GB2637480A

GB2637480A - Implant deployment device

Info

Publication number: GB2637480A
Application number: GB2400427.7A
Authority: GB
Inventors: Boyhan Noel; Duffy Paul; Moroney Deirdre; Heraty Kevin; Mcmahon Tony
Original assignee: Otsuka Medical Devices Co Ltd
Current assignee: Otsuka Medical Devices Co Ltd
Priority date: 2024-01-11
Filing date: 2024-01-11
Publication date: 2025-07-30
Also published as: WO2025149967A1; GB202400427D0

Abstract

An implant deployment device 10 comprising a delivery tube 12 and a handle 14 at a proximal end of the delivery tube. The handle comprises a control element such as a thumbwheel 20 that is movable relative to a housing 16 of the handle, to move a deployment component of the delivery tube. The handle also comprises a detent element 42 that acts separately on the control element and on the deployment component. The detent element is movable relative to the housing from an initial locked position, in which movements of the control element and the deployment component are blocked, to an unlocked position enabled for use, in which deploying movements of the control element and the deployment component are permitted. The device may comprise a unidirectional latch mechanism in which may comprise latch formations on the detent element that are resiliently deflectable around lugs fixed relative to the housing. A corresponding method is also provided.

Description

Implant deployment device This invention relates to an implant deployment device that can be used as a delivery system to deploy an implant, such as a stent, at a target site within the vasculature or elsewhere within a patient's body.

Implant deployment devices typically comprise an elongate flexible delivery tube that extends distally from a proximal handle. The delivery tube may, for example, be a catheter that can be navigated through a patient's vasculature to convey the implant to the target site.

The delivery tube comprises concentric components such as rods, tubes or sheaths that retain the implant before its deployment and that can then be moved relative to each other to deploy the implant. Commonly, the implant is released from the delivery tube by withdrawing an outer sheath in a proximal direction to unsheathe the implant For this purpose, the handle supports any of various control elements such as a lever, a button or a thumbwheel that acts on the components of the delivery tube, allowing a clinician to move those components as required to position and to deploy the implant.

It is, of course, essential that a deployment device enables accurate and reliable placement of an implant. For that purpose, the handle must be comfortable for a clinician to hold and manipulate with either hand and the control elements must be easy to operate and intuitive to use. It is therefore desirable to locate key control elements such as a thumbwheel on a central longitudinal plane about which the handle is substantially symmetrical.

Before deployment, the implant must be protected and held securely in the delivery tube.

Deployment of the implant must occur only as a deliberate action controlled by a clinician and must not occur accidentally, prematurely or partially, either before or during a procedure. For example, unintended movement of, or deliberate tampering with, a control element such as a thumbwheel could occur during packaging, shipping, storage and unpacking of the device. This could lead to unintended deployment of the implant, at least partially, even before a procedure begins.

When a stenting procedure begins, a catheter for delivering the stent is typically introduced into the anatomy via an introducer sheath. The force required to track the catheter through the introducer sheath could cause an outer sheath of the catheter to move proximally relative to the handle and other parts of the catheter, hence potentially causing unintended deployment of the stent during navigation to the target site. Inadvertent operation of a control element on the handle could also cause unintended deployment of an implant For all of these reasons, it desirable for a deployment device to have a lock or detent to prevent unintended deployment of an implant The lock or detent must be released or overcome to initiate deployment A positive locking function is preferred as this can require a deliberate release action, distinct from a deployment action, to release the lock. However, the release action tends to complicate use of the device. Moreover, there is a still a risk that a clinician could unlock the device, begin the implant deployment process, relock the device, and continue deployment later. Bad practice such as this could result in poor implant delivery, compression or elongation of the implant, and damage to the implant or the surrounding vasculature.

Another issue is that locking a control element such as a thumbwheel does not necessarily prevent inadvertent movement of components of the delivery tube. For example, a pull wire within the handle that couples a thumbwheel to the delivery tube can only act in tension and so cannot prevent proximal movement of components of the delivery tube, even if the thumbwheel itself is locked. Moreover, the device may not give a clinician any visual or tactile warning that it is not suitable for use.

It is against this background that the present invention has been devised. From one aspect, the invention resides in an implant deployment device that comprises a delivery tube and a handle at a proximal end of the delivery tube. The handle comprises a control element that is movable relative to a housing of the handle to move a deployment component of the delivery tube to an extent sufficient to deploy an implant from the delivery tube. The handle further comprises a detent element that acts separately on the control element and on the deployment component The detent element is movable relative to the housing from a locked position, in which movement of the control element and the deployment component is blocked, to an unlocked position in which movement of the control element and the deployment component is permitted. Conveniently, the control element and the detent element can be located so as to be operable respectively with a thumb of a hand holding the handle.

