WO2020040652A1

WO2020040652A1 - Scope depth sensing methods

Info

Publication number: WO2020040652A1
Application number: PCT/NZ2019/050106
Authority: WO
Inventors: Gabor Papotti; German Klink; Zach Jonathan WARNER; Zane Paul GELL; Benjamin Elliot Hardinge PEGMAN; Pavlo KOKHANENKO; Callum James Thomas Spence
Original assignee: Fisher & Paykel Healthcare Limited
Priority date: 2018-08-23
Filing date: 2019-08-23
Publication date: 2020-02-27

Abstract

Systems and methods can determine the insertion depth of a scope, and in particular the relative position of a distal end of the scope that includes a lens to the position of the cannula outlet. Systems can include a sensing arrangement that measure the relative position or distance between a datum feature of a scope relative to a datum feature of a cannula to provide a distance of the scope lens beyond the cannula outlet.

Description

SCOPE DEPTH SENSING METHODS

FIELD OF THE DISCLOSURE

[0001] The present disclosure relates in some aspects to humidifier systems and components of humidifier systems for gases to be supplied to a patient, including systems and components configured to determine the insertion depth of a scope within a surgical cavity.

BACKGROUND

[0002] Various medical procedures require the provision of gases, typically carbon dioxide, to a patient during the medical procedure. For example, two general categories of medical procedures often require providing gases to a patient. These include closed type medical procedures and open type medical procedures.

[0003] In closed type medical procedures, an insufflator is arranged to deliver gases to a body cavity of the patient to inflate the body cavity and/or to resist collapse of the body cavity during the medical procedure. Examples of such medical procedures include laparoscopy and endoscopy, although an insufflator may be used with any other type of medical procedure as required. 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 laparoscopic procedures, a medical practitioner typically inserts a medical instrument through one or more natural openings, small puncture(s), or incisions 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 into the body cavity. Such procedures are widely used, for example, on the peritoneal cavity, or during a thoracoscopy, mediastinoscopy, colonoscopy or other colorectal procedures, gastroscopy, bronchoscopy, gynecological procedures, urological procedures, or any other procedures.

[0004] In open type medical procedures, such as open surgeries for example, gases are used to fill a surgical cavity, with excess gases spilling outward from the opening. The gases can also be used to provide a layer of gases over exposed body part for example, including internal body parts where there is no discernible cavity. For these procedures, rather than serving to inflate a cavity, the gases can be used to prevent or reduce desiccation and infection by covering exposed body parts with a layer of heated, humidified, sterile gases. [0005] An apparatus for delivering gases during these medical procedures can include an insufflator arranged to be connected to a remote source of pressurized gases, such as a gases supply system in a hospital for example. The apparatus can be operative to control the pressure and/or flow of the gases from the gases source to a level suitable for delivery into the body cavity, usually via a cannula or needle connected to the apparatus and inserted into the body cavity, or via a diffuser arranged to diffuse gases over and into the wound or surgical cavity.

[0006] The internal body temperature of a human patient is typically around 37°C. It can be desirable to match the temperature of the gases delivered from the apparatus 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, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or l5°C 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 at a desired fixed or variable humidity and/or a desired fixed or variable gas temperature. The gases at the desired gas temperature and/or humidity can be dry cold gas, dry hot gas, humidified cold gas, or humidified hot gas for example. Further, the gases delivered into the patient’s body can be relatively dry, which can cause damage to the body cavity, including cell death or adhesions. In many cases, a humidifier is operatively coupled to the insufflator. A controller of the apparatus can energize a heater of the humidifier located in the gases flow path to deliver humidification fluid (e.g., water vapor) to the gases stream prior to entering the patient’s body cavity.

[0007] The humidified gas can be delivered to the patient via further tubing which may also be heated. The insufflator and humidifier can be located in separate housings that are connected together via suitable tubing and/or electrical connections, or located in a common housing arranged to be connected to a remote gas supply via suitable tubing.

SUMMARY

[0008] During endoscopic procedures, such as laparoscopy, thoracoscopy, colonoscopy, sigmoidoscopy, gastroscopy, bronchoscopy, etc., a scope or other medical instrument may be inserted through a surgical incision or a natural body opening into an enclosed body cavity. For example, during laparoscopic surgery an endoscope may be surgically inserted through a small incision through the peritoneum into the abdominal cavity. The scope may be inserted through a cannula or similar structure which may be configured to receive the endoscope and/or other surgical tools and establish a pathway between the body cavity and the ambient environment which allows a surgeon or physician to operate internally within the body cavity through the cannula. The scope, e.g., endoscope, laparoscope, or another visualization tool may be needed by the surgeon to visualize the inside of the body cavity and perform a procedure inside the body cavity such as a surgical operation for example. During such endoscopic procedures, it is common to insufflate the body cavity with a fluid, including gases or liquids (e.g., air or carbon dioxide), saline, or any other suitable gases or liquid. In some cases, while the term gas or gases can be used to refer to the fluid that is inserted through the cannula and/or into the cavity as described herein, it is understood that any fluid, including any gas or liquid, can be used to expand or increase the volume of the body cavity or perform other functions including those disclosed herein. The expansion of the body cavity may provide for additional workspace for the surgeon and/or provide better visibility of target structures within the body cavity. Insufflators are commonly used pieces of equipment for establishing and maintaining an insufflated environment. Insufflators are generally configured to provide non-continuous or pulsatile flow comprising phases of positive pressure for inducing the flow of an insufflation gas into the body cavity to expand the cavity and phases of no gas flow (off phases) for maintaining the pressure and/or volume of the body cavity below a threshold pressure and/or volume. Insufflation gas introduced into the body cavity may gradually leak from the body cavity through an imperfect seal between the body cavity and the cannula and/or through backflow through the insufflation line. Accordingly, insufflators may switch between phases or pulses of positive pressure and no pressure to attempt to maintain the body cavity at a desired pressure and/or volume. The insufflator may comprise a pressure sensor for monitoring pressure within the body cavity and may be configured to switch between phases of positive pressure and no pressure (or between phases of higher and lower pressure) to maintain the desired pressure and/or volume. Pressure may also be released through venting features inserted into the body cavity or attached to a cannula or may be actively released through suctioning or other means. Ventilation may advantageously remove smoke generated from electrosurgery, electrocautery, laser cutting or cauterizing, or other types of energy from the body cavity, which can prevent or at least reduce condensation and/or fogging. While the application of fluids, for example gases, surrounding the medical instrument is described as potentially important for visualization of the surgical area by a scope or other visualization device, the application of fluids as described herein can be used in applications such as electrocautery tools, graspers, and other instruments.

[0009] Condensation and/or fogging occurs when the temperature of a gas falls below the dew point temperature for the level of humidity the gas is carrying, and/or if there are surfaces significantly below the dew-point temperature. The human body is a warm and humid environment, having a temperature of about 37°C. When cold (such as at or below typical room temperature and/or below a typical human body temperature) cameras, scopes, or other medical instruments are inserted into this environment, condensation can form as fog on the lens, and/or as droplets of humidification liquid, for example, water on the scope, which can drip down onto the lens area. Further, although the humidification and heating of the insufflation gases can reduce damage to the patient’s tissue in the surgical cavity, the humidification and heating of the gases can exacerbate the problem of condensation and/or fogging. Condensation can occur on various surfaces on a medical instrument. When condensation forms on a viewing surface of a medical instrument, this is observed as a fogging effect which manifests as an impairment of visibility through a lens or any other viewing surface of a medical instrument (such as, for example, a mirror or transparent or translucent window). When condensation forms on various surfaces of a medical instrument, the condensation can coalesce into water droplets. This can occur directly on the viewing surface or other surfaces which can then migrate to or be deposited on the viewing surface. Accordingly, as used herein condensation and/or fogging means condensation generally and in some instances, specifically with respect to condensation on a viewing surface (i.e. fogging).

[0010] In some embodiments, disclosed herein is a surgical apparatus that can comprise a cannula including a body, a cannula inlet, a cannula outlet, a passage defined within the body and extending between the inlet and the outlet; a medical instrument comprising an elongate shaft and removably insertable into the passage defined in the body; and a sensor arrangement comprising one or more sensors, the one or more sensors being disposed on at least one of the cannula and the medical instrument. The medical instrument may be a surgical instrument. The sensor arrangement is configured to determine a relative position of an instrument datum feature relative to a cannula datum feature. The relative position corresponds to an instrument insertion distance beyond the cannula outlet. The cannula can be single use (disposable) or reusable. Alternatively, parts of the cannula can be single use (disposable) or reusable. The cannula may be made of materials that are biocompatible and/or sterilizable. In the present disclosure, features of the different examples of cannulas can be incorporated into or combined with one another.

[0011] In some configurations, the relative position is a distance between the instrument datum feature and the cannula datum feature.

[0012] In some configurations, the medical instrument is a surgical scope or a laparoscope configured to allow visualization of a surgical cavity and contents of the surgical cavity. The medical instrument may be a surgical instrument.

[0013] In some configurations, the sensor arrangement includes a single sensor located on the cannula.

[0014] In some configurations, the sensor arrangement includes a single sensor located on the datum feature of the cannula.

[0015] In some configurations, the cannula comprises a flange, the inlet being defined in the flange and at least one of the sensors positioned on the flange, the at least one of the sensors configured to determine a distance between the flange and a medical instrument. The medical instrument may be a surgical instrument.

[0016] In some configurations, a single sensor is located on a portion of the medical instrument and configured to determine the relative position of the instrument datum feature relative to the cannula datum feature. The medical instrument may be a surgical instrument.

[0017] In some configurations, a single sensor is located on the scope datum feature.

[0018] In some configurations, the surgical apparatus further comprises an emitter and a receiver, the emitter emitting a signal that is received by the receiver, the sensor arrangement configured to determine the distance between the instrument datum feature and the cannula datum feature based on the time taken for the receiver to receive the signal, and/or based on the strength/magnitude of the signal received by the receiver. In some configurations, the sensing arrangement further comprises an emitter and a receiver, the emitter emitting a signal that is received by the receiver, the sensor arrangement configured to determine the distance between the instrument datum feature and the cannula datum feature based on the time taken for the receiver to receive the signal, and/or based on the strength/magnitude of the signal received by the receiver.

