Method and apparatus for thread transection of a ligament

Abstract

A method and apparatus for transecting soft tissue, such as a ligament, and more particularly, the transverse carpal ligament. An hollow introducer needle and a threadlike cutting element enable the method to performed in a minimally invasive manner. The cutting element is routed into position about the target ligament such that the cutting element both enters and exits the body from the same side of the ligament. The substantially smooth exterior surface of the cutting element serves to provide for a kerf-less cut.

What is claimed is: 
     
         1 . A method for transecting a soft tissue within a body, comprising the steps of:
 providing a flexible thread-like cutting element having a substantially smooth surface;   providing a hollow introducer needle;   extending said hollow introducer needle into said body at a first location transversely adjacent said soft tissue and out of said body at a second location transversely adjacent to said soft tissue and opposite said first location so as to traverse said soft tissue on a first side thereof;   extending said cutting element through said hollow introducer needle to leave said cutting element projecting proximally and distally from said introducer needle;   retracting said introducer needle from said body so as to leave said cutting element in place;   re-extending said hollow introducer needle into said body at said first location and out of said body at said second location or into said body at said second location and out of the body at said first location so as to traverse said soft tissue on a second side thereof opposite said first side;   extending an end of said cutting element through said hollow introducer needle such that said end portion projects from said hollow introducer needle;   retracting said introducer needle from said body to thereby leave said cutting element in place looped about said soft tissue with both end portions extending from the same location of said body; and   exerting force on the ends of said cutting element so as to achieve a kerf-less transection of said soft tissue.   
     
     
         2 . The method of  claim 1 , wherein unequal forces are exerted on the ends of said cutting element to alternately pull said cutting element in opposite directions to transect said soft tissue. 
     
     
         3 . The method of  claim 2 , further comprising the steps of providing a powered hand tool for alternately reciprocating ends of a cutting element and attaching said projecting ends thereto. 
     
     
         4 . The method of  claim 1 , wherein unequal forces are exerted on the ends said cutting element so as to pull said cutting element in a single direction to transect said soft tissue. 
     
     
         5 . The method of  claim 1 , wherein substantially equal forces are simultaneously exerted on both ends of said cutting element to transect said soft tissue. 
     
     
         6 . The method of  claim 1 , wherein an imaging device is relied upon to visualize said extensions of said hollow retrieval needle within said body. 
     
     
         7 . The method of  claim 6 , wherein said imaging device comprises an ultrasound imaging device. 
     
     
         8 . The method of  claim 1 , wherein a liquid is injected into the body in and around such soft tissue prior to said routing of said cutting element about said soft tissue so as to provide space for the extension of the hollow introducer needle thereinto. 
     
     
         9 . The method of  claim 1 , further comprising the step of positioning a protective tube about both end portions of said cutting element projecting from said body. 
     
     
         10 . The method of  claim 1 , wherein one end of said cutting element is first extended through said hollow needle from its first end and wherein said same end of the cutting element is subsequently re-extended through said needle from its second end. 
     
     
         11 . The method of  claim 1 , wherein one end of said cutting element is first extended through said hollow needle from its first end and wherein its opposite end of the cutting element is subsequently re-extended through said needle from its first end. 
     
     
         12 . The method of  claim 1 , wherein said soft tissue comprises a ligament. 
     
     
         13 . The method of  claim 12 , wherein said ligament comprises the transverse carpal ligament. 
     
     
         14 . A system for transecting a soft tissue within a body, comprising:
 a flexible cutting element having a substantially smooth surface; and   an introducer needle having a hollow interior extending from its proximal end to its distal end with an internal diameter sufficient to receive said flexible cutting element, having a distal tip, and having a length sufficient to extend from a first location transversely adjacent to such soft tissue to a second location transversely adjacent to such soft tissue and opposite to such first location;   
     
     
         15 . The system of  claim 14  further comprising an imaging device capable of visualizing said hollow introducer needle with said body relative to said soft tissue. 
     
     
         16 . The system of  claim 15 , wherein said visualizing device comprises an ultrasound imaging device. 
     
     
         17 . The system of  claim 14 , wherein said cutting element has stiffened end sections to facilitate insertion into and extension through said hollow introducer needle. 
     
     
         18 . The system of  claim 14 , wherein said cutting element has a diameter less than 1.0 mm. 
     
     
         19 . The system of  claim 14 , wherein said cutting element has a zero bend radius. 
     
     
         20 . The system of  claim 14 , wherein said cutting element has a bend radius less than about half the thickness of said soft tissue. 
     
     
         21 . The system of  claim 14 , wherein said cutting element has a breaking strength of greater than 2 lbs. 
     
     
         22 . The system of  claim 14 , wherein said cutting element has a braided or twisted structure or comprises a monofilament. 
     
     
         23 . The system of  claim 14 , further comprising a power tool for alternately reciprocating ends of said cutting element. 
     
     
         24 . The system of  claim 14 , further comprising a hollow sleeve dimensioned to receive both ends of said cutting element and configured for retaining said cutting element therein during its reciprocation.