The device can comprise a locking member that is engaged with the control element when the detent element is in the locked position and that is disengaged from the control element by movement of the detent element into the unlocked position. For example, the locking member and the detent element may have opposed sliding surfaces that interact with a cam action during movement of the detent element to disengage the locking member from the control element The locking member can be biased into engagement with the control element and disengaged from the control element against that bias. For example, the locking member may comprise a locking arm that supports a locking pawl, such that the locking pawl is biased into engagement with the control element by resilience of the locking arm. The locking pawl may be supported by a ratchet hub that restricts the control element to unidirectional movement The device may further comprise a unidirectional latch mechanism that is arranged to block movement of the detent element back from the unlocked position to the locked position. Such a latch mechanism can comprise latch formations on the detent element that are resiliently deflectable around lugs fixed relative to the housing, and that may be unable to deflect back around the lugs after the detent element reaches the unlocked position.

The detent element may have a proximal portion exposed outside the housing in a position adjacent to the control element and a distal portion within the housing acting on the deployment component. The exposed proximal portion of the detent element can comprise a grip protrusion that is disposed distally of the control element and that is substantially aligned with the control element in a central longitudinal plane of the housing. Conveniently, the detent element can be moved proximally relative to the housing into the unlocked position and the control element can then be moved proximally relative to the housing to deploy the implant The detent element may comprise a distal pawl that, when the detent element is in the locked position, is engaged with an adaptor that is disposed within the housing and is fixed to the deployment component. The distal pawl maybe engaged with the adaptor against resilient bias of the detent element, to move clear of the deployment component under that bias when disengaged from the adaptor. When the detent element is in the locked position, the distal pawl may be engaged between the adaptor and an opposed stop formation of the housing. A guide formation, which could be defined by the stop formation, can define a guide path to be followed by the distal pawl. Initially, the guide path can be transverse to a direction of movement of other parts of the detent element into the unlocked position. For this purpose, the detent element may comprise a flexure that allows the distal pawl to move relative to the other parts of the detent element when following the guide path.

On being moved into the unlocked position, the detent element could instead disengage from a locking member that previously blocked movement of the deployment component, thereby to release the locking member to move aside and to release the deployment component for movement. Alternatively, on being moved into the unlocked position, the detent element could pivot a locking member that previously blocked movement of the deployment component to release the deployment component for movement The control element is apt to be a thumbwheel that can be turned to tension a pull element connected to the deployment component, hence retracting the deployment component proximally to deploy the implant The pull element may, for example, be wound onto a spool that is coaxial with the thumbwheel about a common axis of rotation and that is offset along that axis from the thumbwheel. The pull element may follow a path that comprises a first leg extending proximally from the deployment component to a pulley disposed proximally within the handle with respect to the spool, and a second leg extending distally from the pulley to the spool. In that case, the pulley can be oriented with respect to the handle such that an entry of the first leg of the pull element onto the pulley lies substantially in a common plane with the thumbwheel and an exit of the second leg of the pull element from the pulley lies on the same side of that plane as the spool.

The inventive concept embraces a corresponding method of enabling an implant deployment device to deploy an implant from a delivery tube of the device. The method comprises moving a detent element on a handle of the device from a locked position into an unlocked position. The detent element thereby releases a control element of the handle and a deployment component of the delivery tube from respective locked states for respective deployment movements relative to a housing of the handle. Subsequently, the control element can be moved to effect deployment of the implant by moving the deployment component of the delivery tube. That movement of the control element can be restricted to unidirectional movement.

The control element can be moved in a direction of movement corresponding to a direction of movement of the detent element into the unlocked position. For example, the detent element can be moved by applying proximal force to the detent element at a location distal to the control element, and then the control element can be moved by applying proximal force to the control element Movement of the detent element back to the locked position from the unlocked position can be prevented.

The deployment component of the delivery tube can be released by disengaging a distal pawl of the detent element from an adaptor that is disposed within the housing and is fixed to the deployment component The distal pawl can be guided on a path that is transverse to a direction of movement of other parts of the detent element into the unlocked position.

In summary, an implant deployment device of the invention comprises an elongate delivery tube and a handle at a proximal end of the delivery tube. The handle comprises a housing and a control element such as a thumbwheel that is movable relative to the housing. That movement, in turn, moves a deployment component of the delivery tube, such as an outer sheath, to an extent sufficient to deploy an implant from the delivery tube. The handle also comprises a detent element that acts separately and simultaneously on the control element and on the deployment component The detent element is movable relative to the housing from an initial locked position, in which movements of the control element and the deployment component are blocked, to an unlocked position enabled for use, in which deploying movements of the control element and hence of the deployment component are permitted.

In order that the invention may be more readily understood, reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a side view of an implant deployment device of the invention; Figure 2 corresponds to Figure 1 but is cut away longitudinally to show internal Features of the device; Figure 3 is a perspective view of the device from its distal end; Figure 4 is an exploded perspective view of the device from its proximal end; Figure 5 is a perspective view of a ratchet hub of the device; Figure 6 is a perspective view of a thumbwheel of the device; Figure 7 is a side view in longitudinal section of the ratchet hub of Figure 5 assembled with the thumbwheel of Figure 6; Figure 8 is an enlarged perspective view of a detent element of the device; Figures 9a and 9b are plan views cut away on lines A-A and B-B showing how the detent element of Figure 8 interacts with the ratchet hub of Figure 5 to unlock the thumbwheel; Figure 10 is a cut-away perspective view of the device with the thumbwheel unlocked as shown in Figure llb and a distal pawl of the detent element unlocking a delivery tube of the device; Figures 11a and 11b are cut-away side views showing the distal pawl of the detent element locking and unlocking the delivery tube; Figure 12 is an enlarged cut-away perspective view of a distal portion of the device, showing the distal pawl of the detent element locking the delivery tube; Figures 13a and 13b are enlarged cut-away plan views showing operation of a latch arrangement that blocks reverse motion of the detent element; and Figures 14a to 20b are schematic side views showing operation of alternative mechanisms for locking the delivery tube of the device.