[0019] In some configurations, the emitter is disposed on the scope datum feature and the receiver is disposed on the cannula datum feature.

[0020] In some configurations, the emitter is disposed on the cannula datum feature and the receiver is disposed on the scope datum feature.

[0021] In some configurations, the emitter is configured to emit an acoustic, optical, or electromagnetic signal, and the receiver is configured to receive the acoustic, optical, or electromagnetic signal.

[0022] In some configurations, the sensing arrangement comprises an inductive sensor located either on the instrument or the cannula, wherein the inductive sensor is configured to determine a relative position based on induction response due to interaction with a metallic feature on the instrument or the cannula, wherein the metallic feature is the datum feature of the cannula or the instrument.

[0023] In some configurations, the instrument comprises a reflective surface, the sensing arrangement comprises an emitter and a receiver, the emitter and the receiver are located on the cannula, the emitter is configured to emit a signal and the receiver configured to detect a reflected signal, and the insertion distance beyond the cannula outlet being determined based on a reflected emittance.

[0024] In some configurations, the reflected emittance is a magnitude or time of flight of the signal, and the magnitude or time of flight corresponds to the insertion distance of the instrument beyond the cannula outlet.

[0025] In some configurations, the emitted signal is emitted in a pattern to define a plane extending generally vertically outward from the outlet of the cannula, which may also be referred to herein as a cannula outlet.

[0026] In some configurations, the emitter generates a field selected from the group consisting of: a magnetic field, an electromagnetic field, and an electrostatic field, and the receiver includes a coil configured to measure field strength when located within the field generated by the emitter, the field strength corresponding to a relative position of the emitter and receiver, the relative position corresponding to an insertion depth of the instrument beyond the cannula outlet. [0027] In some configurations, the emitter is configured to generate a field comprising a magnetic field or an electric field, the receiver generates energy or a voltage in response to being located in the field generated by the emitter, a magnitude of the energy or voltage corresponding to the relative position of the emitter and receiver, and the relative position corresponding to an insertion depth of the instrument beyond the cannula outlet.

[0028] In some configurations, the sensor arrangement comprises a Hall effect sensor.

[0029] In some configurations, the sensor arrangement comprises an ultrasound, laser, or infrared active or passive transmitter and receiver.

[0030] In some configurations, the cannula comprises an elongate shaft, the elongate shaft including the passage and the inlet and outlet defined in the shaft, the shaft including a coil within the shaft, the coils generating a magnetic field or electrical field, and the scope depth is determined based on the inductance of the coil.

[0031] In some configurations, the sensing arrangement comprises a tracking arrangement, the tracking arrangement configured to track movement of the instrument within the passage and thereby determine the insertion depth of the instrument beyond the cannula outlet.

[0032] In some configurations, the tracking arrangement comprises a position tracking arrangement.

[0033] In some configurations, the tracking arrangement comprises one or more of: an encoder wheel, an LED emitter and receiver, and a laser emitter and receiver.

[0034] In some configurations, the tracking arrangement is located within the passage of the cannula.

[0035] In some configurations, the tracking arrangement comprises a linear sensor disposed on the instrument, the tracking arrangement configured to detect a linear position of the linear sensor in order to determine the insertion depth of the instrument beyond the cannula outlet.

[0036] In some configurations, the sensing arrangement comprises a pressure sensor, the pressure sensor configured to determine an insertion distance based on a pressure difference detected by the pressure sensor as the instrument is moved within the passage. [0037] In some configurations, the sensing arrangement comprises a spring, a force sensor, and one or more springs, the force sensor configured to detect the force on the springs, the force on the springs corresponding to the insertion depth of the instrument beyond the cannula outlet.

[0038] In some configurations, the sensing arrangement comprises a processor configured to process the sensor arrangement.

[0039] In some configurations, the sensing arrangement comprises one or more motion sensors and a remote processor, the remote processor configured to track the position of the instrument from a zero position, the position being determined from the motion sensor measurements.

[0040] In some configurations, the motion sensors comprise at least one of an accelerometer and a gyroscope.

[0041] In some configurations, the motion sensors comprise signal generators.

[0042] In some configurations, disclosed herein is an apparatus for determining the position of an instrument within a surgical cannula, the apparatus comprising a sensing arrangement comprising at least a plurality of sensors, for example, a pair of sensors, the sensors in the sensor arrangement positioned on the cannula or instrument; a processor arranged in electronic communication with the pair of sensors, the processor configured to determine a position of the instrument relative to the cannula based on the sensor outputs. The processor is configured to determine an insertion depth of the instrument beyond the cannula outlet and/or determine a position of an end of the instrument relative to the cannula outlet.

[0043] In some configurations, the processor comprises an electronic processor.

[0044] In some configurations, the plurality of sensors, for example, a pair of sensors comprises motion sensors.

[0045] In some configurations, the plurality of sensors, for example, a pair of sensors comprise wireless signals that provide a position signal.

[0046] In some configurations, the sensing arrangement comprises a field emitter, the processor configured to receive at least one parameter related to a field disturbance, field strength or eddy currents induced in the sensors due to the presence of the field, the processor configured to determine an insertion distance based on the change in the parameter. [0047] In some configurations, the field emitter comprises one or more surgical lights or other light sources.

[0048] In some configurations, the emitter is configured to emit an electromagnetic field, electrostatic field, or magnetic field.

[0049] In some configurations, the sensing arrangement comprises a camera and the sensors are reference points, the camera configured to determine position of the reference points, the processor configured to determine an insertion depth of the instrument beyond the cannula outlet.

[0050] In some configurations, also disclosed herein is a sensing arrangement for a surgical apparatus, comprising one or more sensors being disposed on an attachment structure configured to attach to at least one of the cannula and the medical instrument, the cannula including a body, a cannula inlet, a cannula outlet, a passage defined within the body and extending between the inlet and the outlet; and the medical instrument comprising an elongate shaft and removably insertable into the passage defined in the body. The sensor arrangement is configured to determine a relative position of an instrument datum feature relative to a cannula datum feature. The relative position corresponds to an instrument insertion distance beyond the cannula outlet. The medical instrument may be a surgical instrument.

[0051] In some configurations, a sensing arrangement further comprises a processor arranged in electronic communication with the sensing arrangement, the processor configured to determine a position of the instrument relative to the cannula based on sensor outputs, the processor configured to determine an insertion depth of the instrument beyond the cannula outlet and/or determine a position of an end of the instrument relative to the cannula outlet.

[0052] In some configurations, the attachment structure comprises a ring configured to attach to a proximal end of the instrument.

[0053] In some configurations, the attachment structure comprises a ring configured to attach to the shaft of the instrument.

[0054] In some configurations, the attachment structure comprises an adhesive, magnet, clip, and/or screw.

[0055] In some configurations, the attachment structure comprises a push and release clamp. [0056] In some configurations, the attachment structure comprises a circumferentially expandable and contractable elastic band.

[0057] In some configurations, the attachment structure is configured to friction fit with a portion of the cannula or the instrument.

[0058] In some configurations, the attachment structure comprises a suction element.

[0059] In some configurations, the attachment structure comprises a sleeve configured to fit over the outside of the cannula body.

[0060] In some configurations, the attachment structure comprises a sleeve configured to fit within the passage of the cannula body.

[0061] In some configurations, the attachment structure comprises a sleeve configured to fit over the outside of the shaft of the scope.

[0062] In some configurations, a surgical apparatus comprises a cannula and an instrument insertable into the cannula, and a sensing arrangement disposed on the cannula and/or instrument. The sensing arrangement comprises a tracking arrangement, the tracking arrangement configured to track movement of the instrument within the passage and thereby determine the insertion depth of the instrument beyond the cannula outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0063] These and other features, aspects, and advantages of the present disclosure are described with reference to the drawings of certain embodiments, which are intended to schematically illustrate certain embodiments and not to limit 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 reasonably skilled in the art would be able to appreciate that these figures illustrate a slice of a three dimensional cannula. In some cases, the projection surfaces have not been shown for clarity. For example, projecting hole surfaces have not been shown in some views.

[0064] Figure 1 illustrates schematically an example medical gases delivery apparatus.

[0065] Figures 2A-3 illustrate schematically an example medical gases delivery apparatus. [0066] Figures 4-20 illustrate various embodiments of surgical cannula systems configured to measure the distance between a scope lens relative to a cannula outlet.

[0067] Figures 21-26 illustrate various embodiments of surgical cannula systems including an external sensing/detection arrangement.

[0068] Figures 27-31 illustrate various embodiments of calibration features for surgical cannula systems configured to measure the distance between a scope lens relative to a cannula outlet.

[0069] Figures 32-39C illustrate various embodiments of embedding or mounting features for surgical cannula systems configured to measure the distance between a scope lens relative to a cannula outlet.

DETAILED DESCRIPTION

[0070] Although certain embodiments and examples are described below, those of skill in the art will appreciate that the disclosure extends beyond the specifically disclosed embodiments and/or uses and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the disclosure herein disclosed should not be limited by any particular embodiments described below.

Example Medical Gases Delivery Systems

[0071] Gases can be introduced to a surgical cavity, such as, for example, the peritoneal cavity via a cannula inserted through an incision made in patient’s body (such as the abdominal wall). The cannula can be coupled to an insufflator. The gases flow from the insufflator can be increased to inflate the surgical cavity (such as to maintain a pneumoperitoneum, which is a cavity filled with gas within the abdomen). The introduced gases can inflate the surgical cavity. A medical instrument such as, for example, a scope can be inserted through the cannula into the inflated surgical cavity. As defined herein, a scope is any imaging device that records or captures visual images or a stream of images or a video stream. For example, an endoscope, another scope, camera unit, or other vision system can be inserted into the cavity and visibility in the cavity can be assisted by insertion of fluids, which including gases or liquids, such as air or carbon dioxide. The camera unit can include a lens inserted through a trocar. A trocar includes a cannula and obturator. The lens can be connected to a camera positioned, for example, outside the surgical cavity. After initial insufflation and insertion of the instrument (such as a laparoscope for example) through the primary cannula, additional cannulas can be placed in the surgical cavity under laparoscopic observation. Gases and/or surgical smoke can be vented from the surgical cavity using venting features integrated into the cannula, or a venting attachment on one of the cannulas placed in the surgical cavity. At the end of the operating procedure, all instruments and cannulas are removed from the surgical cavity, the gases are expelled, and each incision is closed. For thoracoscopy, colonoscopy, sigmoidoscopy, gastroscopy, bronchoscopy, and/or others, the same or substantially similar procedure for introducing gases to a surgical cavity can be followed. The quantity and flow of gases can be controlled by the clinician performing the examination and/or automatically by the surgical system. A surgical system may be an insufflation system.

