Rotary handle stent delivery system and method

A delivery device according to principles described herein includes a catheter having three concentric shafts including an inner core, an outer sheath over the inner core and an outer support shaft at least partially extending over the inner core and the outer sheath. A timing belt having a plurality of belt teeth on a surface of the timing belt is coupled to an outer sheath over a medical device or stent on the inner core such that movement of the timing belt link causes movement of the outer sheath from its position over the medical device or stent. The delivery device is actuated by rotation of a thumbwheel a thumbwheel coupled to a barrel having a plurality of teeth such that rotation of the thumbwheel causes movement of the barrel such that the barrel teeth engage the belt teeth to cause movement of the timing belt causing movement of the outer sheath.

BACKGROUND OF THE INVENTION

Field of the Invention

Embodiments of the present invention relate to a stent delivery device, specifically a single-handed thumbwheel driven delivery handle.

Background

There are a number of medical conditions and procedures in which a device such as a stent is placed in the body to create or maintain a passage. There are a wide variety of stents used for different purposes, from expandable coronary, vascular and biliary stents, to plastic stents used to allow the flow of urine between kidney and bladder.

Self-expanding stents, as well as balloon expandable stents, may also be used to treat various issues with the vascular system, including, but not limited to May-Thurner Syndrome and Deep Vein Thrombosis.

Stents are usually delivered in a compressed condition to the target site and then, deployed at that location into an expanded condition to support the vessel and help maintain it in an open position. The delivery system used to implant or deploy at the stent target site in the diseased vessel using a delivery system.

Stents are commonly delivered using a catheter delivery system. A common type of delivery system for delivering a self-expanding stent is called a pull back delivery system. This type of delivery system utilizes two catheters or shafts which are concentrically arranged, one around another. The stent is carried axially around the distal end of the inner catheter or shaft. The stent is carried to the delivery site on the distal end of the delivery device, held in its compressed delivery position by the outer shaft or catheter. Once at the desired placement site, the outer shaft is pulled back, releasing the stent to self-expand.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a rotary handle stent delivery system and method that obviates one or more of the problems due to limitations and disadvantages of the related art.

In accordance with the purpose(s) of this invention, as embodied and broadly described herein, this invention, in one aspect, relates to a delivery device according to principles described herein including a catheter having three concentric shafts including an inner core, an outer sheath over the inner core and an outer support shaft; a timing belt having a plurality of belt teeth on a surface of the timing belt; a timing belt link coupled to the outer sheath such that movement of the timing belt link causes movement of the outer sheath; a barrel having barrel teeth corresponding to belt teeth; and a thumbwheel coupled to the barrel such that rotation of the thumbwheel causes movement of the barrel such that the barrel teeth engage the belt teeth to cause movement of the timing belt causing movement of the outer sheath.

In another aspect, a system for delivery of an intraluminal stent according to principles described herein includes a delivery device with a catheter having three concentric shafts including an inner core having the intraluminal stent thereon; an outer sheath over the stent in an unexpanded state on the inner core therein, the outer sheath holding the stent in an unexpanded state, the outer sheath translatable coaxially over the inner core and the intraluminal stent; and an outer support shaft at least partially extending over the inner core and the outer sheath; a timing belt having a plurality of belt teeth on a surface of the timing belt; a timing belt link coupled to the outer sheath such that movement of the timing belt link causes movement of the outer sheath to expose the intraluminal stent; a barrel having barrel teeth corresponding to belt teeth; and a thumbwheel coupled to the barrel such that rotation of the thumbwheel causes movement of the barrel such that the barrel teeth engage the belt teeth to cause movement of the timing belt causing movement of the outer sheath.