Referring firstly to Figures 1 to 4 of the drawings, an implant deployment device 10 comprises an elongate flexible delivery tube 12 extending distally from a handle 14. The components of the handle 14 are primarily made of injection-moulded plastics.

The handle 14 has a hollow elongate case or housing 16 that is divided into two parts along a central longitudinal plane 18 that contains the proximal end of the delivery tube 12. The housing 16 is sized and shaped to fit comfortably into the grip of a clinician's hand and is substantially symmetrical about the central longitudinal plane 18 For ambidextrous use.

A distally-tapering distal portion of the housing 16 supports a deployment control element in the form of a thumbwheel 20. The thumbwheel 20 protrudes through a slot 22 in an upper side of the housing 16 and is oriented in the central longitudinal plane 18. As will be explained, rotational movement of the thumbwheel 20 about an axis orthogonal to the central longitudinal plane 18 acts on the delivery tube 12 to deploy an implant such as a stent.

In this example, the delivery tube 12 comprises an inner sheath 24 disposed within an outer sheath 26 in concentric relation. An implant (not shown) can be accommodated in a distal end portion of the delivery tube 12, in an annular space defined by a radial gap between the inner and outer sheaths 24, 26. Proximal movement of the outer sheath 26 relative to the inner sheath 24 exposes and releases the implant for deployment For this purpose, the inner sheath 24 is fixed relative to the housing 16 whereas the outer sheath 26 is retractable proximally into the housing 16. The outer sheath 26 can therefore be regarded as a movable deployment component of the delivery tube 12.

As best appreciated in Figure 2, a proximal end of the inner sheath 24 is in fluid communication with a rigid tubular shaft 28 that extends longitudinally through the housing 16. The shaft 28 could instead be a proximal portion of the inner sheath 24. The shaft 28 terminates proximally in a Luer connector 30 that protrudes from the proximal end of the housing 16. Irrigation fluid can thereby be introduced into the inner sheath 24. Conversely, the outer sheath 26 terminates proximally in a hub or adaptor 32 that can slide proximally with the outer sheath 26 along the shaft 28. The adaptor 32 can slide along most of the length of the shaft 28 to allow a correspondingly large proximal movement, or stroke, of the distal end of the outer sheath 26. This enables the device 10 to deliver and unsheathe an implant of considerable length.

The thumbwheel 20 acts on the outer sheath adaptor 32 by applying tension to a pull wire 34.

The pull wire 34 is attached at one end to a proximal side of the outer sheath adaptor 32 and is wound at the other end around a spool 36 that is fixed to, and coaxial with, the thumbwheel 20. Proximal movement of the protruding part of the thumbwheel 20 winds the pull wire 34 onto the spool 36.

An idler pulley 38 located near the proximal end of the housing 16 guides the pull wire 34 along a path within the housing 16 that extends between the spool 36 and the outer sheath adaptor 32. In following that path, the pull wire 34 extends proximally along a first leg from the outer sheath adaptor 32 to the idler pulley 38, bends around the proximal side of the idler pulley 38 with guidance from a circumferential groove in the outer edge of the idler pulley 38, and then reverses in direction to extend distally along a second leg from the idler pulley 38 to the spool 36.

The first leg of the pull wire 34 lies on a longitudinal axis that is substantially aligned with the central longitudinal plane 18 and substantially parallel to the axis of movement of the outer sheath adaptor 32 and the outer sheath 26 along the shaft 28. Conversely, as the spool 36 is offset from the thumbwheel 20 along its axis of rotation, and as the thumbwheel 20 lies on the central longitudinal plane 18 for ambidextrous symmetry of the handle 14, the spool end of the second leg is similarly offset from the central longitudinal plane 18.

To accommodate the different orientations of the first and second legs of the pull wire 34, the idler pulley 38 is inclined relative to the central longitudinal plane 18. In other words, the idler pulley 38 turns about an axis that is transverse to and intersects, but is not orthogonal to, the central longitudinal plane 18. The inclination of the idler pulley 38 is such that the first leg of the pull wire 34 enters the idler pulley 38 substantially on the central longitudinal plane 18 whereas the second leg of the pull wire 34 exits the idler pulley 38 out of the central longitudinal plane 18, on the same side of that plane 18 as the spool 36. In this way, elegantly, the idler pulley 38 initiates divergence of the second leg of the pull wire 34 from the central longitudinal plane 18 as the pull wire 34 approaches the spool 36.

