WO2018120750A1

WO2018120750A1 - Self-expanding stent delivery system and related components thereof

Info

Publication number: WO2018120750A1
Application number: PCT/CN2017/092498
Authority: WO
Inventors: 刘浩; 魏继昌; 龚霄雁
Original assignee: 苏州茵络医疗器械有限公司
Priority date: 2016-12-28
Filing date: 2017-07-11
Publication date: 2018-07-05

Abstract

Provided are a system for use in self-expanding stent delivery, and a catheter assembly and a gear drive assembly (4) thereof. The catheter assembly comprises: an inner tube (3) and an outer tube (2), the outer tube (2) being sleeved over at least a portion of the inner tube (3), while the inner tube (3) and the outer tube (2) are configured to move oppositely in the axial direction; a stent loading area which accommodates a stent in a contracted state is formed between an inner wall of the outer tube (2) and an outer wall of the inner tube; the catheter assembly further comprises at least one restriction member (33), wherein the restriction member (33) is disposed on the outer wall of the inner tube (3) and is located in the stent loading area, the restriction member (33) being configured to hold the stent which is accommodated in the stent loading area when the inner tube (3) and the outer tube (2) move oppositely. The gear drive assembly (4) further comprises: a first gear (41) and a second gear (42), which are disposed coaxially, the first gear (41) being connected to the outer tube (2) by means of a first rack (411), while the second gear (42) is connected to the inner tube by means of a second rack (421), the outer tube (2) and the inner tube (3) being driven to move oppositely in the axial direction by means of the first gear (41) and the second gear (42) rotating.

Description

Self-expanding stent delivery system and related components

Cross-reference to related applications

The present application claims the Chinese invention patent application with the application number 201611237539.4, the Chinese utility model patent application with the application number 201621454714.0, the Chinese invention patent application with the application number 201611236566.X, and the application number 201621455696.8, which is filed on December 28, 2016. The rights and priority of the Chinese Utility Model Patent Application, the entire contents of which are incorporated herein by reference.

Technical field

The present invention relates to the field of medical devices, and more particularly to a self-expanding stent delivery system and a catheter assembly thereof, a gear drive assembly.

Background technique

The stent treatment is a minimally invasive interventional procedure with stent treatment, which has less trauma, less complications and good effect, and has become the main method for treating peripheral vascular stenosis.

Stent therapy typically requires the use of a delivery system to implant a self-expanding stent into the body. In the prior art, the stent delivery system generally includes an interconnected catheter assembly and a handle portion. The catheter assembly generally includes an outer tube and an inner tube. The outer tube and the inner tube are both hollow, and the inner tube can be used for guiding the guide wire. A bracket loading area is formed between the tube and the outer tube, and the bracket in the contracted state is received in the bracket loading area, the handle portion includes a housing adapted to be gripped and a drive assembly for driving the movement of the inner tube or the outer tube.

During the operation, the doctor uses the guide wire to guide the delivery system preloaded with the stent in the contracted state to reach the lesion, and the release position of the stent is determined by the development point on the stent or the delivery system, after which the inner tube is fixed and the drive assembly is operated. The tube is retracted backwards in the axial direction, so that the stent is released from the stent loading area and enters the blood vessel, and the released stent expands in an expanded state by its own expansion force, and is attached to the inner wall of the blood vessel.

For a self-expanding stent, it is in a contracted state prior to release, in the stent loading region between the inner wall of the outer tube and the outer wall of the inner tube, due to its high shrinkage (especially a braided stent), During the release process of the stent into the blood vessel, the released stent is prone to shrinkage, resulting in inaccurate positioning of the stent, and the relative movement of the stent and the outer wall of the inner tube is easy to occur, resulting in inaccurate stent release. At this time, if the bracket is not positioned properly or the bracket has other product problems, it is difficult for the user to retract the bracket to the outer tube to reposition the release bracket or retract the delivery system.

During the operation, in the early stage of stent release, the stent needs to be released slowly because of the need for precise positioning; after the stent is positioned accurately, it can be released quickly. The existing stent delivery system mainly controls the release speed of the stent through the experience and feel of the doctor, which is easy to cause the stent to be released and positioned inaccurately, and also has high requirements for the doctor's experience.

Summary of the invention

In view of the above technical deficiencies, the present invention provides a self-expanding stent delivery system, and a catheter assembly thereof, a gear drive assembly.