In yet another aspect, a method of delivering an medical device to a body according to principles described herein uses a delivery device with a catheter having three concentric shafts including an inner core, an outer sheath over the inner core and an outer support shaft; a timing belt having a plurality of belt teeth on a surface of the timing belt; a timing belt link coupled to the outer sheath such that movement of the timing belt link causes movement of the outer sheath; a barrel having barrel teeth corresponding to belt teeth; a thumbwheel coupled to the barrel such that rotation of the thumbwheel causes movement of the barrel such that the barrel teeth engage the belt teeth to cause movement of the timing belt causing movement of the outer sheath; and a medical device over an outer diameter of the inner core; the method includes rotating the thumbwheel in a predetermined direction to cause the timing belt to move in direction associated with the predetermined direction of thumbwheel rotation to cause the timing belt link to move the outer sheath in a desired direction; and deploying the medical device from a distal end of the inner core to the body as the outer sheath moves in the desired direction.

Further embodiments, features, and advantages of the rotary handle stent delivery system and method, as well as the structure and operation of the various embodiments of the rotary handle stent delivery system and method, are described in detail below with reference to the accompanying drawings.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the rotary handle stent delivery system and method with reference to the accompanying figures. Various embodiments disclosed herein illustrate a device and associated method for delivering expandable stents or other medical devices to implant or deploy a stent or other medical device to a target site in the diseased vessel.

FIGS. 1(a)-(c)show various embodiments of a stent delivery handle according to principles described herein. As illustrated, the handle10includes a housing14and a thumbwheel/thumbwheel assembly18, with a triaxial catheter22extending therefrom. The catheter may extend through strain relief26from the housing10. The strain relief26can take any form, such as being made of polyolefin or other similar flexible material.

Referring toFIG. 2, the catheter22includes three concentric or “coaxial” tubes/shafts (a triaxial design): inner core42, outer sheath34and an outer support shaft38. The outer sheath34may be tapered or stepped, as illustrated inFIG. 2, or may not be tapered, depending on the application. The outer support shaft38may be a PEEK (polyaryletheretherketone) tubing extrusion or other similar structure. The outer support shaft38can be manufactured from any semi-rigid material. PEEK exhibits good mechanical properties to provide support for the smaller diameter of the outer sheath and is flexible. PEEK is also an off-the-shelf component. A material other than PEEK may be used to form the outer support sheath, and the invention described herein is not limited to PEEK for use in the outer support shaft38. Functionally, the outer support shaft38and inner core are fixed in position at the proximal end of the delivery system and the outer sheath translates coaxially over the inner core and inside the outer support shaft38. A medical device such as a self-expanding stent (not shown) is held in a reduced delivery configuration for insertion and transport through a body lumen to a predetermined site for deployment. The stent (not shown) is carried axially around the inner core42and is held in its reduced delivery configuration by the outer sheath34. The inner core42may be a braid reinforced tube that extends from the distal end to the proximal end of the device. In some embodiments, the inner core42may extend from the very distal end to the very proximal end (e.g. all the way from end to end). The inner diameter of the tube of the inner core42is sized for tracking over a guidewire and the outer diameter of the tube of the inner core42at the distal end is where the stent (not show) will be crimped between to inner core band markers (50). The outer support shaft38is used to stiffen the delivery device so that the arc of the inner core42will not change outside of the body when the outer sheath34is pulled back to release the stent (not shown) to self-expand. The outer support shaft38is connected to the handle10at the proximal end of the device, which stiffens the delivery system and reduces friction at the treatment insertion site so that the inner core42will not be urged forward as the middle shaft/outer sheath34is pulled backward. As illustrated inFIG. 2, the catheter22may include a distal tip46. The inner core42may further include at least one inner core marker band50such that self-expanding stent is crimped and loaded at the distal end of the catheter and located over the inner core between two inner core marker bands50(only one is shown inFIG. 2) to prevent axial movement of the stent. The crimped and loaded self-expanding stent is circumferentially constrained by the outer sheath34. The outer sheath34may also include an outer sheath marker band54.

