Patent Publication Number: US-2006004394-A1

Title: Double-ended conduit with graded locking sleeves

Description:
RELATED APPLICATION  
      The present patent document claims the benefit of the filing date under 35 U.S.C. §119(e) of Provisional U.S. Patent Application Ser. No. 60/570,660, filed May 13, 2004, which is hereby incorporated by reference. 
    
    
     BACKGROUND  
      1. Technical Field  
      The present invention relates to a tubular member for use in joining attachable tissue segments, and more particularly, to a tubular conduit for end-to-end anastomosis of medical grafts, body vessels, and the like.  
      2. Background Information  
      Anastomosis is the joinder of hollow vessels to create an internal communication between them. An anastomosis is generally created by a surgical procedure that joins two body vessels, vascular grafts, or a body vessel and a graft, in order to create or restore a pathway for fluid flow through the joined structure. Commonly, an anastomosis is created by vascular surgery to join two blood vessels, grafts, or a blood vessel and a graft, to create or restore blood flow therethrough.  
      Current devices and techniques exist which allow for open-ended surgical attachment of harvested blood vessels or grafts for purposes such as the avoidance of a vessel blockage, replacement of diseased vessels, and vascular access. Such techniques include sewing or otherwise attaching a vessel or graft between open ends of existing vessels. Examples of vessel pairs which are frequently joined by a vessel or graft include an internal mammary artery and a coronary vessel, the radial artery and cephalic vein, the brachial artery and cephalic vein, the brachial artery and basilica vein, the ulnar artery and a basilica vein, and a brachial artery and branches of the antecubital vein, among others.  
      It is generally preferred to join such vessels utilizing the patient&#39;s natural vessels. This connection may be between two natural vessels positioned in their natural place of orientation in the body, or alternatively, utilizing one or more natural vessels harvested from another portion of the patient&#39;s anatomy. Utilizing a vessel harvested from another portion of the patient&#39;s anatomy minimizes the possibility that the patient will experience incompatibility or rejection problems of the type that may occur when using graft materials that originate from an external source, or from using exogenous tissue. In addition, such harvested vessels provide a ready supply of biological tissue that has already proven to be biologically compatible with the patient.  
      At times, however, suitable body vessels may not be available for harvesting. In such cases, a synthetic vessel (e.g., TEFLON® or DACRON®) or an exogenous vessel may be used. Synthetic vessels have been found to be effective in many instances. However, such vessels have shown a greater propensity to become narrowed than do natural arteries or veins. Exogenous vessels may also be utilized in an appropriate case. However, there is a greater likelihood of patient incompatibility with such vessels when compared to vessels harvested from the patient.  
      Many different types of anastomosis connections between a vessel and a graft are known in the medical arts. For example, an anastomosis connection may be utilized to join vessels from the end of a graft to the side of a vessel, commonly referred to as an end-to-side connection. An anastomosis connection may also be utilized to join the end of a graft to the end of a vessel, commonly referred to as an end-to-end connection. A side-to-side connection of a vessel and a graft may also be established. This type of connection is commonly referred to as a fistula.  
      End-to-end connections are generally considered beneficial because they essentially mimic the normal flow of fluid through the natural vessel. With regard to such end-to-end connections, however, it is important to insure that a secure and leak-free connection be established. Prior art connection devices are at times unsecure, and also have been prone to leakage. While synthetic joinder materials are available, such materials are often complicated and difficult to use. A need exists for an improved device for end-to-end connection that provides a secure and leak-free connection, that is relatively easy for the surgeon to manipulate and insert, and that is cost-effective.  
     BRIEF SUMMARY  
      The present invention addresses the problems of the prior art by providing an improved conduit for an end-to-end anastomosis connection. The conduit may comprise a double-ended conduit having graded locking sleeves.  
      In one embodiment, the present invention comprises an apparatus for use in end-to-end anastomosis. The apparatus comprises a hollow tubular conduit having two ends, and a pair of opposing locking sleeves disposed along an outer surface of the conduit. At least one of the ends may include a barbed ring adjacent the end. Each of the locking sleeves has an inner diameter related to an outer diameter of the conduit in a manner such that little or no clearance extends therebetween.  