[0072] Figures 1 and 2A-C illustrate schematically using an example surgical system 1 during a medical procedure. Features of Figures 1 and 2A-C can be incorporated into each other. The same features have the same reference numerals in Figures 1 and 2A-C. As shown in Figure 1 , the patient 2 can have a cannula 15 inserted within a cavity of the patient 2 (for example, an abdomen of the patient 2 in the case of a laparoscopic surgery), as previously described.

[0073] As shown in Figures 1 and 2A-C, the cannula 15 can be connected to a gases delivery conduit 13 (for example, via a Luer lock connector 4). The cannula 15 can be used to deliver gases into a surgical site, such as within the cavity of the patient 2. The cannula 15 can include one or more passages to introduce gases and/or one or more medical instruments 20 into the surgical cavity. The medical instrument can be a scope, electrocautery or electrosurgery, ultrasound, laser cutting or cauterising tool, or any other instrument. The medical instrument 20 can be coupled to an imaging device 30, which can have a screen. The imaging device 30 can be part of a surgical system, which can include a plurality of surgical tools and/or apparatuses. A surgical system can include a surgical stack. In some configurations, the cannula 15 can be used in a system that includes a supplementary gases source.

[0074] As shown in Figure 2A, the system can include a venting cannula 22, which can have substantially the same features as the cannula 15. The venting cannula may include a leak device coupled to the venting cannula. The leak device may include a valve that allows and/or controls venting. The valve can be automatically controlled by a controller associated with the gases source (e.g., insufflator) or by a controller in the humidifier. The valve can also be manually actuated (for example, by turning a tap by hand or by a foot pedal, or otherwise). The leak device can include a filtration system to filter out smoke and the like. The venting cannula 22 can also alternatively be coupled to a recirculation system (see Figure 23) that is configured to recirculate the gases from the surgical cavity back to the insufflator for re delivery into the surgical cavity. The gases can also be filtered and/or dehumidified prior to being returned to the insufflator. As shown in Figures 2B and 3, the cannula 15 can include a venting attachment such that a venting cannula 22 may not be necessary. The cannula 15 may include two or more passages. One passage can be configured to deliver gases and/or the medical instrument into the surgical cavity. Another passage can be configured to vent gases out of the surgical cavity.

[0075] As shown in Figures 1, 2A and 2B, the gases delivery conduit 13 can be made of a flexible plastic and can be connected to a humidifier chamber 5. The humidifier chamber 5 can optionally or preferably be in serial connection to a gases supply 9 via a further conduit 10. The gases supply or gases source can be, for example, an insufflator, bottled gases, or a wall gases source. The gases supply 9 can provide the gases without humidification and/or heating. A filter 6 be connected downstream of the humidifier's outlet 11. The filter can also be located along the further conduit 10, or at an inlet of the cannula 15. The filter can be configured to filter out pathogens and particulate matter in order to reduce infection or contamination of the surgical site from the humidifier or gases source. The gases supply can provide a continuous or intermittent flow of gases. The further conduit 10 can also preferably be made of flexible plastic tubing.

[0076] The gases supply 9 can provide one or more insufflation gases, such as carbon dioxide, to the humidifier chamber 5. The gases can be humidified as they are passed through the humidifier chamber 5, which can contain a volume of humidification fluid, e.g., water 8.

[0077] Any type of humidifier can be configured to incorporate the humidifier chamber 5. The humidifier chamber 5 can include a plastic formed chamber having a metal or otherwise conductive base 14 sealed thereto. The base can be in contact with the heater plate 16 during use. The volume of humidification fluid 8 contained in the chamber 5 can be heated by a heater plate 16, which can be under the control of a controller or control means 21 of the humidifier. The volume of humidification fluid 8 within the chamber 5 can be heated such that it evaporates, mixing the humidification fluid, e.g., water vapor with the gases flowing through the chamber 5 to heat and humidify the gases. The illustrated humidifier is a warm passover humidifier. The warm passover humidifier can be adapted to humidify gases by heating a humidification fluid (e.g., water) within a chamber and passing the gases over the heated humidification fluid. The gases become humidified as the gases pass over the heated humidification fluid.

[0078] The controller or control means 21 can be housed in a humidifier base unit 3, which can also house the heater plate 16. The heater plate 16 can have an electric heating element therein or in thermal contact therewith. One or more insulation layers can be located between in the heater plate 16 and the heater element. The heater element can be a base element (or a former) with a wire wound around the base element. The wire can be, for example, a nichrome wire (or a nickel-chrome wire). The heater element can also include a multi-layer substrate with heating tracks electrodeposited thereon or etched therein. The controller or control means 21 can include electronic circuitry, which can include a microprocessor for controlling the supply of energy to the heating element. The humidifier base unit 3 and/or the heater plate 16 can be removably engageable with the humidifier chamber 5. The humidifier chamber 5 can also alternatively or additionally include an integral heater. The controller or control means can be housed in the insufflator, the cannula, the humidifier, and/or be external to the aforementioned components.

[0079] The heater plate 16 can include a temperature sensor, such as a temperature transducer or otherwise, which can be in electrical connection with the controller 21. The heater plate temperature sensor can be located within the humidifier base unit 3. The controller 21 can monitor the temperature of the heater plate 16, which can approximate a temperature of the humidification fluid 8.

[0080] A temperature sensor can also be located at the or near the outlet 11 to monitor a temperature of the humidified gases leaving the humidifier chamber 5 from the outlet 11. The temperature sensor can also be connected to the controller 21 (for example, with a cable or wirelessly). Additional sensors can also optionally be incorporated, for example, for sensing characteristics of the gases (such as temperature, humidity, flow, or others, for example) at a patient end of the gases delivery conduit 13.

[0081] The gases can exit out through the humidifier's outlet 11 and into the gases delivery conduit 13. The gases can move through the gases delivery conduit 13 into the surgical cavity of the patient 2 via the cannula 15, thereby inflating and maintaining the pressure within the cavity. Preferably, the gases leaving the outlet 11 of the humidifier chamber 5 can have a relative humidity of, for example, up to around 100%, for example at 100%. As the gases travel along the gases delivery conduit 13, further condensation can occur so that humidification fluid (for example, water vapor) can condense on a wall of the gases delivery conduit 13. Further condensation can have undesirable effects, such as detrimentally reducing the humidification fluid content of the gases delivered to the patient. In order to reduce and/or minimize the occurrence of condensation within the gases delivery conduit 13, a heating element, such as, for example, a heater wire 14 can be provided within, throughout, or around the gases delivery conduit 13. The heater wire 14 can be electronically connected to the humidifier base unit 3, for example by an electrical cable 19 to power the heater wire. In some embodiments, other heating elements could be included in addition or alternatively, e.g., a conductive ink, or a flexible PCB. In some cases, the PCB could be flexible, or rigid and pre shaped to an arcuate shape for example. In some embodiments, the heating element could be, for example, discrete Positive Temperature Coefficient ("PTC") heaters, or heaters including conductive plastic/polymer. Optionally, the heating element can include an inductive heating element. Optionally, the heating element can include a chemical heating element, for example, silica beads. Optionally, the cannula can be pre-heated prior to insertion.

[0082] The heater wire 14 can include an insulated copper alloy or nichrome resistance wire, other types of resistance wire, or other heater element, and/or be made of any other appropriate material. The heater wire can be a straight wire or a helically wound element. An electrical circuit including the heater wire 14 can be located within walls of the gases delivery tube 13. The gases delivery tube 13 can be a spiral wound tube. Alternatively, the gases delivery tube 13 can include a non-helical or straight tube. Optionally, the gases delivery tube 13 can be corrugated or non-corrugated. The heater wire 14 can be spirally wound around an insulating core of the gases delivery conduit 13. The insulating coating around the heater wire 14 can include a thermoplastics material which, when heated to a predetermined temperature, can enter a state in which its shape can be altered and the new shape can be substantially elastically retained upon cooling. The heater wire 14 can be wound in a single or double helix. Measurements by the temperature sensor and/or the additional sensor(s) at the patient end of the conduit 13 can provide feedback to the controller 21 so that the controller 21 can optionally energize the heater wire to increases and/or maintain the temperature of the gases within the gases delivery conduit 13 (for example, between approximately 35° C and 45° C) so that the gases delivered to the patient can be at the desired temperature, which can be at or close to 37° C or above or below the internal body temperature (for example, approximately l°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, lO°C, or l5°C above or below 37° C).

[0083] The controller or control means 21 can, for example, include the microprocessor or logic circuit with associated memory or storage means, which can hold a software program. When executed by the control means 21, the software can control the operation of the surgical, for example, insufflation system 1 in accordance with instructions set in the software and/or in response to external inputs. For example, the controller or control means 21 can be provided with input from the heater plate 16 so that the controller or control means 21 can be provided with information on the temperature and/or power usage of the heater plate 16. The controller or control means 21 can be provided with inputs of temperature of the gases flow. For example, the temperature sensor can provide input to indicate the temperature of the humidified gases flow as the gases leave the outlet 11 of the humidifier chamber 5. A flow sensor can also be provided in the same position as or near the temperature sensor or at other appropriate location within the surgical system 1. The controller 21 can control a flow regulator which regulates the flow rate of gases through the system 1. The regulator can include a flow inducer and/or inhibiter such as a motorized fan or pump. Valves and/or vents can additionally or alternatively be used to control the gases flow rate.