Referring now also to Figures 5 to 8 of the drawings, the device 10 further comprises a ratchet hub 40 shown in Figure 5 that is fixed to the housing 16 and an unlocking slider or detent element 42 shown in Figure 8 that is movable relative to the housing 16. Advantageously, the ratchet hub 40 and the detent element 42 each perform two different functions, as will now be explained.

When assembled as shown in Figure 7, the ratchet hub 40 shown in Figure 5 cooperates with the thumbwheel 20 shown in Figure 6 to restrict the thumbwheel 20 to unidirectional rotation, whereby the spool 36 attached to the thumbwheel 20 can only tension the pull wire 34 to retract the outer sheath 26 proximally into the handle 14. The direction of rotation is such that, intuitively, the exposed part of the thumbwheel 20 must be moved proximally to effect corresponding proximal movement of the outer sheath 26. Rotation of the thumbwheel 20 in the opposite direction is prohibited by the ratchet hub 40 because such movement could otherwise cause the pull wire 34 to become entangled within the handle 14, possibly preventing deployment of an implant and so causing an implanting procedure to be abandoned.

The thumbwheel 20 has an externally-knurled circumferential flange 44 that surrounds a shallow recess 46 provided in one side of the thumbwheel 20 as shown in Figure 6. The recess 46 accommodates the ratchet hub 40 and has features that interact with the ratchet hub 40 to control movement of the thumbwheel 20. The opposite side of the thumbwheel 20 is generally flat and plain.

More specifically, the recess 46 in the thumbwheel 20 has a stepped profile in radial section. That profile comprises outer and inner circumferential shoulders 48, 50, each facing radially inwardly toward the axis of rotation of the thumbwheel 20, and an integral central web 52 within the inner shoulder 50 that defines the base of the recess 46. The circular outer shoulder 48 defines the radially outer boundary of the recess 46. The central web 52 includes an integral spigot 54 that is centred on the axis of rotation.

The inner shoulder 50 has a saw-toothed profile defining a unidirectional rack whose ratchet teeth 56 face radially inwardly toward the axis of rotation. Each ratchet tooth 56 has a radially-oriented lock face 58 and a ramp face 60 that is oriented at an obtuse angle to a radius of the thumbwheel 20. Conversely, the central web 52 is formed with a circumferential array of notches 62 that face axially, parallel to the axis of rotation. The notches 62 are equiangularly spaced around the axis of rotation. In this example, the notches 62 are obtusely angled relative to respective radii of the central web 52, hence allowing the notches 62 to overlap angularly with their neighbours in the array.

The ratchet hub 40 comprises a generally circular disc-like base plate 64 that fits snugly within the outer shoulder 48 of the thumbwheel 20 and has a central aperture to accommodate the spigot 54 of the thumbwheel 20. Integrally-moulded resilient ratchet pawls 66 are angularly spaced about the central aperture on one face of the base plate 64, facing into the recess of the thumbwheel 20. The ratchet pawls 66 face in the same circumferential direction, opposed to the lock faces 58 of the ratchet teeth 56, and are biased radially outwardly by their resilience.

As will be apparent from Figure 7, the tips of the ratchet pawls 66 can deflect radially inwardly to surmount the ramp faces 60 of the ratchet teeth 56 as the thumbwheel 20 turns in the permitted direction shown. Conversely, the tips of the ratchet pawls 66 engage with and jam against the lock faces 58 of the ratchet teeth 56 if an attempt is made to turn the thumbwheel 20 in the opposite, prohibited direction.

Figure 7 also shows that the tips of the ratchet pawls 66 are staggered, in other words spaced apart by a circumferential distance that is a non-integer multiple of the pitch of the ratchet teeth 56. Thus, when the tip of one ratchet pawl 66 is engaged with a lock face 58 of a ratchet tooth 56, the tip of the other ratchet pawl 66 is mid-way along the ramp face 60 of another ratchet tooth 56. As a result, a clinician feels and hears more frequent and finer clicks when turning the thumbwheel 20 and experiences greater precision of operation.

In addition to its ratchet function, the ratchet hub 40 also has a locking function to lock the thumbwheel 20 selectively against rotation. For this purpose, the ratchet hub 40 further comprises an integrally-moulded locking member comprising a locking arm 68 that is cantilevered from the base plate 64 on the same face as the ratchet pawls 66, hence also facing into the recess of the thumbwheel 20.

The locking arm 68 is resiliently biased out of the plane 18 of the base plate 64, hence bending about an axis that is generally parallel to that plane 18. Under that bias, an integral locking pawl 70 at the free end of the locking arm 68 engages with one of the notches 62 in the central web 52 of the thumbwheel 20. That engagement locks the thumbwheel 20 against any rotation.

The locking arm 68 further comprises an integral cam formation 72 near its free end. A slot 74 that penetrates the base plate 64 accommodates the cam formation 72, which thereby protrudes from the face of the base plate 64 opposed to the ratchet pawls 66 and the locking arm 68. The cam formation 72 diverges from the base plate 64 in the distal direction.

As will be explained, the thumbwheel 20 is unlocked by proximal movement of the detent element 42 relative to the housing 16, The detent element 42 will therefore be described now with reference to Figure 8.

