Abstract:
A surgical fastener application apparatus for applying surgical fasteners of general U-shape to body tissue is provided which includes a housing having a handle portion and a trigger mechanism, an elongated body portion extending from the housing, the elongated body portion having generally annular cross-sectional area substantially along the length thereof and defining a longitudinal pathway therein, and a firing mechanism operatively connected to the housing and including a pair of substantially parallel push rods positioned within the longitudinal pathway of the elongated body portion, the firing mechanism being capable of driving a surgical fastener inserted in a distal end portion of elongated body portion to the body tissue in response to operation of the trigger mechanism.

Description:
This application claims the benefit of Provisional application Ser. No. 60/196,517, filed Apr. 11, 2000. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to the field of endoscopic surgical devices. More specifically, the present disclosure relates to an endoscopic fastener applying device for repairing torn tissue such as torn meniscus tissue. 
     2. Background of Related Art 
     One known technique for repairing torn meniscus tissue involves the use of a pair of surgical needles which are inserted through cannuli into the knee on opposite sides of a meniscal tear. The ends of the needles include a length of suture material which is pushed down through the cannuli and across the tear. An incision is made in the skin at the point where the needle exits the knee joint so that the leading end of each needle may be grasped and pulled through the joint. The ends of the sutures are then grasped after the needles are removed from the suture ends and the suture is then tied so that a horizontal suture is created in the meniscus. This procedure is repeated for placement of as many sutures as necessary to repair the meniscus tear. As is apparent, this process is both time consuming and difficult to effect. 
     A subsequent improvement over this procedure is outlined in U.S. Pat. No. 5,002,562, the contents of which are incorporated herein by reference. In this procedure, a barbed clip and an instrument for applying the clip are utilized. The instrument has a pair of opposed arcuate jaws which are shaped to hold a complementary-shaped curved surgical clip therebetween, such that the barbs of the clip are retained within notches in the jaws until the clip is inserted. The legs of the clip are joined by a flexible suture material. The jaws are biased in a normally open position, and as the jaws are pushed into the tissue, the jaws are scissored or closed together until they preferably overlap to move the legs of the clip together until they cross. The jaws are then reopened and backed out of the tissue, with the barbs of the clip retaining the clip in position in the tissue. 
     A further refinement to meniscal repair is illustrated in U.S. Pat. No. 5,997,552, the contents of which are incorporated herein by reference. This patent details a meniscal fastener applying device which applies fasteners sequentially from a longitudinally extending magazine. An advancing mechanism is operatively associated with an elongated body portion of the device for sequentially advancing surgical fasteners from a fastener supply to a firing position in alignment with a firing mechanism. The fastener includes a pair of anchor members whose proximal-most ends are connected by a suture material offset from the central longitudinal axis thereof. Because of the parallel over-under orientation of the firing mechanism and the longitudinally extending fastener magazine, the elongated body portion of the device requires a substantial cross-sectional area and necessarily requires a correspondingly wide distension of the knee joint to access the meniscal tissue to be repaired. 
     SUMMARY 
     A single shot meniscal repair device is provided which incorporates a minimally sized elongate body portion configured to hold a single fastener adjacent a distal end thereof. The elongate body portion is part of a disposable loading unit structure which facilitates up to 360° rotation about the longitudinal axis of the elongate body portion. In an alternate embodiment, at least a distal portion of the elongate body portion is angled off axis to enhance the versatility of the device. The fastener applied by the device includes a pair of anchor members interconnected by a flexible material. The flexible material extends from a respective side of the anchor members, thus maintaining the proximal ends thereof clear to receive the full driving force from the firing assembly without the risk of damaging the connecting flexible material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various embodiments are described herein with reference to the drawings, wherein: 
     FIG. 1 is a perspective view of one embodiment of the meniscal repair device of the present disclosure; 
     FIG. 2 is a perspective view with parts separated of the meniscal repair device of FIG. 1; 
     FIG. 3 is a perspective view showing the elongate body portion of the meniscal repair device of FIG. 1; 
     FIG. 4 is a perspective view showing a 10° upsweep version of the elongate body portion in accordance with one embodiment of the meniscal repair device of the present disclosure; 
     FIG. 5 is a perspective view showing a 30° left/right bend version of the elongate body portion in accordance with one embodiment of the meniscal repair device of the present disclosure; and 
     FIG. 6 is an enlarged perspective view showing the fastener used in the meniscal repair device of the present disclosure. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Preferred embodiments of the presently disclosed stapler will now be described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. 
     Referring now to the drawings, FIG. 1 illustrates a first embodiment of the fastener applying device shown generally as  10 . Briefly, the staple applying device  10  includes a housing assembly  12  and a disposable loading unit  13  having an elongated body portion  14  defining a longitudinal axis thereof. The elongated body portion  14  is preferably minimally dimensioned for arthroscopic utilization. 
     The components of the housing assembly  12  of the fastener applying device  10  are best illustrated in FIG.  2 . The housing assembly  12  includes a housing formed from molded housing half-sections  12   a  and  12   b  within which the components of the housing assembly  12  are positioned. The housing assembly  12  further includes a movable handle  22  and a stationary handle  24  which is formed from portions extending from housing half-sections  12   a  and  12   b  to form a pistol grip type handle. Movable handle  22  and stationary handle  24  facilitate remote actuation of a firing assembly  52  through the elongated body portion  14  to effect the ejection of a surgical fastener  30  from the distal end of the elongated body portion  14 . 
     The movable handle member  22  is secured to the housing half sections  12   a  and  12   b  by a pin  26  which permits rotation of the movable handle  22  relative to the stationary handle  24 . A handle spring  28  is connected to the movable handle  22  by a pin  20  and to the housing  12  by a pin  34  so as to bias the movable handle  22  to an open position. The pin  20  is dimensioned to be received in openings  21  formed in the movable handle  22 . 