The triaxial design allows for more optimal delivery system stability and accurate placement during stent deployment as compared to a traditional 2-coaxial delivery system. The system in introduced into the body at an access location thorough an introducer sheath with hemostasis valve. Where the stent delivery system enters the introducer sheath into the body friction is generated at the hemostasis valve. Therefore, during deployment of a traditional 2-axis system as the outer sheath is being retracted, it wants to move relative to the introducer sheath due to friction, resulting in the inner core pushing out the stent versus retracting the outer sheath. The operator needs to compensate for this and move the entire delivery catheter while deploying the stent to maintain consistent placement during deployment. With long high radial force stents (such as venous stents) this can result in distal/proximal movement (accordion effect) of the entire delivery system during deployment of the stent and can result in inaccurate deployment or malposition of the stent. The triaxial design mitigates this effect as the outer support shaft38is inserted through the introducer sheath and therefore the friction between the outer sheath translation and introducer sheath hemostasis valve is eliminated.

FIG. 3illustrates an exploded view of features of a delivery handle according to principles described herein. The exemplary embodiment illustrated inFIG. 3includes a two-part housing114aand114b, where the respective two parts114aand114bmay be snap fit together for assembly. The thumbwheel18may comprise two wheels118aand118b, an axle58, and a bearing62. The wheels118aand118bmay include teeth on an inner barrel66thereof. Although only one inner barrel is shown inFIG. 3on wheel118b, wheel118amay also include an inner barrel with teeth. The teeth on the inner barrel66are sized to correspond with teeth on a timing belt70. A timing belt link74connects the outer sheath34to the timing belt70. The housing may include a bushing78, which may be a separate component or may be integral to the housing14. The bushing may be formed of PEEK or other suitable material. The exemplary handle ofFIG. 3further includes at least one idler pulley82for tensioning and guiding the timing belt. Also shown inFIG. 3idler pulley axles86corresponding to the idler pulleys82of the embodiment ofFIG. 3. The exemplary delivery handle ofFIG. 3further includes a tensioner assembly90, the tensioner assembly90including a torsion spring94, a tensioner arm98, a tensioner pulley102, a tensioner arm axle106and a tensioner pulley axle112. In the presently described embodiment, the timing belt has teeth on one side (outer diameter or periphery) of the belt and the inner diameter (inner surface) is smooth or substantially smooth or flat. The smooth or flat surface of the timing belt70contacts the idler pulleys82and the tensioner pulley102.

In the exemplary embodiment ofFIG. 3, the outer support shaft38is fixed to the handle housing14, and both the inner core42and outer sheath34are contained within the inner diameter of the outer shaft38. The inner core42will be bonded at the proximal end along with a metal (e.g., stainless steel) shaft30to a female luer116, which is coupled to or clamped into the handle body14. In an aspect of the present invention, the metal shaft30may be bonded to the outer diameter of the inner core42to provide support/rigidity at the proximal end where the inner core42is unsupported in the handle body10. The support of the metal shaft30over the inner core42mitigates potential deformation/buckling of proximal unsupported inner core42during stent deployment. As the outer sheath34is pulled back to release/deploy the stent, the inner core42is put into compression, therefore the unsupported proximal end of the inner core could deform. The bonded metal shaft30provides support and column strength to unsupported proximal inner core42. The metal shaft30may be sized such that is slides over the outer diameter of the inner core42and through the inner diameter of the outer sheath34. The metal shaft30does not impact the inner diameter of the inner core42, so a guidewire (not shown) can still pass through entire assembly. A material other than metal may be used to for the support shaft, and the invention described herein is not limited to metal for use in the support shaft30.

The outer sheath34is coupled to or bonded to the timing belt link74to deliver the stent by retracting the outer sheath34by movement of the thumbwheel, which in turn engages the teeth of the timing belt70via the inner barrel66and the teeth on the inner barrel66. The metal shaft30that is coupled to or bonded to the inner core42/female luer116is a guide rail that the outer sheath34and timing belt link74move proximally over during deployment.

