Deployment handle for an implant deployment device

A deployment handle (112) for an implant deployment device (10) facilitates withdrawal of a sheath (18). The deployment handle (112) includes two separate actuators: a trigger (130) and a sliding actuator (330). The trigger (130) can be used to effect small step-wise movement of a carriage (120) that is connected to a sheath (18) to be withdrawn. The sliding actuator (330) can be used to effect continuous movement of a carriage (120) to withdraw a sheath (18). In order to transmit movement of either the trigger (130) or the sliding actuator (330) to the carriage (120), a flexible rack (380) is used. The flexible rack (380) includes upper teeth (390) and lower teeth (395) for engagement with the trigger (130) and the sliding actuator (330) respectively. The ability of the flexible rack (380) to bend back on itself means that unnecessary elongation of the deployment handle (112) is avoided.

TECHNICAL FIELD

The present invention relates to a deployment handle for an implant deployment device, and to an implant deployment assembly.

BACKGROUND OF THE INVENTION

The use of delivery devices employing catheters has long been known for a variety of medical procedures, including procedures for establishing, re-establishing or maintaining passages, cavities or lumens in vessels, organs or ducts in human and veterinary patients, occlusion of such vessels, delivering medical treatments, and other interventions. For these procedures, it has also long been known to deliver an implant by means of a catheter, often intraluminally. For example, a stent, stent-graft, filter or occlusion device may be delivered intraluminally from the femoral artery for deployment.

For procedures in which a prosthesis or other device is implanted into a patient, the device to be implanted is normally held onto the catheter in a compressed state and then released from the catheter so as to expand to its normal operating state, prior to withdrawal of the catheter from the patient to leave the implant in position.

A variety of delivery mechanisms is known in the art. These generally involve positioning the implant on a distal part of a delivery device, that is, at an end furthest from the external manipulation end used by the clinician during the deployment procedure. The prosthesis or implant is normally held at the distal end of the catheter by a suitable restraining mechanism, restraining wires being just one known example. It is also conventional to cover the implant with a sheath in order to protect the implant and also the patient's vasculature or organs during the delivery process. Once the implant has been positioned at the location in which it is to be released, the sheath is retracted along the catheter to expose the implant. The implant is then expanded, either automatically, if the implant is of the self-expanding type, or by a suitable expanding mechanism if not, such as by means of an expansion balloon.

In cases where a sheath or other covering is provided, some delivery devices include a mechanism by which the sheath can be withdrawn by being pulled back towards the external manipulation end of the delivery device, that is, towards the surgeon or other clinician. The force required to withdraw such a sheath may be very large. Furthermore, the resistance to withdrawal of a sheath may vary, which can cause problems for a controlled and safe release of an implant.

The sheath may be withdrawn by the surgeon or clinician gripping the proximal end of the sheath with one hand, and the catheter with the other hand, and pulling back the sheath relative to the catheter. This method is not only hard work, but also the surgeon or clinician is unable to exert much control over the withdrawal process. Moreover, use of such force to withdraw a sheath may result in shifting of the previously carefully placed implant.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved deployment handle for an implant deployment device and an improved implant deployment assembly.

According to a first aspect of the present invention there is provided an implant deployment device handle, including: at least one actuator including a coupling element to couple the actuator to a component of an implant deployment device to be withdrawn, wherein the coupling element includes a flexible rack; wherein the flexible rack is arranged to translate movement of at least one actuator in a withdrawal direction to corresponding withdrawal of a component coupled thereto.

The use of a flexible rack assists in reducing the size of the handle as the rack may be bent double within the handle.

The flexible rack preferably includes asymmetric teeth. These preferably include an abutment service and a sloping surface. Such asymmetric teeth allow incremental movements of the flexible rack in one direction only.

The flexible rack is preferably formed substantially as a “U” shape. This arrangement allows the components of the handle to be located in as small a volume as possible.

The flexible rack preferably includes a first set of teeth on a first surface and a second set of teeth on a second surface opposite the first surface. This arrangement assists in the minimizing the size of the handle.

According to a second aspect of the present invention, there is provided an implant deployment device handle, including: a first actuator and a second actuator; at least one coupling element to couple the first actuator and the second actuator to a component of an implant deployment device to be withdrawn; the first actuator operable to withdraw a component of an implant deployment device coupled thereto by a first distance by a single actuation thereof; the second actuator operable to withdraw a component of an implant deployment device coupled thereto by a second distance by a single actuation thereof; wherein the second distance is greater than the first distance, and wherein the first actuator is operable to be actuated a plurality of times in order to withdraw the component by the second distance.