In accordance with an embodiment of the present invention, a catheter assembly for a self-expanding stent delivery system is provided, the catheter assembly including an inner tube and an outer tube, the outer tube sleeve being outside of at least a portion of the inner tube, The inner tube and the outer tube are configured to be movable relative to each other in the axial direction, and a bracket loading area for housing the bracket in a contracted state is formed between an inner wall of the outer tube and an outer wall of the inner tube, the duct assembly Also included is at least one restriction member disposed on an outer wall of the inner tube and located in the bracket loading area, the restriction member being configured to be able to jam when the inner tube and the outer tube are relatively moved The bracket in the rack loading area. The catheter assembly further includes a push step disposed on an outer wall of the inner tube, the push step being located at a proximal end of the stent loading region, configured to move relative to the outer tube when the inner tube is opposite the outer tube A proximal end face of the stent can be placed to transport the stent out. For example, the restraining member can be an elastic annular member that fits over the inner tube and that has an interference fit with the outer tube and the stent in a collapsed state. Alternatively, the annular member is in a state in which the outer surface is rounded, or the annular member is a hollow cone. The ring member is made of the following materials: silica gel, TPU, rubber, PI, Pebax, nylon, PC or PE, and the like. The annular member is glued or welded to be sheathed outside the inner tube, or the inner tube is injection molded integrally with the annular member by injection molding. For example, the restricting member may also be a barbed member, the barb member being composed of a sleeve portion and an elastic portion extending from the sleeve portion, the sleeve portion being sleeved outside the inner tube, The elastic portion is configured to be able to catch the bracket housed in the rack loading area when the inner tube and the outer tube move relative to each other. The sleeve portion is glued or welded by glue The sleeve is fixed outside the inner tube. Optionally, the elastic portion is a semi-fan structure, or the elastic portion is composed of two semi-fan structures and a gap between the two semi-fan structures, or the elastic portion is a semi-sector structure. And the scallop of the semi-sector structure has at least one serration, or the elastic portion is a semi-sector structure and the sides of the semi-sector structure have serrations.

In accordance with another embodiment of the present invention, a gear drive assembly for a self-expanding stent delivery system is provided, wherein the self-expanding stent delivery system includes a catheter assembly, the catheter assembly including an inner tube and an outer tube, The outer tube is sleeved outside at least a portion of the inner tube, the inner tube and the outer tube are configured to be movable relative to each other in the axial direction, and the inner wall of the outer tube and the outer wall of the inner tube are formed to be in a contracted state a rack loading area of the bracket, the gear drive assembly includes a first gear and a second gear disposed coaxially, the first gear being coupled to the outer tube by a first rack, the second gear passing A second rack is coupled to the inner tube to drive the outer tube and the inner tube to move axially relative to each other by rotating the first gear and the second gear. The gear drive assembly further includes a roller disposed coaxially with the first gear and the second gear, the first gear and the second gear being rotated by rotating the roller. For example, the diameter ratio of the first gear and the second gear is equal to or close to the shortening ratio of the loaded bracket. The diameter of the roller is greater than the diameter of the first gear and the second gear. The diameter ratio of the first gear to the second gear may be 10:1 to 1:10. The gear drive assembly may further include a push button configured to be coupled to the second rack for urging the second rack to move to move the inner tube; or The racks are coupled for urging the movement of the first rack to drive the outer tube to move.

In accordance with yet another embodiment of the present invention, a self-expanding stent delivery system including the catheter assembly described above is also provided.

In accordance with still another embodiment of the present invention, a self-expanding stent delivery system including the aforementioned gear drive assembly is also provided.

In accordance with yet another embodiment of the present invention, a self-expanding stent delivery system including the catheter assembly and gear drive assembly described above is also provided.

The self-expanding stent delivery system of the invention can be used for conveying an intravenous stent, a peripheral vascular stent, a carotid artery stent, an aortic stent graft, an intra-orbital stent graft, a radial artery stent graft, an intestinal stent, a biliary stent, and the like.

By adopting the embodiment of the invention, the following beneficial effects are obtained:

Due to the restriction member provided on the outer wall of the inner tube, the bracket can be clamped and fixed during the withdrawal of the outer tube and the release of the bracket, so that the bracket can be pushed forward to the outer tube at any time before the release is completed, and the bracket is repositioned. . At the same time, it can also avoid the relative movement of the stent with the outer wall of the inner tube and the inner wall of the outer tube during the release process, thereby increasing the accuracy of the stent release.

