Abstract:
A system for delivering at least one medical device to a desired location for treatment, and then selectively deploy it in position, includes an improved handle. One of the possible features of the handle may be to selectively hold the delivery system components at any desired configuration during deployment and positioning of the medical device. Another possible feature of the handle may be more than one mode of operation, in which the deployment of the medical device can selectively proceed at more than one speed.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION  
         [0001]    1. Technical Background  
           [0002]    The present invention relates generally to medical devices, and more particularly to a medical device delivery system with an improved two-way handle having a compound mechanism.  
           [0003]    2. Discussion  
           [0004]    The present invention involves medical devices, and also the delivery systems used to convey them to a desired location for treatment, and then deploy them in position. Many such medical devices are resiliently compressed to a smaller initial size for containment, protection, storage and eventual delivery from inside a catheter system. Upon deployment, the medical devices may resiliently expand to a larger deployed size.  
           [0005]    A successful example of a delivery catheter system, in this case for a self-expanding stent, is described in U.S. Pat. No. 6,019,778 entitled “Delivery Apparatus For A Self-Expanding Stent,” to Wilson et al. issued Feb. 1, 2000. The disclosure of this patent is incorporated by reference in the present application, and generally discloses a flexible catheter system shown in a representative diagrammatic form in FIG. 10, including coaxially arranged inner and outer catheter members, each having a hub affixed to its proximal end. The outer sheath is described in the &#39;778 patent as an elongated tubular member having distal and proximal ends, which is made from an outer polymeric layer, an inner polymeric layer, and a braided reinforcing layer between them. The inner shaft is described in the &#39;778 patent as being located coaxially within the outer sheath and has a flexible tapering distal end, which generally extends distally beyond the distal end of the outer sheath. The inner shaft member also is shown as including a stop which is positioned proximal from the distal end of the outer sheath. A self-expanding stent is located within the outer sheath, and is located between the stop on the inner shaft member and the outer sheath distal end. To deploy the stent the outer sheath is withdrawn by a physician in a proximal direction, while the inner shaft member is held in position.  
           [0006]    Additional examples of different types of known self-expanding stent delivery systems are shown in U.S. Pat. No. 4,580,568 issued to Gianturco on Apr. 8, 1986; as well as U.S. Pat. No. 4,732,152 issued to Wallsten et al. Mar. 22, 1988.  
           [0007]    In operation, these known medical device delivery systems are generally advanced within a body of a patient along a desired vascular path or other body passageway, until the medical device within the catheter system is located at a desired site for treatment. While watching the relative positions of the medical device and the catheter system components with respect to a stenosis on a video x-ray fluoroscopy screen, the physician holds the proximal hub attached to the inner shaft member in a fixed position with one hand, while simultaneously gently withdrawing the proximal hub attached to the outer tubular sheath with the other hand.  
           [0008]    For several reasons, this deployment operation may require some measure of delicate skill. For example, among these reasons is the dynamic blood flow at the desired site for treatment, which may be further disrupted by the presence of a lesion or stenosis to be treated. Another factor is the gradual resilient expansion of a medical device as the outer sheath is retracted. This gradual expansion presents an opportunity for a possible reverse “watermelon-seed” phenomenon to occur. This reverse watermelon-seed effect may cause the resilient medical device to tend to push the outer sheath back in a proximal direction with a force that tends to follow a curve similar shown in FIG. 15.  
           [0009]    As a result, the physician may need to accurately hold the two proximal hubs in a specific relative position, holding them against this expansion force, while attempting to very accurately position the medical device up until contact with the anatomy. One of the possibilities that may affect the positioning of the deployed medical device is that the inner shaft should preferably be held stationary in the desired position. If the physician&#39;s hand that holds the inner shaft hub does inadvertently move during deployment, it is possible that the medical device may be deployed in a non-optimum position.  
           [0010]    Another possible factor is that the inner and outer catheter shaft members, like any other elongated object, do not have infinite column strength, which may present an opportunity for the position and movement of each proximal hub to differ from the position and movement of the respective distal ends of the inner and outer shaft members. Yet another factor is that the position of the medical device may be adjusted up until the point at which a portion of the expanding portion of the medical device touches the sidewalls of the body passage, so that the position of the medical device should preferably be carefully adjusted until immediately before a portion of the medical device touches the anatomy.  
           [0011]    Some known catheter systems require two-handed operation, such as those with a pair of independent hubs, one hub on the inner and outer shaft member, respectively. Other known catheter systems include a pistol and trigger grip, with a single mode of deployment, involving a single trigger pull to deploy the associated medical device.  
           [0012]    Accordingly, although physicians may be capable of operating such known systems with great skill, it is desirable to provide an improved catheter delivery system capable of facilitating easier and more accurate deployment and positioning of resiliently expansive medical device.  