The detent element 42 is an elongate integrally-moulded component that comprises, in distal succession from the proximal end: a proximal yoke 76; a latch formation comprising a pair of resilient wings 78; and a distal pawl 80.

The yoke 76 of the detent element 42 comprises a loop 82 of an elongated, longitudinally-extending stadium shape. The loop 82 fits into a complementary groove 84 formed longitudinally in the housing 16, as can be seen in Figures 2 and 3. The groove 84 is longer than the loop 82 to allow the detent element 42 to move proximally relative to the housing 16 into a finishing, unlocked position shown in Figure 3 from a starting, locked position in which the loop 82 is at the distal end of the groove 84, as shown in Figure 2. The groove 84 also surrounds the aforementioned slot 22 through which the thumbwheel 20 protrudes from the housing 16. Thus, the protruding part of the thumbwheel 20 also protrudes through the loop 82.

A skirt 86 on the underside of the yoke 76 extends into the slot 22 in the housing 16. Retaining flanges 88 projecting outwardly from the skirt 86 engage the wall of the housing 16 around the slot 22 while allowing the yoke 76 to slide longitudinally within the surrounding groove 84.

The skirt 86 of the yoke 76 is interrupted by a cut-out 90. On the distal side of the cut-out 90, the skirt 86 tapers proximally to define an outwardly-facing ramp surface 92 that is inclined inwardly from the outer side of the skirt 86 toward the inner side of the skirt 86. On its side opposed to the cut-out 90, the skirt 86 of the yoke 76 also has a curved elongate recess 94 that accommodates the spool 36 attached to the thumbwheel 20.

Referring now also to Figures 9a, 9b and 10, Figure 9a shows the loop 82 of the yoke 76 in its distal starting position whereas Figures 9b and 10 show the loop 82 in its proximal finishing position. It will be apparent that the cut-out 90 in the skirt 86 accommodates the cam formation 72 that protrudes from the base plate 64 of the ratchet hub 40, and that the cam formation 72 thereby lies in the path of the ramp surface 92 of the skirt 86 as the yoke 76 moves proximally.

In the distal starting position of the yoke 76 shown in Figure 9a, the ramp surface 92 of the skirt 86 lies distally with respect to the cam formation 72 of the ratchet hub 40 and is not yet engaged with the cam formation 72. Conversely, in the proximal finishing position of the yoke 76 shown in Figures 9b and 10, the ramp surface 92 has moved proximally into engagement with the cam formation 72. This engagement between the opposed sliding surfaces of the ramp surface 92 and the cam formation 72 deflects the locking arm 68 of the ratchet hub 40 against its resilient bias to pull the locking pawl 70 clear of the notches 62 in the central web of the thumbwheel 20, which frees the thumbwheel 20 for rotation.

The loop 82 of the yoke 76 has an outward protrusion serving as a thumb grip 96 at its distal end, aligned on the central longitudinal plane 18 with the distal end of the protruding thumbwheel 20. A clinician can simply press a thumb against the distal side of the thumb grip 96 to slide the detent element 42 proximally. This action unlocks the thumbwheel 20 for unidirectional rotation as described above. Elegantly, the thumbwheel 20 can then be turned by continued proximal movement of the thumb after sliding the thumb across the top of the thumb grip 96. These thumb movements are intuitive and simple to perform, yet distinct and deliberate enough to avoid unintended deployment of an implant Returning to Figure 8, a central spine 98 of the detent element 42 extends distally from a distal end of the yoke 76 on an axis that is offset from, but generally parallel to, the plane 18 of the skirt 86. That offset allows the spine 98 to be accommodated within the distally-tapering distal portion of the housing 16.

The resilient wings 78 extend laterally from and converge proximally with a proximal portion of the spine 98. The wings 78 form part of a one-way or unidirectional latch mechanism whose operation will be described later with reference to Figures 13a and 13b. The spine 98 also has a distal portion that is joined integrally to the proximal portion by a flexure such as a live hinge 100. The hinge 100 is formed by a transverse band of reduced thickness between the proximal and distal portions of the spine 98.

The spine 98 terminates distally in guide arms 102 that extend laterally from the distal end of the distal portion and in the distal pawl 80 that comprises a central strut 104 and a laterally-extending cross-bar 106 in a hammerhead configuration. The central strut 104 is inclined relative to the distal portion of the spine 98 about an axis that is orthogonal to the central longitudinal plane 18. By virtue of the inclination of the central strut 104, the cross-bar 106 can engage the outer sheath adaptor 32 when the detent element 42 is in its distal starting position.

In this respect, reference is now also made to Figures 11a, llb and 12. Figures lla and 12 show the detent element 42 in its distal starting position. Here, the cross-bar 106 is engaged on its distal side with a proximal shoulder 108 of the outer sheath adaptor 32 and on its proximal side with stop formations or bosses 110 that are moulded integrally within the two parts of the housing 16. In this way, the cross-bar 106 of the distal pawl 80 locks the outer sheath 26 directly against proximal movement, instead transferring proximal loads into the detent element 42 and the housing 16 of the handle 14. As best appreciated in Figures 8 and 12, the cross-bar 106 has a central notch 112 to accommodate the pull wire 34 connected to the outer sheath adaptor 32.