FIG. 4is a cross-sectional view of an assembled handle according to principles described herein. The exemplary embodiment illustrated inFIG. 4shows one part114bof the two-part housing, where the respective two parts may be snap fit together for assembly. Other assembly methods may be used to mate the two parts together such as welding, bonding, gluing or other method. It is contemplated that each side of the two part housing is symmetrical and complementary, but such configuration is not required. The parts of the thumbwheel assembly18may be formed by molding, such as injection molding. The housing14may be unitary.

FIG. 4illustrates one wheel of the thumbwheel assembly18that may comprise two wheels118aand118b, an axle58, and a bearing62. The bearing may include a ball bearing with an inner and outer grooved bearing race. The bearing serves to reduce rotational friction between the thumbwheel and the axle and may be eliminated if the frictional forces are acceptable. An acetal bushing or other method of friction reduction may be used in place of the bearing62.

The wheels118aand118bmay include teeth on an inner barrel66thereof. Although only one inner barrel is shown inFIG. 4on wheel118b, wheel118amay also include an inner barrel with teeth. The teeth on the inner barrel66are sized to correspond with a timing belt70. The inner barrel may be formed by molding, such as injection molding, and the teeth may be formed as part of the molding or other method such that the teeth are integral to the inner barrel66. In another aspect, the teeth may be separable from the inner barrel66.

As shown, the timing belt link74connects the outer sheath34to the timing belt70. The exemplary handle ofFIG. 4further includes at least one idler pulley82for tensioning and guiding the timing belt74. Also shown inFIG. 4idler pulley axles86corresponding to the idler pulleys82of the embodiment ofFIG. 4. The exemplary delivery handle ofFIG. 4further includes a tensioner assembly90, the tensioner assembly90including a torsion spring94, a tensioner arm98, a tensioner pulley102, a tensioner arm axle106and a tensioner pulley axle112. In the exemplary embodiment ofFIG. 4, the outer support shaft38is fixed to the handle housing14, and both the inner core42and outer sheath34are contained within the inner diameter of the outer shaft38. The inner core42will be bonded at the proximal end along with a metal (e.g., stainless steel) shaft30to a female luer116, which is coupled to or clamped into the handle body14.

FIG. 5further illustrates motion of the thumbwheel18, timing belt70and timing belt link74for deployment of a stent according to principles described herein. As illustrated inFIG. 5, outer sheath34is translated proximally over guide tube/inner core42by the timing belt70by rotating the thumbwheel in the direction of the arrow. The timing belt70is driven by an operator via dual thumbwheel assembly18, which may comprise integrally molded gear teeth, the pitch and shape of which correspond to teeth of the timing belt70for synchronizing/engaging the timing belt and causing movement of the timing belt to cause movement of the timing belt link, which is coupled to the outer sheath34to cause movement thereof for unsheathing (deploying) a stent provided therein. The diameter of the inner barrel66, number of teeth on timing belt70, and the pitch/frequency of the teeth on the timing belt70may each be adjusted/modified to allow for variable mechanical advantage during stent deployment and variable translation ratio. In addition, variable speed delivery may also be achieved by actuating the thumbwheel assembly18at the desired speed.

In the embodiment illustrated inFIG. 5, rotation of the portion thumbwheel18external to the handle proximally (in the direction of the arrow) causes an upper portion of the portion of the timing belt adjacent the portion of the thumbwheel internal to the handle to move distally (in the direction of the arrow). The timing belt70extends around an idler pulley82such that a portion of the timing belt70adjacent the timing belt link74move proximally (in the direction of the arrow), engaging the timing belt link74to move the timing belt link74proximally, which moves the outer sheath34coupled thereto proximally, thereby unsheathing the stent for deployment. Movement may be reversed for re-sheathing of catheter following stent deployment.

FIGS. 6(a)-(c)are cross-sectional views of the delivery device according to principles described herein and illustrates motion of the timing belt link74and outer sheath34upon movement of the thumbwheel18counterclockwise in the context ofFIGS. 6(a)-(c). It should be appreciated that the direction of thumbwheel rotation described herein is described in the context of the cross-section provide, but that it is contemplated that the portion of thumbwheel external to the handle14will be rotated rearward (in a proximal direction). It is also contemplated that the configuration of the timing belt70may be adjusted (for example, looped over the thumbwheel) to modify the direction of rotation of the thumbwheel corresponding to the proximal movement (retraction) of the outer sheath34.

