Abstract:
A barbed bodily tissue connector for insertion into tissue comprises an elongated body having a substantially polygonal periphery in cross-section including at least three sides. Each side meets an adjacent side at an edge of the elongated body. A plurality of barbs project from the edges of the body. The barbs are configured such that they are yieldable in a direction toward the body and resist retraction from tissue in an opposite direction.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     This application is a continuation application of U.S. patent application Ser. No. 10/420,119, filed on Apr. 2, 2003, which is a continuation application of U.S. patent application Ser. No. 09/629,428, filed on Jul. 31, 2000, now abandoned, which is a continuation application of U.S. patent application Ser. No. 08/324,529, filed on Oct. 18, 1994, now U.S. Pat. No. 6,241,747, which is a continuation-in-part application of U.S. patent application Ser. No. 08/055,989, filed on May 3, 1993, now abandoned. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to a barbed tissue connector, and more particularly, to such a connector which can be used to quickly and effectively close a body wound.  
         [0003]     Human wounds are typically repaired with a filament introduced into the tissue by a needle attached to one end. After piercing the opposing faces of the wound, the needle is removed, and the ends of the suture are tied together with at least three overhand knots. Such a technique requires considerable time and expertise on the part of the surgeon. There are also a number of other drawbacks to repairing a wound in this manner. For example, it is very difficult to use sutures to repair wounds where there is insufficient space to properly manipulate the suture, especially those wounds repaired using fiber optic visualization. The suture forms a loop as it is tied, and this loop constricts blood flow to the tissue in its confines, promoting necrosis of the wound margins. Further, if the needle&#39;s passage was noncircular, the tissue will be distorted as it is secured by the suture.  
         [0004]     Alternatives to conventional sutures are known in the prior art. Staples, as shown, for example, in U.S. Pat. No. 4,994,073, to Green, are often used for approximating the superficial layer of the wound. Staples, however, are generally unsuitable for deeper layers of tissue.  
         [0005]     The patent to Alcamo, U.S. Pat. No. 3,123,077, discloses a roughened suture which can be passed through tissue in one direction, but resists movement in the opposite direction. The Alcamo suture, however, still must be sewn, as by a conventional technique, and the trailing end must be secured with knots. Thus, although there is less slippage of the suture in the wound, most of the disadvantages of sutures noted above are also found in the Alcamo suture.  
         [0006]     The patent to Tanner, U.S. Pat. No. 3,716,058, discloses a relatively rigid suture with one or more barbs on opposite ends of an arcuate body. One disadvantage of the Tanner suture is that the rigid barbs, which protrude from the suture as it is inserted, will lacerate tissue and prevent retrograde repositioning. Further, since the barbs are only placed at the ends of the suture, the forces applied to the tissue by the barbs will be limited to a relatively small area; this substantially increases the pressure on the blood vessels ensnared by a barb and severely restricts blood flow to the area.  
         [0007]     It will be seen from the foregoing that there is a need for a tissue connector which can be placed more expeditiously than sutures, is self-retaining, obviates distortion of the tissue, can close tissue inaccessible to conventional procedures, and which preserves blood flow by broadly distributing the retention force.  
       SUMMARY OF THE INVENTION  
       [0008]     It is an object of the present invention to overcome the aforementioned problems in the prior art and to provide an improved tissue connector.  
         [0009]     In accordance with the present invention there is provided a barbed tissue connector comprising: an elongated body having a point formed on one end, the body being formed of a material sufficiently hard for the point to pierce tissue and enable the connector to be inserted in tissue when a substantially axial force is applied to the body; and a plurality of barbs projecting from the body, the barbs being disposed around the periphery of the body along a length of the body which extends from adjacent the one end to a predetermined location on the body, the barbs being configured such that they are yieldable in a direction toward the body and are generally rigid in an opposite direction, and the barbs being sufficiently resilient to return to a predetermined position after deflection therefrom.  
         [0010]     In one embodiment of the present invention, the barbed tissue connector includes an elongated body and a plurality of barbs which are disposed in a helical pattern on the body and extend from a pointed end of the connector to a predetermined location on the body. Each barb includes a first side, which forms an obtuse angle with the body, and a second side which forms an acute angle with the body. The body is substantially rigid and sufficiently resilient to return to a predetermined position after deflection therefrom. When the connector is inserted in tissue to repair a wound, the pointed end pierces tissue and the barbs yield toward the body to facilitate entry of the connector.  
         [0011]     When the connector has been placed in a desired position in tissue, the barbs strongly resist movement away from this position. The connector can be inserted by gripping the connector in the hand and pushing the connector into the tissue, or the connector can be inserted by means of an inserting device which is withdrawn when the connector is in place.  
