximal end of the cannula; a cannula shaft extending from the housing, the cannula shaft defining a delivery lumen; and a proximal end housing attachable to the cannula housing to retain at least one seal, wherein the delivery lumen comprises a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow relative to a distal end of the cannula shaft. [0049] The proximal end housing may be configured to clip onto the cannula housing. The proximal end housing may comprise one or more apertures configured to cooperate with one or more corresponding protrusions on the cannula housing to attach the proximal end housing to the cannula housing.

[0050] The cannula housing may comprise: a delivery port housing comprising a delivery port; and a venting port housing comprising a venting port, wherein the proximal end housing may be configured to secure the delivery port relative to the venting port.

[0051] The cannula may be configured to receive a medical instrument therein. The medical instrument to be received may comprise an obturator. The cannula may be configured to inhibit rotational movement of the obturator relative to the cannula upon receipt of the obturator in the cannula. The proximal end housing may comprise one or more obturator accommodating portions configured to engage corresponding locating elements of the obturator for restricting relative rotation between the obturator and the cannula.

[0052] The one or more obturator accommodating portions comprise one or more recesses in the proximal end housing configured to receive one or more corresponding protrusions of the obturator.

[0053] According to another disclosed aspect, there is provided a surgical kit, comprising: a cannula as described in at least one example herein; and an obturator.

[0054] The obturator may comprise one or more locating elements configured to cooperate with corresponding obturator accommodating portions of the proximal end housing. The one or more locating elements may include at least one locking finger extending outwardly from lower surface of the obturator body. The at least one locking finger may be configured to be received in a corresponding aperture in the cannula. The at least one locking finger may comprise a locking tab configured to engage with corresponding engagement tab in the cannula. [0055] According to another disclosed aspect, there is provided a system for providing fluid to a body cavity of a patient during a surgical procedure, the system comprising: a cannula as described in at least one example herein; one or more fluid flow tubes for connecting to the delivery lumen and/or the venting lumen.

[0056] The system may further comprise an obturator. The obturator may comprise one or more locating elements configured to cooperate with one or more corresponding obturator accommodating portions of the cannula housing.

[0057] The system may comprise one or more filters in connection with the one or more fluid flow tubes.

[0058] According to another disclosed aspect, there is provided a cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; a cannula shaft extending from the housing, the cannula shaft defining a delivery lumen; and a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow to the body cavity, wherein the delivery outlet comprises at least one diffusion aperture, wherein the delivery lumen comprises a blind distal end, wherein the blind distal end comprises a penetrating tip of the cannula shaft.

[0059] According to another disclosed aspect, there is provided a cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; a cannula shaft extending from the housing, the cannula shaft defining a delivery lumen; and at least one guide element configured to position a medical instrument within the cannula, wherein the delivery lumen comprises a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow to the body cavity, wherein the delivery lumen is configured to direct at least a portion of the fluid flow along the delivery lumen, wherein the delivery outlet comprises at least one aperture and an open distal end of the delivery lumen.

[0060] The at least one aperture may be configured to diffuse at least a portion of the fluid flow from the delivery lumen into the body cavity. The at least one aperture may comprise at least one diffusion aperture. The at least one aperture may comprise a plurality of diffusion apertures.

[0061] The plurality of diffusion apertures may be located at or adjacent to a distal end of the cannula shaft. The plurality of diffusion apertures may be spaced from a distal end of the cannula shaft.

[0062] The plurality of diffusion apertures may be spaced around the cannula shaft. The plurality of diffusion apertures may be substantially evenly spaced around the cannula shaft.

[0063] The second lumen may be configurable as a venting lumen and/or as a second delivery lumen

[0064] A resistance to fluid flow through the at least one diffusion aperture may be less than a resistance to fluid flow through the open distal end of the delivery lumen, when the medical instrument is received in the cannula.

[0065] The delivery outlet may be configured to deliver a greater percentage of the fluid flow through the at least one diffusion aperture than through the open distal end of the delivery lumen. The delivery outlet may be configured to deliver between about 60% and about 80% of the fluid flow through the at least one diffusion aperture. The delivery outlet may be configured to deliver about 70% of the fluid flow through the at least one diffusion aperture.

[0066] The at least one guide element may comprise a plurality of guide elements. The at least one guide element may be configured to position the shaft of the medical instrument within the delivery lumen. The at least one guide element may hold the medical instrument shaft substantially concentrically within the delivery lumen. The at least one guide element may comprise one or more protrusions extending inwardly from an inner surface of the cannula shaft. At least one guide element may be located at or adjacent to a distal end of the cannula shaft. At least one guide element may be spaced from a distal end of the cannula shaft.

[0067] The at least one guide element may comprise two or more guide elements, wherein the two or more guide elements are axially spaced apart.

[0068] The cannula shaft may further define a second lumen. The second lumen may be configured as a venting lumen. The venting lumen may comprise a venting inlet, comprising an open distal end of the venting lumen. The venting inlet may comprise at least one venting inlet aperture extending through a side wall of the venting shaft and in fluid communication with the venting lumen at or adjacent to a distal end of the venting shaft.

[0069] The cannula shaft may include a delivery shaft defining the delivery lumen, and a second shaft defining the venting lumen. The delivery shaft and the second shaft may be at least partially nested relative to each other. At least part of the delivery outlet may be positioned distally of the venting inlet.

[0070] The venting inlet may comprise a substantially annular opening. The venting inlet may comprise one or more openings extending through a side wall of the cannula shaft. The venting inlet may comprise a plurality of openings extending through a side wall of the cannula shaft. The plurality of openings may be spaced around the cannula shaft. The plurality of openings are substantially evenly spaced around the cannula shaft.

[0071] The cannula shaft may include a tapered distal tip portion. A maximum outer diameter of the tapered distal tip portion may be substantially equal to a maximum outer diameter of the cannula shaft.

[0072] According to another disclosed aspect, there is provided a cannula for delivering fluid to and venting fluid from a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; and a cannula shaft extending from the housing, the cannula shaft defining: a first lumen; and a second lumen, wherein the first lumen is a delivery lumen, wherein at least part of a delivery outlet of the delivery lumen is positioned distally of a distal opening venting inlet of the second lumen.

[0073] The delivery outlet may comprise an open distal end of the delivery lumen. The delivery outlet may comprise a diffuser in fluid communication with the delivery lumen. The diffuser may be located at or adjacent to the distal end of the cannula shaft.

[0074] The diffuser may comprise at least one diffusion aperture extending through a side wall of the cannula shaft. The at least one diffusion aperture may be spaced from a distal end of the cannula shaft. At least one diffusion aperture may be positioned distally of the distal opening of the second lumen.

[0075] The distal opening of the second lumen may comprise an open distal end of the second lumen. The distal opening of the second lumen may comprise at least one aperture extending through a side wall of the second shaft and in fluid communication with the second lumen, at or adjacent to a distal end of the second shaft.

[0076] The cannula shaft may include a delivery shaft defining the first lumen, and a second shaft defining the second lumen. The first shaft and the second shaft may be at least partially nested relative to each other.

[0077] The distal opening of the second lumen may comprise a substantially annular opening. The distal opening of the second lumen may comprise one or more openings extending through a side wall of the cannula shaft. The distal opening of the second lumen may comprise a plurality of openings extending through a side wall of the cannula shaft.

[0078] The second lumen may be configured as a venting lumen. The second lumen may be configured as a second delivery lumen

[0079] The plurality of openings may be spaced around the cannula shaft. The plurality of openings may be substantially evenly spaced around the cannula shaft. [0080] According to another disclosed aspect, there is provided a cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; and a cannula shaft extending from the housing, wherein the cannula shaft comprises a delivery outlet configured to deliver fluid flow to the body cavity, wherein the delivery outlet comprises: an open distal end; and at least one diffusion aperture extending through a side wall of the cannula shaft, wherein a resistance to fluid flow through the at least one diffusion aperture is less than a resistance to fluid flow through the open distal end when a medical instrument is received in the cannula shaft.

[0081] The at least one diffusion aperture may be located at or adjacent to the distal end of the cannula shaft. The at least one diffusion aperture may be spaced from a distal end of the cannula shaft.

[0082] The delivery outlet may comprise a plurality of diffusion apertures in spaced array around the cannula shaft. The plurality of diffusion apertures may be spaced substantially evenly around the cannula shaft.

[0083] The delivery outlet may be configured to deliver a greater percentage of the fluid flow through the at least one diffusion aperture than through the open distal end. The delivery outlet may be configured to deliver between about 60% and about 80% of the fluid flow through the at least one diffusion aperture, or to deliver about 70% of the fluid flow through the at least one diffusion aperture.

[0084] The at least one diffusion aperture may direct at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft. The angle may be between about 10 degrees and about 60 degrees.

[0085] The at least one diffusion aperture may taper towards a distal end. The at least one diffusion aperture may be at least partly defined by a fluid directing surface configured to direct at least part of the fluid flow. The fluid directing surface may directs the at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft. The cannula shaft may taper inwardly in a region of the at least one diffusion aperture, such that at least a distal portion of the at least one diffusion aperture is angled relative to a longitudinal axis of the cannula shaft.

[0086] According to another disclosed aspect, there is provided a cannula comprising: a cannula housing; and a cannula shaft extending from the cannula housing between the cannula housing and a distal end of the cannula, the cannula shaft defining: a first lumen; a second lumen; and a third lumen, wherein the first, second and third lumens extend at least partially through the cannula shaft, wherein the first, second and third lumens are separate from each other and provide respective first, second and third fluid flow paths through the cannula shaft, wherein the cannula comprises a first port in fluid connection with the first lumen, a second port in fluid connection with the second lumen, and a third port in fluid connection with the third lumen, wherein each of the first, second and third ports is configured for connection to a respective fluid source and/or venting element.

[0087] The first lumen may be configured as a first delivery lumen. The first lumen may comprise a first delivery outlet. The first delivery outlet may be configured to deliver first fluid flow relative to a distal end of the cannula shaft. The first delivery outlet may be configured to diffuse at least a portion of the first fluid flow from the first delivery lumen. The first delivery outlet may be configured to diffuse fluid into a body cavity of a patient during a surgical procedure. The first delivery outlet may comprise at least one diffuser in fluid communication with the delivery lumen. The diffuser may comprise at least one diffusion aperture. The at least one diffusion aperture may extend through a side-wall of the cannula shaft.

[0088] The first delivery outlet may be provided at a distal end of the cannula shaft. At least part of the first delivery outlet may be positioned distally of a distal opening of the second lumen. [0089] The second lumen may be configured as a venting lumen. The distal opening of the second lumen may be configured as a venting inlet. The venting inlet may be configured to receive fluid from a body cavity of a patient during a surgical procedure.

[0090] The third lumen may be configured as a second delivery lumen. The second delivery lumen may comprise a second delivery inlet configured for connection to a second fluid source and a second delivery outlet configured to deliver second fluid flow relative to the distal end of the cannula shaft.

[0091] The cannula shaft may comprise an inner shaft defining the first lumen and an outer shaft defining the second lumen. The inner shaft and the outer shaft may be at least partially nested relative to each other.

[0092] The cannula shaft may further comprise a divider extending between an outer surface of the inner shaft and an inner surface of the outer shaft to define the third lumen between the inner shaft and the outer shaft.

[0093] The first port may be configured as a first fluid delivery port configured for connection to a first fluid source. The second port may be configured as a venting port configured for connection to a venting element. The venting port may be positioned distally of the first fluid delivery port.

[0094] The third port may be configured as a second fluid delivery port. The third port may be positioned distally of the first fluid delivery port and the venting port.

[0095] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

BRIEF DESCRIPTION OF THE DRAWINGS

[0096] These and other features, aspects, and advantages of the present disclosure are described with reference to the drawings, which are intended to illustrate certain examples and not to limit the scope of the disclosure. In some cases, a “slice” has been shown for clarity purposes for some sectional and cross-sectional views of a three-dimensional cannula. A person skilled in the art would be able to appreciate that these figures illustrate a slice of a three-dimensional cannula. In some cases, projecting surfaces have not been shown for clarity.

[0097] Figure 1 illustrates, schematically, a surgical system, including a cannula, for providing fluid to and venting fluid from a body cavity of a patient during a surgical procedure according to one example of the present disclosure;

[0098] Figure 2 illustrates, schematically, a surgical system, including a cannula, for providing fluid to and venting fluid from a body cavity of a patient during a surgical procedure according to one example of the present disclosure, used with a medical instrument received in the cannula;

[0099] Figure 3 illustrates, schematically, a surgical system, including a cannula, for providing fluid to and venting fluid from a body cavity of a patient during a surgical procedure according to one example of the present disclosure;

[0100] Figure 4 is a perspective view of a cannula according to one example of the present disclosure;

[0101] Figure 5 is a front view of the cannula of Figure 4;

[0102] Figure 6 is a side view of the cannula of Figure 4;

[0103] Figure 7 is a top view of the cannula of Figure 4;

[0104] Figure 8 is a bottom view of the cannula of Figure 4;

[0105] Figure 9 is a perspective view of a proximal end of the cannula of Figure 4;

[0106] Figure 10 is a perspective longitudinal sectioned view of the proximal end of the cannula of Figure 4;

[0107] Figure 11 is a front view of a distal end of the cannula of Figure 4; [0108] Figure 12 is a sectioned view of the cannula of Figure 4, taken along line B-B of Figure 11;

[0109] Figure 13 is a perspective view of a distal end region of the cannula of Figure 4;

[0110] Figure 14 is a perspective view of a distal tip portion of the cannula of Figure 4;

[0111] Figure 15 is a front view of a distal end region of the cannula of Figure 4, illustrating fluid flowing from a delivery outlet of the cannula and into a venting inlet of the cannula;

[0112] Figure 16 is a perspective view of a distal end of a cannula according to another example of the present disclosure;

[0113] Figure 17 is a longitudinal sectioned view of the distal end region of the cannula of Figure 16;

[0114] Figure 18 is a sectioned view of the cannula of Figure 16, taken along line A-A of Figure 17;

[0115] Figure 19 is a perspective exploded view of the proximal end of the cannula of Figure 4, showing a proximal end housing of the cannula removed;

[0116] Figure 20 is a perspective view of a proximal end of the cannula of Figure 4;

[0117] Figure 21 is a perspective view of a proximal end of an obturator;

[0118] Figure 22 is a perspective view showing the obturator of Figure 21 received in the cannula of Figure 4;

[0119] Figure 23 is a perspective view of a proximal end housing of a cannula according to an example of the present disclosure;

[0120] Figure 24 is a top view of the proximal end housing of Figure 23;

[0121] Figure 25 is a longitudinal sectioned view of the proximal end housing of Figure 23; [0122] Figure 26 is a front view of a distal end region of the cannula of Figure 4, illustrating example fluid flow paths of fluid flowing from a delivery outlet of the cannula;

[0123] Figure 27 is a front view of a distal end region of the cannula of Figure 4, illustrating example fluid flow paths of fluid flowing from a delivery outlet of the cannula;

[0124] Figure 28 is a front view of a distal end region of the cannula of Figure 4, illustrating example fluid flow paths of fluid flowing from a delivery outlet of the cannula into a venting inlet of the cannula;

[0125] Figure 29 illustrates, schematically, a surgical system, including a cannula, for providing fluid to a body cavity and a separate cannula for venting fluid from a body cavity during a surgical procedure according to one example of the present disclosure;

[0126] Figure 30 is a perspective view of a cannula according to a further example of the present disclosure, having dual concentric lumens and a closed distal end;

[0127] Figure 31 is a perspective view of a distal tip portion of the cannula of Figure 30;

[0128] Figure 32 is a longitudinal sectioned view of the cannula of Figure 30;

[0129] Figure 33 is a front view of a cannula according to a further example of the present disclosure, including a first lumen configured for fluid delivery, the first lumen having diffusion apertures and a closed distal end; and a second lumen configured for venting of fluid and/or delivery of insufflation fluid, the second lumen having an open distal end;

[0130] Figure 34 is a longitudinal sectioned view ofthe cannula of Figure 33;

[0131] Figure 35 is a front view of a cannula according to a further example of the present disclosure, including tabs for accommodating sutures.