As shown inFIG. 6(a), in an introducing position, the timing belt link is at a distal end of the handle housing. As the thumbwheel18is actuated in a predetermined direction, e.g. in the context of the cross-section shown, counterclockwise, the timing belt link/shuttle74moves proximally. Because the timing belt link/shuttle74is coupled to the outer sheath34, the outer sheath moves proximally with the timing belt link/shuttle to expose a stent or other medical device mounted on the inner core42(not shown).FIG. 6(b)illustrates the positioning of the timing belt link/shuttle in a partially deployed position (e.g. the stent is partially deployed (not shown)). As the thumbwheel18is further rotated in a timing belt link/shuttle74further translates proximally to allow for full deployment of the stent or medical devices from the of the inner core42, as shown inFIG. 6(c). In the embodiment here described, the thumbwheel18is actuated such that the upper side (external portion) of the thumbwheel is rotated proximally to cause the timing belt link/shuttle74to transit proximally. It is appreciated that the configuration/path of the timing belt70may be configured such that a distal rotation of the upper side (external portion) of the thumbwheel18may cause the timing belt link/shuttle74to transit proximally to cause the outer sheath34to retract from the inner core42to allow deployment of the medical device (not shown).

Although not shown in the figures, the thumbwheel may be a single thumbwheel with appropriate teeth corresponding to the teeth of the timing belt. As illustrated in the top view ofFIG. 7, a thumbwheel comprising two wheels allows for a balanced design in which the catheter may exit the handle at a central portion of the distal end of the handle.FIG. 7shows an assembled handle10and housing14, and a thumbwheel assembly18having a first thumbwheel118aand a second thumbwheel118bseparated by inner barrel66. This configuration facilitates operation of the delivery device by holding the handle from either the left or the right side, allowing for comparable operation regardless of whether the operator is left or right handed.

FIG. 8illustrates a perspective view of the delivery device according to principles described herein, including the catheter device. As shown inFIG. 8, the timing belt70extends around idler pulleys82and the tensioner pulley102of tensioner90. The tensioner pulley102is coupled to the torsion spring94via the tensioner arm98. Tension is maintained on the timing belt by torsion spring94on tensioner arm axle106, which urges the tensioner pulley102into contact with the timing belt70via the tensioner arm98.

FIG. 9is a cross-sectional line drawing showing detail of an exemplary embodiment of the thumbwheel assembly18and the timing belt link74. As illustrated inFIG. 9, one part118bof a two-part thumbwheel18has an outer surface122that may be textured for ease of use. The thumbwheel part118bmay also include an inner surface or rim126. An inner barrel66extends from the thumbwheel part118band has a plurality of barrel teeth130thereon. The barrel teeth130on the inner barrel66are sized to correspond with a timing belt (not shown). Although not illustrated, the barrel teeth130may have a standard periodicity (pitch) or may have a variable periodicity (pitch) such that actuation of the thumbwheel assembly may cause movement of the timing belt (not shown) and thus translation of outer sheath34at a first rate when barrel teeth of a first periodicity engage the timing belt (not shown) and at a second rate when barrel teeth of a second periodicity engage the timing belt (not shown). Such variable rate may be imparted by having different spacing/periodicity/pitch of the teeth on the timing belt instead of or in addition to having different spacing/periodicity/pitch of the barrel teeth130on the inner barrel66.FIG. 9further illustrates the thumbwheel bearing62and the thumbwheel axle58.

A safety locking feature (not shown) may be incorporated in the handle design such to mitigate inadvertent actuation of the handle during transit and storage. The safety locking feature may be a removal/disposal or toggle feature that engages the teeth on the inner barrel to lock it in place and prevent rotation. The safety locking feature may also be a feature that engages the timing belt link to prevent its translation.