Patent Application
20090210046
The present invention relates generally to handles for medical device delivery systems and, more particularly, to a handle for a vascular stent delivery system.
Stents are generally cylindrically shaped devices which function to hold open and sometimes expand a segment of a blood vessel or other arterial lumen, such as coronary artery. 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. They are particularly suitable for use to support and hold back a dissected arterial lining which can occlude the fluid passageway there through. Stents are particularly useful in the treatment and repair of blood vessels after a stenosis has been compressed by percutaneous transluminal coronary angioplasty, percutaneous transluminal angioplasty, or removed by atherectomy or other means, to help improve the results of the procedure and reduce the possibility of restenosis. Stents, or stent like devices, are often used as the support and mounting structure for implantable vascular grafts which can be used to create an artificial conduit to bypass the diseased portion of the vasculature, such as an abdominal aortic aneurism.
A variety of devices are known in the art for use as stents and have included coiled wires in a variety of patterns that are expanded after being placed intraluminally on a balloon catheter; helically wound coiled springs manufactured from an expandable heat sensitive metal; and self expanding stents inserted into a compressed state for deployment into a body lumen. One of the difficulties encountered in using prior art stents involve maintaining the radial rigidity needed to hold open a body lumen while at the same time maintaining the longitudinal flexibility of the stent to facilitate its delivery and accommodate the often tortuous path of the body lumen.
Prior art stents typically fall into two general categories of construction. The first type of stent is expandable upon application of a controlled force, often through the inflation of the balloon portion of a dilatation catheter which, upon inflation of the balloon or other expansion means, expands the compressed stent to a larger diameter to be left in place within the artery at the target site. The second type of stent is a self expanding stent formed from shape memory metals or superelastic nickel titanium alloys, which will automatically expand from a compressed state when the stent is advanced out of the distal end of the delivery, or when a restraining sheath which holds the compressed stent in its delivery position is retracted to expose the stent.
Some prior art stent delivery systems for delivery and implanting self expanding stents include an inner member upon which the compressed or collapsed stent is mounted and an outer restraining sheath which is initially placed over the compressed stent prior to deployment. When the stent is to be deployed in the body vessel, the outer sheath is moved in relation to the inner member to “uncover” the compressed stent, allowing the stent to move to its expanded condition. Some delivery systems utilize a “push pull” type technique in which the outer sheath is retracted while the inner member is pushed forward. Another common delivery system utilizes a simple pull back delivery system in which the self expanding stent is maintained in its compressed position by an outer sheath. Once the mounted stent has been moved at the desired treatment location, the outer sheath is pulled back via a deployment handle located at a remote position outside of the patient, which uncovers the stent to allow it to self expand within the patient. Still other delivery systems use an actuating wire attached to the outer sheath. When the actuating wire is pulled to retract the outer sheath and deploy the stent, the inner member must remain stationary, preventing the stent from moving axially within the body vessel.
Controlled deployment of the stent can be a desirable feature in various applications. This can be particularly true when attempting to deploy a self-expanding stent which may tend to spring forwardly when withdrawing the sheath. Further, it can be desirable to employ a system which provides such control and which can accomplish both effectively concerning a medical device.
Accordingly, it has been found to be desirable to have a handle for a delivery system which provides additional control. It has been contemplated that a handle including multiple structures providing varied control may address this need.
The present invention disclosed herein satisfies these and other needs.
Briefly and in general terms, the present invention is directed towards a system for delivering a medical device within vasculature. In one aspect, the medical device is a self-expanding stent.
In one embodiment, the handle assembly includes a plurality of sub-assemblies which cooperate to accomplish the delivery of a medical device within a patient's body. The handle assembly can include a trigger assembly and a thumbwheel assembly each of which are operatively associated with a shuttle assembly. A locking mechanism can be further provided to lock these assemblies in place prior to use.
In a particular aspect, the present invention includes a handle assembly including a belt attached at one end to a shuttle assembly and configured about a thumbwheel spool at its other end. In one embodiment, the shuttle assembly is configured to move longitudinally with respect to a handle casing of the handle assembly. The shuttle assembly can further be attached to a sheath or other structure enclosing the medical device. Further, the shuttle assembly can be activated in a plurality of ways. That is, the shuttle assembly can be manipulated via a trigger assembly operatively connected to the shuttle and can alternatively be translated by rotating the thumbwheel assembly which includes the thumbwheel spool.