[0084] A patient input 18 located on the humidifier base unit 3 can allow a user (such as a surgeon or nurse for example) to set a desired gases temperature and/or gases humidity level to be delivered. Other functions can also optionally be controlled by the user input 18, such as control of the heating delivered by the heater wire 14 for example. The controller 21 can control the system 1, and in particular to control the flow rate, temperature, and/or humidity of gas delivered to the patient, to be appropriate for the type of medical procedure for which the system 1 is being used. [0085] The humidifier base unit 3 can also include a display for displaying to the user the characteristics of the gas flow being delivered to the patient 2.

[0086] Although not shown, the humidifier can also optionally be a passover or bypass humidifier, which can include the chamber with a volume of water or any other type of humidification fluid, but may not include a heater plate for heating the humidification fluid (for example, water). The chamber can be in fluid communication with the insufflation fluid supply such that the insufflation fluid(s) are humidified by the humidification fluid vapor (for example, water vapor) evaporated from the volume of humidification fluid as the insufflation fluid(s) pass over the volume of humidification fluid.

[0087] When in use, the humidifiers described above can be located outside an “operating sterile zone” and/or adjacent the insufflator. As a result, the medical personnel would not be required to touch the humidifier when moving the cannula during the operation to maneuver the medical instruments within the surgical cavity. The humidifier may not need to be sterilized to the same extent as the medical instruments. Furthermore, the humidifier being located outside the“operating sterile zone” can reduce obstructions to the medical personnel during the operating procedure that may restrict movements of the medical personnel and/or the medical instruments in the already crowded space.

[0088] As shown in Figure 3, the system may be used without a humidifier so that the gases supply 9 can be coupled directly to the cannula 15.

Examples of Scope Insertion Depth Measurement Systems

[0089] In some embodiments, systems and methods for determining the depth of a medical instrument relative to an outlet or distal end of a cannula (e.g., the position of the scope lens relative to the cannula outlet), are disclosed herein. Such systems and methods can be utilized or modified for use with a wide variety of cannula systems, including conventional cannula systems as well as directed gas flow systems as described for example above.

[0090] The systems can include any number of emitters and/or receiving sensors, some examples of which are disclosed in detail elsewhere herein. For example, a sensor could receive inputs from one, two, or more emitters. As another example, one, two, or more sensors could receive input from a single emitter. Furthermore, in some configurations systems can include one, two, or more sensors without any emitters. Different sensor types require different forms of signals, references/receivers, senders/emitters, etc. The sensors can be configured to determine either the distance between the scope and cannula, the relative position of a first and second different tools which can be translated into distance, or relative movement/motion of the first and second different tools from the zero point which can be translated into distance. The sensor type for measuring scope depth inside the cannula could be, for example, any of the following:

• [0091] Reflective: Sending a signal which is reflected from a surface back to a receiver located near the emitter. Emitter and receiver can be on the cannula or the scope, and the reflective surface is on the other. The strength of the reflected signal, or the time it takes to be reflected back is translated into a distance.

• [0092] Single path: Emitter on either the cannula or scope, sending a signal directly to a receiver located on the other. The strength of the measured signal, or the time it takes for the receiver to pick up the signal, is translated into a distance measurement.

• [0093] Field based: creation of a field (e.g. electromagnetic, electrostatic, magnetic, etc.) from the cannula or scope, where the location of the other is sensed by either detection of field strength, or through disturbing the field in some way.

• [0094] Contact: Scope makes contact with sensor to determine movement or position of the scope - can be contact with encoder mechanism, or variable resistor.

• [0095] Linear: A sensor or reference placed along the length of the scope, which could be encoder based, or variable resistor based, which is measured to determine the movement or position of the scope.

• [0096] Force based: Using a spring or flexible material to create a variable force between the scope & cannula that changes depending on scope depth insertion.

• [0097] Camera system: using the video feed from the laparoscopic camera to determine scope depth based on image processing.

• [0098] Pressure: Using pressure changes in the insufflation gas supply that can change when the scope is inserted into the gas supply cannula to determine the depth of the scope. • [0099] System based: Using an external system or processor to measure the location or movement of the cannula & scope relative to each other, with both acting as reference locations.

[0100] Any feature that can function as a reference point (e.g., on the cannula and/or the medical instrument) may be referred to herein as datum features. Some non-limiting examples of cannula datum features can include, for example, the proximal end, any point along the cannula shaft, or the distal end of the cannula, or sleeve attachments on the same as disclosed elsewhere herein. Some non-limiting examples of scope datum features can include, for example, the distal end of the scope (e.g., where a scope lens resides), any portion of the scope shaft, or a scope attachment. Any number of elements, some examples of which are described herein can assist in identification of the relative location of the cannula datum features with respect to the scope datum features, including emitters, sensors, reflective surfaces, and others. In some embodiments, these systems and methods can be configured for determining lateral (horizontal plane) deviation of a medical instrument with respect to a cannula lumen. This can provide error compensation to the vertical depth measurement if the instrument is angled slightly. An example is when a smaller scope is inserted through a larger- sized cannula.

[0101] Figure 4 illustrates a surgical cannula system 400 including a cannula 420, according to some embodiments of the invention. The cannula 420 can include an upper housing 422, elongate shaft 424, proximal end 426 including cannula inlet 427, distal end 428 including cannula outlet 429, and a passage or lumen (not shown) fluidly connecting the cannula inlet 427 and the cannula outlet 429 configured to house a medical instrument therethrough. The medical instrument may be a surgical instrument. The medical instrument could be a scope 440 including a proximal end 444 and distal end 446 shown extending beyond the distal end 428 of the cannula 420, and removably insertable into the passage of the cannula 420, such as concentric with a longitudinal axis of the cannula 420 in some cases. The scope 440 can include an emitter 451 configured to emit a signal, such as an electromagnetic signal to a receiver sensor 453 operably attached to a portion of the cannula 420, such as on the proximal end 426 of the cannula 420 as illustrated. The emitter 451 can be placed on a portion of the scope 440, such as on an attachment structure 442, and in operable communication with the receiver 453. The attachment structure 442 could be an elongate member extending radially outwardly from (or ring extending circumferentially outward from the scope 420), and transverse to a longitudinal axis of the scope 440 in some cases as shown. The time it takes the signal from the emitter 451 to reach the receiver 453 on the cannula 420, or the strength of the measured signal for example can be utilized by a processor to extrapolate or otherwise determine the insertion depth of the scope 440.

[0102] In some embodiments, an electromagnetic signal emitter can include any one, two, or more physical feasible frequencies or frequency bands, in the visible spectrum or otherwise (above or below) including but not limited to radio waves, microwaves, infrared waves, visible light, ultraviolet radiation, and/or X-rays. Electromagnetic signal emitters could also involve, for example, magnetic energy, RF energy, microwave energy, and/or ultrasound energy, including high-frequency and low-frequency ultrasound energy.

[0103] Figure 5 illustrates an embodiment of a surgical cannula system 500 including a cannula 520 that can include any number of features of the embodiment of Figure 4, except that both the emitter 551 and the receiver sensor 553 are located on a portion, such as the attachment structure 542 of the medical instrument (e.g., scope 540). The signal sent by the emitter 551 can reflect off a portion of the cannula 520 such as the proximal end 526 of the cannula 520 as illustrated with arrows. In some embodiments, depending on the cannula 520 geometry a portion, such as the proximal end 526 of the cannula 520 can include a reflective ring 521 or other shape to better allow the signal sent by the emitter 551 to reflect off the proximal end 526 of the cannula 520 and be sensed by the receiver 553. Also illustrated in Figure 5 is the distal end 528 of the cannula 520 as well as the distal end 546 of the scope 540.

[0104] Figure 6 illustrates an embodiment of a surgical cannula system 600 including a cannula 620 and a medical instrument (e.g., scope 640) that can include any number of features of the embodiment of Figures 4 and 5, and also illustrating that the emitter 651 and receiver sensor 653 can both be positioned on a portion of the cannula 620, such as the proximal end 626 of the cannula 620 as shown. The emitter 651 and receiver sensor 653 can be part of an integrated unit, or separate in some embodiments. The emitter 651 can send a signal in the direction of arrows to a flange 642 or other structure on the scope 640, such that the signal can reflect off the natural geometry of the flange 642 (which may be a datum feature) and back to the receiver sensor 653. The scope insertion depth can thus be extrapolated or otherwise be determined by a processor based upon the data received from the receiver sensor 653. [0105] Figure 7 illustrates an embodiment of a surgical cannula system 700 including a cannula 720 and a medical instrument (e.g., scope 740) that can include any number of features of the embodiment of Figures 4-6, and also including an inductive sensor 753 that can interact with a metallic reference attachment 742 (which may be a datum feature) or other feature of the scope 740 as shown. The sensor can in some cases include an induction loop. Electric current generates a magnetic field, which collapses generating a current that falls toward zero from its initial state when the input electricity ceases. The inductance of the loop changes according to the material inside it and since metals are much more effective inductors than other materials the presence of metal increases the current flowing through the loop. This change can be detected by sensing circuitry within the inductive sensor 753. The inductive response measured by the inductive sensor 753 can be transmitted to a processor to extrapolate or otherwise determine the scope 740 insertion depth.

[0106] Figure 8 illustrates an embodiment of a surgical cannula system 800 including a cannula 820 and a medical instrument (e.g., scope 840) that can include an emitter 851 and receiver 853 that can be as previously described, and operably attached proximate or at the distal end 828 of the cannula 820 to create an electromagnetic signal plane, which can be emitted in the direction of arrows to all possible depths of the scope 740. A reflective element (e.g., attachment) 821 can be placed on or proximate the distal end 846 of the scope 840 to function as a scope datum feature. The reflected response can be measured, and thus the scope insertion depth can thus be extrapolated or otherwise be determined by a processor based upon the data received from the receiver sensor 853.