[0132] Figure 36 is a perspective view of a distal tip portion of the cannula of Figure 35;

[0133] Figure 37 illustrates, schematically, a surgical system according to a further example of the present disclosure, including a first cannula configured for providing fluid to and venting fluid from a body cavity of a patient during a surgical procedure, and a second cannula configured to receive a medical instrument and/or provide insufflation;

[0134] Figure 38 is a perspective view of a cannula according to a further example of the present disclosure, including three lumens;

[0135] Figure 39 is a perspective, exploded view of the cannula of Figure 38;

[0136] Figure 40 is a longitudinal sectioned view of the cannula of Figure 38 ;

[0137] Figure 41 is a sectioned view of the cannula of Figure 40 taken along line A-A of Figure 40;

[0138] Figure 42 is a sectioned view of the cannula of Figure 40 taken along line B-B of Figure 40;

[0139] Figure 43 illustrates, schematically, a surgical system according to a further example of the present disclosure, including the cannula of Figure 38; and

[0140] Figure 44 illustrates, schematically, a surgical system according to a further example of the present disclosure, including a first cannula configured for providing a first fluid to a body cavity of a patient, a second cannula configured for providing a second fluid to the body cavity of the patient and configured to receive a medical instrument; and a third cannula configured for venting fluid from the body cavity of the patient.

DETAILED DESCRIPTION

[0141] Although certain examples are described below, it will be appreciated that the disclosure extends beyond the disclosed examples and/or uses, and includes obvious modifications and equivalents thereof. It is intended that the scope of the disclosure should not be limited by any particular examples described below. It will be appreciated that while some features may be disclosed in relation to one or more examples, and other features be disclosed in relation to one or more other examples, combining these features together in one or more further examples is within the scope of the disclosure. It would consequently be understood that any combinations of any disclosed features in an example of the cannula is within the scope of the disclosure.

Examples of medical fluid delivery systems

[0142] A cannula according to the present disclosure may form part of a fluid delivery and/or venting system. It will be appreciated that “fluid” as referred to herein may refer to any gas or liquid, or a combination thereof. Where the term “gas” is used specifically, it should be understood that the cannulas and/or systems may also be suitable for use with other fluids. The fluid may include components that may be carried in fluid flow, such as aerosolised medicaments (e.g. in delivery flow) and/or particulate matter (e.g. smoke in venting flow), for example. Cannulas according to the present disclosure may generally be used in medical procedures for the delivery and/or venting of fluids to and from a body cavity of a patient. In some examples, the fluid may include CCE gas.

[0143] Example fluid delivery systems incorporating a cannula 1000 according to the present disclosure are shown in Figures 1, 2, 3 and 29 and 44. The cannula 1000 is configured to deliver fluid to the body cavity 2 of a patient. It will be appreciated that the cannula 1000 (or other example cannulas disclosed herein) is not limited to use with the illustrated systems and may be used with a variety of types of surgical systems. For example, the cannula may be used in connection with a fluid source such as a flow generator, blower, insufflator, high- pressure wall source, gas bottle, fluid recirculation system or other suitable fluid source.

[0144] The cannula 1000 may be further configured to vent fluid from the body cavity 2. For example, cannula 1000 may be configured for use with a venting element such as an active suction source (such as a wall vacuum source), recirculation system, passive venting or other suitable venting element.

[0145] An example surgical system is shown in Figure 1. In this example, the cannula 1000 is shown as part of a fluid recirculation system 1 and is configured to provide fluid to and vent fluid from a body cavity 2 of a patient. Example recirculation circuits are described in PCT/NZ2015/050059, filed on 15 May 2015, the disclosure of which is hereby incorporated by reference in its entirety. [0146] The fluid recirculation system 1 may comprise a flow generator 5 in connection with the cannula 1000. The flow generator 5 may facilitate movement of fluid around the fluid recirculation system 1. The delivered and vented fluid may comprise gases, for example. The flow generator 5 may comprise one or more pumps. Various types or styles of pumps may be used, including but not limited to one or more of a diaphragm compressor, radial compressor, a peristaltic pump, or a rotary pump.

[0147] The flow generator 5 may include one or more components that are configured to be reusable. For example, the flow generator 5 may be configured such that a fluid flow path of the fluid recirculation system 1 is decoupled from a motor or other operating component(s) of the flow generator 5. Additionally and/or alternatively, the flow generator 5 may include one or more disposable components. For example, the flow generator 5 may include a disposable pump cartridge or chamber, which may be releasably connectable to a pump or motor of the flow generator 5. The cartridge/chamber maybe fluidly sealed, to isolate fluid within the cartridge/chamber from other operating component(s) of the flow generator 5. Additionally and/or alternatively, the fluid recirculation system 1 may include one or more filters in the gas flow path to mitigate the risk of smoke or particulate matter coming into contact with the flow generator 5 (or other components of the system which are configured to be reusable).

Additionally and/or alternatively, the flow generator 5 may include a disposable component that is both coupled (directly or indirectly) to a pump and in direct contact with fluid.

[0148] It can be desirable to match the temperature of gases delivered from the system as closely as possible to the typical human body temperature. It can also be desirable to deliver gases above or below internal body temperature, such as, for example, any degree between 1 ° C to 10° C, at about 15° C, or more or less above or below internal body temperature for example, or ranges including any two of the foregoing values. It can also be desirable to deliver gases of a desired fixed or variable humidity and/or a desired fixed or variable temperature. The desired humidity may be a fixed value or a range of values. The desired temperature may be a fixed value or a range of values. The delivered gases can be dry cold gas, dry warm gas, humidified cold gas, or humidified warm gas for example.

[0149] Gases for delivery into the patient’s body may be relatively dry, which can cause damage to the body cavity, such as cell desiccation, cell death and/or adhesions. In some examples, the system may include a humidifier. For example, a humidifier 10 may be optionally located between the fluid source and the body cavity. In examples shown in Figures 1, 2 and 43, the humidifier 10 is operatively coupled to the recirculation system 1. Additionally and/or alternatively the fluid recirculation circuit 1 may include a heat and/or moisture exchanger. In the examples shown in Figures 3, 29 and 44, the humidifier 10 is located downstream of flow controller 55. A controller of the system may energize a heater of the humidifier 10 to deliver humidification fluid to the gas flow stream prior to the gas entering the body cavity 2. The humidification fluid may be water. The humidified and/or heated gas can be delivered to the patient via further tubing. The controller of the system may energize heating of the tubing.

[0150] Where present, various styles or types of humidifiers may be used in combination with the other elements of the surgical system. The humidifier may include a chamber (for example, a “pass-over” humidifier). Other humidifier types are also contemplated, such as a humidifier including a wicking or other suitable absorbent material for holding humidification fluid. A suitable humidifier may comprise a humidifier chamber, or medium to hold humidification fluid, and a heater configured to heat at least one of a gas and the humidification fluid.

[0151] Some examples may include a fluid recirculation system 1 that does not include a humidifier in the recirculation circuit. Instead, the fluid recirculation system 1 may be configured to preserve heat and/or humidity inherent in the system (including from patient), as much as possible. For example, heat and/or humidity may be maintained by use of one or more of: insulated tubing, heated tubing, a condensate management device/feature (e.g. including media that absorbs liquid and can release humidity into gas flowing over and/or through the media). A moisture trap can include such media, or the media can be part of and/or embedded in the tubing.

[0152] The fluid recirculation system 1 may comprise one or more fluid tubes. The one or more fluid tubes may be connected to form a fluid flow path. For example, as shown in Figures 1 and 2, fluid flow around the recirculation system 1 may be provided via fluid tubes 11, 12, 13. The recirculation system 1 including fluid tubes 11, 12, 13 is shown in combination with example cannulas 4000 and 7000 in Figures 37 and 43, respectively. In the systems illustrated in Figures 1, 2, 37 and 43, tube 11 may deliver fluid from the flow generator 5 to the humidifier 10. Similarly, tube 12 may deliver fluid from the humidifier 10 to the cannula 1000 and into the body cavity 2. The tube 13 may vent fluid from the body cavity 2, via the cannula 1000, and recirculate the fluid back to the flow generator 5. The fluid recirculation system 1 may be configured to retain heat and/or humidity in the fluid recirculation system 1. One or more of the tubes 11, 12, 13 may be configured to heat or cool the fluid. For example, one or more of the fluid flow tubes 11, 12, 13 may be heated and/or insulated to minimise loss of heat and or humidity of the fluid as the fluid moves around the fluid recirculation system 1, before returning the fluid to the body cavity 2 of the patient.

[0153] The fluid recirculation system 1 may include one or more filters. The filter(s) may be configured to filter smoke and or particulate matter from the fluid, before returning the fluid to the body cavity 2 of the patient.

[0154] The fluid may pass through one or more filters or filter units in connection with the tubes 11, 12 and/or 13. For example, as shown in Figures 1, 2, 37 and 43 a filter 15a may be provided upstream of the flow generator 5. Additionally and/or alternatively, a filter 15b may be provided downstream of an outlet of the humidifier 10 and in fluid connection with tube 12 to filter the humidified gas.

[0155] In some examples, the fluid recirculation system 1 may include one or more filters and/or filter units in connection with the flow generator 5, for example to filter out particulate or other contaminating matter. For example, one or more filters may be provided within, before and/or after (i.e. upstream or downstream of) the flow generator 5.

[0156] In at least one example, a filter positioned upstream of the flow controller 5 may be configured to filter particulate matter, liquid, or other contaminants from the fluid to maintain integrity of one or more components of the flow controller 5 (e.g. pump features).

[0157] One or more filters may be associated with a heating element which may be operable to heat fluid passing through the filter and/or heat the filter medium. The heating element may be located downstream, optionally spaced apart from, the one or more filters. The heating element and the one or more filters may be located in a housing that couples to or is in fluid communication with the outlet of the humidifier 10 at a first end and the tube 12 at a second end. The first end and the second end may be angled (such as orthogonal, for example) with respect to each other. [0158] The system may additionally include (or may be used in combination with) a medical instrument 20. The cannula 1000 may be configured to receive the medical instrument 20. For example, Figure 2 shows the cannula 1000 in use for delivering fluid to and venting fluid from the body cavity 2, as well as receiving medical instrument 20 to facilitate insertion of the medical instrument 20 into the body cavity. The medical instrument may be any appropriate instrument for use within the body cavity, such as an obturator, a scope, an electro-surgery tool (such as an electrocautery tool), or the like.

[0159] As shown in Figures 1, 2 and 37, an insufflation system may be provided in parallel to the fluid recirculation system 1. For example as shown in Figures 1, 2 and 37, fluid may be delivered to the body cavity through an insufflation cannula 50, which is connected to a flow controller 55 and inserted into the body cavity 2. The flow controller 55 may include an insufflator, for example. The flow controller 55 may be operative to control the pressure and/or flow of the fluid from a fluid source to a level suitable for delivery into the body cavity 2.

[0160] In the examples of Figures 1, 2 and 37, the flow controller 55 may be used for initial insufflation. Similarly, the flow controller 55 shown in Figure 43 may be used for initial insufflation, in combination with example cannula 7000. That is, the flow controller 55 may be used to control the injection of gas into the body cavity 2 of the patient, for example, to distend the pneumoperitoneum, to create a working space for the surgeon. The flow controller 55 may be configured to maintain pressure in the body cavity 2 as the fluid recirculation system 1 vents gas from the body cavity 2 and returns the gas to the body cavity 2.

[0161] The insufflator may provide additional fluid flow to compensate for any leaks in the system. One or more leaks may be intentionally designed into the surgical system and/or recirculation system 1. For example, a vent or opening may be located downstream of a filter and/or in a tube of the recirculation system. The insufflator may be controllable to provide additional fluid flow to the body cavity 2, which may assist to clear smoke and/or debris within the body cavity 2.Figure 3 shows a fluid delivery system 3a, configured to deliver insufflation fluid to the body cavity 2 of the patient through the cannula 1000. In this example, the flow controller 55 is connected via a fluid delivery tube 16 to the cannula 1000 to deliver insufflation fluid to the body cavity 2. The flow controller 55 may be connected to a suitable fluid source, such as wall source 56 and/or gas bottle 57, for example. A humidifier

10 as described above may be provided between the flow controller 55 and the body cavity 2.

[0162] The system 3a may include one or more filters, such as filter 15b which is positioned downstream of an outlet of the humidifier 10. Additionally and/or alternatively, the system 3a may comprise one or more filters at other points. For example, the system 3a may include one or more filters downstream of the flow controller 55 and/or downstream from the cannula.

[0163] The system may have functionality for suction and/or venting of fluid from the body cavity 2. Venting may be provided via venting tube 17 in fluid connection with the cannula 1000 to vent fluid from the body cavity 2. The venting tube 17 may be configured for connection to a venting element comprising a suction source, such as a suction canister or theatre wall suction port 19. The venting tube may be in connection with one or more filters, such as filter 15c.

[0164] In other examples, venting may be provided via a separate venting cannula. For example, Figure 29 shows a further configuration of a fluid delivery system 3b including a cannula 1000 in connection with a fluid flow controller 55 (for example, an insufflator). A humidifier 10 may be located between the flow controller 55 and the body cavity 2. A medical instrument 20 may be inserted into the cavity 2 via the cannula 1000. In this example, the cannula 1000 is configured for gas delivery and venting is provided via a separate venting path including at least one venting cannula 60. Venting may be provided via evacuation line 62 in fluid connection with the venting cannula 60. The evacuation line 62 may be configured for connection to a suction source 64, such as a theatre wall suction port and/or suction canister 65. The evacuation line 62 may be in connection with one or more filters 68, such as a smoke filter.

[0165] The cannula 1000 may be configured for use with a medical instrument 20. A system including a cannula 1000 configured to receive a medical instrument 20 may minimise the number of cannulas required for a surgical procedure, by enabling insufflation fluid delivery as well as venting and/or medical instrument insertion to be performed through a single cannula 1000, thus obviating the requirement for a separate insufflation cannula. [0166] The cannula 1000 may be configured to receive a medical instrument 20, such as indicated in Figures 2 and 3 and 29. The cannula 1000 of Figure 1 may similarly be configured to receive a medical instrument. Example cannulas 4000, 7000 and 50 shown in Figures 37, 43 and 44, respectively, may be similarly configured to receive a medical instrument 20. The medical instrument 20 may comprise a surgical scope or an obturator, for example.

[0167] In other examples, the system may include a cannula which is includes a blind, closed (or substantially closed) distal end. The distal end of the cannula may be closed sufficiently to inhibit passage of a medical instrument through the cannula. For example, the cannula may at least inhibit passage of a medical instrument beyond a distal end of the cannula. In such examples, access for a medical instrument may be provided through a separate cannula. For example, the cannula 4000 as shown in Figures 30-32 includes a blind distal end 4340. In this example, the cannula 4000 is configured for delivering and/or venting fluid to and/or from the body cavity.

[0168] Figure 37 shows an example system including the cannula 4000. In this example the cannula 4000 is connected to a recirculation system 1 including a flow controller 5, and optionally including a humidifier 10. One or more separate cannulas may be provided in addition to cannula 4000. For example, as shown in figure 37, the system includes an insufflation cannula 50, which is connected to a flow controller 55 and inserted into the body cavity 2. In the illustrated example system, the insufflation cannula 50 is configured to receive a medical instrument 20.

[0169] In some examples, a surgical system can include monitoring equipment that is used together with the system. For example, Figures 3 and 29 show a medical instrument 20 (for example, a surgical scope) in connection with an external monitor 21 to allow displaying of images and/or data recorded by the medical instrument.

[0170] In some examples, a system may include a cannula configured for delivering a first fluid to the body cavity, delivering a second fluid to the body cavity and venting fluid from the body cavity. For example, the cannula may be configured for delivering a first fluid to the body cavity for insufflation, and/or delivering a second fluid to the body cavity for therapeutic purposes, and/or for venting fluid from the body cavity. The example system shown in Figure 43 includes a cannula 7000 configured for delivery of a first fluid and a second fluid to the body cavity 2, and for venting of fluid from the body cavity 2. Delivery of the first and second fluids and venting of the fluid may, in some examples, be simultaneous, or may be performed separately.

[0171] The cannula 7000 may be configured such that it includes three fluid flow paths. The cannula 7000 may have three inlets corresponding to the three fluid flow paths. The cannula 7000 may have three outlets corresponding to the three fluid flow paths.