     An actuation arm member  32  is operatively associated with the movable handle  22  and is pivotably connected to the lower end of the stationary handle  24  by pin  34 . A cam roller member  36  is rotatably mounted to the movable handle  22  and is configured to engage and move along a cam path surface  38  defined on the actuation arm member  32  by the proximal facing outer surface thereof. Engagement between the cam roller member  36  and the cam path surface  38  effectuates counter-clockwise rotation of the actuation arm member  32  about pin  34  when the instrument is viewed from the right side, as shown in FIG.  2 . 
     A latch member  40  is pivotably mounted to the top portion of the actuation arm  32  by pivot members  41 . The latch member  40  is dimensioned and configured to detachably engage with a firing block  42  which is slidably mounted in the housing assembly  12 . An engaging spring  46  connects the latch member  40  to the actuation arm member  32  so as to pivot the latch member  40  about pivot members  41  into engagement with the firing block  42 . The latch member  40  has a hook member  49  pivotable about pivot members  41  into engagement with a post  51  formed on the firing block  42 . 
     As mentioned above, the firing block  42  is slidably mounted in the housing assembly  12  and is movable in response to corresponding movement of the movable handle member  22 . A mounting projection  50  extends from the end of the firing block  42  and is dimensioned and configured so as to detachably engage with the proximal end  53  of firing plate  52 . 
     A bearing washer  60  is received about and engages a central portion  55  of the firing block  42 , and a snap washer  62  is fixedly attached to the distal end portion  42   b  of the firing block  42  to capture and retain a compression spring  58  therebetween. Upon actuation of the handle assembly, the compression spring  58  is compressed between bearing washer  60  and snap washer  62  creating a force urging firing block  42  in a distal direction. Additional washers  65  for sealing, spacing and fitting purposes may be operatively associated with the distal end portion  42   b  of the firing block  42 . 
     As described above, proximal movement of the movable handle  22  causes the cam roller  36  to engage the cam path surface  38  and rotate actuating arm member  32  and latch member  40  in a counter-clockwise direction when viewing the instrument from the right side, as shown in FIG.  2 . The hook member  49  formed on the latch member  40  engages post  51  formed on the firing block  42  to slide the firing block  42  proximally as latch member  40  and actuating cam member  32  rotate counter-clockwise in response to proximal movement of handle  22 . The proximal movement of the firing block  42  causes bearing washer  60  to engage a bearing surface  64  defined on the interior of the housing assembly  12  (See FIG.  2 ). As the firing block  42  is moved proximally, the compression spring  58  is compressed between the washer  60  and the snap washer  62  creating a force urging firing block  42  in a distal direction. After the spring  58  has been compressed, the latch member  40  contacts a camming wall  66  defined in the proximal end portion of the housing assembly  12  which, in turn, causes the latch member  40  to pivot clockwise about members  41  to disengage hook member  49  from post  51 . The release of stored energy from the compression spring  58  urges the firing block  42  to move distally resulting in corresponding distal movement of the firing plate  52 . 
     As firing plate  52  moves distally, it engages rod holder  70  and continues in combined distal movement to drive parallel push rods  72  distally to engage and eject fastener  30 . Upon completion of the firing motion, handle  22  is relaxed thus withdrawing firing block  42  and firing plate  52  proximally relative to rod holder  70  and push rods  72 . 
     The disposable loading unit  13  includes rotational housing  80  formed of housing half-sections  80   a  and  80   b.  Mounted within housing  80  are the firing plate  52  and rod holder  70 . The elongate body portion  14  is mounted to housing  80  by pins  82  and extends distally therefrom. Push rods  72  are attached to rod holder  70  and are disposed within the elongate body portion  14 . A new fastener  30  is disposed adjacent a distal end  74  of elongate body portion  14 . 
     Once firing is completed, the expended disposable loading unit  13  is rotated relative to the housing  12  effectively disengaging firing plate  52  from mounting projection  50  on firing block  42 . The expended disposable loading unit is then withdrawn distally from housing  12  and discarded. A new disposable loading unit is inserted into housing  12  and rotated to engage mounting projection  50  with proximal end  53  of mounting plate  52 . The device  10  is then ready for subsequent firing. 
     Referring to FIG. 3, the elongate body portion  14  is illustrated in a series of views. Rods  72  are configured and dimensioned to travel coaxially within the elongate body portion  14 . The cross-sectional dimensions of elongate body portion  14  are minimized to more easily facilitate introduction to the operative site. A locating barb  76  can be positioned at a distal end of the elongate body portion  14  to assist in stabilizing the device at the firing point. 
     FIGS. 4 and 5 illustrate alternate embodiments of elongate body portion  14  wherein the distal portion is upswept by 10° (FIG. 4) or bent left/right by 30° (FIG.  5 ). Elongate body portions shown in FIGS. 4 and 5 are otherwise substantially the same as shown in FIG.  3 . 
     A fastener  30  for use in device  10  is illustrated in FIG. 6 in a series of views. Fastener  30  includes a pair of anchor members  90  linked by a flexible member  92 . Preferably, the entire fastener is formed of bioabsorbable material which resorbs at an appropriate rate to facilitate healing of a tear in the meniscus. Each of the anchors  90  has a tapered distal end  94  and a planar proximal end  96 . Flexible member  92  extends between adjacent side surfaces  98  of anchors  90  spaced between the proximal end  96  and the distal end  94  thereof. This configuration protects the flexible member  92  from inadvertent damage caused by the rods  72 . Each anchor member  90  is further provided with a series of radial projections  100  on its periphery to inhibit withdrawal of the anchor members  90  once they have been positioned within body tissue.