The inclusion of two actuators enables the user to select whether controlled step-wise actuation or a continuous withdrawal is used.

The coupling element is preferably connected to a withdrawal member, the withdrawal member including a connector for a component to be withdrawn. Preferably, the coupling element translates movement of an actuator to the withdrawal member thereby to effect withdrawal of a component. This provides a convenient way of causing withdrawal of the component to be withdrawn by means of the first actuator and/or the second actuator.

The coupling element preferably couples both the first actuator and the second actuator to a component to be withdrawn. Use of only a single coupling element to couple two actuators to a component to be withdrawn reduces the number of components required within the handle.

The first actuator is preferably able to move between a proximal position and a distal position, and wherein movement towards the proximal position is in a withdrawal direction, and wherein the first actuator is biased into its distal position. With this arrangement, the user only needs to impart effort when withdrawal is desired; this facilitates the use of the handle and withdrawal of the component. The first actuator may be a trigger.

The second actuator is preferably a sliding actuator able to slide from a distal position to a proximal position, and wherein movement from the distal position to the proximal position is in a withdrawal direction. A sliding actuator allows withdrawal of the component in a single continuous movement, or in a series of smaller manually controlled proximal movements.

Preferably the coupling element includes a flexible rack. The flexible rack may include a first set of teeth on a first surface and a second set of teeth on a second surface opposite the first surface. In the preferred embodiment, the first actuator engages with at least one of the first set of teeth and the second actuator engages with at least one of the second set of teeth. This arrangement allows for a compact design.

According to a third aspect of the present invention, there is provided an implant deployment device handle, including: a trigger operable to withdraw a component of an implant deployment device coupled thereto by a first distance by a single actuation thereof; a slidable actuator operable to withdraw a component of an implant deployment device coupled thereto by a second distance by a single actuation thereof; wherein the second distance is greater than the first distance, and wherein the first actuator is operable to be actuated a plurality of times in order to withdraw the component by the second distance; and wherein a flexible rack is arranged to translate movement of the trigger and of the slidable actuator in a withdrawal direction to corresponding withdrawal of a component coupled thereto.

According to a fourth aspect of the present invention there is provided a kit including an implant deployment device including a component to be withdrawn, and a deployment handle as described above.

The component to be withdrawn may be a sheath for covering an implant to be deployed.

The kit may include an implant to be deployed. The implant may be a stent, a stent graft, a filter or an occlusion device.

DETAILED DESCRIPTION

It is to be understood that the Figures are schematic and do not show the various components in their actual scale. In many instances, the Figures show scaled up components to assist the reader.

In this description, when referring to a deployment assembly, the term distal is used to refer to an end of a component which in use is furthest from the surgeon during the medical procedure, including within a patient. The term proximal is used to refer to an end of a component closest to the surgeon and in practice in or adjacent an external manipulation part of the deployment or treatment apparatus.

On the other hand, when referring to an implant such as a stent or stent graft, the term proximal refers to a location that in use is closest to the patient's heart, in the case of a vascular implant, and the term distal refers to a location furthest from the patient's heart.

The example of delivery system shown inFIGS. 1 to 3is the applicant's delivery system for its Zilver™ stent and in particular for its Zilver™ biliary stent.

The delivery assembly10shown inFIG. 1includes a tubular handle12, conventionally made of a plastics material, and a hub14, also made of a plastics material. A safety lock16is removably fitted into a portion of the handle12, for purposes to be described below.

An introducer catheter (or sheath)18, made of any of the conventional or otherwise suitable catheter materials known in the art, extends from and is attached to the handle12, in this example by a threaded nut15. Housed within the introducer catheter18is an inner catheter36(visible inFIG. 3) which carries stent30and which is provided at its distal end with a flexible introducer tip20. The inner catheter36has a bore passing therethrough for the introduction of a guide wire34, shown inFIGS. 2 and 3.

The handle12is provided with a side arm flushing port22, of conventional form, for flushing the space inside the introducer catheter18.

The hub14is fixed to a metal cannula24which is itself attached to the inner catheter36.

The delivery assembly10is provided with radiopaque markers26. In this example, the proximal marker26is located on the introducer catheter18, while the distal marker26is provided on the inner catheter36, as will be apparent fromFIG. 3.

The hub14is provided with an inner support stylet28operable to receive and support a guide wire34, which guide wire34passes through the inner stylet28, the hub14, the metal cannula24, the inner catheter26and out of distal end of the introducer tip20.