[0172] In some examples, the cannula 7000 may be provided in connection with a recirculation circuit 1 as shown in Figure 43. The recirculation circuit may include one or more features of recirculation circuit 1 as described above with reference to Figures 1, 2, and 37. The system may include a flow controller 55 connected to cannula 7000. In some examples, the cannula 7000 may be configured to receive a medical instrument (such as a scope or obturator, for example).

[0173] In some examples, a system may include separate cannulas configured for delivering at least first and second fluids to the body cavity (such as separate cannulas configured for fluid delivery insufflation and fluid delivery therapeutic purposes), and/or for venting fluid from the body cavity. The example system shown in Figure 44 includes a cannula 1000 configured for delivery of fluid to the body cavity 2. The cannula 1000 may be provided in connection with a flow controller 55a. The fluid delivered through the cannula 1000 may be optionally heated and/or humidified (e.g. by humidifier 10).

[0174] The system may include an insufflation cannula 50, which is connected to a second flow controller 55b and inserted into the body cavity 2 for providing insufflation gas to the body cavity. In the illustrated example system, the insufflation cannula 50 is configured to receive a medical instrument 20. In this example (although not shown) the cannula 1000 may be configured to inhibit passage of a medical instrument through the cannula 1000 to the body cavity 2. For example, the cannula 1000 may include a blind distal end.

[0175] The system may comprise at least one venting cannula 60. Venting may be provided via evacuation line 62 in fluid connection with the venting cannula 60. The evacuation line 62 may be configured for connection to a suction source 64, such as a theatre wall suction port and/or suction canister 65. The evacuation line 62 may be in connection with one or more filters 68, such as a smoke filter.

[0176] More detailed examples of cannulas according to the present disclosure are described below. Reference numerals of the same or substantially the same features may share the same last two digits.

Examples of cannulas

[0177] The present disclosure provides examples of a cannula for delivering fluid to and/or venting fluid from, a body cavity of a patient. Figures 4 to 8 show various views of an example cannula 1000 of the present disclosure. Figures 9 to 15 and 19 illustrate various regions and/or components of the cannula 1000 in greater detail. Alternative examples of a cannula, or components of a cannula, disclosed herein may include one or more features of the cannula 1000, or of components of the cannula 1000. For example, any of cannulas 2000, 4000, 5000, 6000, 7000 may include one or more features of cannula 1000, and vice versa.

[0178] A surgical system for delivering fluid to a body cavity, as described above with reference to one or more of Figures 1, 2, 3, 29, 37, 43 or 44 for example, may incorporate any of the example cannulas disclosed herein.

[0179] A cannula according to the present disclosure may be single use (disposable) or reusable. Alternatively, one or more parts of the cannula may be single use (disposable) or reusable. The cannula may be made of materials that are biocompatible and/or sterilisable.

[0180] The cannula 1000 comprises a cannula housing 1100 and a cannula shaft 1200 extending from the housing 1100. As shown in Figure 10, the cannula shaft 1200 defines a delivery lumen 1300, which is configured to deliver fluid flow to the body cavity of a patient during a surgical procedure. In the illustrated examples, the cannula shaft 1200 includes a delivery shaft 1310, which defines the delivery lumen 1300. As illustrated, the delivery shaft 1310 comprises an elongate cylindrical tube, although non-cylindrical shapes and/or noncircular cross-sections are also contemplated.

[0181] The delivery lumen 1300 can be provided in fluid communication with a delivery inlet. In the illustrated examples, the delivery inlet is provided in the form of delivery inlet port 1110 in the cannula housing 1100. The delivery inlet port 1110 can be configured for connection to a fluid source. For example, the delivery inlet port 1110 may be connectable to a fluid delivery tube in fluid communication with the fluid source to facilitate fluid flow from the fluid source into the delivery lumen 1300. The delivery inlet port 1110 may connect to a fluid delivery tube via a press-fit connection (such as a taper fit, for example) or a Luer lock connection, although other suitable connection types may also be used.

Delivery outlet and diffusion

[0182] The delivery lumen 1300 comprises a delivery outlet 1320 configured to allow fluid flow to exit the delivery lumen 1300. The delivery outlet 1320 may comprise one or more openings of the delivery lumen 1300. For example, the delivery outlet 1320 may include an open distal end 1340 of the delivery lumen 1300.

[0183] The delivery outlet 1320 may be configured to diffuse at least a portion of the fluid flow from the delivery lumen 1300 into the body cavity of the patient. The delivery outlet 1320 may further comprise one or more additional openings. For example, the delivery outlet 1320 may comprise a diffuser, such as one or more diffusion apertures 1350, 2350, for example. Diffusion of the fluid flow may advantageously reduce velocity of the fluid as it enters the body cavity, thus reducing one or more risks associated with jetting.

[0184] This may be particularly relevant for examples of a cannula 1000 which are configured to receive a medical instrument, particularly within the delivery lumen 1300. Insertion of a medical instrument into the cannula may restrict the cross-sectional area through which the fluid can flow out of the open distal end 1340 of the delivery lumen 1300. When the flow rate is held constant (e.g. by a flow generator configured to maintain a substantially constant flow rate) a restriction in cross-sectional area of the open distal end may increase the pressure of the fluid at the delivery outlet and thus increase the velocity of the fluid exiting the cannula through the open distal end. Provision of a diffuser (such as one or more diffusion apertures, for example) may increase the overall cross-sectional area of the delivery outlet (including the open distal end and/or the diffusion apertures) and prevent such an increase in fluid pressure, thus reducing the velocity with which the fluid flow exits the delivery outlet. When pressure is held constant, the reduction in cross-sectional area may reduce the flow rate. [0185] Diffusion of fluid flow, for example to reduce jetting, may also be desirable in examples in which the cannula 1000 is configured to inhibit passage of a medical instrument through the cannula, such as where the cannula 1000 includes a blind distal end. Further, diffusion apertures may direct the fluid in one or more directions relative to the cannula shaft, reducing the velocity of the fluid in any one direction.

[0186] In the example cannula 1000 of Figure 4, the delivery outlet 1320 comprises an open distal end 1340 of the delivery lumen and a plurality of diffusion apertures 1350. The diffusion apertures 1350 may be provided through a side wall of the delivery shaft 1310 and in fluid communication with the delivery lumen 1300. The diffusion apertures 1350 may be configured to diffuse at least a portion of the fluid flow that exits the delivery lumen 1300 into the body cavity. The delivery outlet 1320 may be configured such that fluid flows from the delivery lumen 1300 into the body cavity through both the open distal end 1340 and through the diffusion apertures 1350. For example, Figure 15 illustrates fluid flow from the delivery outlet of an example cannula, through both the open distal end 1340 and through the diffusion apertures 1350, when a medical instrument 20 is received within the cannula 1000 and is positioned at and/or extending from the open distal end 1340.

[0187] In other examples, the delivery outlet 1320 may include diffusion apertures 1350, and may include a blind distal end rather than the open distal end 1340. This may be the case, for example, where the cannula 1000 is configured to inhibit passage of a medical instrument therethrough. In such cases, the delivery lumen 1300 may have a substantially blind distal end. The cannula 1000 may be configured such that fluid delivery is through the diffusion apertures 1350 only. This may be the case, for example, when the cannula 1000 is not configured to receive a medical instrument.

[0188] One example of a cannula 4000 including a blind distal end is shown in Figures 30- 32. The cannula 4000 includes a delivery shaft 4310 defining a delivery lumen 4300 and a venting shaft 4410 at least partially defining a venting lumen 4400. The delivery shaft 4310 comprises a delivery outlet 4320 configured to allow fluid flow to exit the delivery lumen 4300. The delivery outlet 4320 may comprise one or more openings of the delivery lumen 4300. In this example, the delivery lumen 4300 includes a blind (or closed) distal end 4340. The delivery outlet 4320 includes a plurality of diffusion apertures 4350. The distal end 4340 of the cannula 4000 may include a penetrating tip 4341, as described in further detail below. [0189] The diffusion apertures 1350 of the example cannula 1000 shown in Figure 4 are shown in greater detail in Figure 13. The diffusion apertures 1350 may be configured to diffuse fluid flow around the cannula shaft and/or past a distal end of the cannula shaft. The diffusion apertures 1350 may be spaced around a diameter of the delivery shaft 1310. In some examples, the diffusion apertures 1350 may be spaced uniformly (or substantially uniformly) around the delivery shaft 1310. In some examples, the diffusion apertures 1350 may be arranged around the delivery shaft 1310 non-uniformly.

[0190] In some embodiments, the apertures 1350 may be arranged in pairs. The pairs of apertures may be uniformly spaced around the delivery shaft 1310, as shown in Figure 13, for example. In other examples, the diffusion apertures can be spaced non-uniformly around a diameter of the cannula shaft 1200.

[0191] The diffusion apertures 1350 may be provided at, or adjacent to, a distal end of the cannula shaft 1200 (or the delivery shaft 1310). Provision of fluid delivery apertures, such as diffusion apertures, at or adjacent to a distal end of the cannula shaft 1200 may minimise a distance that the cannula shaft needs to be inserted into the body cavity 2. In other examples, diffusion apertures 1350 may be located in other locations. For example, diffusion apertures 1350 may be located at the distal tip 1360 portion and/or below the venting inlet 1420. In other examples, diffusion apertures 1350 may be provided along a length of the shaft of the cannula 1000. Where delivery apertures are provided further up a length of the shaft, a deeper insertion of the cannula 1000 into the body cavity may be required.

[0192] In some examples, for example, as shown in Figure 13, the diffusion apertures may be provided through a tapered region of the distal tip portion 1360 of the cannula shaft 1200.

[0193] The diffusion apertures 1350 may be spaced from a distal end of the cannula shaft 1200. For example, in the example cannula 2000 shown in Figure 16, delivery outlet 2320 includes an open distal end 2340 of delivery lumen 2300, and diffusion apertures 2350 through a portion of the delivery shaft 2310 which is spaced from a distal end of cannula shaft 2200. Diffusion apertures 2350 may be spaced from a distal end of cannula shaft 2200 by a region of the distal tip portion 2360. For example, the diffusion apertures 2350 may be spaced from the distal end of the cannula shaft 2200 by a tapered region of the distal tip portion 2360, as shown in the example cannula 2000 of Figure 16. [0194] Diffusion apertures 2350 may be through a portion of the delivery shaft 2310 which extends substantially parallel with the axis X. In further examples, diffusion apertures 1350, 2350 may be provided at any other location along the length of a cannula shaft, such as in a middle region of the shaft, for example. In the illustrated examples the diffusion apertures 1350, 2350 are aligned in an axial direction of the cannula shaft 1200, 2200. However, in other examples, diffusion apertures may be staggered or otherwise spaced along a length of (e.g. relative to the axial direction of) the cannula shaft.

[0195] The delivery outlet 1320, 2320 may be configured to deliver a desired proportion of the fluid through the at least one diffusion aperture 1350, 2350. A desired proportion may be one which reduces or substantially eliminates jetting of the fluid flow that may cause damage to body tissues. The desired proportion may depend on the conditions of the fluid flow including, for example, flow rate, humidity and/or temperature of the fluid. One or more of the shape and/or size of the diffusion apertures 1350, 2350, the shape and/or size of the open distal end 1340, 2340, a distance of the diffusion apertures 1350, 2350 from the distal end and/or a relative size of the open distal end 1340, 2340 to the diffusion apertures 1350, 2350 may be configured to adjust the ratio of fluid flow through the diffusion apertures 1350, 2350 to fluid flow through the open distal end 1340, 2340.

[0196] The delivery outlet 1320, 2320 may be configured to provide a desired proportion of the fluid flow delivered through the diffusion apertures 1350, 2350. For example, a ratio of resistance to fluid flow through the diffusion apertures 1350, 2350 to a resistance to fluid flow through the open distal end 1340, 2340 of the delivery lumen 1300, 2300 may be configured to provide the desired proportion.

[0197] For example, a resistance to fluid flow through the diffusion apertures 1350, 2350 may be less than a resistance to fluid flow through the open distal end 1340, 2340 of the delivery lumen 1300, 2300, at least when a medical instrument is received in the cannula 1000, 2000. Alternatively, the delivery outlet 1320, 2320 may be configured such that a resistance to fluid flow through the diffusion apertures 1350, 2350 may be greater than or equal to a resistance to fluid flow through the open distal end 1340, 2340 of the delivery lumen 1300, 2300, at least when a medical instrument is received in the cannula 1000, 2000. [0198] A combined cross sectional area of the diffusion apertures 1350, 2350 may be configured to be greater, equal or less than a cross sectional area of the open distal end 1340, 2340 available for fluid flow to exit the cannula 1000, 2000 when the medical instrument is inserted. The delivery outlet 1320, 2320 may be thus, or otherwise, configured to deliver a greater, equal or lesser percentage of the fluid flow through the diffusion apertures 1350, 2350 than through the open distal end 1340, 2340 of the delivery lumen 1300, 2300.

[0199] In some examples, a combined cross-sectional area of the delivery inlet 1110 may be configured to be less than a total cross sectional area of the delivery outlet 1320, 2320. This may provide an overall diffusing effect at the delivery outlet 1320, 2320.

[0200] Additionally or alternatively, resistance to flow may be configured based on a shape and/or position of one or more of the diffusion apertures 1350, 2350 and/or a shape of the open distal end 1340, 2340.

[0201] In some examples, the proportion of the fluid flow delivered through the at least one diffusion aperture 1350, 2350 may be between about 50% and about 100%, between about 60% and about 100%, between about 60% and about 80% or any value within the stated ranges. In some examples, the delivery outlet 1320, 2320 is configured to deliver about 70% of the fluid flow through the at least one diffusion aperture 1350, 2350. In some examples, the proportion of the fluid flow delivered through the at least one diffusion aperture 1350, 2350 may be between about 0% and about 50%, between about 10% and about 40%, between about 20% and about 30% or any value within the stated ranges. In some examples, the delivery outlet 1320, 2320 is configured to deliver about 70% of the fluid flow through the at least one diffusion aperture 1350, 235O.In some cases, fluid flow exiting a diffusion aperture 1350, 2350 may have a higher pressure where the diffusion aperture 1350, 2350 is positioned closer to a distal end of the cannula shaft than a diffusion aperture 1350, 2350 positioned closer to a proximal end of the cannula shaft. The diffusion apertures 1350, 2350 may be positioned, shaped and/or distributed along the cannula shaft to provide a desired distribution of flow through the apertures 1350, 2350.

[0202] In some cases, fluid flow exiting a diffusion aperture 1350, 2350 has been found to have a higher pressure at a distal end of the diffusion aperture 1350, 2350 than at a proximal end of the diffusion aperture 1350, 2350. The diffusion apertures 1350, 2350 may be shaped to provide a desired distribution of flow through the apertures 1350, 2350.

[0203] For example, a desired distribution may include an evenly distributed flow through the aperture (for example, from a proximal end of the aperture 1350, 2350 to a distal end of the aperture 1350, 2350). This may reduce a pressure gradient across the aperture.

[0204] For example, each diffusion aperture 1350, 2350 may taper towards its distal end. As can be seen in Figure 13 for example, each diffusion aperture 1350 is wider at a proximal end than at a distal end of the diffusion aperture 1350. As such, each diffusion aperture 1350 has a narrow, substantially trapezoidal shape, tapering towards a distal end of the diffusion aperture

1350.

[0205] In the illustrated examples, each diffusion aperture 1350 is shaped identically to the other diffusion apertures 1350. However, in other examples, at least some of the diffusion apertures may be shaped differently to each other. For example, the diffusion apertures 1350, 2350 may comprise a plurality of apertures of differing sizes and/or shapes, configured to provide a desired flow distribution. The flow distribution may be affected by the number, size, shape and/or positioning of the diffusion apertures 1350, 2350.

[0206] The diffusion apertures 1350, 2350 may be configured to direct at least part of the fluid flow at an angle relative to the cannula shaft 1200, 2200. As shown in Figure 15, for example, one or more of the diffusion apertures 1350 may include a fluid directing surface

1351. The fluid directing surface 1351 may be configured to direct at least part of the fluid flow at an angle relative to the longitudinal axis X of the cannula shaft 1200 by deflecting the fluid flow.

