Endoscopic hook blade and use thereof

Abstract

An endoscopic surgical blade is disclosed. The blade is of a hook design, having an upper cutting surface located on the trailing edge of an arm and a lower cutting surface on the upper edge of the main body of the blade. The blade is part of an endoscopic knife assembly which also contains a knife tube and alignment ring. The endoscopic knife assembly is for use in endoscopic surgery by insertion of the assembly through a slotted cannula. The knife tube is hollow and allows the insertion of an endoscope for viewing of the surgical procedure. A method for a performing an operative procedure on a target tissue in a subject using an endoscopic knife assembly having a hook blade is also described.

1 . A hook blade for an endoscopic knife assembly, comprising:
 an arm having a forward edge, a trailing edge and an upper cutting surface located on the trailing edge;   a main body having an upper edge, a lower edge, a distal section, a proximate section, and a lower cutting surface located on the upper edge of the distal section;   wherein the distal section of the main body angles downward from the proximate section of the main body, forming a downward angle with the proximate section of the main body,   wherein the arm protrudes from the distal section of the main body and extends back towards the main body in a hook-like manner, forming a hook angle with the proximate section of the main body, and   wherein the upper cutting surface and the lower cutting surface meets at a crotch forming a cutting angle between the two cutting surfaces.   
     
     
         2 . The hook blade of  claim 1 , wherein the hook angle is between about 55 degrees and about 75 degrees. 
     
     
         3 . The hook blade of  claim 2 , wherein the hook angle is about 65 degrees. 
     
     
         4 . The hook blade of  claim 1 , wherein the cutting angle is between about 40 degrees and about 60 degrees. 
     
     
         5 . The hook blade of  claim 4 , wherein the cutting angle is about 50 degrees. 
     
     
         6 . The hook blade of  claim 1 , wherein the downward angle is between about 150 degrees and about 175 degrees. 
     
     
         7 . The hook blade of  claim 6 , wherein the downward angle is between about 165 degrees. 
     
     
         8 . The hook blade of  claim 1 , wherein the proximate section of the main body has a tapered end. 
     
     
         9 . The hook blade of  claim 1 , wherein the main body comprises a notch on the lower edge to engage with a knife tube. 
     
     
         10 . The hook blade of  claim 1 , wherein the arm comprises an upper radius on the upper end of the forward edge to prevent the forward edge from damaging tissue as the hook blade is advanced from a cannula. 
     
     
         11 . The hook blade of  claim 10 , wherein the arm further comprises a lower radius on the lower end of the forward edge to prevent the forward edge from damaging tissue as the hook blade is advanced from a cannula. 
     
     
         12 . The hook blade of  claim 1 , wherein the hook blade has a total vertical height in the range of about 4 mm to about 5 mm. 
     
     
         13 . An endoscopic knife assembly, comprising:
 a knife tube having a distal end and a proximate end;   a hook blade attached to the distal end; and   an alignment ring attached near the proximate end,   wherein the hook blade comprises an arm having a forward edge, a trailing edge and an upper cutting surface located on the trailing edge; a main body having an upper edge, a lower edge, a distal section, a proximate section, and a lower cutting surface located on the upper edge of the distal section; wherein the distal section of the main body angles downward from the proximate section of the main body, forming a downward angle with the proximate section of the main body, wherein the arm protrudes from the distal section of the main body and extends back towards the main body in a hook-like manner, forming a hook angle with the proximate section of the main body, and wherein the upper cutting surface and the lower cutting surface meets at a crotch forming a cutting angle between the two cutting surfaces.   
     
     
         14 . The endoscopic knife assembly of  claim 13 , wherein the knife tube comprises one or more slots at the proximate end for the attachment of a locking assembly to the knife tube and alignment ring. 
     
     
         15 . The endoscopic knife assembly of  claim 13 , wherein the slots are located on a plane that is perpendicular to the hook blade attached to the distal end of the knife tube. 
     
     
         16 . The endoscopic knife assembly of  claim 13 , wherein the knife tube is marked on the top or side surface with gradations. 
     
     
         17 . The endoscopic knife assembly of  claim 13 , wherein the alignment ring comprises a flattened surface that is positioned perpendicular to the hook blade attached to the distal end of the knife tube. 
     
     
         18 . The endoscopic knife assembly of  claim 13 , wherein the hook blade is welded to the knife tube. 
     
     
         19 . An instrument kit for implementing an endoscopic surgical procedure comprising:
 an endoscopic knife assembly comprising a hook blade, a knife tube and an alignment ring, wherein the blade comprises an upper cutting surface located on a trailing edge of an arm and a lower cutting surface located on an upper edge of a main body of the blade, the cutting surfaces meeting at an angle at a crotch; and   a slotted cannula for endoscopic surgical procedures,   wherein the endoscopic knife assembly is insertable into the slotted cannula.   
     
     
         20 . The instrument kit of  claim 19 , wherein the main body of the blade comprises a notch on a lower edge of the main body to engage with the knife tube. 
     
     
         21 . A method for a performing a operative procedure on a target tissue in a subject, comprising:
 establishing an entry portal,   inserting a cannula having open proximal and distal ends,   inserting an endoscope into the cannula, said endoscope comprising an endoscopic knife assembly having a hook blade,   advancing said endoscope so that the hook blade moves distal to and is in contact with the target tissue, and   operatively engaging the target tissue with the hook blade.   
     
     
         22 . The method of  claim 21 , wherein said operative procedure is an endoscopic surgical procedure selected from the group consisting of carpal tunnel release, cubital tunnel release, plantar fascia release, lateral release for patella realignment, release of the extensor tendons, release of the posterior and other compartments of the leg, and forearm fascial release. 
     
     
         23 . The method of  claim 21 , wherein said method further comprises a step of withdrawing the hook blade back towards the cannula to perform the operative procedure on the target tissue. 
     
     
         24 . The method of  claim 21 , wherein said cannula comprises an open slot extending along the length of the cannula. 
     
     
         25 . The method of  claim 21 , wherein said inserting of said endoscope comprising an endoscopic knife assembly having a hook blade is preceded by the insertion of another endoscope comprising a means for visualization of the target tissue. 
     
     
         26 . The method of  claim 25 , wherein said cannula is a clear cannula. 
     
     
         27 . The method of  claim 26 , further comprising visualization of anatomic structures surrounding the cannula. 
     
     
         28 . The method of  claim 21 , wherein said establishing an entry portal comprises making an incision.