Since the driving component of the conveying system is a gear driving component, the outer tube and the inner tube can be driven to move in opposite directions at the same time, thereby solving the problem that the bracket is not released due to the shortening of the bracket, and the moving speed of the inner and outer tubes can be Controlled by precise calculations. At the same time, through the design of the roller and the push button, the stent can be released at different rates during the operation, for example, the stent is slowly released in the early stage of the stent release, and the stent is quickly released in the later stage.

DRAWINGS

1 is a schematic structural view of a self-expanding stent delivery system according to an embodiment of the present invention;

2 is a schematic structural view of a self-expanding stent delivery system for removing a housing according to an embodiment of the present invention;

3 is a schematic structural view of a first gear, a second gear, and a roller of the gear drive assembly of FIG. 2;

Figure 4 is a schematic structural view of the gear drive assembly of Figure 2 connected to the outer tube;

Figure 5 is a structural schematic view showing the gear drive assembly of Figure 2 connected to the inner tube;

6 is a schematic structural view of a catheter assembly for removing an outer tube according to an embodiment of the present invention;

7 is a schematic structural view of a catheter assembly for removing an outer tube according to another embodiment of the present invention;

8 is a partial enlarged schematic view of a catheter assembly when a stent is loaded, in accordance with an embodiment of the present invention;

9A is a schematic structural view of a restricting member and an inner tube according to an embodiment of the present invention;

9B is a schematic structural view of a restricting member and an inner tube according to another embodiment of the present invention;

9C is a schematic structural view of a restricting member and an inner tube according to still another embodiment of the present invention;

Figure 10A is a schematic illustration of a restraining member in accordance with an embodiment of the present invention;

Figure 10B is a schematic illustration of a restraining member in accordance with another embodiment of the present invention;

Figure 10C is a schematic illustration of a restraining member in accordance with yet another embodiment of the present invention;

Figure 10D is a schematic illustration of a restraining member in accordance with yet another embodiment of the present invention.

detailed description

The various aspects of the invention are described in detail below with reference to the drawings and specific embodiments. The components in the drawings are not necessarily drawn to scale, and the emphasis is on the principles of the invention.

In various embodiments of the invention, well-known structures, materials, or operations are not shown or described in detail. Also, the described features, structures, or characteristics may be combined in any manner in one or more embodiments. In addition, those skilled in the art should understand that the various embodiments described below are for illustrative purposes only and are not intended to limit the scope of the invention. It will also be readily understood that the elements or components of the various embodiments described herein and illustrated in the Figures can be arranged and designed in a variety of different configurations. The numerical values referred to in the present specification and the appended claims are to be understood as being modified by the "about" unless specifically indicated or apparent from the context, "about" is understood to be within the normal tolerances of the art, for example Within ±5% of the specified value.

Referring to Figure 1, a self-expanding stent delivery system in accordance with an embodiment of the present invention is illustrated. In the present embodiment, a delivery system for delivering a self-expanding stent to a body, that is, a self-expanding stent delivery system, includes: a housing 1, a catheter assembly mainly composed of an outer tube 2 and an inner tube 3, and a gear drive assembly 4. Wherein, a part of the inner tube 3 is located in the casing 1, a part of which protrudes into the inside of the outer tube 2, the outer tube 2 is sleeved outside at least a part of the inner tube 3, and the inner wall of the outer tube 2 and the outer wall of the inner tube 3 form a useful relationship. The bracket tube loading area (not shown) for accommodating the bracket in the contracted state, the inner tube 3 and the outer tube 2 are configured to be relatively movable in the axial direction, and the bracket can be loaded from the bracket loading area by the relative movement of the inner tube and the outer tube Delivered and expanded.

2 is a schematic view showing the structure of a self-expanding stent delivery system after removing the housing. 2, the gear drive assembly 4 may include a first gear 41 and a second gear 42 disposed coaxially, wherein the first gear 41 is coupled to the outer tube 2 through the first rack 411, and the second gear 42 is passed through the second The rack 421 is connected to the inner tube 3, and the outer tube 2 and the inner tube 3 are respectively driven to move relative to each other in the axial direction by rotating the first gear 41 and the second gear 42, and the moving speed ratio of the outer tube 2 and the inner tube 3 is first. The diameter ratio of the gear 41 and the second gear 42. For example, when the ratio of the diameter of the first gear to the diameter of the second gear is approximately equal to the shortening ratio of the bracket (the shortening ratio of the bracket is the difference between the length of the bracket in the compressed state and the length of the expanded state and the length in the expanded state) The ratio can be better to prevent the release of the stent from shortening and better ensure that the stent can be accurately positioned. For example, the diameter ratio of the first gear to the second gear may be 10:1 to 1:10.