[0207] The fluid directing surface 1351 may be an angled surface of the diffusion aperture 1350, such as a chamfered or bevelled edge of the aperture, for example. Fluid flowing in a direction parallel to the longitudinal axis X of the cannula shaft 1200 along the delivery lumen 1300 may hit the fluid directing surface 1351 and be deflected out of the delivery lumen 1300 at an angle relative to the longitudinal axis X. In some examples, a distal edge of the diffusion aperture 1350 may be defined by the fluid directing surface 1351. [0208] Additionally and/or alternatively, one or more side walls of the diffusion aperture may be defined by one or more fluid directing surfaces 1351. As such, the fluid may be deflected at an angle of between about 0 degrees and about 90 degrees, about 5 degrees and about 70 degrees, or about 10 degrees and about 60 degrees relative to the longitudinal axis X of the cannula shaft. Deflection of the fluid flow may reduce the velocity of the fluid flow, at least in the direction parallel to the longitudinal axis X of the cannula shaft. This may be advantageous for reducing or preventing jetting of the fluid flow. As shown in Figure 13, for example, each diffusion aperture 1350 includes a fluid directing surface in the form of chamfered distal edge 1351. As indicated in Figure 15, the distal edge 1351 directs fluid flow out of the diffusion aperture 1350 at an angle relative to the longitudinal axis X of the cannula shaft 1200.

[0209] It may be desirable, in some cases, to have a component of the fluid flow exiting the one or more diffusion apertures 1350, 2350 in a direction less than 90 degrees from (or in some examples, substantially parallel to) the longitudinal axis X of the cannula shaft 1200, 2200. The diffusion apertures 1350, 2350 may be configured such that a portion of the fluid flow from the diffusion apertures 1350, 2350 may travel beyond, about or adjacent to a distal end of the cannula shaft 1200, 2200, for example. This may contribute to vision benefits provided by directed gas flow, as discussed in more detail below. The illustrative fluid flow paths in Figure 15 show a diffused delivery of fluid without jetting. In this example, fluid flow from the diffusion apertures 1350 is deflected at an angle relative to the longitudinal axis X of the cannula shaft 1200, yet travels distally beyond the distal end of the cannula shaft 1200 and distally beyond the distal end of a medical instrument 20 located within the cannula 1000.

[0210] Further example fluid flow paths are shown in Figures 26 to 28. Figures 26 and 27 illustrate diffused fluid flow in the absence of venting. As shown in Figure 26, fluid flowing from the open distal end 1340 travels close to and beyond the end of a medical instrument 20 received in the cannula 1000. Fluid flowing from the diffusion apertures 1350, although deflected relative to the longitudinal axis X, may also travel close to the end of the medical instrument 20, and thus may also contribute to vision benefits. For example, fluid flowing from the diffusion apertures 1350 close to and beyond the end of the medical instrument 20 may prevent smoke, vapour, particulate matter and the like from obstructing a viewing portion of a scope. [0211] As the distance from the cannula 1000 increases, the fluid flow may mix to create a substantially cone-shaped flow pattern. The substantially cone-shaped flow pattern may be induced at least partly by gas flow deflecting from one or more fluid directing surfaces of one or more diffusion apertures. The delivered fluid may swirl within the body cavity 2 (for example, when reaching an internal wall of the body cavity 2), as shown in Figure 27. Figure 28 shows example flow paths with the addition of venting. The fluid may flow from the cannula 1000 in the cone-shaped flow pattern and may swirl in the cavity before being evacuated from the cavity via one or more venting inlets of the cannula. For example, the fluid may be encouraged to swirl upwards towards one or more venting inlets of the cannula.

[0212] The diffusion apertures 1350 may be angled relative to longitudinal axis X of the cannula shaft 1200. The cannula shaft 1200 may taper inwardly at a distal portion comprising the diffusion apertures 1350, for example. As can be seen in at least Figures 13 and 14, the cannula 1000 can include a distal tip portion 1360. At least a portion of an inner surface and/or outer surface of the distal tip portion 1360 may taper towards a central longitudinal axis X of the cannula shaft 1200 to form a tapered region. For example, Figures 13 and 14 show distal tip portion 1360 having a tapered outer surface. In some examples, the diffusion apertures 1350 can extend through a side wall of the tapered region of distal tip portion 1360. As such, the diffusion apertures 1350 can be provided at an angle relative to the longitudinal axis X of the cannula shaft 1200. A distal surface (such as fluid directing surface 1351 as described above) of the diffusion aperture 1350 may be aligned with a portion of the delivery lumen 1300 above the diffusion aperture 1350, such that fluid flowing along the delivery lumen 1300 hits the distal surface of the diffusion aperture 1350.

[0213] Alternatively or additionally, the diffusion apertures 1350 may be provided through a non-tapered region of the cannula shaft 1200. For example, in the examples shown in at least Figures 13 and 14, the apertures 1350 may be alternatively or additionally provided on a non- tapered region of the distal tip portion 1360. For example, as shown in cannula 2000 in Figures 16 and 17, a tapered portion of the distal tip portion 2360 of the cannula 2000 is positioned distally of the diffusion apertures 1350. In this example, the diffusion apertures 2350 extend through a portion of the cannula shaft 2200 which is substantially parallel to the longitudinal axis X of the cannula shaft 2200. [0214] The diffusion apertures 2350 may be provided on a distal tip portion 2360 of the cannula shaft 2200. In some examples, the apertures 2350 may be provided distally to one or more venting apertures 2440. In other examples, such as but not limited to examples without a venting inlet, the diffusion apertures 2350 may be provided anywhere along the cannula shaft 2200. In other examples, the configuration of venting lumen and delivery lumen may be reversed, such that the venting apertures 2440 function as diffusion apertures for fluid delivery. In such examples, the apertures 2440 configured for fluid delivery may be located further toward a proximal end of the cannula 2000 than apertures configured for venting.

[0215] As shown in Figure 14, the distal tip portion 1360 may be a separable component, configured for connection to the delivery shaft 1310. However, in other examples, the distal tip portion may be integral with the delivery lumen). For example, in the cannula 2000 of Figures 16 and 17, the distal tip portion 2360 is integral with the delivery shaft 2310.

Dual lumen cannula

[0216] The cannula may be configured to both deliver fluid to the body cavity of the patient, and to vent fluid from the body cavity of the patient, during the surgical procedure. The cannula shaft may define a delivery lumen and a venting lumen. In such examples, the cannula may be considered a “dual lumen” cannula. As described in more detail below, the “dual lumen” cannula may be configured (or configurable) to deliver more than one fluid to the body cavity 2. For example, the “dual lumen” cannula maybe configured for delivery of a first fluid and/or a second fluid to the body cavity of the patient.

[0217] The cannula may be configured to facilitate delivery of the first fluid and the second fluid simultaneously or separately. The first fluid and the second fluid may be the same fluid, or may be different fluids. For example, both the first fluid and the second fluid may include warm, humidified carbon dioxide. The first fluid and the second fluid may be delivered from a common fluid source or from distinct fluid sources.

[0218] The cannula shaft may define a venting lumen, which is configured to vent fluid from the body cavity of the patient during a surgical procedure. The venting lumen may define a fluid flow path from a venting inlet to a venting outlet. The venting inlet may be configured to be positioned within the body cavity and the venting outlet may be configured to be positioned outside of the body cavity, in order to facilitate venting of fluid from the body cavity.

[0219] Delivery and venting of fluid within the one cannula may obviate or reduce the need for a separate venting device (such as a discrete venting cannula, for example) for venting of fluid from the body cavity. This may minimise the number of ports required into the patient body cavity and may simplify the surgical set-up. Simultaneous delivery and venting of fluid to/from the body cavity through a single cannula may provide advantages in maintaining a relatively stable pressure within the body cavity. Further, simultaneous delivery and venting of fluid to/from the body cavity through a single cannula may provide safety benefits. For example, if delivery and venting are provided in separate interfaces, accidental removal of either the delivery or venting cannula may result in either rapid inflation or collapse of the body cavity. By contrast, if a dual lumen cannula, such as the example dual lumen cannulas described herein, were to be disconnected from the body cavity, the body cavity would slowly deflate naturally as both the fluid delivery and venting would be removed simultaneously.

[0220] In the example cannula 1000, as shown in Figure 10, the cannula shaft 1200 includes a venting shaft 1410, which defines the venting lumen 1400. As illustrated, the venting shaft 1410 comprises an elongate cylindrical tube, although non-cylindrical shapes are also contemplated. The venting lumen 1400 provides a fluid flow path between a venting inlet 1420 at or adjacent to a distal end of the venting lumen (as described in further detail below) and a venting outlet.

[0221] As shown in the illustrated examples, the venting outlet can be in the form of a venting outlet port 1120 in the cannula housing 1100. The venting outlet port 1120 may be configured for connection to a venting element, such as suction source 64 and/or suction canister 65, which may be provided in connection with a filter such as filter 68. For example, the venting outlet port 1120 may be configured to connect to a venting tube in fluid communication with a venting element to facilitate fluid flow from the venting lumen 1400 out of the venting port 1120. The venting element may provide suction to the venting tube, for example. The venting outlet port 1120 may connect to such a venting tube via a press-fit connection (such as a taper fit, for example), although other suitable connection types may also be used. [0222] The cannula 1000 may be configured to define an outer lumen and an inner lumen. For example, the cannula 1000 may comprise shafts which are at least partially nested relative to one another. As shown in Figure 10, for example, the delivery shaft 1310 may be partially nested within the venting shaft 1410. As such, in this example, the venting lumen 1400 is configured as an outer lumen of the cannula shaft 1200, and the delivery lumen 1300 is configured as an inner lumen of the cannula shaft 1200. However, the reverse configuration may be employed. That is, in other examples, the delivery lumen may be configured as the outer lumen while the venting lumen is configured as the inner lumen.

[0223] Where the delivery lumen is configured as the inner lumen, the venting (outer) lumen may provide insulation to the delivery lumen. This may assist to prevent or reduce changes in temperature (for example, cooling of warmed fluid) of the fluid flowing in the delivery lumen and/or condensation forming within the cannula shaft before the fluid reaches the body cavity. The venting (outer) lumen may also prevent or reduce contact between tissue of the body cavity and the delivery (inner) lumen. This may reduce the risk of overheating of tissue contacting and/or immediately surrounding the cannula shaft. Further, providing the delivery lumen as an inner lumen of the cannula shaft may allow the cannula to provide directed flow of fluid relative to a medical instrument received within the cannula, as discussed in more detail below.

[0224] As shown in the example of Figure 10, the delivery and venting shafts 1310, 1410 can be positioned substantially concentrically relative to each other. Alternatively, other example cannulas may comprise delivery and venting shafts which are axially spaced from one another. In still further examples, the cannula may comprise a delivery shaft and a venting shaft provided in other arrangements, such as side by side, for example.

[0225] One example of a cannula 5000 having two lumens is shown Figures 33 and 34. The cannula 5000 includes a first shaft 5310 and a second shaft 5410. In the illustrated example, the shaft 5310 is a delivery shaft 5310 and the shaft 5410 is a venting shaft 5410, defining a respective delivery lumen 5300 and venting lumen 5400. In the illustrated example, the delivery lumen 5300 and venting lumen 5400 extend alongside of and parallel to each other within the cannula shaft 5200. The shafts 5310, 5410 may share a common wall, as shown, or may be separate from each other. Although the shafts 5310 and 5410 are described as delivery and venting shaft, it is also contemplated that the shafts both be used for fluid delivery. [0226] A proximal end of the cannula 5000 includes a delivery port 5110, and a venting port 5120, configured for connection to respective fluid flow tubes. The venting shaft 5410 has an open distal end, defining a venting inlet 5420. The delivery shaft 5310 comprises a delivery outlet 5320 including a plurality of diffusion apertures 5350. In this example, the delivery shaft 5310 includes a blind distal end 5340. The example cannula 5000 is configured to inhibit passage of a medical instrument therethrough. However, in other examples, the cannula 5000 may be configured to receive a medical instrument, for example within the delivery lumen 5300, which may be configured with an open distal end.

[0227] The cannula shaft 1200 may comprise one or more spacer elements 1250, configured to position the delivery shaft 1310 and the venting shaft 1410 relative to each other. For example, one or both of the delivery shaft 1310 and venting shaft 1410 may comprise at least one spacer element 1250 configured to position the delivery shaft 1310 and the venting shaft 1410 relative to each other. The one or more spacer elements 1250 may be positioned in any suitable arrangement around the cannula shaft. For example, the one or more spacer elements 1250 may be equally or unequally spaced around the cannula shaft 1200. As shown in the example of Figure 12, four spacer elements 1250 are equally spaced about a centre of the delivery lumen 1300.

[0228] The at least one spacer element 1250 may comprise at least one protrusion provided on a wall of the delivery shaft 1310 and/or on a wall of the venting shaft 1410. For example, where the delivery shaft 1310 is configured as an inner shaft and the venting shaft 1410 is configured as an outer shaft, the one or more spacer elements 1350 may comprise one or more protrusions on an outer surface of the delivery shaft 1310 and/or one or more protrusions on an inner surface of the venting shaft 1410. The protrusions 1250 may be configured to extend from the venting shaft 1410 and/or the delivery shaft 1310 to contact the other of the venting shaft 1410 and delivery shaft 1310 to maintain a distance between the venting shaft 1410 and the delivery shaft 1310 at least at the location of the spacer element 1250.

[0229] In some examples a plurality of spacer elements 1250 may cooperate to maintain a relative alignment between the venting shaft 1410 and the delivery shaft 1310 (such as concentric alignment, for example). It will be appreciated that the spacer elements 1250 may be arranged adjacent one, or both, of the proximal and distal ends of the cannula shaft 1200, continuously between the ends, or discontinuously at spaced intervals between the ends. The spacer elements 1250 may be straight, or curved (for example, provided in a spiral configuration in the longitudinal direction).

[0230] As one example, Section B-B of the cannula shaft 1200 shown in Figure 12 illustrates an example of spacer elements 1250 provided on an internal surface of an outer shaft (in this example, the venting shaft 1410) of the cannula shaft 1200. In this example, the spacer elements 1250 are configured as a plurality of ribs provided adjacent to the distal end of the venting shaft 1410 to position the delivery shaft 1310 relative to the venting shaft 1410. The spacer elements 1250 can be evenly spaced and may have rotational symmetry with each other about the longitudinal axis X of the cannula shaft, as shown in Figure 12, such that the delivery shaft 1310 is positioned concentrically within the venting shaft 1410. However in other examples, the spacer elements 1250 may differ in size and/or shape from each other and/or may be dissymmetrical with each other about the longitudinal axis X.

[0231] Additionally and/or alternatively, the at least one spacer element may comprise an inwardly directed wall portion of the cannula shaft. As shown in Figures 16 and 17, for example, the cannula 2000 includes an inwardly directed wall portion 2250 at a distal end of the venting shaft 2410. The inwardly directed wall portion 2250 may extend from the outer shaft (in this example, the venting shaft 2410) to the inner shaft (in this example, the delivery shaft 2310). The inwardly directed wall portion 2250 may be configured to hold the delivery shaft 2310 to position the delivery shaft 2310 relative to the venting shaft 2410. In still further examples, other spacer structures suitable for positioning the inner and outer shafts relative to each other may be used.

[0232] In some examples, an outer shaft of the cannula shaft 1200 may comprise an outer diameter substantially equal to a maximum outer diameter of a distal tip portion 1360 of the cannula 1000. For example, the example cannula 1000 shown in Figure 4 includes a distal tip portion 1360 having an enlarged outer diameter relative to a proximal region of the delivery shaft 1310. An outer diameter of the venting shaft 1410 ofthe cannula 1000 can be configured to be substantially equal to the maximum outer diameter of the distal tip portion 1360. In other examples, the outer shaft of the cannula shaft can comprise an outer diameter greater than a maximum diameter of a distal tip portion of the cannula. Figures 16 and 17, show an alternative example of a cannula 2000 in which an outer diameter of the (outer) venting shaft 2410 of the cannula shaft 2200 is larger than a maximum diameter of the distal tip portion 2360.

[0233] The venting inlet 1420 may comprise one or more openings at or adjacent to a distal end of the venting shaft 1410. In the example cannula 1000 illustrated in Figures 4 to 15, the venting inlet 1420 can comprise an open distal end of the venting lumen 1400. In this example, the venting inlet is defined as a substantially annular opening between the distal end of the venting shaft 1410 and an outer surface of the delivery shaft 1310.