[0107] Figure 9 illustrates an embodiment of a surgical cannula system 900 including a cannula 920 and a medical instrument (e.g., scope 940) that can include an emitter 941 and receiver sensor 943 attached or integrated within a portion (e.g., proximal end) of the cannula 920. The emitter 941 can be configured to send an electromagnetic field F in the direction of arrows toward a medical instrument (e.g., scope attachment 942 serving as a scope datum feature) configured to generate eddy currents E from the primary magnetic fields, which in turn generate secondary magnetic fields. The feedback of disturbances/fluctuations in the primary magnetic field F from the secondary magnetic field generated by the eddy currents E can be sent to a processor to determine scope insertion depth. [0108] Figure 10 illustrates an embodiment of a surgical cannula system 1000 including a cannula 1020 and a medical instrument (e.g., scope 1040) that can include an emitter 1041 attached or integrated within a portion (e.g., proximal end) of the cannula 1020. The emitter 1041 can be configured to send an electromagnetic or electrostatic field EF in the direction of arrows toward a medical instrument (e.g., scope attachment 1042). A receiver sensor 1043 on a portion of the scope 1040 (e.g., scope attachment 1042) can be configured to generate voltage based on the field strength. The measured voltage/field strength and/or the time it takes the signal to reach the receiver sensor 1043 can be data inputs sent to a processor to determine scope insertion depth.

[0109] Figure 11 illustrates an embodiment of a surgical cannula system 1100 including a cannula 1120 and a medical instrument (e.g., scope 1140) that can include a fixed magnet 1141 attached or integrated within a portion (e.g., proximal end) of the cannula 1120. The fixed magnet 1141 can be configured to send a magnetic field MF in the direction of arrows toward a medical instrument (e.g., scope attachment 1142). A receiver sensor 1143 on a portion of the scope 1140 (e.g., scope attachment 1142) can be a Hall effect sensor configured to detect the strength of the magnetic field. A Hall effect sensor can include a transducer that varies its output voltage in response to a magnetic field. In a Hall effect sensor, a thin strip of metal can have a current applied along it. In the presence of a magnetic field, the electrons in the metal strip are deflected toward one edge, producing a voltage gradient across the short side of the strip (perpendicular to the feed current). Hall effect sensors can be advantageous in some embodiments over inductive sensors in that, while inductive sensors respond to a changing magnetic field which induces current in a coil of wire and produces voltage at its output, Hall effect sensors can detect static (non-changing) magnetic fields. The strength of the magnetic field MF detected by the receiver (e.g., Hall effect) sensor 1043 can be data inputs sent to a processor to determine scope insertion depth.

[0110] Figure 12 illustrates an embodiment of a surgical cannula system 1200 including a cannula 1220 and a medical instrument (e.g., scope 1240) that can include one or a plurality of coils 1241 wrapped around, or embedded within a wall 1225 of the shaft 1224 of the cannula 1220. Once the medical instrument (e.g., scope 1240) that can include metallic components in some cases passes through the segment of the cannula shaft 1224 including the coils 1241, the inductance of the coils 1241 can change (e.g., increase). The change in inductance can be measured by a sensor (not shown) proximate the coils 1241 and be data inputs sent to a processor to determine scope insertion depth.

[0111] Figure 13 illustrates an embodiment of a surgical cannula system 1300 including a cannula 1320 and a medical instrument (e.g., scope 1340) that can include an emitter 1341 that can include one or more optical emitting elements, e.g., a laser or LEDs spaced apart from a photocell receiver sensor 1343, the emitter 1341 and sensor 1343 integrated within or otherwise attached to a portion of the cannula 1320, such as the proximal end of the cannula shaft 1324 as illustrated. The change in movement of the scope can be measured by the receiver 1343 and be data inputs sent to a processor to determine scope insertion depth.

[0112] Figure 14 illustrates an embodiment of a surgical cannula system 1400 including a cannula 1420 and a medical instrument (e.g., scope 1440) that can include a rotatable mechanical wheel encoder 1441 integrally formed with, or operably attached to a wall 1425 of the cannula shaft 1424 that contacts the scope 1440. The wheel encoder 1441 can function somewhat similarly to a computer mouse scroll wheel, and be configured to limit the inner diameter of the lumen of the cannula 1420 and rotate with friction against a sidewall of the scope 1440. The wheel encoder 1441 can be configured to have enough flexible give to adjust to different scope sizes, but still have sufficient friction to rotate when a scope 1440 abuts the wheel encoder 1441. A sensor 1443 can be integrally formed with or otherwise attached to the wheel encoder 1441 to determine the number of rotations of the wheel encoder, which can be data inputs sent to a processor to determine scope insertion depth.

[0113] Figure 15 illustrates an embodiment of a surgical cannula system 1500 including a cannula 1520 and a medical instrument (e.g., scope 1540) that can include a strip of material 1541 integrally formed with or operably attached along part of, or the entire length of a sidewall of the scope 1540, and extending generally axially along the longitudinal axis of the scope 1540. The strip 1541 could be a variable resistor, or a linear encoder that can be monitored and/or actuated by a fixture on the cannula 1520 to track movement or position. Also illustrated is a contact 1543 integrally formed with or operably attached to a portion of the cannula 1520, such as the proximal end of the upper cannula housing for example as shown. In some embodiments, the contact can be a magnet, such as shown, and can be drawn via a magnetic force in the direction of arrow toward the strip 1541 which could also include magnetic material. The contact 1543 on the cannula 1520 and the strip 1541 on the scope 1540 can create a variable resistor circuit in some embodiments, and the contact 1543 could include, for example, a contact arm that completes the electrical circuit; a magnet to engage an electrical contact held captive inside the strip; or a mechanical engagement with the strip 1541 that holds the electrical contact mechanism in place. If the strip 1541 is encoder-based, the contact 1543 could include an emitter/receiver system; be optically reflection based; include a magnet to activate sensors in the strip; include sensors which will activate on magnetic interference feedback from the strip; or be electrostatic or capacitance based. Sensors operably attached to the strip 1541 and/or the contact 1543 can detect a change of resistance of the circuit and/or movement or position of the strip 1541, which can be data inputs sent to a processor to determine scope insertion depth.

[0114] Figure 16 illustrates an embodiment of a surgical cannula system 1600 including a cannula 1620 and a medical instrument (e.g., scope 1640) that can include a first contact 1641 operably attached to a portion of the scope 1640, a second contact 1643 operably attached to a portion of the cannula 1620 (e.g., proximal end of the cannula 1620) and configured to contact a more distal portion of the scope 1640, and a conduit 1645 in operable connection with the first contact 1641 and the second contact 1643 and configured to create a variable resistor circuit leveraging the conductive body of the scope 1640. A sensor on the scope 1640 and/or cannula 1620 can be configured to measure the resistance of the circuit. The first contact 1641 is attached to the scope 1640 at a fixed relatively more proximal point as illustrated, while the second contact 1643 can contact the scope 1640 at a more variable distal point depending on the insertion depth of the scope 1640. The variation of insertion of the scope 1640 can cause a differing length of the conductive metal scope body to be part of the circuit, changing the resistance measured by the sensor, which can be data inputs sent to a processor to determine scope insertion depth.

[0115] Figure 17 illustrates an embodiment of a surgical cannula system 1700 including a cannula 1720 and a medical instrument (e.g., scope 1740) that can include a pressure sensor 1743 within the lumen of the cannula 1720, the sensor 1743 configured to detect a change in pressure within the lumen of the cannula 1720. The pressure measured by the sensor 1743 can be compared with predetermined pressure response values for scope insertion of a certain size through the cannula, which can be data inputs sent to a processor to determine scope insertion depth. The cannula can be configured, e.g., by modifying the geometries in the gases delivery pathway, to achieve a desired pressure response curve behavior as the scope 1740 is inserted to a particular depth.

[0116] Figure 18 illustrates an embodiment of a surgical cannula system 1800 including a cannula 1820 and a medical instrument (e.g., scope 1840) that can include a force sensor 1843 on a portion of the scope 1840, such as an attachment structure 1842 as illustrated. A spring element 1841 can include a spring or material that can function as a spring (e.g., compressible foam, a sponge, or other material to compress on contact with the cannula 1820 and provide a force response 1841). The force measured by the sensor 1843 can be data inputs sent to a processor to determine scope insertion depth.

[0117] Figure 19 illustrates an embodiment of a surgical cannula system 1900 including a cannula 1920 and a medical instrument (e.g., scope 1940) that can include a stretch sensor 1943 operably connected to a tension element 1941 connecting a portion (e.g., scope attachment 1942) of the scope 1940 and a portion (e.g., proximal end of the cannula 1920) of the cannula 1920. The tension element 1941 could be a flexible tether in some embodiments. The stretch measured by the sensor 1943 can be data inputs sent to a processor to determine scope insertion depth.

[0118] Figure 20 illustrates an embodiment of a surgical cannula system 2000 including a cannula 2020 and a medical instrument (e.g., scope 2040). The distal end of the scope 2040 is shown extending distally from the distal end of the cannula 2020 (and even more distally in phantom 2040’) into the surgical cavity SC. The direct image feedback from an image sensor 2043, e.g., camera on the scope can determine depth of insertion utilizing hardware and/or software configured for image processing by the change between static images and the distance to anatomical landmarks (e.g., organs) of interest using software. In some embodiments, the hardware or software can also be configured to automatically calibrate depth measurements, and/or calibrate other sensors described elsewhere herein.

[0119] Some embodiments can also include multiple reference sensor systems with external sensing, including non-limiting examples described further below.

[0120] Figure 21 illustrates an embodiment of a surgical cannula system 2100 including a cannula 2120 and a medical instrument (e.g., scope 2140), and also including a 3D motion sensing system. One, two, or more motion sensors 2143 can be operably attached to either or both of the scope 2140 and/or cannula 2120 to determine relative positioning of the scope 2140 relative to the cannula 2120. Motion can be tracked from a zero point to determine relative positioning. Any of the motion sensors 2143 could include, for example, one or more of: a 3-axis accelerometer, 3-axis gyroscope, 3-axis earth magnetic field position, or other motion sensors. The sensors 2143 can be configured to send data to an external processor 2199 (or internal processing unit in other embodiments) through a wired or wireless (e.g., Bluetooth, Wi-Fi, Zigbee, LTE, or other protocol) connection. The processor 2199 can be configured to track the motion of the scope 2140 and/or cannula 2120 from the zero (calibration) point to determine the position of the scope relative to the cannula.