In some embodiments of the present invention, the gear drive assembly 4 may further include a first gear, The two gear coaxial roller 43 (shown in FIG. 3) can drive the coaxial rotary motion of the first gear 41 and the second gear 42 through the rolling roller 43, thereby driving the inner tube 3 and the outer tube 2 in the axial direction. mobile. For example, the diameter of the roller 43 may be larger than the diameters of the first gear 41 and the second gear 42 to ensure slow rotation of the first gear and the second gear.

In some embodiments of the present invention, the gear drive assembly 4 may further include a push button 44 located at one end of the second rack 421 and connected to the second rack 421. By pushing or pulling the button 44, The second rack is directly moved to drive the inner tube to move, and the outer tube is also relatively moved, so that the bracket can be quickly released and retracted. For example, if the diameter ratio of the first gear and the second gear is 2:1, the push button is pushed forward by 10 mm, the inner tube is advanced by 10 mm, the outer tube is simultaneously withdrawn by 20 mm, and the entire bracket is released by 30 mm.

In some embodiments of the present invention, the push button is located at one end of the first rack 411 and is connected to the first rack 411. By pushing or pulling the button 44, the first rack can be directly moved to drive the outer tube to move. Allows the stent to be released and retracted quickly.

During the operation, through the first gear and the second gear of the gear drive assembly 4, the outer tube and the inner tube can simultaneously move in the opposite direction in the axial direction, that is, the outer tube 2 can be retracted while the inner tube 3 can push the bracket toward Push forward to compensate for the shortening of the bracket. By controlling the diameter ratio of the first gear and the second gear, the speed ratio of the outer tube to the inner tube can also be determined, so that the bracket can be positioned more accurately when the diameter of the gear is shorter than the diameter of the bracket.

In addition, the additionally disposed roller 43 can drive the first gear and the second gear to rotate slowly, and the additionally provided push button 44 connected to the first rack or the second rack can quickly push the first rack or the second rack. . In this way, in the early stage of the stent release, the rotating wheel 43 can rotate the gear slowly, and the inner tube and the outer tube move slowly relative to each other to realize the slow release of the bracket; in the later stage of the bracket release, the push button 44 can be pushed to directly push the inner tube or The outer tube is used to rapidly rotate the gear, and the inner tube and the outer tube move relatively quickly to achieve rapid release of the bracket.

As shown in FIG. 4, an outer joint 21 can also be connected at the proximal end of the outer tube 2, and the outer tube 2 is connected to the first rack 411 via the outer joint 21. The flushing port 22 can also be connected to the outer pipe joint 21, and the three-way valve can be connected to the port 22 through the hose, and the flushing liquid or the contrast agent is introduced into the outer tube 2 through the interface during the operation. In the present invention, the outer tube 2 may be a flexible plastic tube or a plastic metal composite tube.

As shown in Fig. 5, the inner tube 3 has a hollow structure to facilitate the passage of the guide wire, and the proximal end of the inner tube A luer connector 31 is provided for connecting the syringe to introduce the flushing liquid to flush the inner lumen of the inner tube 3 or to inject the contrast medium into the inner tube 3. The distal end of the inner tube 3 is provided with a tapered head (TIP head) 32 which extends beyond the distal end of the outer tube 2 and can be used to guide the catheter assembly to move therein.

In alternative embodiments, other forms of drive assembly may be employed to drive the inner or outer tube movement.

Figures 6 and 7 show two embodiments of a catheter assembly with an outer tube removed, respectively. As shown in FIGS. 6 and 7, a restricting member 33 may be provided on the outer wall of the inner tube 3, and the proximal end of the bracket is caught by the restricting member 33 in the gap between the inner tube 3 and the outer tube 2. Specifically, the restricting member 33 may be disposed at the distal end of the inner tube 3 at the loading area of the bracket, and when the outer tube 2 and the inner tube 3 are relatively moved, as long as the proximal end of the bracket is still in the bracket loading area, the limiting member 33 will keep in contact with the bracket and catch the bracket in the loading area of the bracket, for example, the proximal part of the bracket, when the bracket needs to be retracted, the bracket can be retracted by clamping the proximal end of the bracket In the outer tube.