[0234] In some examples, it may be possible to configure the shaft 1410 as a secondary delivery shaft, rather than a venting shaft, such that the venting inlet 1420 provides a secondary delivery outlet. In such cases the cannula 1000 could be considered to include two gas delivery lumens. One delivery lumen may be used as a first delivery path, for delivery of a first fluid, while the second delivery lumen may be used as a second delivery path, for delivery of a second fluid. As described above, the first and second fluids may be the same fluid, or may be different from each other. For example, one lumen may be used for insufflation (introduction of optionally cold and/or dry or optionally warm and/or humidified gas for initial distension of patient tissue to create the working space, and maintenance of pressure inside the working space during surgery by replacing any gas that might have leaked from the body cavity), while the other lumen may be used for delivery of a therapy gas (optionally warmed/humidified). For example, the venting shaft 1410 may be used as a secondary delivery shaft for insufflation, while therapy delivery may be provided via the delivery outlet 1320 (for example including diffusion apertures 1350 and/or distal end opening 1340), or vice versa.

[0235] In some examples, the venting inlet 1420 may be continuous around a periphery of the shaft, while in other examples the venting inlet 1420 may be discontinuous. For example, the venting inlet 1420 may be divided into separate lumens. The separate lumens may or may not be in fluid communication with one or more other lumens. In the example of Figure 13, the venting inlet 1420 is divided by the spacer elements 1250, which extend longitudinally to define multiple inlet lumens. The spacer elements 1250 may be continuous or discontinuous, such that the multiple inlet lumens may or may not be in fluid communication with each other. In other examples, the spacer elements may include dimples or bumps which may interrupt the continuity of the venting inlet 1420 without extending longitudinally to define separate lumens.

[0236] Additionally and/or alternatively, the venting inlet may comprise one or more venting apertures extending through a side wall of the cannula shaft and in fluid communication with the venting lumen. For example, in the example illustrated in Figures 16 to 18, a plurality of venting apertures 2440 extend through a side wall of the venting shaft 2410. As can be appreciated from Figure 17, in this example, a distal end of the venting lumen 2400 is closed by the wall portion 2250. However, in other examples, the venting inlet may comprise an open distal end of the venting lumen in addition to one or more venting apertures extending through the side wall of the cannula shaft.

[0237] As shown in Figure 16, the venting apertures 2440 can be spaced around the venting shaft 2410. The venting apertures 2440 may be configured to provide substantially even venting around the cannula shaft 2200. The venting apertures 2440 may be aligned relative to an axial direction of the cannula shaft 2200, as shown in Figure 16 for example, to form a ring around the cannula shaft 2200. In other examples, the venting apertures 2440 may be unevenly spaced around the cannula shaft 2200 and/or may be spaced relative to an axial direction of the cannula shaft 2200. The venting apertures 2440 may be positioned adjacent to a distal end of the venting shaft 2410 and/or the cannula shaft 2200. In other examples, the venting apertures 2440 may be spaced from a distal end of the venting shaft 2410.

[0238] Although the cannula of Figures 16-18, is described above as having a delivery lumen 2300 and a venting lumen 2400, in some examples, it may be possible to use the venting lumen 2400 as a secondary delivery lumen, such that the venting apertures 2440 provides a secondary delivery outlet. In such cases the cannula 2000 could be considered to include two gas delivery lumens. For example, the venting shaft 2410 and venting apertures 2440 of the cannula 2000 may be used for insufflation, while therapy delivery may be provided via the delivery outlet 2320 (for example including diffusion apertures 2350 and/or distal end opening 2340), or vice versa.

[0239] The delivery shaft may extend distally beyond a distal end of the venting shaft. One or more apertures or openings of the delivery outlet may be positioned distally of one or more openings or apertures of the venting inlet. For example, as shown in Figure 13, the open distal end 1340 of the delivery lumen 1300 and the plurality of diffusion apertures 1350 can be positioned distally of the venting inlet 1420 of the venting lumen 1400. Similarly, in the example illustrated in Figure 16, the distal end opening of the delivery lumen 2340 and the plurality of diffusion apertures 2350 are positioned distally of the venting inlet 2440. In other examples, the venting shaft can extend distally beyond a distal end of the delivery shaft. This may be the case, for example, where the venting lumen is configured as an inner lumen of the cannula shaft, nested within an outer delivery lumen. In still further examples, a distal end of the venting shaft and a distal end of the delivery shaft may be substantially aligned.

[0240] In some examples, the cannula may include one or more projections at a distal end of the cannula shaft. The one or more projections may be configured to inhibit or minimise entrainment of fluid (such as air) from external to the body cavity 2, for example in the event that the cannula is partially withdrawn from the body cavity 2.

[0241] One example of a cannula 6000 including projections 6411 is shown in figures 35 and 36. In this example, the venting shaft 6410 includes distally extending projections 6411 at the distal end of the venting shaft 6410, adjacent to the venting inlet 6420. As shown in detail in Figure 36, the projections 6411 have a tapered shape, however, other shapes are also contemplated. The projections 6411 may be spaced apart from a distal end of the delivery shaft 6310. The proj ections 6411 may be flush with a distal end of the delivery shaft 6310.

The projections 6411 may be configured to minimise impedance of fluid delivery. For example, the projections 6411 may be positioned to minimise any overlapping with the diffusion apertures 6350. In the example of figure 36, the projections 6411 are positioned between adjacent diffusion apertures 6350. The projections 6411 may serve to decrease an exposed area of the distal end of the delivery shaft 6310. This may assist in mitigating risk of entrainment of air from outside the body cavity into the venting inlet 6420 should the cannula 6000 be withdrawn, or dislodged from the body cavity 2 of the patient . In the illustrated example, the cannula 6000 includes an open distal end 6340. However, in other examples, the cannula 6000 may include a blind distal end.

[0242] In some cases, provision of venting adjacent the distal end of a medical instrument can assist to remove smoke by venting fluid from the cavity, for example, close to the smoke source. For example, where the medical instrument includes a viewing portion at its distal end (such as a surgical scope, for example) venting adjacent to the distal end of the medical instrument can allow removing of fluid within or around the field of vision. Similarly, venting adjacent a distal portion of an instrument such as electrocautery device, may also assist to remove smoke by venting gas from close to the smoke source.

[0243] Figures 15 and 26 to 28 illustrate delivery of fluid to, and, in Figures 15 and 28, venting of fluid from, adjacent the distal end of a medical instrument 20. This can create a recirculatory effect, such that fluid travels away from the distal end of the cannula 1000 and medical instrument 20 and, subsequently, back towards the venting inlet 1420, which may be positioned proximally of the delivery outlet 1320. This may affect the environment immediately surrounding the distal end of the medical instrument 20. For example, venting may facilitate recirculation flow, which may enhance removal of smoke and/or other particulate matter, from a field of view of the medical instrument 20. Provision of venting adjacent to the delivery outlet 1320 may allow the recirculation flow to move smoke away from the field of view of the medical instrument 20 and vent smoke out of the body cavity without the smoke re-entering the field of view of the medical instrument 20.

[0244] In some cases, the cannula shaft 1200 may be configured to receive a medical instrument 20 therein. Depending on a length of the cannula shaft 1200, a length of the medical instrument 20 and a depth of insertion of the medical instrument 20 into the cannula shaft 1200, a distal end of the medical instrument 20 may or may not protrude distally beyond a distal end of the cannula shaft 1200. The length of the cannula shaft may be configured relative to the length of the medical instrument 20 and a predetermined insertion depth of the medical instrument 20. The distal end of the medical instrument 20 may extend distally past the distal end of the cannula shaft 1200 (as shown in Figures 15 and 22, for example). In other examples, a distal end of the cannula shaft 1200 may be positioned adjacent to, or extend beyond, a distal end of the medical instrument 20.

[0245] In examples comprising nested delivery and venting shafts, the cannula housing may comprise a corresponding nested structure. For example, as shown in Figure 10, the cannula housing 1100 may comprise a delivery port housing 1115 and a venting port housing 1125, wherein the delivery port housing 1115 comprises the delivery port 1110 and the venting port housing 1125 comprises the venting port 1120. [0246] The delivery port 1110 and/or venting port 1120 may extend from the delivery port housing 1115 and the venting port housing 1125, respectively, transverse to the longitudinal axis of the cannula shaft 1200. The delivery port housing 1115 and the venting port housing 1125 can be at least partially nested relative to each other. In Figure 10, the delivery port housing 1115 and venting port housing 1125 are shown as separate components, which may be attached (and, in some examples, fixed, for example by gluing) to the delivery shaft 1310 and the venting shaft 1410, respectively, during assembly of the cannula 1000. In other configurations, the delivery port housing 1115 may be integral with the delivery shaft 1310 and/or the venting port housing 1125 may be integral with the venting shaft 1410.

[0247] The delivery port 1110 and the venting port 1120 may be positioned in a stacked arrangement, as shown in Figure 10 for example, in which the delivery and venting ports 1110, 1120 are substantially aligned with each other relative to the longitudinal axis X. However, alternative orientations of the delivery and venting ports 1110, 1120 relative to each other are also contemplated. For example, the delivery and venting ports 1110, 1120 may be provided at different angles relative to each other, as shown in Figures 2 and 3 and/or on different sides or faces of the cannula.

Seals

[0248] The cannula 1000 can comprise one or more seals, such as seals 1710, 1720, 1730 which will be discussed in more detail below. The one or more seals may be configured to prevent or reduce fluid flow from exiting the cannula shaft 1200 other than through the delivery outlet and/or the venting outlet. For example, one or more seals may be configured to seal a proximal end of the cannula 1000 to prevent fluid flow from escaping at a proximal end of the cannula. For example, there may be sealing in the proximal end of the cannula 1000. One or more seals may be further configured to prevent entrainment of fluid (such as air) into the cannula and/or into a venting tube. This may be particularly important in cases where the cannula 1000 is used as part of a recirculation system in which vented fluid is re-introduced into the body cavity of the patient.

[0249] The cannula 1000 may comprise a seal configured to seal the delivery lumen 1300 and/or the venting lumen 1400 at a proximal end of the cannula 1000. The seal may be configured to provide a substantially fluid-tight seal at a proximal end of an outer lumen of the cannula shaft 1200, for example. As shown in Figure 10, for example, a port housing seal 1710 is configured to seal the venting lumen 1400 from the outside environment. Sealing of the venting lumen 1400 may prevent air entrainment from outside the cannula 1000 into the venting port 1120 and/or an attached venting tube (not shown in Figure 10). In this example, the port housing seal 1710 comprises an O-ring. However, other suitable seal types may be used.

[0250] One or both of the delivery port housing 1115 and the venting port housing 1125 may comprise a recess configured to receive the port housing seal 1710. As shown in Figure 10, the port housing seal 1710 may be positioned between an outer surface of the delivery port housing 1115 and an inner surface of the venting port housing 1125. The port housing seal 1710 may additionally or alternatively be positioned between the delivery port 1110 and the venting port 1120.

[0251] The cannula 1000 can further comprise an instrument seal 1720, as shown in Figure 10 for example. The instrument seal 1720 may be configured to provide a substantially fluid- tight seal between the cannula housing 1100 and a medical instrument, when a medical instrument is received in the cannula 1000. The instrument seal 1720 may define an aperture 1721 for receiving a medical instrument therethrough. The instrument seal may be configured to extend between the cannula housing 1100 and an outer surface of the medical instrument to provide a substantially fluid-tight seal therebetween. As shown in Figure 10, the instrument seal 1720 can extend inwardly from an inner surface of the delivery port housing 1115 and may be configured to seal between the delivery port housing 1115 and a medical instrument.

[0252] The instrument seal 1720 may be flexible. For example, the instrument seal may flex during insertion and/or removal of the medical instrument 20 to the cannula 1000. The instrument seal 1720 may be configured such that it is easier to insert a medical instrument 20 into the cannula 1000 than to remove a medical instrument 20 from the cannula. The instrument seal 1720 may enhance retention of the medical instrument within the cannula 1000.

[0253] The cannula 1000 may additionally and/or alternatively comprise one or more seals configured to seal a proximal end of the cannula 1000 when no medical instrument is inserted into the cannula 1000. The cannula 1000 may comprise a proximal end port seal 1730, configured to seal a lumen of the cannula 1000 from the outside environment when no medical instrument is inserted into the cannula 1000. This may prevent or reduce fluid flow leaking out of the cannula 1000 from a proximal end of the lumen. For example, the cannula 1000 may be configured such that fluid is released from the delivery lumen 1300 at the distal end of the delivery lumen 1300 through the delivery outlet 1320.

[0254] As shown in Figure 10, for example, a proximal end port seal 1730 can be provided at a proximal end of the delivery port housing 1115. The proximal end port seal can seal across a proximal end opening of the delivery port housing 1115, thus sealing the delivery lumen 1300 from the outside environment. In the illustrated example, the proximal end port seal 1730 is provided in sealing abutment with the instrument seal 1720. However, in other examples, the proximal end port seal 1730 and instrument seal 1720 may be spaced from each other.

[0255] The proximal end port seal 1730 may be configured to allow passage of a medical instrument therethrough. For example, the proximal end port seal 1730 may comprise a slit or other opening to permit a medical instrument to be inserted through the proximal end port seal 1730. The slit or opening may close to provide a substantially fluid-tight seal across the proximal end of the delivery port housing 1115 when no instrument is inserted in the cannula 1000. The proximal end port seal 1730 may be flexible. For example, the proximal end port seal may flex during insertion and/or removal of the medical instrument 20 to the cannula 1000. The proximal end port seal 1730 may be configured such that it is easier to insert a medical instrument 20 into the cannula 1000 than to remove a medical instrument 20 from the cannula. The proximal end port seal 1730 may enhance retention of the medical instrument within the cannula 1000.

[0256] One or more seals of the cannula 1000, 2000, 4000, 6000, 7000 may be configured to be received within the cannula 1000, 2000, 4000, 6000, 7000 for example within the cannula housing 1100. The cannula housing 1100 may include one or more seal positioning features configured to limit or restrict movement of one or more seals relative to the housing. For example, as shown in Figure 10, the proximal end port seal 1730 and the instrument seal 1720 are nested within the delivery port housing 1115. In shown in this example, a seal positioning feature can be configured as a seal seat 1116 in the delivery port housing 1115. The seal seat 1116 extends radially inward from an inner surface of the delivery port housing 1115 and is configured to limit movement of the seals 1720, 1730 in at least the distal direction relative to the cannula housing 1100.

Proximal end housing

[0257] The cannula 1000, 2000, 4000, 6000, 7000 may comprise a proximal end housing 1500 attachable to the cannula 1000. The proximal end housing 1500 may be attachable to the cannula housing 1100, for example. The proximal end housing 1500 may cover a portion of the cannula housing 1100, in the manner of a cap.

[0258] For example, the cannula 1000 can comprise a proximal end housing 1500. Figures 4 to 10 show the cannula 1000 with the proximal end housing 1500 attached to the cannula housing 1100. Figure 19 shows a proximal end of the cannula 1000 with the proximal end housing 1500 detached from the cannula housing 1100.

[0259] The proximal end housing 1500 may be configured to attach to the cannula housing 1100. For example, the proximal end housing 1500 may be configured to clip onto or otherwise mate with the cannula housing 1100. As shown in Figure 19, the proximal end housing 1500 can comprise one or more apertures 1510 configured to mate with corresponding protrusion(s) 1126 on the cannula housing 1100, to secure the proximal end housing 1500 to the cannula housing 1100 (for example, by clipping onto the cannula housing 1100). In this example, the protrusions 1126 are provided on the venting port housing 1125. However, in other example, the proximal end housing 1500 may be secured to the cannula housing 1100 (for example, secured to the venting port housing 1125) by ultrasonic welding, screws, press-fit, threaded connection, gluing, or other suitable connection means. In some examples, the proximal end housing 1500 may be configured to be releasably attachable to the cannula housing 1100. In other examples, the proximal end housing 1500 may be fixedly connected to the cannula housing 1100.