Conversely, Figures 10 and 1 lb show the detent element 42 in its proximal finishing position with the cross-bar 106 of the distal pawl 80 pulled away and disengaged from the outer sheath adaptor 32 and the bosses 110. This movement of the distal pawl 80 is due to tension applied to the spine 98 by proximal movement of the yoke 76. Thus, on being moved proximally to unlock the thumbwheel 20 by interacting with the ratchet hub 40, the detent element 42 also releases the outer sheath 26 for proximal movement when a clinician subsequently operates the thumbwheel 20.

Guide formations 114 within the housing 16 engage the guide arms 102 that extend laterally from the distal end of the spine 98 to guide movement of the cross-bar 106 when it is being disengaged from the outer sheath adaptor 32 and the bosses 110. As best appreciated in Figures 10 to 12, the guide formations 114 comprise parallel flanges that are integrally moulded with the two parts of the housing 16. The guide formations 114 receive the outer ends of the guide arms 102 in a gap between them. That gap defines a guide path 116 for the guide arms 102 to follow in response to proximal movement of the detent element 42.

The guide path 116 defined by the guide formations 114 does not merely extend in a proximal direction, parallel to the sliding movement of the yoke 76. Instead, a distal segment of the guide path 116 is acutely angled transverse to the proximal direction. Thus, the guide formations 114 serve as a cam ramp so that proximal movement of the yoke 76 applies mechanical advantage to pull the cross-bar 106 away from the outer sheath adaptor 32 and the bosses 110.

Once the cross-bar 106 is clear of the retraction path of the outer sheath adaptor 32, the guide arms 102 then enter a proximal segment of the guide path 116 that is substantially parallel to the sliding movement of the yoke 76. Movement of the guide arms 102 along the distal segment of the guide path 116 followed by their entry into the proximal segment of the guide path 116 is facilitated by bending of the live hinge 100 between the proximal and distal portions of the spine 98.

Figures 13a and 13b illustrate the aforementioned unidirectional latch mechanism that comprises the proximally-converging wings 78 extending laterally from the proximal portion of the spine 98. Inwardly-facing lugs 118 are moulded integrally within the two parts of the housing 16 in mutual opposition about the central longitudinal plane 18. The lugs 118 divide a distal compartment 120 of the latch mechanism from a proximal compartment 122 of the latch mechanism.

When the detent element 42 is in its locked, distal starting position as shown in Figure 13a, the wings 78 lie in the distal compartment 120. When the detent element 42 is then moved into its unlocked, proximal finishing position as shown in Figure 13b, the resilient wings 78 deflect inwardly around the lugs 118 and then snap back outwardly when they enter the proximal compartment 122.

The deflection of the wings 78 imparts initial resistance to movement of the detent element 42, hence requiring that movement to be a deliberate release movement on the part of a clinician.

The snap-back action of the wings 78 then provides audible and tactile confirmation to the clinician that the detent element 42 has reached its unlocked position and that the thumbwheel is therefore now free to be turned to deploy an implant On entering the proximal compartment 122, the distal tips of the wings 78 bear against the proximal side of the lugs 118 to prevent distal movement of the detent element 42 back to the locked starting position. This therefore prevents any attempt a clinician might make to interrupt and resume deployment of the implant after re-locking the device 10. The irreversible proximal position of the yoke 76 also indicates, and prevents concealment of, any accidental premature operation of or deliberate tampering with the device 10. If a clinician chooses a device 10 in which the detent element 42 is not in its locked distal position, the clinician can be instructed to discard that device 10 and to choose another device 10 that is clearly locked and ready for its single use.

The schematic drawings of Figures 14a to 20b illustrate alternative detent mechanisms for locking the outer sheath 26 of an implant deployment device 10. Like numerals are used for like features, but details such as the pull wire 34 that acts on the outer sheath adaptor 32 to retract the outer sheath 26 have been omitted for clarity.

In the mechanism of Figures 14a and 14b, a pivoting lock element 124 bears against the outer sheath adaptor 32 to block its proximal movement when the detent element 42 is in the distal locked position as shown in Figure 14a. In that starting position, a distal end of the detent element 42 engages a slot 126 in the lock element 124 to stop the lock element 124 pivoting away from the outer sheath adaptor 32. When the detent element 42 is slid proximally into its Finishing position as shown in Figure 14b, the distal end of the detent element 42 disengages from the slot 126 to allow the lock element 124 to pivot away from the outer sheath adaptor 32.

The outer sheath 26 can then slide proximally along the inner sheath 24 when the thumbwheel is turned, causing the outer sheath adaptor 32 and the outer sheath 26 to move proximally past the lock element 124.