           [0013]    In addition, it is desirable to provide an advanced catheter deployment mechanism having two modes of operation. In the first mode of operation, the delivery mechanism preferably provides a precisely adjustable link between the inner and outer catheter shaft members, such that the relative position of the outer sheath with respect to the inner catheter shaft member can be precisely and selectively adjusted. Yet at any selected position, the delivery mechanism should preferably maintain this selected relative position of the inner and outer catheter shaft members, while resisting any force that may be present tending to move the inner or the outer catheter shaft members with respect to the other. In a second mode of operation, the delivery mechanism should preferably enable the physician to rapidly withdraw the outer tubular sheath with respect to the inner catheter shaft member preferably in a proximal direction with a single easy motion.  
           [0014]    The present invention provides such a desirable medical device delivery mechanism, with an integrated handle replacing the functions of the separate proximal hubs of the prior inner and outer catheter shaft members, and also providing desired dual modes of operation.  
           [0015]    These and other various objects, and advantages and features of the invention will become apparent from the following description and claims, when considered in conjunction with the appended drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is an external perspective view of a medical device delivery mechanism and handle, arranged according to the principles of the present invention;  
         [0017]    [0017]FIG. 2 is a partial longitudinal cross-sectional view of a medical device delivery system arranged according to the present invention in an initial configuration;  
         [0018]    FIGS.  3 - 5  are partial longitudinal cross-sectional views of the medical device delivery system of FIG. 2, in various operating configurations;  
         [0019]    [0019]FIG. 6 is an exploded view of the medical device delivery system components;  
         [0020]    FIGS.  7 - 9  are partial cross-sectional views of a distal end portion of the medical device delivery system of FIG. 2, corresponding to various operating configurations;  
         [0021]    [0021]FIG. 10 is an external perspective view of a known medical device delivery system;  
         [0022]    FIGS.  11 - 14  are perspective views of proximal and distal ends of a medical device delivery system arranged according to the principles of the present invention, in various operating configurations; and  
         [0023]    [0023]FIG. 15 is a diagrammatic example of a possible graph showing total resistive forces with respect to positional distance, of a medical device delivery system arranged according to the principles of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    The following description of the preferred embodiments of the present invention is merely illustrative in nature, and as such it does not limit in any way the present invention, its application, or uses. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention.  
         [0025]    Referring to the drawings, a medical device delivery system is depicted, with one of the preferred embodiments of the present invention being shown at  10 . The illustrated stent delivery catheter system  10  of course depicts only one of many different medical device delivery systems designs that are within the scope of the present invention. For clarity and convenience, the present detailed description will only describe such an example of a delivery system for stents.  
         [0026]    One possible medical device delivery system that may be used with the present invention is any appropriate system in which an outer sheath is provided, surrounding an inner shaft. A medical device may be carried within the outer sheath during delivery to a desired site for treatment, where the outer sheath may be retracted, while the inner shaft and medical device are held in place.  
         [0027]    The novel concept of the present invention may also be used for medical device delivery systems in which the motion of the operator to deploy the medical device is selected from any suitable possibility, including axial motion in the proximal direction or the distal direction, or a rotational motion, a trigger actuator, a gear mechanism, or any other type of actuator that may be preferred, depending upon a particular application. Indeed, the present unique concept may be used for medical device delivery systems in which the medical device is deployed in any suitable manner, including retracting an outer sheath in a proximal direction or a distal direction, or uncovering a medical device in various ways, including withdrawing portions of outer sheath members in proximal and distal directions, simultaneously or sequentially.  
         [0028]    The present invention may provide several advantages individually, or any combination of such advantages, including for example: (i) single-handed operation of the medical device delivery system; (ii) a mechanism providing leverage or mechanical advantage, to adjust or reduce the forces needed to operate the system; (iii) improved accuracy in positioning the medical device during deployment; (iv) a capability of holding the delivery system components in a fixed relative position during an intermediate point in deploying a medical device; and (v) multiple operational modes of operation, including for example a first mode of fine and precise control of the deployment process, and a second mode of rapid and easy deployment.  
         [0029]    The particular embodiment  10  of the present invention selected for illustration in the drawings includes a handle, shown in detail in FIGS.  1 - 6 . A first and second main body housing  12  and  14  are arranged in a side-by-side configuration, as shown for example in FIG. 1. Other components include inner and outer shaft members  16  and  18  respectively, an anchoring member  20 , a proximal hub  22  with an actuator or knob  24  and a corresponding flush lumen tube  26  and valve  28 , as well as a threaded base member  30  and a rotating finger ring  32 .  
         [0030]    The main body housings  12  and  14  each preferably have several gripping knurls  34  for providing a physician with a good gripping surface, a longitudinal slot  36  defining a channel for sliding the movable actuator  24  and limiting the extent of possible travel for the actuator  24  and proximal hub assembly  22 , a side opening  38  through which a physician can operate the rotating finger ring  32 , a proximal anchoring aperture  40  adapted to capture a portion of the anchoring member  20 , a distal shaft aperture  42  through which the inner and outer shaft members  16  and  18  extend, and several openings for receiving fasteners  44  to hold the main body housings  12  and  14  together. The main body housings  12  and  14  also define a circular annular bearing shelf or shoulder  46 . A distal surface of rotating finger ring  32  touches this shoulder  46  in an initial configuration, and rotation of the rotating finger ring  32  causes it to advance along threaded base  30  and press on shoulder  46 , resulting in very precise and sensitive withdrawing movement of outer shaft member  18  in a proximal direction.  
