Patent Publication Number: US-2015080917-A1

Title: Knot pusher and suture cutter instrument

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional of U.S. application Ser. No. 12/397,213, filed Mar. 3, 2009, which claims the benefit of U.S. Provisional Application No. 61/033,653, filed Mar. 4, 2008, the entire disclosures of which are incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to methods of arthroscopic surgery and, more specifically, to an improved knot pusher/suture cutter instrument used for manipulating suture during methods of tissue repair. 
     BACKGROUND OF THE INVENTION 
     Tissue repair typically requires the surgeon to pass suture material through selected tissue, form a plurality of surgical knots extracorporeally and then move the knots into position adjacent the desired tissue to be sutured. In such procedures, the surgeon must tie the knots on the suture strands after the suture is threaded through the selected tissues to be sutured, and then cut the remaining suture strands from the surgical site. High strength suture materials, such as FiberWire®, for example, are difficult to cut mainly because of their increased strength. 
     An improved surgical instrument that acts both as a knot pusher instrument (forcing the knots down into the proper position) and as a suture cutter (cutting the ends of suture) is needed. An instrument that cuts suture clean and without difficulty, regardless of the strength of the suture material, is also needed. 
     SUMMARY OF THE INVENTION 
     The present invention provides a combination knot pusher/suture cutter device for manipulating a knotted suture to properly locate the knot relative to the tissue being sutured, and then for removing excess suture from the knot. 
     The combination knot pusher/suture cutter device of the present invention comprises a body member including a handle and an inner member (or inner rod) having a knot-engageable section at the opposite end (distal end) for engaging and moving the knotted suture by manipulation of the handle. The knot-engageable section of the inner member comprises a slot at its distal end which allows suture to be threaded through it. The inner member is provided within an outer sleeve that is designed to be actuated by a spring and a thumb pusher (trigger) located on a surface of the handle. By actuating the thumb trigger (for example, by sliding forward the thumb trigger), the outer sleeve is advanced and the suture post is cut. 
     Other features and advantages of the present invention will become apparent from the following description of the invention, which refers to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  illustrates a perspective view of a combined knot pusher/suture cutter assembly according to an embodiment of the present invention; 
         FIG. 2  illustrates another perspective view of the combined knot pusher/suture cutter assembly of  FIG. 1 ; 
         FIG. 3  illustrates an expanded view of the distal end of the combined knot pusher/suture cutter assembly of  FIG. 1 ; 
         FIG. 4  illustrates a side view of the combined knot pusher/suture cutter assembly of  FIG. 1 ; 
         FIG. 5  illustrates another side view (rotated 90 degrees) of the combined knot pusher/suture cutter assembly of  FIG. 1  (with suture threader attached); 
         FIG. 6  illustrates a top view of the combined knot pusher/suture cutter assembly of  FIG. 5 ; 
         FIG. 7  illustrates an expanded view of the distal end of the combined knot pusher/suture cutter assembly of  FIG. 1 ; and 
         FIG. 8  illustrates an expanded view of the distal end of the combined knot pusher/suture cutter assembly of  FIG. 7  (in the advanced or post-cut position). 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following detailed description, reference is made to various specific embodiments in which the invention may be practiced. These embodiments are described with sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be employed, and that structural and logical changes may be made without departing from the spirit or scope of the present invention. 
     The present invention provides a combination knot pusher/suture cutter device for manipulating a knotted suture to properly locate the knot relative to the tissue being sutured, and then for removing excess suture from the knot. The combined knot pusher/suture cutter assembly of the present invention comprises a body member including a handle and an inner member (or inner rod) having a knot-engageable section at the opposite end (distal end) for engaging and moving the knotted suture by manipulation of the handle. The knot-engageable section of the inner member comprises a slot at its distal end which allows suture to be threaded through it. The inner member is provided within an outer sleeve that is designed to be actuated by a spring and a thumb pusher (trigger) located on a surface of the handle. By actuating the thumb trigger (for example, by sliding forward the thumb trigger), the outer sleeve is advanced and the suture post is cut. 
     Referring now to the drawings, where like elements are designated by like reference numerals,  FIGS. 1-8  illustrate a combined knot pusher/suture cutter assembly  100  of the present invention. As shown in the drawings, the combined knot pusher/suture cutter assembly  100  comprises a handle  1 , an inner rod or inner tube  2  disposed within an outer tube  5 , a thumb pusher (trigger)  3  in communication with a spring  4 , and a suture threader  6  that is configured to securely engage the outer tube  5 . A knot-engageable/suture cutter section  10  is provided at most distal end of the knot pusher/suture cutter assembly  100  as shown, for example, in  FIG. 7 . 