      In another embodiment, the present invention comprises a method for end-to-end anastomosis of vessels. An anastomosis device includes a hollow tubular conduit having two ends, a barbed ring adjacent at least one of the ends, and first and second locking sleeves disposed along an outer surface of the conduit. Each of the locking sleeves has an inner diameter related to an outer diameter of the conduit such that little or no clearance extends therebetween. A first vessel is slid in axial direction over one of the ends of the conduit and over an adjacent barbed ring toward a center portion of the conduit. A second vessel is then slid axially from the opposite side of the conduit over the other end of the conduit toward a center portion of the conduit. The first vessel is further slid axially toward the center portion between the first locking sleeve and the conduit outer surface, such that the first vessel frictionally engages the first locking sleeve and the conduit outer surface. The second vessel is further slid axially toward the center portion between the second locking sleeve and the conduit outer surface, such that the second vessel frictionally engages the second locking sleeve and the conduit outer surface. The first and second sleeves may then be locked around the respective first and second vessels, such as by sliding the sleeves axially in a direction away from the center portion of the conduit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side view, partially in section, of an embodiment of the double-ended conduit of the present invention;  
       FIG. 2  is a sectional view of a locking sleeve of the apparatus of  FIG. 1 ;  
       FIG. 3  is an end view of the locking sleeve of  FIG. 2 ;  
       FIG. 4  is a side view, partially in section, of the double-ended conduit of  FIG. 1 , showing the joinder of two vessels;  
       FIG. 5  is a view of the conduit of  FIG. 4 , showing the locking sleeves in a locked position;  
       FIG. 6  is a side view, partially in section, of an alternative embodiment of a double-ended conduit;  
       FIG. 7  is a view of the conduit of  FIG. 6 , showing the locking sleeves in a locked position; and  
       FIG. 8 a  side view, partially in section, of another alternative embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED EMBODIMENTS  
      For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.  
      The present invention comprises a percutaneous anastomosis connection system for establishing an end-to-end anastomosis connection between two hollow structures in the body. The particular connections resulting from use of the inventive apparatus may be, for example, a graft-to-graft connection, a vessel-to-graft connection, or a vessel-to-vessel connection. For a vessel-to-vessel connection, the connection may be established between natural vessels, exogenous vessels, synthetic vessels, or any combination of the foregoing.  
      Although it is expected that the apparatus will normally be utilized to connect blood vessels, other body vessels may be joined to vessels, other body structures, grafts, synthetic or exogenous vessels. One non-limiting example of a connection of this type comprises the connection of the ureter vessel to the urethra. For applications in bodily systems, such as the circulatory system, ultrasound guidance can be utilized to help establish connection between the apparatus and other structures in the system, such as an artery, a vein, or both an artery and a vein. Those skilled in the art will appreciate that other bodily connections can be made using the apparatus and method of the present invention, and that medical guidance systems other than ultrasound may be utilized in an appropriate case, all of which are considered within the scope of the invention.  
      Such hollow body vessels, such as blood vessels, are joined in a manner to permit or restore fluid flow therebetween. The anastomosis connection provides a means to bridge the vessels within the body of a patient in end-to-end fashion. The term “vessel” is used herein in inclusive fashion to include body vessels or other hollow structures (both endogenous and exogenous), medical grafts, synthetics, and other segments that may be joined by the apparatus of the present invention.  
      In a preferred embodiment, the inventive apparatus for establishing the end-to-end anastomosis connection comprises a double-ended tubular conduit. The tubular conduit is provided with a plurality of locking sleeves for locking the vessels, etc., to be joined. Preferably, the locking sleeves are oriented such that a separate locking sleeve is provided at each axial end of the conduit. The double-ended tubular conduit may also include one or more grasping elements, such as a barbed ring, disposed near each axial end of the tube. Preferably, the locking sleeves have a graded internal diameter that decreases in the direction of the center of the tubular conduit.  
      The invention will now be described in connection with the figures.  FIG. 1  illustrates one embodiment of an apparatus  10  for establishing an end-to-end anastomosis of medical grafts, blood vessels or other hollow body structures. Apparatus  10  comprises a generally cylindrical hollow tubular conduit  12  having opposing axial ends  14 ,  16 . Tubular conduit  12  preferably includes one or more grasping structures, such as barbed rings  18 ,  20  positioned along the circumference of conduit  12 . Each one of opposing ends  14 ,  16  is disposed on a separate side of an imaginary midline  25  that separates tubular conduit  12  into two half-sections, or ends.  
      Apparatus  10  also includes opposing sleeves  24 ,  26  circumferentially disposed on the outer surface of tubular conduit  12 . Each one of sleeves  24 ,  26  is preferably disposed on a separate side of imaginary midline  25 . Preferably sleeves  24 ,  26  have a graded internal diameter. Sleeve  24  is aligned such that the internal diameter of the sleeve decreases toward the center of the conduit (i.e., toward imaginary center line  25 ), from a maximum diameter end  28  to a minimum diameter end  30 . Sleeve  26  is aligned such that the internal diameter of the sleeve decreases toward the center of the conduit, from a maximum diameter end  29  to a minimum diameter end  31 .  
       FIG. 2  is a cross-sectional view of sleeve  24  showing diameters  28 ,  30 .  FIG. 3  is an end view of sleeve  24 , taken from the orientation of  FIG. 1 . The outer diameter of conduit  12  is sized relative to the minimum inner diameter  30 ,  31  of sleeves  24 ,  26  such that there is little or no clearance between the conduit outer diameter and the sleeve minimum diameter.  