The distal end of the inner catheter36, adjacent the introducer tip20, supports a stent30, in this example a Zilver™ biliary stent obtainable from the applicant. The introducer catheter18overlies and acts as a holding sheath for the stent30. This stent30is provided, in this example, with its own radiopaque markers32, in a form known in the art.

The safety lock16acts to lock the metal cannula24in an extended position relative to the handle12, as shown inFIG. 1, and thus to lock the introducer catheter18over the inner catheter36, until the time of deployment.

Referring now toFIGS. 2 and 3, a stent is deployed, in this case in a biliary tract of a patient, by first introducing a guide wire34through an access catheter (not shown) across the distal segment of the target lesion40of the biliary tract. Once the guide wire34is in place, the introducer catheter18is fed over the guide wire34until the distal end of the introducer catheter18is over the target lesion40. During this process the introducer catheter18is flushed with saline solution through the side arm flushing port22.

Once the introducer catheter18has been located at the deployment site, the stent30held by the delivery assembly10is ready to be deployed. This position of the delivery assembly10is shown inFIG. 2, with the two markers26appearing either side of the target lesion site40.

In order to deploy the stent30, the safety lock16is removed, which allows the handle12to be slid over the metal cannula24. In other words, once the safety lock16has been removed, the handle12can be pulled back whilst holding the hub14steady. This action of pulling back the handle12retracts the introducer catheter18from the inner catheter36with the result that the stent30is exposed and allowed to expand gradually as the introducer catheter18moves backwards relative to the inner catheter36.FIG. 3shows the introducer catheter18fully withdrawn and the stent30fully deployed at the target lesion40.

Once the stent30has been deployed, the delivery assembly can be withdrawn by pulling the handle12and the hub14together in a withdrawal direction, that is, out of the patient. This procedure is known in the art in particular in connection with deployment of the applicant's Zilver™ stent.

Referring now in particular toFIGS. 4 and 5, the components found within a preferred embodiment of a deployment handle112are now described.

The deployment handle112includes a deployment handle body110, which is formed of two parts, a “lower” part and an “upper” part (not shown). Together these form an outer casing for the working components of the deployment handle112having an overall size and shape suited to be hand-held.

The inner catheter36runs longitudinally through the deployment handle112, which is located at the proximal end thereof. The deployment handle112includes a carriage120that is connected to the sheath18via a connection element170. The carriage120is able to slide in a proximal direction (towards the right as shown inFIGS. 4 and 5) and co-operates with two actuators: a trigger130and a sliding actuator330.

The trigger130is able to move back and forth (proximally and distally) by approximately 5 mm. It is located such that in its distal position it overlaps a finger hole340positioned towards the distal end of the casing110so that it can be actuated by a finger of a user. In its proximal position, the trigger130is aligned with the proximal edge of the finger hole340, further proximal movement of the trigger130thereby being prevented. The trigger130is biased into its distal position by a coiled torsion spring140that abuts the trigger130and the edge of the casing110. The trigger130includes a proximally extending trigger extension350that includes, at the proximal end thereof, trigger extension teeth360. The function of these is described below.

The sliding actuator330is able to slide proximally and distally along the handle within a guide channel172(seeFIGS. 6 and 7). The sliding actuator330includes a knob335that extends through a longitudinal slot in the casing110of the deployment handle112so that it can be accessed by a user. The sliding actuator330includes a hook370, the function of which is described below.

The trigger extension teeth360and the sliding actuator hook370are able to engage with upper teeth390and lower teeth395respectively of a moveable double-sided flexible rack380. The flexible rack380may be made from nylon or polyethylene for example. The flexible rack380is fixed at one end to the carriage120such that movement of the flexible rack380causes corresponding movement of the carriage120. The flexible rack380has a leading end382(the end attached to the carriage120) and a trailing end384. The flexible rack380forms a U-shape within the deployment handle112wherein its leading end382is located above its trailing end384, and the curved part of the “U” is towards the distal end of the handle.

The teeth390,395of the flexible rack380are asymmetric such that they include an abutment surface and a sloping surface. The trigger extension teeth360and the sliding actuator hook370have a shape that corresponds to the teeth390,395. The trigger extension teeth360and the sliding actuator hook370thus engage with the teeth390,395such that movement of the trigger130or the sliding actuator330in a proximal direction causes the leading end382of the flexible rack380to move proximally because the abutment surfaces of the teeth390,395are engaged with the trigger extension teeth360or the sliding actuator hook370. However, when movement of the trigger130or the sliding actuator330is in a distal direction, the trigger extension teeth360and the sliding actuator hook370are able to slide over the sloping surfaces of the teeth390,395due to resiliency of the trigger extension350and the sliding actuator hook370. This enables the flexible rack380to remain longitudinally stationary as the trigger130or the sliding actuator330moves in the distal direction.