         [0012]     A principal advantage of the barbed tissue connector of the present invention is that it permits a surgeon to rapidly and securely attach the edges of a wound in human tissue without the necessity for threading and tying numerous individual stitches or for the use of a complicated or elaborate tool to insert the connector. The connector is configured to minimize damage to tissue when inserted and to minimize scarring or tissue necrosis across the wound. The connector is capable of insertion into the faces of a wound, can connect tissue at the bottom of a deep wound, and can connect tissue which is inaccessible to a staple. Finally, the connector of the present invention can be inserted quickly and accurately by a surgeon who only has access to tissue from a small opening or from only one direction, as, for example, during an endoscopic procedure.  
         [0013]     Other features and advantages will become apparent upon reference to the following description of the preferred embodiment when read in light of the attached drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a side view of the connector of the present invention, with a section broken away to more clearly show the arrangement of the barbs;  
         [0015]      FIG. 2  is an end view of the connector shown in  FIG. 1 ;  
         [0016]      FIG. 3  is a side view of another embodiment of the present invention, with a section of a connector broken away;  
         [0017]      FIG. 4  is a side view of another embodiment of the present invention;  
         [0018]      FIG. 5  is a side view of another embodiment of the present invention;  
         [0019]      FIG. 6  is a side view of another embodiment of the present invention;  
         [0020]      FIG. 7  is a sectional view taken along the line  7 - 7  in  FIG. 6 ;  
         [0021]      FIG. 8  is a side view of another embodiment of the present invention;  
         [0022]      FIG. 9  is a sectional view taken along the line  9 - 9  in  FIG. 8 ;  
         [0023]      FIG. 10  is a perspective view of an inserting device for use with a barbed tissue connector of the present invention; and  
         [0024]      FIG. 11  is a view showing the inserting device and connector in a wound.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     The present invention allows a surgeon to rapidly and securely attach the edges of a wound in human tissue without the necessity for threading and tying numerous individual stitches or for using a complicated or elaborate tool. As used herein, the term “wound” means an incision, laceration, cut, or other condition where suturing, stapling, or the use of another tissue connecting device might be required.  
         [0026]     With reference to  FIGS. 1 and 2 , there is shown a barbed tissue connector  2  constructed in accordance with the present invention. Connector  2  includes a body  4  which is generally circular in cross section and a plurality of closely-spaced barbs  6  which extend around the periphery of the body  4 . A pointed end  9  is formed on the body  4  to facilitate penetration of the connector  2  into tissue. The body  4  preferably has sufficient dimensional stability to assume a substantially rigid configuration during use and is sufficiently resilient to return to a predetermined shape after deflection therefrom. In some applications, it may be desirable for the body  4  to be flexible and substantially nonresilient so that the shape of an inserted connector will be determined by surrounding tissue.  
         [0027]     Barbs  6  serve to hold the connector in tissue and resist retraction of the connector from the tissue. The barbs  6  can be arranged in any suitable pattern, for example, in a helical pattern as shown in  FIG. 1 . In a helical pattern of barbs  6 , it is preferable that the number of barbs occupying one revolution not be an integer, thereby avoiding parallel axial rows of barbs; such an arrangement provides a more uniform distribution of forces on the tissue and lessens the tendency of an inserted connector  2  to cut through tissue. If the number of barbs in one revolution is not an integer, the barbs in successive revolutions will be offset, as shown in  FIG. 2 , and the amount of offset will determine which barbs are in axial alignment. For example, if the barbs in successive revolutions are offset by ½ barb, the barbs in every second revolution will be in axial alignment, and by extension, if the barbs in each successive revolution are offset by 1/x barb, the barbs in every x revolution will be in axial alignment.  
         [0028]     As shown in  FIG. 1 , each barb  6  includes a first side  8  which forms an obtuse angle alpha with the body  4  and a second side  10  which forms an acute angle beta with the body  4 . Each barb  6  tapers to a point  7 , and the amount of difference between the angle alpha of side  8  and angle beta of side  10  will control the amount of taper in the barb  6 . A barb  6  which tapers from a broad base to a narrow tip can be effective in resisting retraction, yet will yield toward the body  4  during insertion to reduce the effort and tissue damage associated with insertion of the connector  2 . The barbs  6  can be generally conical, as shown in  FIG. 1 , or they can be any other shape which will function in substantially the same manner as the conical barbs.  