[0260] The proximal end housing 1500 may be configured to secure one or more components of the cannula housing 1100 in relative position and/or orientation. For example, the proximal end housing 1500 may be attachable to the cannula housing 1100 to secure and/or position the delivery port 1110 relative to the venting port 1120. As shown in Figure 19, the proximal end housing 1500 can be configured to attach to the venting port housing 1125 to secure the delivery port housing 1115 between the venting port housing 1125 and the proximal end housing 1500.

[0261] The proximal end housing may be additionally and/or alternatively configured to retain at least one seal of the cannula 1000, 2000, 4000, 6000, 7000. For example, the proximal end housing may be configured to secure one or more seals in position relative to the cannula housing 1100 (or a corresponding housing of cannula 2000, not shown). Figures 23 to 25, for example, illustrate an alternative example proximal end housing 3500 which may be configured to attach to the cannula housing 1100 of cannula 1000. The proximal end housing 3500 can comprise one or more projections configured to abut the one or more seals of the cannula 1000, for example.

[0262] As shown in Figures 23 to 25, a proximal end housing 3500 can include projections 3510 which can include one or more seal abutting portions 3511. The one or more seal abutting portions 3511 may extend in a distal direction from an inner surface of the proximal end housing 3500 at its proximal end. The one or more seal abutting portions 3511 can be configured to apply force to a surface or edge, such as a top surface, for example, of one or more seals.

[0263] Where the cannula 1000 is configured to receive a medical instrument 20, the one or more seal abutting portions 3511 may be configured to apply force to one or more seals configured for sealing the instrument port, and or one or more seals configured for sealing against the medical instrument 20, such as the proximal end port seal 1730 and/or the instrument seal 1720 shown in Figure 10, for example, when the proximal end housing 3500 is attached to the cannula housing 1100. As such, when the proximal end housing 3500 is attached to the cannula housing 1100, the instrument seal 1720 and proximal end port seal 1730 are compressed between the one or more seal abutting portions 3511 and the seal seat 1116 of the delivery port housing 1115, thereby increasing retention of the seals 1720, 1730. The one or more seal abutting portions 3511 may assist to prevent inversion of one or more seals 1720, 1730 when the medical instrument is withdrawn from the cannula.

[0264] Where the cannula 1000, 2000, 6000, 7000 is configured to receive a medical instrument 20, the proximal end housing 3500 can further comprise an instrument port 3520. The instrument port 3520 may extend through the proximal end housing 3500 and may be configured to receive a medical instrument therethrough.

[0265] The proximal end housing 3500 may comprise one or more projections configured as guide elements for positioning a medical instrument within the cannula 1000, 2000, 6000, 7000. As shown in Figure 25, the projections 3510 may include guide elements 3512 for positioning a medical instrument.

[0266] The guide elements 3512 may comprise inwardly extending portions of the projections 3510 and may be configured to abut the outer surface of a medical instrument received through the instrument port 3520. The guide elements 3512 may cooperate with further guide elements of the cannula shaft (as described in further detail below) to position the medical instrument within the cannula 1000 (or cannulas 2000, 6000, 7000). The guide elements 3512 may be configured to position the medical instrument substantially centrally within the cannula shaft. For example, in the example of Figure 25 the guide elements 3512 are each substantially equal in size and can be configured to hold the medical instrument substantially centrally relative to the proximal end housing 3500. However, in other examples, the guide elements 3512 may be configured to hold the medical instrument off- centre relative to the proximal end housing and/or the cannula shaft. In other examples, the guide elements 3512 may allow for a clearance around an outer surface of the medical instrument 20. The guide elements 3512 may thus, or otherwise, allow for positioning of the medical instrument 20 relative to the cannula shaft at a range of angles.

[0267] Where the cannula is not configured to receive a medical instrument, the cannula housing and/or the proximal end housing may be differently configured accordingly. For example, the proximal end housing may not include an instrument port, guide elements for positioning the medical instrument, or be configured to retain a proximal end port seal or an instrument seal.

[0268] For example, cannula 4000 shown in figures 30-32 is not configured to receive a medical instrument. As such, the proximal end housing 4500 does not include an instrument port, or guide elements. The proximal end housing 4500 may instead have a closed proximal end 4520. In this example, the proximal end housing 4500 is configured to extend across and seal a proximal end of the delivery lumen 4300 (and/or the venting lumen). Medical instrument accommodation and guide elements

[0269] The cannula 1000, 2000, 6000, 7000 may be configured to receive a medical instrument 20 therein. The medical instrument may comprise a surgical scope (such as a laparoscope), for example. Additionally and/or alternatively, the medical instrument may comprise an obturator, as is discussed in further detail below. For example, an obturator may be used during initial insertion of the cannula 1000, 2000, 6000, 7000 and withdrawn to allow subsequent insertion of a surgical scope. In other examples the cannula 1000, 2000, 6000, 7000 may be configured to inhibit passage of a medical instrument therethrough, as previously described, for example with reference to cannulas 4000 and/or 5000.

[0270] The cannula 1000, 2000 may comprise at least one guide element configured to position the medical instrument 20 relative to the cannula shaft 1200, 2200. The cannula 1000, 2000 may include guide elements in combination with, or addition to, any of the above described features. The at least one guide element may be configured to limit movement of the medical instrument 20 within the cannula 1000, 2000. For example, the at least one guide element may be configured to prevent or limit contact between the medical instrument 20 and the cannula shaft 1200, 2200. Examples of guide elements are described herein with reference to example cannulas 1000 and 2000. However, guide elements as described herein may be included in other example cannulas which may be configured to receive a medical instrument, such as cannulas 6000 and/or 7000.

[0271] Detailed examples of guide elements that may also be used in combination or in addition to those described herein are described in International Application No. PCT/NZ2019/050100, titled "DIRECTED GAS FLOW SURGICAL CANNULA FOR PROVIDING GASES TO A PATIENT", filed on August 16, 2019, or in PCT/IB2021/05115, titled “DIRECTED GAS FLOW ACCESSORY FOR PROVIDING GASES TO AND VENTING GASES FROM A PATIENT”, filed on December 2, 2021, the disclosures of which are hereby incorporated by reference in their entirety.

[0272] In some cases, the guide elements 1600 can be arranged at an inner wall of the cannula 1000, 2000. The guide elements can be defined by the inner wall, or can be mountable to or adjacent the inner wall. For example, the guide elements can extend inwardly from an inner wall of the cannula shaft 1200, 2200. The guide elements may extend inwardly relative to the inner wall such that, in use, the guide elements are positioned between the inner wall and the medical instrument 20. In some cases, the cannula 1000, 2000 may comprise a plurality of the guide elements. For example, where the cannula shaft 1200, 2200 defines an inner shaft and an outer shaft, the at least one guide element may be provided in or on an inner wall of the inner shaft.

[0273] The guide elements may extend partway along the longitudinal length of the inner wall of the cannula shaft 1200, 2200. It will be appreciated that the guide elements may be arranged adjacent one, or both, of the proximal and distal ends of the cannula shaft 1200, 2200, continuously between the ends, or discontinuously at spaced intervals between the ends. The guide elements may extend to a distal end of the cannula shaft 1200, 2200 and terminate flush with the distal end of the inner wall. In other examples, a terminal end of one or more of the guide elements may be spaced from the distal end of the cannula shaft 1200, 2200.

[0274] As illustrated in Figure 13, for example, guide elements 1600 can be positioned at, or adjacent to, an open distal end 1340 of the delivery lumen 1300. In this example, the guide elements 1600 are provided as ribs on an inner wall, at least of the distal tip portion 1360 of the cannula 1000. Figure 13 shows guide elements 1600 at a distal tip portion 1360 of the cannula 1000. In other examples (not shown), guide elements 1600 may extend further longitudinally. For example, the guide elements 1600 may extend along the distal top portion 1360 and at least a portion of the cannula shaft 1200. For example, the guide elements 1600 may extend along at least a portion of the cannula shaft 1200. The guide elements 1600 can define a fluid flow path for fluid to travel around the periphery of a medical instrument 20 received within the cannula shaft 1200 (for example as shown in Figure 15). In other examples, the guide elements 1600 may be spaced from a distal end of the cannula shaft 1200. For example, in the alternative example illustrated in Figure 17, guide elements 2600 are spaced from the distal end of the cannula 2000. In this example the guide elements 2600 are again configured in the form of ribs. However, in this case, the guide elements 2600 extend longitudinally to a greater extent (i.e. over a greater portion of the inner wall) than the guide elements 1600 as shown in Figures 13 and 14. It will be appreciated, however, that configuring guide elements as ribs is exemplary and that guide elements may be configured in other forms, such as bumps, dimples, fins, splines, grooves, channels, or via internal geometry of the cannula shaft (such as a polygonal shaft). [0275] Additionally and/or alternatively the cannula 1000, 2000 may further comprise guide elements at or adjacent to a proximal end of the cannula shaft 1200, 2200. In other examples, the cannula 1000, 2000 may comprise guide elements which are spaced from a proximal end of the cannula shaft. For example, Figure 10 shows guide elements 1610 positioned at a proximal end of the delivery shaft 1310. Additionally and/or alternatively, in some examples, guide elements may be provided in or on an inner surface of the cannula housing 1100, such as in or on an inner surface of the delivery port housing 1115 for example.

[0276] The cannula 1000, 2000 may comprise more than one guide element, or more than one set of guide elements, such as ribs 1600, 2600. The more than one set of guide elements can be located at any position, or multiple positions, along the length of the cannula 1000, 2000. For example, the cannula 1000, 2000 may include both distal guide elements and proximal guide elements. The guide elements may be configured to cooperate to position a medical instrument within the cannula shaft 1200, 2200, by providing axially spaced points of contact with the medical instrument 20. The guide elements may be thus configured to maintain axial positioning of the medical instrument 20 relative to the cannula shaft 1200, 2200, by preventing angling of the medical instrument 20 within the cannula 1000, 2000. Additionally and/or alternatively, axial positioning of the medical instrument 20 may be maintained by providing at least one guide element which extends longitudinally along a length of the cannula shaft 1200, 2200.

[0277] In examples in which one or more projections on the proximal end housing (such as projections 3510 of proximal end housing 3500) are configured as guide elements, the proximal and/or distal guide elements may further cooperate with the projections 3510 of the proximal end housing 3500 to position the medical instrument 20 within the cannula shaft 1200, 2200. In such examples, the projections of the proximal end housing 3500 may provide an axially spaced point of contact with the medical instrument 20 to prevent angling of the medical instrument 20 within the cannula 1000, 2000.

[0278] Guide elements 1600, 2600 can in some cases, be further configured to direct the fluid flow around the medical instrument 20. The at least one guide element 1600, 2600 may position the medical instrument 20 such that at least one fluid flow path is defined between the inner wall and the medical instrument 20. For example, as shown in Figure 18, the guide elements 2600 define fluid flow paths between adjacent guide elements 2600, an outer surface of the medical instrument 20 and an inner surface of the delivery shaft 2310. The guide elements 2600 may facilitate directing of fluid flow out from the open distal end 2340 of the delivery shaft 2310 and around an end of the medical instrument 20. The guide elements 2600 can be spaced uniformly (or substantially uniformly) around the diameter of the delivery shaft 2310. In other examples, the guide elements 2600 can be spaced non-uniformly around the diameter of the delivery shaft 2310, and/or spaced non-uniformly axially along the delivery shaft 2310, creating fluid flow paths of different sizes.

[0279] In some cases, particularly where the medical instrument 20 comprises a viewing portion (such as in the case of a laparoscope, for example) it can be desirable to create a micro-environment at, around, near or adjacent a distal end of the medical instrument 20 to overcome some of the condensation, fogging, or other issues that can cause reduced visibility. A directed gas flow around the medical instrument 20 can allow for the creation of the microenvironment to be controlled around the viewing portion or a working end of the medical instrument 20. This micro-environment can isolate the viewing portion from the warm and humid environment of the surgical cavity, e.g. the pneumo-peritoneum. The medical instrument 20 with the viewing portion can be either held concentrically or off-axis, relative to the cannula 1000, 2000, surrounded by a fluid pathway. This may cause the fluid flow to conform to, and in some cases substantially enclose, the medical instrument 20. The fluid may then cover the viewing portion of the medical instrument 20 and, to a certain extent, form a barrier between the viewing portion and the surrounding environment. If the conditions of the delivered fluid are controlled, this can allow a degree of control of the environment around the medical instrument 20. Further, the fluid flow may be advantageously directed to an area of interest by adjusting the positioning of the cannula and/or the medical instrument 20.

[0280] In one or more examples, the guide elements 1600, 2600 may be configured to position the medical instrument 20 substantially concentric and/or co-axially to a longitudinal axis X defined by the cannula shaft 1200, 2200. The guide elements 1600, 2600 may be configured to position a medical instrument 20 concentric with the delivery lumen 1300, 2300. For example, as shown in Figures 17 and 18, the guide elements 2600 can be spread radially to hold a medical instrument 20 substantially concentric with the delivery lumen 2300. However, in other examples, the guide elements may be configured to position the medical instrument axially spaced relative to the delivery lumen (for example, linearly spaced or at an angle to the axis). Positioning the medical instrument 20 substantially concentric with the delivery lumen 2300 may be advantageous in facilitating a substantially even flow of fluid between the outer wall of the medical instrument 20 and the inner wall of the delivery shaft 2310. The guide elements 2600 may be configured to direct fluid flow substantially concentrically around the medical instrument 20. This may enhance direction of fluid flow relative to a distal end of the medical instrument 20, This may be advantageous in enhancing visibility in examples in which the medical instrument 20 comprises a scope (such as a laparoscope for example), as discussed above.

[0281] In some examples, the at least one guide element may include a non-circular crosssection of the delivery lumen. The medical instrument may have a circular or substantially circular shaft. Therefore, no matter the positioning of the medical instrument shaft within the delivery lumen, fluid can flow through the delivery lumen.

Obturator accommodation

[0282] In some examples, the medical instrument 20 may comprise an obturator. In such examples, the cannula 1000, 2000 may be configured to receive the obturator, through a lumen of the cannula shaft 1200, 2200, for example. The obturator may aid insertion of the cannula into a patient cavity or other surgical access port. The cannula 1000, 2000 may comprise one or more obturator accommodating portions. The obturator accommodating portions may be configured to engage corresponding locating elements of the obturator, for restricting relative rotation between the obturator and the cannula 1000, 2000. The obturator accommodating portions may be configured to inhibit rotational movement of the obturator relative to the cannula 1000, 2000 upon receipt of the obturator in the cannula 1000, 2000. The cannula 1000, 2000 and the obturator may move substantially as one object, which may improve control and function of the obturator. Figures 20 and 21 illustrate perspective views of proximal ends of the cannula 1000 and an obturator 30, respectively. The obturator 30 can be positioned within the cannula 1000, as shown in Figure 22. The proximal end housing 1500 of the cannula 1000 can comprise one or more obturator accommodating portions, which may be configured in the form of recesses 1530. The recesses can be configured to engage corresponding locating elements of the obturator, which may be configured as protrusions 33. [0283] The protrusions 33 may be provided at or adjacent to a proximal end of 31 the obturator 30, as shown in Figure 21. The cooperation of the protrusions 33 and recesses 1530 may serve to align the obturator 30 axially relative to the cannula 1000. Further, the recesses 1530 and protrusions 33 can cooperate to restrict rotation of the obturator 30 relative to the cannula 1000 when the obturator 30 is received in the cannula 1000. Figure 22 shows the obturator 30 received within the cannula 1000, with the protrusions 33 of the obturator 30 received in the recesses 1531 of the proximal end housing 1500 of the cannula 1000. As can be appreciated from Figure 22, a length of the cannula 1000 may be configured such that a distal, penetrating end 32 of the obturator 30 extends distally of the cannula shaft 1200 when the obturator 30 is received in the cannula 1000.

[0284] In some examples, the obturator 30 may be lockable to the cannula 1000. The obturator may include one or more locking elements. For example, the one or more locating elements, such as protrusions 33, of the obturator may provide a locking function. The one or more locating elements can include at least one locking finger extending outwardly or distally from a lower surface of the obturator body, the at least one locking finger configured to be received in a corresponding aperture in the cannula. The locking finger can comprise a locking tab configured to engage with a corresponding engagement tab in the cannula.