The outer wall of the distal end of the inner tube 3 is further provided with a pushing step 34, and the pushing step 34 is located at the proximal end of the loading area of the bracket. When the outer tube 2 and the inner tube 3 are relatively moved, as long as the proximal end of the bracket is still in the loading area of the bracket In the middle, the pushing step 34 abuts against the proximal end surface of the bracket, and when the inner tube moves distally, the pushing step pushing bracket moves together distally to push and release the bracket from the bracket loading area. The restriction member 33 can be disposed between the TIP head 32 and the push step 34.

As shown in Fig. 8, the bracket 5 is loaded between the TIP head 32 and the pushing step 34, the pushing step 34 abuts against the proximal end surface of the bracket 5, and the restricting member 33 catches the proximal end portion of the bracket 5, after a part of the bracket is released, If the stent needs to be withdrawn, the outer tube is pushed distally, the inner tube moves to the proximal side, the proximal end portion of the stent is caught by the restriction member, and the stent can be retracted into the outer tube.

In some embodiments of the present invention, the restricting member 33 may be an elastic annular member (as shown in FIG. 6), for example, may be made of silica gel, TPU (thermoplastic polyurethane elastomer), rubber, PI (polyimide), Pebax. (block polyether amide elastomer), nylon, PC (polycarbonate) or PE (polyethylene) or the like. Such an annular member is fixed outside the inner tube, and has good friction performance and elasticity. When the bracket is housed in a contracted state into the bracket loading area between the inner and outer tubes, the bracket, the restricting member and the outer tube can be formed. Fit. Through the friction between the three, the proximal end of the bracket is fixedly fixed, so that the bracket can be retracted at any time before being released completely, and the bracket can be repositioned at the same time; at the same time, the bracket accommodated in the loading area of the bracket during the release of the bracket can be ensured. There is no relative movement between the outer wall of the inner tube and the inner wall of the outer tube. Increase the accuracy of the stent release. In some embodiments, the annular member may be glued or welded to be fixed to the inner tube, or the inner tube may be injection molded integrally with the annular member by injection molding.

As shown in FIGS. 9A to 9C, the annular member may have a smooth outer surface or may have a hollow cone or other shape.

In other embodiments of the present invention, the restricting member 33 may be a barb (as shown in FIG. 7), and the barb member is composed of a sleeve portion 331 and an elastic portion 332 extending from the sleeve portion 331. The portion 331 is sleeved outside the inner tube 3, and the elastic portion 332 is used to clamp the proximal end portion of the bracket to restrict its movement. For example, the elastic portion may face the proximal end or the distal end. In some embodiments, the cuff portion may be glued or welded to be secured to the inner tube. The bracket in the contracted state can be caught in the bracket loading area by the elastic portion of the barb piece, so that the bracket can be retracted at any time before the bracket is released, and the bracket stored in the rack loading area during the bracket release process can also be ensured. There is no relative movement between the outer wall of the inner tube and the inner wall of the outer tube, which increases the accuracy of the release of the stent.

As shown in FIGS. 10A to 10D, the elastic portion 332 of the barb member may be a half-sector structure, or may be composed of two half-sector structures and have a gap between the two semi-sector structures, or a semi-sector structure. And the scallop of the semi-sector structure has at least one serration, or a semi-sector structure and the side wall of the semi-sector structure has at least one serration.

In the case where the same principle is employed, the restricting member 33 can adopt various structures, and is not limited to the annular member or the barb member. In an alternative embodiment, one, two or more restraining members may also be attached to the inner tube.

Other forms of catheter assembly may also be employed in alternative embodiments.

It is to be noted that the above is an embodiment for explaining the idea, concept or principle of the present invention, and the present invention is not limited to the above embodiment. Various modifications may be made to the above-described embodiments in accordance with the inventive concept, concept or principle, and more embodiments are obtained.