In the mechanisms shown in Figures 15a to 17b, a distal pawl 128 of the detent element 42 bears against a proximal shoulder 108 of the outer sheath adaptor 32 to block proximal movement of the outer sheath 26 as shown in Figures 15a, 16a and 17a. A proximal stop formation 130 holds the distal pawl 128 of the detent element 42 against the outer sheath adaptor 32. Proximal movement of the detent element 42 relative to the stop formation 130, as shown in Figures 15b, 16b and 17b, causes a distal portion of the detent element 42 to deflect around the stop formation 130, hence disengaging the distal pawl 128 from the outer sheath adaptor 32. Resilient straightening bias of the detent element 42 then swings the distal pawl 128 away from the outer sheath adaptor 32, freeing the outer sheath 26 to slide proximally along the inner sheath 24 when the thumbwheel 20 is turned.

In Figures 15a and 15b, the distal portion of the detent element 42 is joined to the remainder of the detent element 42 by a live hinge 132. Also, the distal portion of the detent element 42 has a protrusion 134 with a proximally-facing surface that is arranged to bear against the stop formation 130 when the detent element 42 is in the distal locked position shown in Figure 15a. Proximal movement of the detent element 42 as shown in Figure 15b disengages the protrusion 134 from the stop formation 130 in addition to disengaging the distal pawl 128 from the proximal shoulder 108 of the outer sheath adaptor 32.

In the mechanisms of Figures 16a and 16b and Figures 17a and 17b, the stop formation 130 has a ramp shape that complements, respectively, curved and inclined distal portions of the detent element 42. Proximal movement of the detent element 42 as shown in Figures 16b and 17b disengages the distal pawl 128 from the proximal shoulder 108 of the outer sheath adaptor 32. Flexing of the detent element 42 caused by the ramp shape of the stop formation 130 then deflects the distal portion away from the retraction path of the outer sheath adaptor 32.

In the mechanisms shown in Figures 18a to 19b, the detent element 42 acts on a pivoting lock element 124 that is joined to a distal end of the detent element 42 by a live hinge 132. When the detent element 42 is in its distal locked starting position as shown in Figures 18a and 19a, a distal pawl 128 of the lock element 124 engages a proximal shoulder 108 of the outer sheath adaptor 32. Proximal movement of the detent element 42 as shown in Figures 18b and 19b pivots the lock element 124 to lift the distal pawl 128 out of engagement with the outer sheath adaptor 32 to free the outer sheath 26 to slide proximally along the inner sheath 24 when the thumbwheel 20 is turned.

The pivoting lock element 124 of Figures 18a and 18b is generally L-shaped and is pivoted between the limbs of the L shape. The distal end of the detent element 42 is joined to the lock element 124 at an end of one of the limbs, and the distal pawl 128 of the lock element 124 is at an end of the other of the limbs. When the detent element 42 is in its distal locked starting position as shown in Figure 18a, the distal pawl 128 of the lock element 124 bears against the proximally-facing shoulder 108 of the outer sheath adaptor 32. Pivoting the lock element 124 by proximal movement of the detent element 42 as shown in Figure 18b lifts the distal pawl 128 of the lock element 124 out of engagement with the outer sheath adaptor 32.

The pivoting lock element 124 of Figures 19a and 19b is generally triangular and is pivoted about a first corner of the triangle. The distal end of the detent element 42 is joined to the triangle at a second corner of the triangle, whereas the distal pawl 128 of the lock element 124 is at a third corner of the triangle. When the detent element 42 is in its distal locked starting position as shown in Figure 19a, the distal pawl 128 of the lock element 124 protrudes between, and so is sandwiched by, a fixed distally-facing stop formation 130 and the proximally-facing shoulder 108 of the outer sheath adaptor 32. Pivoting the lock element 124 by proximal movement of the detent element 42 as shown in Figure 19b pulls the distal pawl 128 of the lock element 124 out of engagement with the stop formation 130 and the outer sheath adaptor 32.

Turning finally to Figures 20a and 20b, the detent element 42 shown here comprises segments 136 that are joined in series by live hinges 132. When the detent element 42 is in its distal locked starting position as shown in Figure 20a, a distal one of the segments 136 is received in a slot 138 defined between stop formations 130. In that slot 138, the distal segment 136 is held against the proximally-facing shoulder 108 of the outer sheath adaptor 32 to prevent proximal movement of the outer sheath 26. Proximal movement of the detent element 42 pulls the distal segment 136 out of the slot 138 and therefore out of engagement with the outer sheath adaptor 32 as shown in Figure 20b. The live hinges 132 allow the segments 136 of the detent element 42 to follow a curved path away from the retraction path of the outer sheath adaptor 32, aided by resilient straightening bias of the detent element 42.