         [0029]     The configuration of barbs  6  and the surface area of the barbs can vary depending upon the tissue in which the connector  2  is used. The proportions of the barbs  6  can remain relatively constant while the overall length of the barbs and the spacing of the barbs are determined by the tissue being connected. For example, if the connector  2  is intended to be used to connect the edges of a wound in skin or tendon, each barb  6  can be made relatively short to facilitate entry into this rather firm tissue. If the connector  2  is intended for use in fatty tissue, which is relatively soft, the barbs can be made longer and spaced farther apart to increase the holding ability in the soft tissue. As shown in  FIG. 1 , the barbs  6  on connector  2  have a uniform unidirectional configuration, that is, the barbs  6  are uniformly spaced on body  4  and all the sides  8  are oriented in the same direction, facing pointed end  9 . Connector  2  can be inserted into tissue with the sides  8  of each barb  6  facing in the direction of motion. Connector  2  will prevent movement of tissue in the direction in which it was inserted. A pair of connectors  2  inserted adjacent to each other and in opposite directions will prevent movement of tissue in either direction across a wound.  
         [0030]     Connector  2  can be formed of a material sufficiently hard for point  9  to pierce tissue and enable the connector to be inserted in tissue when a substantially axial force is applied to body  4 . Connector  2  is preferably composed of a bioabsorbable compound, such as a polyglycolic acid or polylactic acid polymer or copolymer. The use of a bioabsorbable material eliminates the necessity of removing the connector from the patient, which can be a painful and possibly dangerous process. Connector  2  can be formed, for example, by injection molding.  
         [0031]     In one representative example of connector  2  for use in muscular tissue, the body  4  is formed from polyglycolic acid, has a length of 1 to 5 cm, and a diameter of about 1 mm. The diameter of a circle extending around points  7  of barbs  6  will be about 3 mm, and the barbs are spaced apart from each other on body  4  by a distance of 1 mm. Side  8  forms an angle of 135 degrees with the body  4  and side  10  forms an angle of 75 degrees with the body  4 .  
         [0032]     In  FIG. 3 , there is shown a second embodiment of the present invention in which barbs  16  are arranged in a uniform bidirectional configuration on a barbed tissue connector  12 . Barbs  16  are constructed in the same manner as barbs  6  on connector  2 . A first set of barbs  15  on connector  12  are arranged in a helical pattern and face a pointed end  20 , and a second set of barbs  16  on connector  12  are arranged in a helical pattern and face a pointed end  21 . Each of the pointed ends  20 ,  21  should be sufficiently hard and sharp to easily penetrate tissue in which the connector is to be used. Connector  12  is particularly suitable for applications where the edges of a wound are prone to separate. Connector  12  can be used by inserting one of the ends, for example end  20 , into a first side of a wound (not shown), spreading the wound slightly to expose the second side of the wound, inserting the end  21  of the connector  12  into the second side of the wound, and then pressing the edges of the wound together. The barbs  15  and  16  on the ends of the connector  12  will grasp the tissue on each side of the wound and prevent the edges of the wound from spreading.  
         [0033]     With reference to  FIG. 4 , there is shown another embodiment of the present invention in which a barbed tissue connector  22  has a nonuniform bidirectional configuration. Connector  22  comprises a pointed end  23  and one or more barbs  26  facing a first direction which alternate with one or more barbs  27  facing a second direction. At each axial location, there can be a number, e.g. 4-9, of circumferentially-spaced barbs  26  or  27 . To insert connector  22  into tissue, the surgeon would use an inserting device  80  as described below. The arrangement of barbs  26 ,  27  on connector  22  would prevent any localized movement of tissue relative to the connector in an axial direction.  
         [0034]     With reference to  FIG. 5 , there is shown another embodiment of the present invention in which a barbed tissue connector  32  has a uniform bidirectional configuration. Connector  32  comprises a body  34  having pointed ends  33  and  35 . A plurality of axially-spaced barbs  36  adjacent pointed end  33  face toward end  35 , and a plurality of axially-spaced barbs  37  adjacent pointed end  35  face toward end  33 . Barbs  36  and  37  can be circumferentially-spaced around body  34  at each axial location, or the barbs  36  and  37  can be of the same construction and arranged in the same pattern as barbs  6  on connector  2 . To insert a connector  32 , the surgeon would use an inserting device  80  as described below. If the body  34  of the connector  32  is sufficiently rigid, the connector  32  would prevent tissue retained by the barbs  36  from moving toward end  35  and tissue retained by barbs  37  from moving toward end  33 . It will be apparent that only one end of connector  32  needs to be pointed; two pointed ends are preferable, however, so that the surgeon does not have to take the time to insure that connector  32  is oriented in the inserting device  80  with a pointed end protruding from the inserting device.  