[0121] Figure 22 illustrates an embodiment of a surgical cannula system 2200 including a primary cannula 2220 and a medical instmment (e.g., scope 2240), and also including a secondary cannula 2280 configured to be spaced apart from the primary cannula 2220 and also insertable into a surgical cavity (not shown). Signal emitters 2241 can be operably attached to the scope 2240 and/or the primary cannula 2220 for relative positioning, and emit wireless (e.g., electromagnetic) signals to the secondary cannula 2280 that can include one, two, or more receiver sensors 2243 mounted or otherwise attached to the secondary cannula 2280 and can be data inputs sent to a processor to determine the distance between the receiver sensors 2243 and the scope 2240 and/or the primary cannula 2220 in order to determine the scope insertion depth.

[0122] Figure 23 illustrates an embodiment of a surgical cannula system 2300 including a cannula 2320 and a medical instrument (e.g., scope 2340), and also including an external electromagnetic field generator unit 2341 configured to be spaced apart from the cannula 2320 and scope 2340. The electromagnetic field generator unit 2341 can generate a relatively low energy electromagnetic field within a known topography to determine the location of the cannula 2320 and scope 2340. Receiving sensors 2343 can be operably attached to the scope 2340 and/or the cannula 2320 for relative positioning, and can be configured to measure field disturbance, field strength, and/or eddy currents induced by the field. Any number of the foregoing parameters can be data inputs sent to a processor to determine the distance between the receiver sensors 2343 and the scope 2340 and/or the cannula 2320 in order to determine the scope insertion depth, taking into account the known topography and specifications of the electromagnetic field generator unit 2341. [0123] Figure 24 illustrates an embodiment of a surgical cannula system 2400 including a cannula 2420 and a medical instrument (e.g., scope 2440), and also including an external electromagnetic energy generator unit 2441 configured to be spaced apart from the cannula 2420 and scope 2440. The electromagnetic energy generator unit 2441 can be configured to generate electromagnetic energy to determine the location/position of the cannula 2420 and scope 2440, and in some embodiments can take the form of specially designed surgical theater lights (present or fixed at known or measured positions) extending from a wall, ceiling, or elsewhere of the operating room suite for example, and configured to direct relatively low energy electromagnetic waves (e.g., light waves) in the direction of the cannula 2420 and scope 2440. Receiving sensors 2443 can be operably attached to the scope 2440 and/or the cannula 2420 for relative positioning, and can be configured to measure electromagnetic signal strength measured at the receiving sensors 2443. The receiving sensors 2443 could include coils in some embodiments. Any number of the foregoing parameters can be data inputs sent to a processor, taking into account the measured signal strength and known position of the lights to determine (e.g., via triangulation techniques) the distance between the receiver sensors 2443 and the scope 2440 and/or the cannula 2420 in order to determine the scope insertion depth, taking into account the known topography and specifications of the electromagnetic energy generator unit 2441.

[0124] Figure 25 illustrates an embodiment of a surgical cannula system 2500 including a cannula 2520 and a medical instrument (e.g., scope 2540), and also including an external electromagnetic signal emitter 2541 and receiver sensor 2543 configured to be spaced apart from the cannula 2520 and scope 2540. The electromagnetic signal emitter 2541 and receiver sensor 2543 can both be mounted at desired locations (integrated together as a single unit, or separately) in the operating theater, such as above the surgical working space, such as on an overhead wall W for example. The electromagnetic signal emitter 2541 can be configured to generate an electromagnetic energy signal configured to reflect off a reflective surface 2542 of the scope 2540 and/or a reflective surface 2521 of the cannula 2520. In some embodiments, the emitter 2541 could be mounted proximate surface 2542 or surface 2521, removing the need for an overhead emitter 2541 (e.g., only an overhead receiver sensor 2543 would be mounted above the cannula 2520 and scope 2540). The receiver sensor 2543 can be configured to measure the electromagnetic signal strength received from the emitter 2541. Any number of the foregoing parameters can be data inputs sent to a processor, taking into account the measured signal strength and known position of the emitter 2541 to determine (e.g., via triangulation techniques) the distance between the receiver sensors 2543 and the scope 2540 and/or the cannula 2520 in order to determine the scope insertion depth, taking into account the known topography and specifications of the emitter 2541.

[0125] Figure 26 illustrates an embodiment of a surgical cannula system 2600 including a cannula 2620 and a medical instrument (e.g., scope 2640), and also including an external imaging (e.g., vision) system 2641 configured to be spaced apart from the cannula 2620 and scope 2640. The vision system 2641 could include one, two, or more cameras (e.g., CCD, CMOS, etc.) or other optical system and be configured to determine the position of calibrated reference points attached to the cannula 2620 and/or scope 2640, via infrared, visible light spectrum, ultraviolet, or any other electromagnetic frequency. The cannula 2620 and/or the scope 2640 can include reference elements 2652, 2631 mounted on respective reference points 2642, 2621. The reference elements 2652, 2631 could be reflective balls or another geometric structure arranged in a calibrated arrangement for better detecting by the vision system 2641. In some embodiments, the scope reference elements 2652 could be either the same as, or different from the cannula reference elements 2631. Any number of the foregoing parameters can be data inputs sent to a processor to determine (e.g., via triangulation techniques) the distance between the reference elements 2652, 2631 and extrapolate the relative distance between scope 2640 and cannula 2620 elements, in order to determine the scope insertion depth.

[0126] Some embodiments can also include system calibration features, including non-limiting examples described further below. Calibration features may be particularly advantageous in some cases, particularly considering the variable nature of scope and cannula lengths. If both the scope and cannula length is controlled with bespoke designs, there can still be some form of calibration, but it can be better optimized and controlled:

• Automatic: software based using the distance sensor(s), or using the video feed from the scope camera system.

• Manual: manual calibration - setting the scope to the zero position inside the scope then zeroing the measurement system.

• Extra sensors: extra sensors just used for calibration purposes. • Removing the need for calibration: arranging the system in such a way that calibration is not needed (e.g., calibrated by manufacturing)

[0127] Figure 27 illustrates an embodiment of a surgical cannula system 2700 including a cannula 2720 and a medical instrument (e.g., scope 2740) that can include an emitter 2741 that can include one or more optical emitting elements, e.g., a laser or LEDs spaced apart from a photocell receiver sensor 2743, the emitter 2741 and sensor 2743 integrated within or otherwise attached to a portion of the cannula 2720 that can be as described and illustrated in connection with Figure 13 above. For embodiments such as the foregoing that incorporate sensors anywhere operably attached to the cannula (e.g., in a sidewall of the cannula), the depth between the sensor 2743 and the distal end 2728 of the cannula 2720 can be utilized to offset the system (set a zero point) and calibrate if necessary to determine the depth of the scope 2740 insertion within the cannula 2720. In some embodiments, the sensor(s) 2743 can be placed at or proximate the distal end 2728 of the cannula 2720 so no distance offset is required for calibration.

[0128] Figure 28 illustrates an embodiment of a surgical cannula system 2800 including a cannula 2820 with both the emitter 2851 and the receiver sensor 2853 are located on a portion, such as the attachment structure 2842 of the medical instrument (e.g., scope 2840) that can be as described and illustrated in connection with Figure 5 above, and additionally including a second sensor 2893 configured to sense within the lumen of the cannula 2820 configured to determine the position of the distal end 2846 of the scope 2840 to calibrate the emitter 2851 and the receiver sensor 2853. As such, the system can be advantageously utilized with scopes 2840 of various lengths. The second sensor 2893 can be, for example, an infrared or other electromagnetic wavelength band sensor configured to detect when the distal end 2846 of the scope 2840 passes the second sensor 2893.

[0129] Figure 29 illustrates an embodiment of a surgical cannula system 2900 including a cannula 2920 with both the emitter 2951 and the receiver sensor 2953 are located on a portion, such as the attachment structure 2942 of the medical instrument (e.g., scope 2940) that can be similar to that as described and illustrated in connection with Figure 28 above, except that the second sensor 2993 can be a pressure sensor configured to detect when the distal end 2946 of the scope 2940 passes the second sensor 2993. [0130] Figure 30 illustrates an embodiment of a surgical cannula system 3000 including a cannula 3020 with both the emitter 3051 and the receiver sensor 3053 are located on a portion, such as the attachment structure 3042 of the medical instrument (e.g., scope 3040) that can be similar to that as described and illustrated in connection with Figures 28 and 29 above, except that the second sensor 3093 can be a force sensor operably attached to a seal element extending radially inwardly into the lumen of the cannula 2920, and configured to detect when the distal end 3046 of the scope 3040 contacts the seal element and contacting the force sensor 3093.

[0131] Some embodiments can also include manual system calibration features utilizing a flat external surface, including non-limiting examples described further below. If a flat surface is used to align the distal end of the scope and the cannula, the system can be manually calibrated by the user to accurately determine the scope insertion depth.

[0132] Figure 31 illustrates an embodiment of a surgical cannula system 3100 including a cannula 3120 with both the emitter 3151 and the receiver sensor 3153 are located on a portion, such as the attachment structure 3142 of the medical instrument (e.g., scope 3140) that can be similar to that as described and illustrated in connection with Figure 13 above, and configured for manual calibration. A flat surface FS can be utilized to press the scope 3140 and the cannula 3120 against to ensure the distal end 3146 of the scope 3140 is horizontally aligned with the distal end 3128 of the cannula 3120. A control 3149 such as a button can be positioned on the scope 3140, such as on scope attachment 3142 such that actuation of the control 3149 (e.g., a press and hold of the button, or other maneuver) once the scope and cannula are in contact with the flat surface FS can calibrate/reset the emitter 3151, receiver sensor 3153, and/or associated processor.

[0133] Figure 32 illustrates an embodiment of a surgical cannula system 3200 including a cannula 3220 with both the emitter 3251 and the receiver sensor 3253 are located on a portion, such as the attachment structure 3242 of the medical instrument (e.g., scope 3240) that can be similar to that as described and illustrated in connection with Figure 31 above, and also including indicia 3295 such as visible markings on the sidewall of the cannula 3220 for the operator to use as reference point for manual calibration. The operator can activate the control 3249 as previously described when the operator detects the indicia 3295 upon passing the distal end 3246 of the scope 3228 at the level of the indicia 3295 (e.g., at or proximate the distal end 3228 of the cannula 3220) in some cases.