      Use of apparatus  10  for establishing an anastomosis connection between two vessels will now be described. Initially, tubular conduit  12  is loaded by inserting graded sleeves  24 ,  26  onto respective conduit ends  14 ,  16 . Since there is little or no clearance between the conduit outer diameter and the sleeve minimum diameter, the tubular conduit must normally be flexed, squeezed or otherwise momentarily deformed to allow the locking sleeves to pass over respective grasping structure  18 ,  20 , such as barbed rings, to reach the positions shown in  FIG. 1 . The compositions of tubular conduit  12 , grasping structures  18 ,  20  and sleeves  24 ,  26  are selected to enable the apparatus  10  to be assembled in this manner. Alternatively, the various components of apparatus  10  may be loaded by other means well known in the art.  
      As shown in  FIG. 4 , a first body vessel  40  to be joined is slid in an axial direction (to the right in  FIG. 4 ), over end  14  and barbed ring  18  of tubular conduit  12 , in the direction of the imaginary midline  25 . A second vessel  42  is then slid in an opposite axial direction (to the left in  FIG. 4 ), over end  16  and barbed ring  20  in the direction of imaginary midline  25 . Each one of locking sleeves  24 ,  26  is then urged axially in the direction of the arrows over the ends of respective vessels  40 ,  42  as far as they can slide, to tighten, or lock, the vessel in place. The lack of significant clearance between the conduit outer diameter and the sleeve minimum diameter provides a frictional force that locks, or otherwise pins the vessel end in place between the tubular conduit and each of the respective sleeves, thereby preventing the vessel from migrating.  
      If desired, either or both of sleeves  24 ,  26  can be provided with an additional locking feature to better secure the locking of the vessel to the conduit. In one embodiment, the locking feature comprises a cut-out portion, such as notch  32 , that extends circumferentially along all or part of the circumference of the inner surface of the sleeve. Notch  32  is best shown in  FIG. 2 . Notch  32  can be used to assist in tightly holding, or locking, the sleeves on the barbs or other grasping structures. In the embodiment of  FIG. 4 , respective sleeves  24 ,  26  can be slid axially in the direction of the arrows until they reach respective barbed rings  18 ,  20 . Preferably, the sleeve can be locked and securely held in position by the interconnection of notch  32  with the respective ring  18 ,  20 , as shown in  FIG. 5 .  
      An alternative embodiment of an apparatus  50  for establishing an end-to-end connection is shown in  FIG. 6 . This embodiment includes tubular conduit  52  having axial ends  54 ,  56 . A respective graded sleeve  64 ,  66  is positioned at each axial end  54 ,  56  of the conduit. In this embodiment, the sleeves may be placed around the axial ends  60 ,  62  of the conduit to fasten the vessel or graft in place. Alternatively, a projection, such as a flange, may be incorporated onto each axial end of conduit  52  to secure the connection. A notch can be incorporated into either or both of the graded sleeves as disclosed in the previous embodiment, to receive the projection, or to receive grasping structures  18 ,  20 , as shown in  FIG. 7 . Those skilled in the art will appreciate that other conventional attachment mechanisms may be substituted for those shown, the objective being to securely lock the vessel portion between the sleeve and the conduit.  
      Yet another alternative embodiment of a connection apparatus  70  is shown in  FIG. 8 . Apparatus  70  includes tubular conduit  72 , axial ends  71 ,  73 , barbed rings  78 ,  80 , and sleeves  84 ,  86 . In this embodiment, one or more springs  74 ,  75 ,  76  are provided between sleeves  84 ,  86  to interconnect the sleeves. The embodiment shown in  FIG. 8  includes four springs (one of which is not visible in the sectional view of  FIG. 8 ) spaced about 90 degrees from each other along the circumference of tubular conduit  72 . Those skilled in the art will appreciate that more, or fewer, springs may be used in an appropriate case. The springs may be compressed during loading of the vessels  81 ,  82  on tubular conduit  72 , but preferably have a tendency to elongate in the axial direction to lock the vessel ends on conduit  72 . If desired, sleeves  84 ,  86  can be further secured on barbed rings  78 ,  80 , as illustrated in previous embodiments. In an alternative embodiment, springs can be provided having a tendency to compress in the axial direction.  
      All components described herein are formed of biologically compatible conventional materials having sufficient strength for the purposes described. Preferably, the tubular conduit is formed of a rigid or semi-rigid plastic, of a type suitable for implantation into a human or other animal.  
      Although the inventive apparatus may be conveniently used to join two blood vessels, those skilled in the art will recognize that other known components can likewise be joined, such as synthetic graft material and exogenous materials. Likewise, a blood vessel may be attached to a synthetic graft vessel or an exogenous vessel. Furthermore, the invention is not limited to vascular access, but rather, may also include the applications such as bypass grafting between two blood vessels, including fem-fem (femoral artery and femoral vein) and fem-pop; coronary artery bypass grafting; and shunting outside of the circulatory system to help alter flow of fluid including gastrointestinal tract (e.g., liver and gall bladder), the urinary system (e.g., ureter and urethra), beyond the blood-brain barrier (e.g., for hydroencephalopathy), and in the reproductive system (e.g., ovarian recannulation).  
      It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.