         [0035]     With reference to  FIGS. 6 and 7 , there is shown another embodiment of the present invention in which a barbed tissue connector  42  comprises a body  44  having a pointed end  45  for penetration into tissue. A head  47  is formed on an opposite end of body  44 . A plurality of circumferentially-spaced barbs  46  are formed on body  44  at each of a number of axial locations. As shown in  FIG. 7 , three barbs  46  are formed at each axial location; however, more or less than three barbs  46  could be used for certain applications. Barbs  46  include a first side  48  formed at an obtuse angle to the body  44  and a second side  49  which projects from body  44  at an acute angle. The connector  42  can be forced into tissue by applying a force to the head  47 . The connector  42  can be applied by hand, or it can be inserted using an inserting device  80  as described below.  
         [0036]     The connector  42  can be formed entirely of a bioabsorbable material, or the head  47  and the body  44  can be composed of different materials. For example, the body  44  can be composed of a bioabsorbable material, and the head  47  can be composed of metal for superior strength and to facilitate insertion of the connector  42 . Head  47  can be made flat, as shown in  FIG. 6 , or the head can be formed by a single ring of barbs (not shown) facing in a direction opposite to that of the barbs  46 .  
         [0037]     In use, a series of connectors  42  can be inserted into tissue, such as along the edges and in the field of a skin graft. After an adequate amount of time has passed for the wound to heal, the tissue beneath each head  47  could be depressed slightly to permit the head  47  to be cut from the body  44 . The tissue would then rise up over the cut end of the body. Such a process would reduce scarring which could result from a long-term projection of the body  44  through tissue and would eliminate the necessity to remove connectors  42  from the patient.  
         [0038]     With reference to  FIGS. 8 and 9 , there is shown another embodiment of the present invention in which a barbed tissue connector  52  has a uniform unidirectional configuration. Connector  52  comprises a body  54  having a non-circular cross-sectional shape. Body  54  includes a plurality of barbs  56  which are generally triangular in cross section and are equally spaced around the periphery of the body at a series of axial locations. Each of the barbs  56  includes a first side  58  disposed at an obtuse angle to body  54  and a second side  60  disposed at an acute angle to the body. Body  54  includes a pointed end  53  to facilitate entry in tissue. Use of a non-circular cross-sectional shape increases the surface area of the connector  52  and facilitates the formation of the multiple barbs on the connector. For example, barbs  56  can be formed on a piece of stock having a triangular cross section by removing material at successive axial locations from the three edges of the stock. It will be apparent that a similar process could be used to form barbs on stock of a different cross section (not shown), for example, a rectangular or hexagonal cross section.  
         [0039]     In the use of the disclosed connectors, such as connectors  2  and  42 , the surgeon can grip the connector in one hand and push the connector into the tissue. As an alternative to directly inserting the connectors into the tissue, the surgeon can use an inserting device  80  as shown in  FIGS. 10 and 11 . The inserting device  80  comprises a circular tubular body  82 . The tubular body  82  can be generally arcuate in an axial direction, and the body  82  is sufficiently long to contain at least a portion of a barbed tissue connector C. Device  80  has an inwardly tapered leading end  84  and an outwardly tapered, or flared, trailing end  86 . A handle  83  is provided on body  82  adjacent trailing end  86  to enable the surgeon to manipulate the inserting device  80 .  
         [0040]     In order to facilitate entry of the connector C and the device  80  into tissue, a connector C is positioned in tubular body  82  with a pointed end P of the connector C extending from leading end  84 . In a preferred embodiment, the interior diameter of the body  82  is made slightly smaller than the outside diameter of the connector C so that the barbs B of a connector C in the body  82  will press against the body  82 ; as a result, the connector C will be retained in the body  82  during insertion in tissue with the point P properly positioned outside of the body  82 . The connector can also be positioned in body  82  with a barb B outside of body  82  to insure that the connector C will not be pushed back in the body  82  during insertion. In one application of device  80 , the surgeon inserts the body  82  having connector C therein into the patient&#39;s tissue  87  until the connector C reaches a desired position, for example, the position shown in  FIG. 11 . Device  80  is then withdrawn in the direction of arrow  90 , and a barb, or barbs, B on the connector C penetrates and catches the tissue  87  to hold the connector C in the inserted position.  
         [0041]     Use of the inserting device  80  is particularly recommended when the connector C includes multiple barbs facing more than one direction, such as connectors  22  and  32 , or when the connector is too flexible for insertion without additional support.  
         [0042]     While the present invention has been described with respect to certain preferred embodiments thereof, it is to be understood that numerous variations in the details of construction, the arrangement and combination of parts, and the type of materials used may be made without departing from the spirit and scope of the invention.