         [0031]    In the particular assembly shown in the drawings, main body housings  12  and  14  are held together by fasteners  44 . Anchor aperture  40  fixedly receives anchor  20 , which is affixed to the proximal end of inner shaft member  16 . A proximal end of outer shaft member  18  is affixed to proximal hub  22 , with a flexible strain relief  48  protecting the joint. In the preferred initial configuration, proximal hub  22  is affixed to threaded base  30 , which rotatably carries rotating finger ring  32 , which bears on the shoulder  46  of main body housing  12 .  
         [0032]    The preferred dual operation of the present invention is accomplished by enabling movement of outer shaft member  18  with respect to inner shaft member  16  in two ways. First, by rotating the finger ring  32  to cause it to advance on threaded base  30  and press against shoulder  46 , such that the entire assembly of threaded base  30 , proximal hub  22  and outer shaft member  18  withdraw proximally with respect to main body housing  12  and  14 , and thus with respect to inner shaft member  16 . Second, by simply grasping knob  24  and pulling or pushing it within slot  36 . The first method allows precise and sensitive adjustment, while the second method allows relatively large-scale and rapid movement.  
         [0033]    At the distal end of the medical device delivery system, shown in detail in FIGS.  7 - 9 , distal ends of the inner and outer shaft members  16  and  18  are depicted, as well as whatever medical device is selected, in this particular case a stent  50 . The stent  50  shown in the drawings is of the self-expanding type, and may be captured within a tubular capsule  52  affixed to outer shaft member  18 . The distal end of inner shaft member  16  may be provided with a flexible tapering distal tip  54 . At least a proximal annular stop  56 , and preferably also a distal annular ring  58 , are affixed to inner shaft member  16 . The stop  56  and ring  58 , as well as a distal marker  60  that may be provided, are preferably radiopaque.  
         [0034]    In addition, the inner shaft member  16  assembly, including anchor  20 , inner shaft member  16  and distal tip  54 , may preferably be provided with a through lumen adapted to receive a guidewire  62 .  
         [0035]    In operation, the medical device delivery system  10  is advanced via a body passageway, preferably along a guidewire  62 , until the stent  50  is located within a desired site for treatment. A physician gently rotates the finger ring  32  to slightly pull back outer shaft member  18 . At this point, a small portion of the stent  50  may expand slightly. The handle of the present invention comfortably holds the delivery system  10  in this intermediate configuration, allowing the physician time and flexibility of procedure to selectively optimize the position of the stent  50  within the desired site. This precise adjustment of the position of the stent  50 , before any portion of the stent  50  touches the body passage or vessel  64  in a manner that might inhibit further positional adjustment, is preferable.  
         [0036]    When the physician is satisfied with the positioning, the finger ring  32  may be further rotated to cause a distal end of the stent  50  to gently contact the vessel  64 . When such contact occurs, and the stent is expanded sufficiently to independently hold its position, it is desirable to rapidly and completely withdraw the outer shaft member  18 . To do so, the physician grasps the knob  24  and pulls it back along slot  36 . The outer shaft member  18  may thus be withdrawn as quickly as the physician wishes.  
         [0037]    Various materials may be selected for the components of the present invention, including any material having the desirable performance characteristics. In the particular embodiment shown in the drawings, the inner and outer shaft members  16  and  18 , strain relief  48 , and distal tip  54  may be made of any biocompatible and suitably flexible yet sufficiently strong material, including polymers of various types. Possible selections for such materials include nylons or polyamides, polyimides, polyethylenes, polyurethanes, polyethers, polyesters, etc. In the alternative, some portion or all of the inner and/or outer shaft member  16 ,  18  may be formed of a flexible metal, including for example stainless steel or nitinol hypotube. The stent  50 , stop  56 , ring  58 , marker  60  are preferably made of any biocompatible material that is strong and rigid, including for example stainless steel, platinum, tungsten, etc. The components of the handle of the present invention are preferably made of a material that is strong and rigid, including for example inflexible polycarbonates, or even some metal components.  
         [0038]    Of course, many different variations are included within the scope of the present invention. Some of these variations or alternative embodiments include any possible arrangement of sizes, materials, and designs within the bounds of the following claims.  
         [0039]    It should be understood that an unlimited number of configurations for the present invention could be realized. The foregoing discussion describes merely exemplary embodiments illustrating the principles of the present invention, the scope of which is recited in the following claims. Those skilled in the art will readily recognize from the description, claims, and drawings that numerous changes and modifications can be made without departing from the spirit and scope of the invention.