[0134] Figure 33 illustrates an embodiment of a surgical cannula system 3300 including a cannula 3320 with both the emitter 3351 and the receiver sensor 3353 are located on a portion, such as the attachment structure 3342 of the medical instrument (e.g., scope 3340) that can be similar to that as described and illustrated in connection with Figure 32 above, and also including external sensor 3393 such as metal detection sensor in an external manually- operated device to detect the scope location in the cannula 3320. The feedback from the sensor 3395 can be compared with a distance reading to calibrate the system.

[0135] Figure 34 illustrates an embodiment of a surgical cannula system 3400 including a cannula 3420 and a medical instrument (e.g., scope 3440) that can include a pressure sensor 3443 within the lumen of the cannula 3420, the sensor 3443 configured to detect a change in pressure within the lumen of the cannula 3420 that can be similar to that as described and illustrated in connection with Figure 17. The pressure measured by the sensor 3443 can be compared with predetermined pressure response values for scope insertion of a certain size through the cannula, which can be data inputs sent to a processor to determine scope insertion depth. The cannula can be configured, e.g., by modifying the geometries in the gases delivery pathway, to achieve a desired pressure response curve behavior as the scope 3440 is inserted to a particular depth. Once the known pressure of the scope 3440 at the distal end of the cannula 3420 is achieved and the system is reset/zeroed and calibrated to obtain the scope insertion depth from the cannula 3420.

[0136] In some embodiments, various methods of attachment can be used for the sensor, or the reference/receiver, including any of the following:

• Built-in: Moulded in place, over-moulded in place, or fastened in place (in housing or on PCB);

• Sleeve: a sleeve housing the sensor, or the reference/receiver; can be a sleeve that attaches outside cannula, inside cannula, or outside scope;

• Non-permanent attachment: attach using adhesive, glue, suction, magnets, etc.;

• Mechanical clip-on; attach using friction fit/elastic band, snap-lock/clip, spring release, captive screw tightening mechanism, etc.; • Adaptor between the laparoscopic camera & scope which houses the sensor or reference/receiver.

[0137] Figures 35A-35B illustrate various non-limiting configurations for embedded mounting options for sensors. The emitter 3541 and receiver 3543 could be built into the scope 3540 by the manufacturer, as illustrated in Figure 35A, or embedded in the cannula 3520, and fastened or overmoulded for example as illustrated in Figure 35B.

[0138] Figure 36 illustrates an alternative mounting configuration for the emitter 3641 and receiver 3643, either or both of which can be positioned, for example, on the top (proximal end) of the scope 3640 as an adapter attachment 3642 between the scope 3640 and where the scope camera adapter connects, rather than an attaching to the shaft of the scope 3640 as previously described. The adapter attachment 3642 could take the form of a ring in some cases as to not hinder use of the scope 3640.

[0139] Figures 37A-37H illustrate various non-limiting embodiments of how emitters and receivers can be fastened or otherwise secured to the scope, such as the shaft of the scope. Figure 37A illustrates a ring-like scope attachment 3742, close up views of which will be illustrated in Figures 37B-37F. Figure 37B illustrates an adhesive attachment that can be placed, for example, within the aperture of the ring-like scope attachment 3742. Figure 37C illustrates a magnetic attachment that can be placed, for example, within the aperture of the ring-like scope attachment 3742. Figure 37D illustrates a releasable clip attachment for the ring-like scope attachment 3742, which can be attached to the shaft of the scope. Figure 37E illustrates a screw attachment with a threaded surface for the ring-like scope attachment 3742 that can be rotated in an appropriate direction to releasably fasten the ring-like scope attachment 3742 to the shaft of the scope. Figure 37F illustrates a ring-like scope attachment with a push and release clamp feature for releasable attachment to the shaft of the scope. Figure 37G illustrates a ring-like scope attachment that can comprise elastic material in the form of a band that can circumferentially expand and contract. Figure 37H illustrates a ring-like scope attachment that can be sized and configured to have a friction fit with the shaft of the scope.

[0140] Figures 38A-38C illustrate various non-limiting embodiments of how emitters and receivers (or combined emitter/receiver units) can be fastened or otherwise secured to the cannula, such as the proximal end of the upper cannula housing portion of the scope, among other locations. Figure 38A illustrates a clip attachment. Figure 38B illustrates an adhesive attachment. Figure 38C illustrates a suction attachment.

[0141] In some embodiments, systems that include sensors as described for example elsewhere herein can take the form of a removable or attached sleeve which can be positioned relative to the cannula and/or medical instrument. The sleeve could include, for example, a tubular element with a sidewall configured to fit either outside or inside of a scope or cannula shaft.

[0142] Figure 39 A illustrates an embodiment of a sleeve 3901 positioned on the outside of the shaft of the cannula 3920, that can house induction or other sensors. Figure 39B illustrates an embodiment of a sleeve 3903 operably attached to the inside sidewall of the cannula 3920, that can house any number of a sensor, reference, and/or reflective surfaces. Figure 39C illustrates an embodiment of a sleeve 3905 operably attached to an outer sidewall of the scope 3940, which can house any number of a sensor, reference, and/or reflective surfaces.

[0143] As discussed above, signals or data from sensing systems and methods can be sent to a processing unit which is used to control some aspect of the laparoscopic system. The transmission method could be wired (e.g. a cord), or wireless (e.g. Bluetooth, Wi-Fi, LTE, etc.).

[0144] For the locations of emitters or receiving sensors, where it is illustrated on either the cannula or the scope, the location could be swapped in some embodiments. Furthermore, the location of any reflective surface, a receiver, or datum reference point needed for the sensing method can be switched in some embodiments as well from what is illustrated and described above. Also, mounting positions given are non-limiting examples. For example, where shown on top (proximal end) of the cannula, and at the top (proximal end) of the scope, there could be embodiments that have the same sensing method but with attachment below (or at the distal end) of the cannula and at the bottom (distal end) of the scope.

[0145] Where there are methods for sensing that require an electromagnetic signal, the frequency could by any physically feasible frequency band, in the visible spectrum or otherwise (above or below) including but not limited to radio waves, microwaves, infrared waves, visible light, ultraviolet radiation, and/or X-rays. Electromagnetic signals could also include magnetic energy, RF energy, microwave energy, and/or ultrasound energy, including high-frequency and low-frequency ultrasound energy.

[0146] Where there are methods for sensing that involve the transmission or reflection of a signal, the return strength of the signal can be used to determine the distance, or the“time of flight”; time taken for the reflection to return to the send-point.

[0147] Where attachment mechanisms have been described, these can be applied to either the sensor itself, or any other required attachments/items/features for attaching to either the scope or the cannula. Any of these attachment mechanisms also relate to all sensing methods, where combination is possible, and the same can be applied to the calibration methods described.

Terminology

[0148] Examples of medical gases delivery systems and associated components and methods have been described with reference to the figures. The figures show various systems and modules and connections between them. The various modules and systems can be combined in various configurations and connections between the various modules and systems can represent physical or logical links. The representations in the figures have been presented to clearly illustrate the principles and details regarding divisions of modules or systems have been provided for ease of description rather than attempting to delineate separate physical embodiments. The examples and figures are intended to illustrate and not to limit the scope of the inventions described herein. For example, the principles herein may be applied to a surgical humidifier as well as other types of humidification systems, including respiratory humidifiers.

[0149] As used herein, the term“processor” refers broadly to any suitable device, logical block, module, circuit, or combination of elements for executing instructions. For example, the controller 8 can include any conventional general purpose single- or multi-chip microprocessor such as a Pentium® processor, a MIPS® processor, a Power PC® processor, AMD® processor, ARM® processor, or an AFPHA® processor for example. In addition, the controller 122 can include any conventional special purpose microprocessor such as a digital signal processor or a microcontroller for example. The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein, or can be a pure software in the main processor. For example, logic module can be a software- implemented function block which does not utilize any additional and/or specialized hardware elements. Controller can be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a combination of a microcontroller and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0150] Data storage can refer to electronic circuitry that allows data to be stored and retrieved by a processor. Data storage can refer to external devices or systems, for example, disk drives or solid state drives. Data storage can also refer to fast semiconductor storage (chips), for example, Random Access Memory (RAM) or various forms of Read Only Memory (ROM), which are directly connected to the communication bus or the controller. Other types of data storage include bubble memory and core memory. Data storage can be physical hardware configured to store data in a non-transitory medium.

[0151] Although certain embodiments and examples are disclosed herein, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses, and to modifications and equivalents thereof. Thus, the scope of the claims or embodiments appended hereto is not limited by any of the particular embodiments described herein. For example, in any method or process disclosed herein, the acts or operations of the method or process can be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations can be described as multiple discrete operations in turn, in a manner that can be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures described herein can be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments can be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as can also be taught or suggested herein.

[0152] Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments. As used herein, the terms“comprises,”“comprising,”“includes,”“including,”“has,”“having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, the term“or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term“or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y and at least one of Z each to be present. As used herein, the words“about” or“approximately” can mean a value is within ±10%, within ±5%, or within ±1% of the stated value.

[0153] Methods and processes described herein may be embodied in, and partially or fully automated via, software code modules executed by one or more general and/or special purpose computers. The word“module” refers to logic embodied in hardware and/or firmware, or to a collection of software instructions, possibly having entry and exit points, written in a programming language, such as, for example, C or C++. A software module may be compiled and linked into an executable program, installed in a dynamically linked library, or may be written in an interpreted programming language such as, for example, BASIC, Perl, or Python. It will be appreciated that software modules may be callable from other modules or from themselves, and/or may be invoked in response to detected events or interrupts. Software instructions may be embedded in firmware, such as an erasable programmable read-only memory (EPROM). It will be further appreciated that hardware modules may comprise connected logic units, such as gates and flip-flops, and/or may comprised programmable units, such as programmable gate arrays, application specific integrated circuits, and/or processors. The modules described herein can be implemented as software modules, but also may be represented in hardware and/or firmware. Moreover, although in some embodiments a module may be separately compiled, in other embodiments a module may represent a subset of instructions of a separately compiled program, and may not have an interface available to other logical program units.

[0154] In certain embodiments, code modules may be implemented and/or stored in any type of computer-readable medium or other computer storage device. In some systems, data (and/or metadata) input to the system, data generated by the system, and/or data used by the system can be stored in any type of computer data repository, such as a relational database and/or flat file system. Any of the systems, methods, and processes described herein may include an interface configured to permit interaction with users, operators, other systems, components, programs, and so forth.