Claims

Claims 1. An implant deployment device comprising a delivery tube and a handle at a proximal end of the delivery tube, wherein the handle comprises: a control element that is movable relative to a housing of the handle to move a deployment component of the delivery tube to an extent sufficient to deploy an implant from the delivery tube; and a detent element that acts separately on the control element and on the deployment component and is movable relative to the housing from a locked position in which movement of the control element and the deployment component is blocked to an unlocked position in which movement of the control element and the deployment component is permitted. The device of Claim 1, wherein the control element and the detent element are located so as to operate respectively with one thumb.
2. The device of Claim 1, comprising a locking member that is engaged with the control element when the detent element is in the locked position and that is disengaged from the control element by movement of the detent element into the unlocked position.
3. The device of Claim 2, wherein the locking member is biased into engagement with the control element and is disengaged from the control element against that bias.
4. The device of Claim 3, wherein the locking member comprises a locking arm that supports a locking pawl and the locking pawl is biased into engagement with the control element by resilience of the locking arm.
5. The device of Claim 4, wherein the locking pawl is supported by a ratchet hub that restricts the control element to unidirectional movement
6. The device of any of Claims 2 to 5, wherein the locking member and the detent element have opposed sliding surfaces that interact with a cam action during said movement of the detent element, to disengage the locking member from the control element
7. The device of any preceding claim, further comprising a unidirectional latch mechanism that is arranged to block movement of the detent element back from the unlocked position to the locked position.
8. The device of Claim 7, wherein the latch mechanism comprises latch formations on the detent element that are resiliently deflectable around lugs fixed relative to the housing.
9. The device of Claim 8, wherein the latch formations are unable to deflect back around the lugs after the detent element reaches the unlocked position.
10. The device of any preceding claim, wherein the detent element comprises a proximal portion exposed outside the housing in a position adjacent to the control element and a distal portion within the housing acting on the deployment component
11. The device of Claim 10, wherein the exposed proximal portion of the detent element comprises a grip protrusion that is disposed distally of the control element and is substantially aligned with the control element in a central longitudinal plane of the housing
12. The device of Claim 10 or Claim 11, wherein the detent element is movable proximally relative to the housing into the unlocked position and the control element is then movable proximally relative to the housing to deploy the implant
13. The device of any preceding claim, wherein the detent element comprises a distal pawl that, when the detent element is in the locked position, is engaged with an adaptor that is disposed within the housing and is fixed to the deployment component
14. The device of Claim 13, wherein when the detent element is in the locked position, the distal pawl is engaged between the adaptor and an opposed stop formation of the housing.
15. The device of Claim 13 or Claim 14, comprising a guide formation that defines a guide path to be followed by the distal pawl, that guide path being initially transverse to a direction of movement of other parts of the detent element into the unlocked position.
16. The device of Claim 15 when dependent upon Claim 14, wherein the stop formation also serves as the guide formation.
17. The device of Claim 15 or Claim 16, wherein the detent element comprises a flexure that allows the distal pawl to move relative to the other parts of the detent element when following the guide path.
18. The device of any of Claims 13 to 17, wherein the distal pawl is engaged with the adaptor against resilient bias of the detent element, to move clear of the deployment component under that bias when disengaged from the adaptor.
19. The device of any of Claims 1 to 12, wherein on being moved into the unlocked position, the detent element disengages from a locking member that previously blocks movement of the deployment component and thereby releases the locking member to move aside, releasing the deployment component for movement
20. The device of any of Claims 1 to 12, wherein on being moved into the unlocked position, the detent element pivots a locking member that previously blocks movement of the deployment component to release the deployment component for movement
21. The device of any preceding claim, wherein the control element is a thumbwheel that can be turned to tension a pull element connected to the deployment component, hence retracting the deployment component proximally to deploy the implant
22. The device of Claim 21, wherein the pull element is wound onto a spool that is coaxial with the thumbwheel about a common axis of rotation and is offset along that axis from the thumbwheel.
23. The device of Claim 22, wherein the pull element follows a path that comprises a first leg extending proximally from the deployment component to a pulley disposed proximally within the handle with respect to the spool, and a second leg extending distally from the pulley to the spool.
24. The device of Claim 23, wherein the pulley is oriented with respect to the handle such that an entry of the first leg of the pull element onto the pulley lies substantially in a common plane with the thumbwheel and an exit of the second leg of the pull element from the pulley lies on the same side of that plane as the spool.
25. The device of any preceding claim, wherein the control element and the detent element are located so as to be operable respectively with a thumb of a hand holding the handle.
26. A method of enabling an implant deployment device to deploy an implant from a delivery tube of the device, the method comprising moving a detent element on a handle of the device from a locked position into an unlocked position, the detent element thereby releasing a control element of the handle and a deployment component of the delivery tube from respective locked states for respective deployment movements relative to a housing of the handle.
27. The method of Claim 26, comprising subsequently moving the control element to effect deployment of the implant by moving the deployment component of the delivery tube.
28. The method of Claim 27, comprising restricting said movement of the control element to unidirectional movement
29. The method of any of Claims 26 to 28, comprising moving the control element in a direction of movement corresponding to a direction of movement of the detent element into the unlocked position.
30. The method of Claim 29, comprising moving the detent element by applying proximal force to the detent element at a location distal to the control element, and then moving the control element by applying proximal force to the control element
31. The method of any of Claims 26 to 30, comprising preventing movement of the detent element back to the locked position from the unlocked position.
32. The method of any of Claims 26 to 31, comprising releasing the deployment component of the delivery tube by disengaging a distal pawl of the detent element from an adaptor that is disposed within the housing and is fixed to the deployment component
33. The method of Claim 32, comprising guiding the distal pawl on a path that is transverse to a direction of movement of other parts of the detent element into the unlocked position.