     As more clearly illustrated in  FIG. 7 , inner rod  2  is provided at its most distal end with knot-engageable/suture cutter section  10  that includes a slot  20  which is designed to allow suture to be threaded through it. Slot  20  is in communication with opening  22  ( FIG. 7 ) located at a most distal end  21  of inner rod  2 . Knot-engageable/suture cutter section  10  also a cutting edge  59  ( FIG. 7 ) for cutting suture passing through the slot  20 . 
     Referring now to  FIGS. 3-6 , a method of assembling the combined knot pusher/suture cutter assembly  100  begins by orienting the slot of suture threader  6  ( FIG. 3 ) with the slot of the handle (both slots facing up and forming an angle of about 90 degrees), as shown in  FIG. 6 . The inner rod  2  is sled into the handle  1  with thumb pusher  3  and spring  4  aligned in handle slot. Once alignment is achieved, the inner rod  2  is pressed into handle  1  until bottomed out. Although suture threader  6  may be positioned at about 90 degrees, this position is not necessary. Outer tube  5  is then slid onto inner rod  2  and pressed into the thumb pusher. When the outer tube  5  is advanced over inner rod  2 , the thumb pusher should move easily. 
     A flexible strand such as a suture strand (for example, a high strength suture such as FiberWire®) is threaded from the suture threader  6  into the slot  20  of the inner rod  2  so that the suture exits the hole with about 0.5 in stickout. The suture threader  6  may then be securely attached to the shaft of the outer tube  5 , by snapping the threader to the tube, for example. 
     In use, the surgeon first threads the suture post through the opening  22  at the distal tip using the suture threader attached to the outer tube, so that it exits out through the slot  20  before the outer sleeve  5 . The surgeon then will hold tension on the post, with one hand, and advance the device  100  forward (with the other hand) to slide the knot down until the suture construct is tightly secured. Then the surgeon will slide the thumb trigger  3  forward to advance the outer sleeve  5  and cut the suture. Spring  4  within the handle  1  is designed to return the thumb trigger  3  back to the original position, which (in turn) allows the outer sleeve  5  to move back as well. 
     The combined knot pusher/suture cutter assembly  100  of the present invention is designed to act both as a knot pusher instrument (forcing the knots down into the proper position) and as a suture cutter (cutting the ends of suture). The instrument  100  of the present invention is also designed to cut suture clean and without difficulty, regardless of the strength of the suture material. A special application of the instrument  100  of the present invention is for cutting FiberWire® cleanly and without difficulty. Because of its strength, FiberWire® cannot be cleanly cut by scissoring or clipping (pinching). By sliding the Fiberwire® along a sharp edge, in a relatively short distance, it can be cut cleanly. With the knot pusher/suture cutter assembly  100  of the present invention, because the slot  20  on the inner shaft  2  is at an angle to the outer sleeve  5  and the longitudinal axis of the shaft, the FiberWire® is forced to slide along a sharp edge, thus being cut cleanly. 
     The combined knot pusher/suture cutter assembly  100  of the present invention has also particular application to advancing knots and cutting suture during methods of tissue repair employing cinch stitching. In this particular application, the instrument  100  of the present invention may be employed to push knots and/or cut suture posts once the suture implant constructs have been deployed within the meniscal tissue to be repaired (by using a plurality of first and second trocars carrying the implants on their external surfaces, for example). 
     The present invention also provides methods for meniscal repair by cinch stitching. According to an exemplary embodiment, the method comprises the steps of (i) providing a meniscal cinch assembly comprising first and second trocars, a depth stop adapted to securely engage one of the trocars, and a suture implant construct having first and second implants loaded on the external surface of the first and second trocars; (ii) passing at least one of the first and second implants through tissue to be repaired (for example, the meniscal tissue); and (iii) pushing knots and/or cutting suture material attached to the first and second implants with the combined knot pusher/suture cutter assembly  100  of the present invention. 
     The combined knot pusher/suture cutter assembly  100  described above may be also employed in additional surgical applications that require knot formation and suture cutting, for example, in shoulder applications where the device may be employed as both a knot pusher and a suture cutter. 
     For the purposes of the present invention, the term “high strength suture” is defined as any elongated flexible member, the choice of material and size being dependent upon the particular application. For the purposes of illustration and without limitation, the term “suture” as used herein may be a cable, filament, thread, wire, or any other flexible member suitable for tissue fixation in the body. In a preferred embodiment of the invention, and as described above, the suture comprises a high strength suture sold by Arthrex, Inc. under the tradename FiberWire®. 
     Although the present invention has been described in connection with preferred embodiments, many modifications and variations will become apparent to those skilled in the art. While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Accordingly, it is not intended that the present invention be limited to the illustrated embodiments, but only by the appended claims.