The terms and words used in the description are for the purpose of illustration and description It will be understood by those skilled in the art that various changes may be made in the details of the embodiments described above without departing from the basic principles of the disclosed embodiments. Therefore, the scope of the invention is to be determined by the appended claims, and the claims

Claims

A catheter assembly for a self-expanding stent delivery system, the catheter assembly including an inner tube and an outer tube, the outer tube being outside of at least a portion of the inner tube, the inner tube and the outer tube being configured to be capable of a relatively axial movement, a bracket loading region for receiving a bracket in a contracted state is formed between an inner wall of the outer tube and an outer wall of the inner tube, wherein

The catheter assembly further includes at least one restriction member disposed on an outer wall of the inner tube and located in the bracket loading region, the restriction member configured to move relative to the outer tube when the inner tube is opposite to the outer tube The bracket accommodated in the loading area of the bracket can be caught.
The catheter assembly of claim 1 wherein said catheter assembly further comprises a push step disposed on an outer wall of said inner tube, said push step being located at a proximal end of said stent loading region, the configuration When the inner tube and the outer tube move relative to each other, the proximal end surface of the bracket can be abutted to transport the bracket out.
The catheter assembly according to claim 1, wherein said restricting member is an elastic annular member, said annular member being sleeved outside said inner tube and said outer tube and said in a contracted state The bracket has an interference fit.
The catheter assembly according to claim 3, wherein the annular member is in a state in which the outer surface is rounded, or the annular member is a hollow cone.
The catheter assembly of claim 3 wherein said annular member is made of the following materials: silicone, TPU, rubber, PI, Pebax, nylon, PC or PE.
A catheter assembly according to claim 3, wherein said annular member is glued or welded to be sheathed outside said inner tube, or said inner tube and said annular member are injection molded by injection molding. In one.
The catheter assembly of claim 1 wherein said restricting member is a barbed member. The barb member is composed of a sleeve portion and an elastic portion extending from the sleeve portion, the sleeve portion is sleeved outside the inner tube, and the elastic portion is configured to be when the inner tube is When the outer tube is relatively moved, the bracket accommodated in the loading area of the bracket can be caught.
The catheter assembly of claim 7 wherein said cuff portion is glued or welded to fit over said inner tube.
The catheter assembly according to claim 7, wherein said elastic portion is a half-sector structure, or said elastic portion is composed of two semi-fan-shaped structures and having a gap between the two semi-sector structures. Or the elastic portion is a half-sector structure and the scallops of the semi-sector structure have at least one serration, or the elastic portion is a semi-sector structure and the sides of the semi-sector structure have serrations.
A gear drive assembly for a self-expanding stent delivery system, wherein the self-expanding stent delivery system includes a catheter assembly, the catheter assembly including an inner tube and an outer tube, the outer tube being at least over the inner tube In part, the inner tube and the outer tube are configured to be movable relative to each other in the axial direction, and a bracket loading region for accommodating the stent in a contracted state is formed between the inner wall of the outer tube and the outer wall of the inner tube, characterized in that The gear drive assembly includes:

a first gear and a second gear disposed coaxially, wherein the first gear is coupled to the outer tube by a first rack, and the second gear is coupled to the inner tube by a second rack by rotation The first gear and the second gear drive the outer tube and the inner tube to move relative to each other in the axial direction.
A gear drive assembly according to claim 10, wherein said gear drive assembly further includes a roller disposed coaxially with said first gear and said second gear, said wheel being rotated to rotate said first a gear and the second gear.
The gear drive assembly of claim 11 wherein said roller has a diameter greater than a diameter of said first gear and a diameter of said second gear.
A gear drive assembly according to claim 10, wherein said first gear The ratio of the diameter to the diameter of the second gear is approximately equal to the shortening of the bracket.
The gear drive assembly of claim 13 wherein said first gear and said second gear have a diameter ratio of from 10:1 to 1:10.
A gear drive assembly according to claim 10, wherein said gear drive assembly further comprises a push button, said push button being arranged to be coupled to said second rack for pushing said second tooth The strip moves to drive the inner tube to move; or is coupled to the first rack for pushing the first rack to move the outer tube to move.
A self-expanding stent delivery system characterized by comprising:

A catheter assembly according to any one of claims 1 to 9.
A self-expanding stent delivery system characterized by comprising:

A gear drive assembly according to any one of claims 10 to 15.
A self-expanding stent delivery system characterized by comprising:

a catheter assembly according to any one of claims 1 to 9;

A gear drive assembly according to any one of claims 10 to 15.