In a further aspect of the present invention, the belt has a thickness and a width, the width being greater than the thickness. The belt is configured generally vertically at its connection to the shuttle assembly which is slideably configured within a distal portion of the handle assembly. From this connection, the belt extends proximally past a first side of the thumbwheel assembly and around a proximal spool. The belt is directed distally and is turned counterclockwise to assume a horizontal configuration when viewing the belt from a proximal location. While horizontal, the belt passes a second side of the thumbwheel assembly, extending distally to and about a pair of idler trigger sleeves and a pulley trigger then back proximally to the spool of the thumbwheel assembly.
Accordingly, the present invention contemplates dual methods of the withdrawal of a sheath of the delivery system. In this manner, the operator is provided with enhanced control of the delivery and implantation of a medical device.
These and other features of the present invention become apparent from the following detailed description and the accompanying exemplary drawings.
The present invention relates to a system that delivers and deploys a medical device at a target site within a patient's body, such as a body lumen. For illustration purposes, the following exemplary embodiments are directed to a handle assembly for a system for delivering and deploying a self expanding stent, although it is understood that the present invention is applicable to other medical devices which are implantable in a body lumen as well as other parts of the body. Additionally, the medical device can be either a self-expanding device or a non self-expanding device.
Referring now to
Further, in one aspect, the handle assembly includes a trigger sub-assembly 32 and a thumbwheel sub-assembly 34 each of which are mounted to or within the handle housings 28, 30 and which can be alternatively actuated to effect longitudinal movement of a shuttle assembly 36 (See
The system 20 can further be equipped with a locking mechanism 42. This locking mechanism 42 cooperates both with the thumbwheel sub-assembly 34 and the shuttle subassembly 36 to inhibit activation of those assemblies when the device is not in use.
Turning now to
Furthermore, the trigger sub-assembly 32 includes a trigger handle 48 which is connected to a trigger sliding component 50 (See
The trigger sub-assembly further including a belt 56 which extends back and forth through a plurality of turns within the handle assembly 27. The belt 56 has a thickness and a width, the width being greater than the thickness. In one aspect, the belt 56 has a generally constant width and has generally orthogonally arranged surfaces. As described in more detail below, one end 58 of the belt 56 is attached to the shuttle assembly 36 (See
As shown in
Moreover, the thumbwheel sub-assembly 34 includes an elongate, thumbwheel pivot web assembly 68. The pivot web assembly 68 defines a rail-like sub-structure which extends substantially a length of the handle assembly 22 (See
With reference now to
From its distal terminal end connection to the shuttle assembly 36, the belt 56 extends proximally. As best seen in
Upon reaching a distal portion 80 of the handle housing 28, the belt 56 is routed first about a lower idler 82 then proximally again about a trigger pulley 84. The belt 56 takes yet another turn of direction distally and is routed about an upper idler 86. From here, the belt 56 extends proximally once again in the direction of the thumbwheel sub-assembly 34 (See also
Prior to use, the locking mechanism 42 is placed into engagement with both the shuttle assembly 36 and thumbwheel sub-assembly 34 (See
As stated, in use, either the thumbwheel sub-assembly 34 or the trigger sub-assembly 32 can be actuated to effect longitudinal relative movement between a sheath or similar structure and a medical device to accomplish deployment of the medical device at a treatment site. Moreover, each of the thumbwheel 34 and trigger 32 sub-assembly can be actuated alternatively or in exclusion of the other to accomplish such deployment.
Through the rotation of the thumbwheel 62, the proximal terminal end 60 of the belt 56 gathers about the thumbwheel spool 66 (See
Actuation or rather proximal movement of the trigger 48 of the trigger sub-assembly 32 likewise causes the shuttle assembly 36 to move proximally along the pivot web assembly 68. Here, as the trigger is moved proximally, the trigger slider 50 travels proximally along the trigger retainer assembly 44 (See
Therefore, the handle assembly of the present invention provides a system including a plurality of means for accomplishing relative motion.
It is to be understood that even though numerous characteristics and advantages of the present invention have been set forth in specific description, together with details of the structure and function of the invention, the disclosure is illustrative only and changes may be made in detail, such as size, shape and arrangement of the various components of the present invention, without departing from the spirit and scope of the present invention. It would be appreciated to those skilled in the art that further modifications or improvement may additionally be made to the delivery system disclosed herein without departing from the scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.