[0285] Detailed examples of features of obturators and obturator accommodating portions that may be used in combination with or in addition to those described herein are disclosed in PCT/IB2021/051151, the disclosure of which is hereby incorporated by reference in its entirety.

[0286] In examples where the cannula 1000, 2000 is not configured to receive a medical instrument (such as an obturator), a distal tip of the cannula 1000, 2000 may be configured to function as an obturator tip. For example the cannula 1000, 2000 may be shaped to have a obturator tip including a penetrating distal end. For example, the obturator tip can be a piercing tip, blunt tip, dilating tip, bladed tip, non-bladed tip, optical and non-optical tip, or any other type of obturator tip. Examples of obturator tips which may be used are shown in Figures 5A-5P of PCT/IB2021/051151.

[0287] In the example cannula 4000 shown in Figures 30-32, the delivery shaft 4310 has a blind distal end 4340. As shown in detail in Figure 31, the distal end 4340 has a tapered portion configured to provide a penetrating tip 4341 to facilitate easier insertion of the cannula 4000 to the body cavity 2 of the patient. In the illustrated example, the penetrating tip 4341 has a blunt shape. However, other types of obturator tip are also contemplated. The penetrating tip 4341 may be configured to extend distally beyond a distal end of the venting shaft 4410, so as to provide a leading end during insertion of the cannula 4000.

Securement devices

[0288] A cannula according to examples described herein may include one or more structures configured to inhibit withdrawal of the cannula from the body cavity of the patient. For example, the cannula may include one or more securement devices configured for attaching and/or securing the cannula to the patient. The one or more securement devices may be configured to be positioned within the body cavity 2 of the patient, and/or external to the body cavity 2 of the patient.

[0289] For example, the cannula may include, or be configured to connect with, one or more suture tabs. Each suture tab may be configured to accommodate one or more sutures for securing the cannula to the patient. An example cannula 6000 incorporating suture tabs 6700 is shown in Figures 35, 36 and 38. The cannula 6000 includes a pair of first suture tabs 6700a configured to be positioned outside of the body cavity of the patient. One or more sutures may secure the first suture tabs 6700a to the patient.

[0290] The cannula 6000 may optionally include, or be configured for use with, a component 6080 which may be placed over the cannula. The component 6080 includes a pair of second suture tabs 6700b configured to be positioned outside the body cavity of the patient. One or more sutures may secure the second suture tabs 6700b to the patient. One or more sutures may secure second suture tabs 6700a to suture tabs 6700b. Each of the first and second suture tabs 6700a, 6700b includes one or more suture accommodating structures, configured to receive and secure one or more sutures. The component 6080 may include one or more structures configured to facilitate insertion of the cannula to the body cavity of the patient. For example, component 6080 includes a tapered region, adjacent to the second suture tabs 6700b. The tapered region tapers towards a distal end component 6080.

Tri-lumen cannula [0291] In some examples, a cannula may be configured for delivery of two or more fluids to, and venting of fluid from, the body cavity. The two or more fluids may be the same or may be different. Delivery of multiple fluids and venting of fluid within the one cannula may obviate or reduce the need for additional access devices (such as a discrete fluid delivery and/or venting cannula, for example) for provision of fluid to and/or venting of fluid from the body cavity. This may minimise the number of ports required into the patient body cavity and may simplify the surgical set-up.

[0292] The cannula shaft may define a first lumen, a second lumen and a third lumen. In such examples, the cannula may be considered a “tri-lumen” cannula. The first, second and third lumen may be separate from each other and may provide respective first, second and third fluid flow paths through the cannula shaft. The cannula may comprise a first port in fluid connection with the first lumen, a second port in fluid connection with the second lumen, and a third port in fluid connection with the third lumen. Each of the first, second and third ports may be configured for connection to a respective fluid source and/or venting element.

[0293] The first lumen may be a first fluid delivery lumen configured to deliver fluid to the body cavity of the patient. The second lumen may be a second fluid delivery lumen configured to deliver fluid to a body cavity of the patient. The third lumen may be a venting lumen configured to vent fluid from the body cavity of the patient. However, other configurations of venting and fluid delivery are also contemplated. In some examples, one or more of the first, second and third lumens may be configured for fluid venting and/or fluid delivery. The first, second and third lumens may extend at least partially through the cannula shaft.

[0294] An example cannula 7000 including three flow paths is shown in Figures 38-42. The cannula 7000 may include one or more features as described above with reference to cannulas 1000, 2000 or 6000. The cannula shaft 7200 defines a first lumen 7300, a second lumen 7400 and a third lumen 7301.

[0295] The first lumen 7300 may be a first delivery lumen, which may be configured to deliver a first fluid flow to the body cavity 2 of a patient during a surgical procedure. The cannula shaft 7200 includes a first delivery shaft 7310, which defines the first delivery lumen 7300. As illustrated, the delivery shaft 7310 comprises an elongate cylindrical tube, although non-cylindrical shapes and/or non-circular cross-sections are also contemplated.

[0296] In the illustrated example, the delivery lumen 7300 comprises a first delivery outlet 7320 at a distal end of the cannula shaft 7200, configured to allow fluid flow to exit the delivery lumen 7300. The first delivery outlet 7320 may comprise one or more openings of the first delivery lumen 7300. The first delivery lumen 7300 may be configured for connection to a first fluid source. For example, the first delivery lumen 7300 may be configured for connection with a first delivery port, such as port 7110.

[0297] The delivery outlet 7320 may be configured to diffuse at least a portion of the first fluid flow from the delivery lumen 7300, for example into the body cavity of the patient during the surgical procedure. The delivery outlet 7320 may include a diffuser. The diffuser may include at least one diffusion aperture 7350. For example, the delivery outlet may include an open distal end 7340 of the delivery lumen 7300 and/or one or more diffusion apertures 7350. The diffusion apertures 7350 may share one or more features in common with diffusion apertures 1350 and/or 2350 as described above. In some examples, the delivery lumen 7300 may be configured with a blind distal end, rather than the open distal end 7340.

[0298] In the illustrated example, the cannula shaft 7200 includes a second shaft 7410 defining the second lumen 7400. The second shaft 7410 may be configured as a venting shaft 7410 defining a venting lumen 7400. As illustrated, the venting shaft 7410 comprises an elongate cylindrical tube, although non-cylindrical shapes are also contemplated.

[0299] The second lumen 7400 provides a fluid flow path between a distal opening 7420 of the second lumen 7400 at or adjacent to a distal end of the second lumen 7400, and a port 7120. The distal opening 7420 may be configured as a venting inlet, and the port 7120 may be in the form of a venting outlet port configured for connection to a venting element. The venting inlet 7420 is configured to receive fluid from the body cavity 2 of the patient during the surgical procedure. In the illustrated example, the first delivery outlet 7320 is positioned distally of the venting inlet 7420.

[0300] The delivery shaft 7310 and the venting shaft 7410 may be at least partially nested relative to each other. The cannula 7000 includes athird lumen 7301, which may be configured as a second fluid delivery lumen. The second delivery lumen 7301 may be configured to deliver a second fluid to the body cavity 2. In some examples, the third lumen 7301 may be defined between the venting shaft 7410 and the delivery shaft 7310.

[0301] In some examples, such as shown in Figures 39, 41 and 42, the cannula shaft 7200 includes a divider 7255. The divider 7255 may be configured to extend between the venting shaft 7410 and the delivery shaft 7310 when assembled, to define the third lumen 7301. The divider 7255 may fluidly isolate a portion of the space between the venting shaft 7410 and the delivery shaft 7310 from the venting lumen 7400 to define the third lumen 7301.

[0302] The divider 7255 may comprise a protrusion provided on a wall of the delivery shaft 7310 and/or on a wall of the venting shaft 7410. The divider 7255 may be configured to extend from the venting shaft 7410 and/or the delivery shaft 7310 to contact the other of the venting shaft 7410 and delivery shaft 7310 to a least partially seal therebetween.

[0303] The divider 7255 may be configured to function as a spacer element for maintaining a distance between the venting shaft 7410 and the delivery shaft 7310 at least at the location of the divider 7255. As with the cannula 1000, the cannula shaft 7200 may comprise one or more spacer elements 7250, configured to position the delivery shaft 7310 and the venting shaft 7410 relative to each other. The spacer elements 7250 may include one or more features of spacer elements 1250 as described in relation to cannula 1000. The divider 7255 may be configured to cooperate with one or more spacer elements 7250 to maintain a relative alignment between the venting shaft 7410 and the delivery shaft 7310 (such as concentric alignment, for example).

[0304] The second delivery lumen 7301 may extend from an inlet to a second fluid delivery outlet 7321. The inlet may be in the form of a port, such as inlet port 7121. The port 7121 may be configured for connection to a fluid source. As shown in the example of Figures 38- 42, the port 7121 may be provided in connection with the venting shaft 7410. The divider 7255 may extend around and proximally of the inlet port 7121 to fluidically isolate the inlet port 7121 from the venting lumen 7400. The second fluid delivery outlet 7321 may be substantially in alignment with the distal opening 7420. [0305] As shown in Figure 40, when the cannula 7000 is assembled, the first delivery port 7110 is positioned proximally of the venting port 7120. The inlet port 7121 is positioned distally of delivery port 7110 and venting port 7120.

[0306] In some examples, the first delivery lumen 7300 may be configured for delivery of a fluid for therapeutic purposes. The second fluid delivery lumen 7301 may be configured for delivery of a fluid for insufflation. For example, the second fluid delivery lumen 7301 may be used for insufflation (introduction of, optionally cold/dry gas, for initial distension of patient tissue to create the working space, and maintenance of pressure inside the working space during surgery by replacing any gas that might have leaked from the body cavity). The first fluid delivery lumen 7300 may be used for delivery of a therapy gas (optionally warmed/humidified) .

[0307] The first lumen 7300 may be larger relative to the second and/or third lumens 7400, 7301. The first lumen 7300 may have a larger cross-sectional area compared to a cross- sectional area of the second and/or third lumens 7400, 7301. The first lumen 7300 may be configured to accommodate a greater flow rate than the second and/or third lumens. This may have advantage when the first lumen 7300 is a first fluid delivery lumen for delivery of therapy fluid, as therapy fluid flow may be greater than insufflation fluid flow, for example.

[0308] The first lumen 7300 may be positioned as an innermost lumen of the cannula shaft 7200. The first lumen 7300 may be positioned internally of the second lumen 7400 and/or third lumen 7301. In such an arrangement, the first lumen 7300 may be at least partially insulated by the second and/or third lumens 7400, 7301. This may assist to maintain temperature and/or humidity of fluid flow through the first lumen 7300.

[0309] The third lumen 7301 may be smaller relative to the first lumen 7300 and/or second lumen 7400. The third lumen 7301 may have a smaller cross-sectional area compared to a cross-sectional area of the first and/or second lumens 7300, 7400. The third port in fluid connection with the third lumen 7301 may be smaller relative to the first port in fluid connection with the first lumen, and/or the second port in fluid connection with the second lumen. The third port in fluid connection with the third lumen 7301 may have a smaller cross-sectional area relative to first and/or second port. [0310] The first port in fluid connection with the first lumen may be larger, or substantially the same size as, the second port in fluid connection with the second lumen. The first port may have a larger or substantially the same, cross-sectional area relative to cross-sectional area of the second port.

[0311] Although the lumens 7300, 7301 have been described as configured for delivery, and lumen 7400 described as configured for venting, it is also contemplated that the lumens 7300, 7301 and/or 7400 could each be configured for fluid delivery and/or for venting.

[0312] The cannula 7000 may be configured to receive a medical instrument 20. The cannula 7000 may include a proximal end housing 7500 attachable to the cannula 7000. The cannula 7000 may be configured as described above in relation to proximal end housing 1500 or 3500. The cannula 7000 can comprise one or more seals, such as port housing seal 7710, instrument seal 7721 and end port seal 7730 which may be configured as described above in relation to seals 1710, 1720, 1730 of cannula 1000. In examples where the cannula 7000 is not configured to receive a medical instrument, the proximal end cap 7500 may be as described in relation to proximal end cap 4500 and the instrument seals 7720 may not be included.

Surgical kit

[0313] A cannula 1000, 2000, 4000, 5000, 6000, 7000 according to any of the examples disclosed herein may be comprised in a surgical kit. The surgical kit may include the cannula (for example, cannula 1000, 2000, 4000, 5000, 6000, 7000) and an obturator, such as the obturator 30 described herein for example. Where the cannula is configured (or configurable) to receive a medical instrument, such as in cannula 1000, 2000, 6000, 7000 the obturator 30 may be configured to be received within the cannula 1000, 2000, 6000, 7000, as described above. The surgical kit may alternatively and/or additionally include one or more fluid flow tubes for connecting to one or more delivery lumens and/or a venting lumen. The surgical kit may alternatively and/or additionally include one or more filters configured for connection with the one or more fluid flow tubes (for example, filter 68). The surgical kit may also comprise one or more canisters (for example, canister 65). [0314] It should be emphasized that many variations and modifications may be made to the examples described herein, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. Further, nothing in the foregoing disclosure is intended to imply that any particular component, characteristic or process step is necessary or essential.

Claims

CLAIMS:

1. A cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; and a cannula shaft extending from the housing, the cannula shaft defining: a first lumen; and a second lumen, wherein the first lumen is configured as a delivery lumen and comprises a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow relative to a distal end of the cannula shaft and to diffuse at least a portion of the fluid flow from the delivery lumen into the body cavity.

2. The cannula of claim 1, wherein the delivery outlet comprises at least one diffuser in fluid communication with the delivery lumen.

3. The cannula of claim 2, wherein the diffuser comprises at least one diffusion aperture extending through a side wall of the cannula shaft.

4 The cannula of claim 3, wherein the at least one diffusion aperture is located at or adjacent to the distal end of the cannula shaft.

5. The cannula of claim 4, wherein the at least one diffusion aperture is spaced from a distal end of the cannula shaft.

6. The cannula of any one of claims 3 to 5, wherein the delivery outlet comprises a plurality of diffusion apertures in spaced array around the cannula shaft.

7. The cannula of any one of the preceding claims, wherein the delivery lumen comprises a blind distal end.

8. The cannula of any one of claims 3 to 6, wherein the delivery outlet comprises an open distal end of the delivery lumen.

9. The cannula of claim 8, wherein a resistance to fluid flow through the at least one diffusion aperture is less than a resistance to fluid flow through the open distal end of the delivery lumen when a medical instrument is received within the delivery lumen.

10. The cannula of claim 8 or claim 9, wherein the delivery outlet is configured to deliver a greater percentage of the fluid flow through the at least one diffusion aperture than through the open distal end of the delivery lumen.

11. The cannula of claim 10, wherein the delivery outlet is configured to deliver between about 60% and about 80% of the fluid flow through the at least one diffusion aperture.

12. The cannula of any one of claims 3 to 11, wherein the at least one diffusion aperture directs at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft.

13. The cannula of claim 12, wherein the at least one diffusion aperture tapers towards a distal end.

14. The cannula of any one of claims 11 to 13, wherein the at least one diffusion aperture is at least partly defined by a fluid directing surface configured to direct at least part of the fluid flow.

15. The cannula of claim 14 wherein the fluid directing surface directs the at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft.

16. The cannula of any one of claims 3 to 15, wherein the cannula shaft tapers inwardly in a region of the at least one diffusion aperture such that at least a portion of the at least one diffusion aperture is angled relative to a longitudinal axis of the cannula shaft.

17. The cannula of any one of the preceding claims, wherein the cannula comprises a tapered distal tip portion, wherein a maximum outer diameter of the tapered distal tip portion is substantially equal to a maximum outer diameter of the cannula shaft.

18. The cannula of any one of claims 1 to 17, wherein the second lumen comprises a second delivery lumen, wherein the second delivery lumen comprises a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow relative to a distal end of the cannula shaft.

19. The cannula of any one of the preceding claims, wherein the second lumen comprises a venting lumen, wherein the venting lumen comprises a venting inlet, comprising an open distal end of the venting lumen.

20. The cannula of claim 19, wherein the venting inlet comprises at least one venting inlet aperture extending through a side wall of the cannula shaft and in fluid communication with the venting lumen at or adjacent to a distal end of the cannula shaft.

21. The cannula of claim 20, wherein the venting inlet comprises a plurality of venting inlet apertures in spaced array around the cannula shaft.