[0155] It should be emphasized that many variations and modifications may be made to the embodiments 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

WHAT IS CLAIMED IS:

1. A surgical apparatus, comprising:

a cannula including a body, a cannula inlet, a cannula outlet, a passage defined within the body and extending between the inlet and the outlet;

a medical instrument comprising an elongate shaft and removably insertable into the passage defined in the body; and

a sensor arrangement comprising one or more sensors, the one or more sensors being disposed on at least one of the cannula and the medical instrument,

wherein the sensor arrangement is configured to determine a relative position of an instrument datum feature relative to a cannula datum feature,

wherein the relative position corresponds to an instrument insertion distance beyond the cannula outlet.

2. The surgical apparatus of Claim 1, wherein the relative position is a distance between the instrument datum feature and the cannula datum feature.

3. The surgical apparatus of Claim 1-2, wherein the medical instrument is a surgical scope or a laparoscope configured to allow visualization of a surgical cavity and contents of the surgical cavity.

4. The surgical apparatus of Claim 1-3, wherein the sensor arrangement includes a single sensor located on the cannula.

5. The surgical apparatus of Claim 1-4, wherein the sensor arrangement includes a single sensor located on the datum feature of the cannula.

6. The surgical apparatus of Claim 1-5, wherein the cannula comprises a flange, the inlet being defined in the flange and at least one of the sensors positioned on the flange, the at least one of the sensors configured to determine a distance between the flange and a medical instrument.

7. The surgical apparatus of Claim 1-6, wherein a single sensor is located on a portion of the medical instrument and configured to determine the relative position of the instrument datum feature relative to the cannula datum feature.

8. The surgical apparatus of Claim 1-6, wherein a single sensor is located on the scope datum feature.

9. The surgical apparatus of Claims 1-8, wherein the sensor arrangement further comprises an emitter and a receiver, the emitter emitting a signal that is received by the receiver, the sensor arrangement configured to determine the distance between the instrument datum feature and the cannula datum feature based on the time taken for the receiver to receive the signal, and/or based on the strength/magnitude of the signal received by the receiver.

10. The surgical apparatus of Claim 9, wherein the emitter is disposed on the scope datum feature and the receiver is disposed on the cannula datum feature.

11. The surgical apparatus of Claim 9, wherein the emitter is disposed on the cannula datum feature and the receiver is disposed on the scope datum feature.

12. The surgical apparatus of Claim 9-11, wherein the emitter is configured to emit an acoustic, optical, or electromagnetic signal, and the receiver is configured to receive the acoustic, optical, or electromagnetic signal.

13. The surgical apparatus of any of the preceding claims, wherein the sensing arrangement comprises an inductive sensor located either on the instrument or the cannula, wherein the inductive sensor is configured to determine a relative position based on induction response due to interaction with a metallic feature on the instrument or the cannula, wherein the metallic feature is the datum feature of the cannula or the instrument.

14. The surgical apparatus of any of the preceding claims, wherein the instrument comprises a reflective surface, wherein the sensing arrangement comprises an emitter and a receiver wherein the emitter and the receiver are located on the cannula, the emitter configured to emit a signal and the receiver configured to detect a reflected signal, the insertion distance beyond the cannula outlet being determined based on a reflected emittance.

15. The surgical apparatus of Claim 14, wherein the reflected emittance is a magnitude or time of flight of the signal, wherein the magnitude or time of flight corresponds to the insertion distance of the instrument beyond the cannula outlet.

16. The surgical apparatus of Claim 9-15, wherein the emitted signal is emitted in a pattern to define a plane extending generally vertically outward from the cannula outlet.

17. The surgical apparatus of Claim 9-16, wherein the emitter generates a field selected from the group consisting of: a magnetic field, an electromagnetic field, and an electrostatic field, and the receiver includes a coil configured to measure field strength when located within the field generated by the emitter, the field strength corresponding to a relative position of the emitter and receiver, the relative position corresponding to an insertion depth of the instrument beyond the cannula outlet.

18. The surgical apparatus of Claim 9-17, wherein the emitter is configured to generate a field comprising a magnetic field or an electric field, wherein the receiver generates energy or a voltage in response to being located in the field generated by the emitter, a magnitude of the energy or voltage corresponding to the relative position of the emitter and receiver, the relative position corresponding to an insertion depth of the instrument beyond the cannula outlet.

19. The surgical apparatus of any of the preceding claims, wherein the sensor arrangement comprises a Hall effect sensor.

20. The surgical apparatus of any of the preceding claims, wherein the sensor arrangement comprises an ultrasound, laser, or infrared active or passive transmitter and receiver.

21. The surgical apparatus of any of the preceding claims, wherein the cannula comprises an elongate shaft, the elongate shaft including the passage and the inlet and outlet defined in the shaft, the shaft including a coil within the shaft, the coils generating a magnetic field or electrical field, and wherein the scope depth is determined based on the inductance of the coil.

22. The surgical apparatus of any of the preceding claims, wherein the sensing arrangement comprises a tracking arrangement, the tracking arrangement configured to track movement of the instrument within the passage and thereby determine the insertion depth of the instrument beyond the cannula outlet.

23. The surgical apparatus of Claim 22, wherein the tracking arrangement comprises a position tracking arrangement.

24. The surgical apparatus of Claim 22-23, wherein the tracking arrangement comprises one or more of: an encoder wheel, an LED emitter and receiver, and a laser emitter and receiver.

25. The surgical apparatus of Claim 22-24, wherein the tracking arrangement is located within the passage of the cannula.

26. The surgical apparatus of Claim 22-25, wherein the tracking arrangement comprises a linear sensor disposed on the instrument, the tracking arrangement configured to detect a linear position of the linear sensor in order to determine the insertion depth of the instrument beyond the cannula outlet.

27. The surgical apparatus of any of the preceding claims, wherein the sensing arrangement comprises a pressure sensor, the pressure sensor configured to determine an insertion distance based on a pressure difference detected by the pressure sensor as the instrument is moved within the passage.

28. The surgical apparatus of any of the preceding claims, wherein the sensing arrangement comprises a spring, a force sensor, and one or more springs, the force sensor configured to detect the force on the springs, the force on the springs corresponding to the insertion depth of the instrument beyond the cannula outlet.

29. The surgical apparatus of any of the preceding claims, wherein the sensing arrangement comprises a processor configured to process the sensor arrangement.

30. The surgical apparatus of any of the preceding claims, wherein the sensing arrangement comprises one or more motion sensors and a remote processor, the remote processor configured to track the position of the instrument from a zero position, the position being determined from the motion sensor measurements.

31. The surgical apparatus of Claim 30, wherein the motion sensors comprise at least one of an accelerometer and a gyroscope.

32. The surgical apparatus of Claim 30-31, wherein the motion sensors comprise signal generators.

33. An apparatus for determining the position of an instrument within a surgical cannula, the apparatus comprising:

a sensing arrangement comprising at least a pair of sensors, the sensors in the sensor arrangement positioned on the cannula or instrument; and

a processor arranged in electronic communication with the pair of sensors, the processor configured to determine a position of the instrument relative to the cannula based on the sensor outputs, wherein the processor is configured to determine an insertion depth of the instrument beyond the cannula outlet and/or determine a position of an end of the instrument relative to the cannula outlet.

34. The apparatus of Claim 33, wherein the processor comprises an electronic processor.

35. The apparatus of Claim 33-34, wherein the pair of sensors comprises motion sensors.

36. The apparatus of Claim 33-35, wherein the pair of sensors comprise wireless signals that provide a position signal.

37. The apparatus of Claim 33-36, wherein the sensing arrangement comprises a field emitter, the processor configured to receive at least one parameter related to a field disturbance, field strength or eddy currents induced in the sensors due to the presence of the field, the processor configured to determine an insertion distance based on the change in the parameter.

38. The apparatus of Claim 37, wherein the field emitter comprises one or more surgical lights or other light sources.

39. The apparatus of Claim 37, wherein the emitter is configured to emit an electromagnetic field.

40. The apparatus of Claim 39, wherein the emitter is configured to emit an electrostatic field.

41. The apparatus of Claim 39, wherein the emitter is configured to emit a magnetic field.

42. The apparatus of Claim 33-41, wherein the sensing arrangement comprises a camera and the sensors are reference points, the camera configured to determine position of the reference points, the processor configured to determine an insertion depth of the instrument beyond the cannula outlet.

43. A sensing arrangement for a surgical apparatus, comprising:

one or more sensors being disposed on an attachment structure configured to attach to at least one of the cannula and the medical instrument,

the cannula including a body, a cannula inlet, a cannula outlet, a passage defined within the body and extending between the inlet and the outlet;

the medical instrument comprising an elongate shaft and removably insertable into the passage defined in the body;

wherein the sensor arrangement is configured to determine a relative position of an instrument datum feature relative to a cannula datum feature, wherein the relative position corresponds to an instrument insertion distance beyond the cannula outlet.

44. The sensing arrangement of Claim 43, further comprising a processor arranged in electronic communication with the sensing arrangement, the processor configured to determine a position of the instrument relative to the cannula based on sensor outputs, wherein the processor is configured to determine an insertion depth of the instrument beyond the cannula outlet and/or determine a position of an end of the instrument relative to the cannula outlet.

45. The sensing arrangement of Claim 43-44, wherein the attachment structure comprises a ring configured to attach to a proximal end of the instrument.

46. The sensing arrangement of Claim 43-44, wherein the attachment structure comprises a ring configured to attach to the shaft of the instrument.

47. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises an adhesive.

48. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a magnet.

49. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a clip.

50. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a screw.

51. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a push and release clamp.

52. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a circumferentially expandable and contractable elastic band.

53. The sensing arrangement of Claim 43-46, wherein the attachment structure is configured to friction fit with a portion of the cannula or the instrument.

54. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a suction element.

55. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a sleeve configured to fit over the outside of the cannula body.

56. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a sleeve configured to fit within the passage of the cannula body.

57. The sensing arrangement of Claim 43-46, wherein the attachment structure comprises a sleeve configured to fit over the outside of the shaft of the scope.