A lock button310that extends through an aperture in the casing110of the deployment handle112is able to engage the carriage120to prevent movement thereof.

FIGS. 6 and 7illustrate the arrangement of the components after partial withdrawal of a sheath18(FIG. 6) and full withdrawal (FIG. 7). It can be seen that the trigger130when moved in a proximal direction by a finger of the user, causes proximal movement of the trigger extension350and the trigger extension teeth360. Engagement of the trigger extension teeth360against the abutment surface of the upper teeth390of the flexible rack380causes proximal movement of the leading end382of the flexible rack380. As the flexible rack380is attached to the carriage120, which in turn is attached to the sheath18via the connection element170, movement of the trigger130in a proximal direction by approximately 5 mm causes movement of the carriage120in a proximal direction to the same extent, and thus withdrawal of the sheath18to the same extent. Release of the trigger130results in it returning to its distal position by means of the coiled torsion spring140. The trigger extension teeth360are able to slide over the sloping surfaces of the upper teeth390and reengage with upper teeth390further behind the leading edge382of the flexible rack380. It can thus be seen that repeated actuation and release of the trigger130results in controlled, step-wise movement of the flexible toothed rack380, the carriage120and thus withdrawal of the sheath18in a proximal direction.

The carriage120may also be moved in a single action in a proximal direction by means of the sliding actuator330. As indicated above, the sliding actuator330is able to slide proximally and distally along a guide channel172. The sliding actuator hook370engages with the abutment surface of the lower teeth395. Proximal movement of the sliding actuator330thus causes movement of the leading edge382of the flexible rack380in the proximal direction. The sloping edges of the lower teeth395and the sliding actuator hook370are able to slide over one another when the flexible rack380is being pushed by the trigger extension teeth360due to the resiliency of the sliding actuator hook370. The sliding actuator330is able to move along the length of the guide channel172and thus cause the flexible rack380and the carriage120to move by the same extent and for the sheath18to be withdrawn by the same extent.

It can thus been seen, that this arrangement allows for either withdrawal of the sheath18in small steps (using trigger130) and/or in a continuous movement (using sliding actuator330).

In use, the surgeon or clinician threads the deployment handle112over the inner catheter36and connects the sheath18to be withdrawn to the connection element170. The lock is disengaged from the carriage120by depressing the lock button310. This allows movement of the carriage120. The surgeon can then select which mode of operation to use at any one time. For example, at one stage of deployment, they may wish to ensure that sheath withdrawal only occurs in very slow, controlled steps. At this stage, the trigger130can be used to effect withdrawal. At other times, or in other situations, the surgeon may wish to have more of a feel of the process of uncovering an implant as it occurs. For this reason, they may prefer to use the sliding actuator330. For example, when using the sliding actuator330, it may be possible to feel (for example, through unanticipated resistance) whether there are any problems with the withdrawal process.

It can be seen, therefore, that according to the user's preference, one stage of withdrawal could be effected using the trigger actuator130and a different stage (which could be earlier or later) the sliding actuator330could be used. In some embodiments, it may not be possible to use the trigger actuator130after the sliding actuator330if the sliding actuator has been moved in a proximal direction to its full extent.

The above-described deployment handle provides the choice to the user of whether, at a particular stage of the withdrawal process, the sheath18is withdrawn in several small steps using the trigger130, or in a single continuous movement using the sliding actuator330. The sliding actuator330may even be used to effect withdrawal in several manually-controlled steps rather than in a single step.

An advantage of inclusion of the trigger130is that the handle can be operated single-handedly by the user when the trigger130is used to effect withdrawal.

The use of a flexible rack380provides several advantages. By its formation into a “U” shape a relatively long range of movement can be obtained whilst keeping the handle a convenient size. The flexibility also allows the sloping surfaces of the trigger extension teeth360and the sliding actuator hook370to pass over the sloping surfaces of the rack teeth390,395as the trigger130or the sliding actuator330moves in a distal direction.

The skilled person will appreciate that the described deployment handle112could be used to move or withdraw other components of an implant deployment device10. For example, it could be used to withdraw restraining wires that hold an implant in a constrained configuration.

Another advantage of the disclosed handle is that it can be used as part of a rapid exchange system, in particular in connection with removal of the sheath in a single action by means of the sliding actuator330.

Other uses of the disclosed deployment handle112will be envisaged by the skilled person.

The disclosures of U.S. 61/009,139 from which the present application claims priority, and in the Abstract, are incorporated herein by reference.