22. The cannula of claims 18 or claim 20, wherein the venting inlet comprises a substantially annular opening.

23. The cannula of any one of claims 19 to 22, wherein the venting inlet comprises one or more openings extending through a side wall of the cannula shaft.

24. The cannula of any one of the preceding claims, wherein the cannula shaft includes a delivery shaft defining the delivery lumen, and a second shaft defining the second lumen, wherein the delivery shaft and the second shaft are at least partially nested relative to each other.

25. The cannula of claim 24 wherein the delivery shaft is at least partially nested within the second shaft.

26. The cannula of claim 25, wherein the second shaft is at least partially nested within the delivery shaft.

27. The cannula of any one of claims 24 to 26, wherein the delivery shaft extends distally beyond a distal end of the second shaft.

28. The cannula of any one of claims 24 to 27, wherein the second shaft extends distally beyond a distal end of the delivery shaft.

29. The cannula of any one claims 24 to 28, wherein the delivery shaft and the second shaft are positioned substantially concentrically with respect to each other.

30. The cannula of any one claims 24 to 29, comprising at least one spacer element configured to position the delivery shaft and the second shaft relative to each other.

31. The cannula of any one of the preceding claims, comprising at least one guide element configured to position a medical instrument within the cannula.

32. The cannula of claim 31, wherein the at least one guide element holds a medical instrument shaft substantially concentrically relative to the cannula shaft.

33. The cannula of claim 31 or claim 32, wherein the at least one guide element is provided in or on an inner wall of the cannula shaft.

34. The cannula of any one of the preceding claims, wherein the second lumen is configured as a venting lumen, and wherein the cannula housing comprises a delivery port in fluid communication with the delivery lumen and a venting port in fluid communication with the second lumen, wherein the delivery port is configured for connection to a fluid source, and the venting port is configured for connection to a venting element.

35. The cannula of claim 34, wherein the cannula housing comprises a delivery port housing and a venting port housing, wherein the delivery port housing comprises the delivery port and the venting port housing comprises the venting port, wherein the delivery port housing and the venting port housing are at least partially nested relative to each other.

36. The cannula of claim 35, further comprising a port housing seal configured to provide a substantially fluid-tight seal between the venting port housing and the delivery port housing.

37. The cannula of claim 36, wherein the port housing seal is configured to seal the delivery lumen and/or the venting lumen at a proximal end of the cannula.

38. The cannula of any one of the preceding claims, wherein the cannula housing comprises a proximal end port for receiving a medical instrument therethrough.

39. The cannula of claim 38, further comprising an instrument seal configured to provide a substantially fluid-tight seal between the cannula housing and the medical instrument.

40. The cannula of any one claims 38 to 39, further comprising a proximal end port seal configured to provide a substantially fluid tight seal across the proximal end port when no medical instrument is inserted into the cannula housing.

41. The cannula of any one claims 38 to 40, wherein the cannula further comprises a proximal end housing attachable to the cannula housing.

42. The cannula of claim 41, wherein the proximal end housing is configured to secure the delivery port relative to the venting port.

43. The cannula of claim 41 or claim 42 wherein the proximal end housing comprises one or more apertures configured to cooperate with one or more corresponding protrusions on the cannula housing.

44. The cannula of any one of claims 41 to 43, wherein the proximal end housing is configured to secure one or more seals between the proximal end housing and the cannula housing.

45. The cannula of claim 44, wherein the instrument port extends through the proximal end housing and wherein the proximal end housing comprises one or more protrusions configured to secure one or more seals between the proximal end housing and the cannula housing

46. The cannula of claim 44 or claim 45, wherein the proximal end housing comprises one or more protrusions configured as guide elements for positioning a medical instrument within the cannula.

47. The cannula of any one of the preceding claims, wherein the cannula housing comprises one or more obturator accommodating portions configured to engage corresponding locating elements of an obturator for restricting relative rotation between the obturator and the cannula.

48. The cannula of claim 47, wherein the obturator accommodating portions comprise one or more apertures configured to receive a corresponding one or more locking fingers of the obturator locating elements to releasably secure the obturator to the cannula.

49. A cannula for providing fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing at a proximal end of the cannula; a cannula shaft extending from the housing, the cannula shaft defining a delivery lumen; and a proximal end housing attachable to the cannula housing, wherein the delivery lumen comprises a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow relative to a distal end of the cannula shaft.

50. The cannula of claim 49, wherein the proximal end housing is configured to retain at least one seal at a proximal end of the cannula.

51. The cannula of claim 49 or claim 50, wherein the proximal end housing is configured to clip onto the cannula housing.

52. The cannula of any one of claims 49 to 51, wherein the proximal end housing comprises one or more apertures configured to cooperate with one or more corresponding protrusions on the cannula housing to attach the proximal end housing to the cannula housing.

53. The cannula of any one of claims 49 to 52, wherein the cannula housing comprises: a first port housing comprising a first port; and a second port housing comprising a second port, wherein the proximal end housing is configured to secure the first port relative to the second port, wherein the first port housing is a delivery port housing comprising a delivery port.

54. The cannula of claim 53, wherein the second port housing is a venting port housing comprising a venting port.

55. The cannula of claim 53, wherein the second port housing is a second delivery port housing comprising a second delivery port.

56. The cannula of any one of claims 49 to 55, configured to receive a medical instrument therein.

57. The cannula of claim 56, wherein the medical instrument to be received comprises an obturator, wherein the proximal end housing comprises one or more obturator accommodating portions configured to engage corresponding locating elements of the obturator for restricting relative rotation between the obturator and the cannula.

58. The cannula of claim 57, wherein the one or more obturator accommodating portions comprise one or more recesses in the proximal end housing configured to receive one or more corresponding protrusions of the obturator.

59. A system for providing fluid to a body cavity of a patient during a surgical procedure, the system comprising: the cannula of any one of claims 1 to 58; one or more fluid flow tubes for connecting to the first lumen and/or the second lumen.

60. The system of claim 59, further comprising an obturator, wherein the obturator comprises one or more locating elements configured to cooperate with one or more corresponding obturator accommodating portions of the cannula housing.

61. A cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; a cannula shaft extending from the housing, the cannula shaft defining a delivery lumen; a delivery inlet configured for connection to a fluid source; and a delivery outlet configured to deliver fluid flow to the body cavity; wherein the delivery outlet comprises at least one diffusion aperture, wherein the delivery lumen comprises a blind distal end, wherein the blind distal end comprises a penetrating tip of the cannula shaft.

62. A cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; a cannula shaft extending from the housing, the cannula shaft defining a delivery lumen; and at least one guide element configured to position a medical instrument within the cannula, wherein the delivery lumen comprises a delivery inlet configured for connection to a fluid source and a delivery outlet configured to deliver fluid flow to the body cavity, wherein the delivery lumen is configured to direct at least a portion of the fluid flow along the delivery lumen, wherein the delivery outlet comprises at least one aperture and an open distal end of the delivery lumen.

63. The cannula of claim 61, wherein the at least one aperture is configured to diffuse at least a portion of the fluid flow from the delivery lumen into the body cavity.

64. The cannula of claim 63, wherein the at least one aperture includes a plurality of diffusion apertures located at or adjacent to a distal end of the cannula shaft.

65. The cannula of claim 64, wherein the plurality of diffusion apertures are spaced from a distal end of the cannula shaft.

66. The cannula of claim 65, wherein the plurality of diffusion apertures are spaced around the cannula shaft.

67. The cannula of any one of claims 62 to 66, wherein a resistance to fluid flow through the at least one aperture is less than a resistance to fluid flow through the open distal end of the delivery lumen when the medical instrument is received in the cannula.

68. The cannula of any one of claims 62 to 66, wherein the delivery outlet is configured to deliver a greater percentage of the fluid flow through the at least one aperture than through the open distal end of the delivery lumen.

69. The cannula of claim 68, wherein the delivery outlet is configured to deliver between about 60% and about 80% of the fluid flow through the at least one aperture.

70. The cannula of any one of claims 62 to 69, wherein the at least one guide element is configured to position the shaft of the medical instrument within the delivery lumen.

71. The cannula of claim 70, wherein the at least one guide element holds the medical instrument shaft substantially concentrically within the delivery lumen.

72. The cannula of any one of claims 62 to 71, wherein the at least one guide element comprises one or more protrusions extending inwardly from an inner surface of the cannula shaft.

73. The cannula of any one of claims 62 to 72, wherein at least one guide element is located at or adjacent to a distal end of the cannula shaft.

74. The cannula of any one of claims 62 to 73, wherein at least one guide element is spaced from a distal end of the cannula shaft.

75. The cannula of any one of claims 62 to 74, wherein the at least one guide element comprises two or more guide elements, wherein the two or more guide elements are axially spaced apart.

76. The cannula of any one of claims 62 to 75, wherein the cannula shaft further defines a second lumen.

77. The cannula of claim 76, wherein the second lumen is configured as a venting lumen comprising a venting inlet, the venting inlet comprising an open distal end of the second lumen.

78. The cannula of claim 77, wherein the venting inlet comprises at least one venting inlet in fluid communication with the venting lumen at or adjacent to a distal end of the cannula shaft.

79. The cannula of claim 77 or claim 78, wherein the cannula shaft includes a delivery shaft defining the delivery lumen, and a venting shaft defining the venting lumen, wherein the delivery shaft and the venting shaft are at least partially nested relative to each other.

80. The cannula of any one of claims 77 to 79, wherein at least part of the delivery outlet is positioned distally of the venting inlet.

81. The cannula of any one of claims 77 to 80, wherein the venting inlet comprises a substantially annular opening.

82. The cannula of any one of claims 77 to 81, wherein the venting inlet comprises one or more openings extending through a side wall of the cannula shaft.

83. The cannula of claim 82, wherein the venting inlet comprises a plurality of openings spaced around the cannula shaft.

84. The cannula of any one of claims 62 to 83, wherein the cannula shaft includes a tapered distal tip portion, wherein a maximum outer diameter of the tapered distal tip portion is substantially equal to a maximum outer diameter of the cannula shaft.

85. A cannula for delivering fluid to and venting fluid from a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; and a cannula shaft extending from the housing, the cannula shaft defining: a first lumen; and a second lumen, wherein the first lumen is a delivery lumen, wherein at least part of a delivery outlet of the delivery lumen is positioned distally of a distal opening of the second lumen.

86. The cannula of claim 85, wherein the delivery outlet comprises a diffuser in fluid communication with the delivery lumen, wherein the diffuser is located at or adjacent to the distal end of the cannula shaft.

87. The cannula of claim 85 or claim 86, wherein the diffuser comprises at least one diffusion aperture extending through a side wall of the cannula shaft.

88. The cannula of claim 87, wherein the at least one diffusion aperture is spaced from a distal end of the cannula shaft.

89. The cannula of claim 87 or claim 88, wherein at least one diffusion aperture is positioned distally of the distal opening of the second lumen.

90. The cannula of any one of claims 85 to 89, wherein the distal opening of the second lumen comprises an open distal end of the second lumen.

91. The cannula of claim 90, wherein the distal opening of the second lumen comprises at least one aperture extending through a side wall of the second shaft and in fluid communication with the second lumen at or adjacent to a distal end of the second shaft.

92. The cannula of any one of claims 85 to 91, wherein the cannula shaft includes a first shaft defining the first lumen, and a second shaft defining the second lumen, wherein the first shaft and the second shaft are at least partially nested relative to each other.

93. The cannula of any one of claims 90 to 92, wherein the distal opening of the second lumen comprises a substantially annular opening.

94. The cannula of any one of claims 90 to 93, wherein the distal opening of the second lumen comprises one or more openings extending through a side wall of the cannula shaft.

95. The cannula of claim 94, wherein the one or more openings comprises a plurality of openings spaced around the cannula shaft.

96. The cannula of any one of claims 94 to 95, wherein the second lumen is configurable as a venting lumen and/or as a second delivery lumen.

97. A cannula for delivering fluid to a body cavity of a patient during a surgical procedure, the cannula comprising: a cannula housing; and a cannula shaft extending from the housing, wherein the cannula shaft comprises a delivery outlet configured to deliver fluid flow to the body cavity, wherein the delivery outlet comprises: an open distal end; and at least one diffusion aperture extending through a side wall of the cannula shaft, wherein a resistance to fluid flow through the at least one diffusion aperture is less than a resistance to fluid flow through the open distal end when a medical instrument is received in the cannula shaft.

98. The cannula of claim 97, wherein the at least one diffusion aperture is located at or adjacent to the distal end of the cannula shaft.

99. The cannula of claim 98, wherein the at least one diffusion aperture is spaced from a distal end of the cannula shaft.

100. The cannula of any one of claims 97 to 99, wherein the delivery outlet is configured to deliver a greater percentage of the fluid flow through the at least one diffusion aperture than through the open distal end.

101. The cannula of claim 100, wherein the delivery outlet is configured to deliver between about 60% and about 80% of the fluid flow through the at least one diffusion aperture.

102. The cannula of claim 101, wherein the delivery outlet is configured to deliver about 70% of the fluid flow through the at least one diffusion aperture.

103. The cannula of any one of claims 97 to 102, wherein the at least one diffusion aperture directs at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft.

104. The cannula of any one of claims 97 to 103, wherein the at least one diffusion aperture tapers towards a distal end.

105. The cannula of any one of claims 97 to 103, wherein the at least one diffusion aperture is at least partly defined by a fluid directing surface configured to direct at least part of the fluid flow.

106. The cannula of claim 105, wherein the fluid directing surface directs the at least part of the fluid flow at an angle relative to a longitudinal axis of the cannula shaft.

107. The cannula of any one of claims 97 to 106, wherein the cannula shaft tapers inwardly in a region of the at least one diffusion aperture such that at least a distal portion of the at least one diffusion aperture is angled relative to a longitudinal axis of the cannula shaft.

108. A cannula comprising: a cannula housing; and a cannula shaft extending from the cannula housing between the cannula housing and a distal end of the cannula, the cannula shaft defining: a first lumen; a second lumen; and a third lumen, wherein the first, second and third lumens extend at least partially through the cannula shaft, wherein the first, second and third lumens are separate from each other and provide respective first, second and third fluid flow paths through the cannula shaft, wherein the cannula comprises a first port in fluid connection with the first lumen, a second port in fluid connection with the second lumen, and a third port in fluid connection with the third lumen, wherein each of the first, second and third ports is configured for connection to a respective fluid source and/or venting element.

109. The cannula of claim 108 wherein the first lumen is configured as a first delivery lumen and comprises a first delivery outlet, wherein the first delivery outlet is configured to deliver first fluid flow relative to a distal end of the cannula shaft and to diffuse at least a portion of the first fluid flow from the first delivery lumen.

110. The cannula of claim 109, wherein the first delivery outlet comprises at least one diffuser in fluid communication with the delivery lumen, wherein the diffuser comprises at least one diffusion aperture.

111. The cannula of claim 109 or 110, wherein the first delivery outlet is provided at a distal end of the cannula shaft.

112. The cannula of any one of claims 109 to 111, wherein at least part of the first delivery outlet is positioned distally of a distal opening of the second lumen.

113. The cannula of claim 112, wherein the second lumen is configured as a venting lumen and wherein the distal opening of the second lumen is configured as a venting inlet.

114. The cannula of any one of claims 108 to 113, wherein the third lumen is configured as a second delivery lumen and comprises a second delivery inlet configured for connection to a second fluid source and a second delivery outlet configured to deliver second fluid flow relative to a distal end of the cannula shaft.

115. The cannula of any one of claims 108 to 114, wherein the cannula shaft comprises: an inner shaft defining the first lumen; and an outer shaft defining the second lumen, wherein the inner shaft and the outer shaft are at least partially nested relative to each other, wherein the cannula shaft further comprises a divider extending between an outer surface of the inner shaft and an inner surface of the outer shaft to define the third lumen between the inner shaft and the outer shaft.

116. The cannula of any one of claims 108 to 115, wherein the first port is configured as a first fluid delivery port configured for connection to a first fluid source, wherein second port is configured as a venting port configured for connection to a venting element, and wherein the venting port is positioned distally of the first fluid delivery port.

117. The cannula of claim 116, wherein the third port is configured as a second fluid delivery port, wherein the third port is positioned distally of the first fluid delivery port and the venting port.