Medical retrieval devices

Abstract

A medical retrieval device includes a retrieval assembly comprising a plurality of filaments knotted together at a distal end of the retrieval assembly. The knotted distal end provides the device with an atraumatic distal tip. Various knotting arrangements can be used at the knotted distal end. The retrieval assembly can be collapsed when restrained and expanded when unrestrained.

1 - 26 . (canceled) 
   
   
       27 . A medical retrieval device, comprising:
 a sheath; and   a retrieval assembly comprising a plurality of filaments knotted together in a barrel knot to form a knotted distal end of the retrieval assembly, the retrieval assembly being collapsed when restrained by the sheath and expanded when unrestrained by the sheath.   
   
   
       28 . The medical device of  claim 27 , wherein the barrel knot comprises:
 (a) the plurality of filaments coiled to form a first set of at least two concentric loops, each loop defining a lumen; and   (b) a first overhand knot tied with the plurality of parallel filaments through the lumens of the first set of at least two concentric loops to form the barrel knot at the knotted distal end of the retrieval assembly.   
   
   
       29 . The medical device of  claim 27 , wherein the barrel knot comprises:
 (a) the plurality of filaments grouped together and bent to form a loop defining a lumen wherein an end of the filaments crosses a portion of the filaments; and   (b) the end of the filaments wound around the grouped filaments and through the lumen of the loop two or more times to form the barrel knot at the knotted distal end of the retrieval assembly.   
   
   
       30 . The medical retrieval device of  claim 27 , wherein the knotted distal end does not include an adhesive. 
   
   
       31 . The medical retrieval device of  claim 27 , wherein the knotted distal end includes an adhesive. 
   
   
       32 . The medical retrieval device of  claim 27 , wherein at least one filament forms two legs of the retrieval assembly. 
   
   
       33 . A retrieval assembly, comprising:
 a barrel knot, comprising
 (a) a plurality of filaments; 
 (b) the plurality of filaments coiled to form a first set of at least two concentric loops, each loop defining a lumen; and 
 (c) a first overhand knot tied with the plurality of parallel filaments through the lumens of the first set of at least concentric two loops to form the barrel knot at the knotted distal end of the retrieval assembly. 
   
   
   
       34 . The retrieval assembly of  claim 33 , further comprising a second set of at least two concentric loops formed by coiling the plurality of parallel filaments, and a second overhand knot tied with the plurality of filaments through the lumens of the second set of at least two concentric loops. 
   
   
       35 . The retrieval assembly of  claim 33 , wherein the knotted distal end does not include an adhesive. 
   
   
       36 . The retrieval assembly of  claim 33 , wherein the knotted distal end includes an adhesive. 
   
   
       37 . The retrieval assembly of  claim 33 , wherein at least one filament forms two legs of the retrieval assembly. 
   
   
       38 . The retrieval assembly of  claim 33 , wherein the number of concentric loops is the same as the number of filaments. 
   
   
       39 . The retrieval assembly of  claim 33 , wherein the number of concentric loops is less than the number of filaments. 
   
   
       40 . The retrieval assembly of  claim 33 , wherein the number of concentric loops is greater than the number of filaments. 
   
   
       41 . A retrieval assembly, comprising:
 a barrel knot including
 (a) a plurality of filaments grouped together; 
 (b) the grouped filaments bent to form a loop defining a lumen wherein an end of the filaments crosses a portion of the filaments; and 
 (c) the end of the filaments wound around the grouped filaments and through the lumen of the loop two or more times to form the barrel knot at a knotted distal end of the retrieval assembly. 
   
   
   
       42 . The retrieval assembly of  claim 41 , wherein the knotted distal end does not include an adhesive. 
   
   
       43 . The retrieval assembly of  claim 41 , wherein the knotted distal end includes an adhesive. 
   
   
       44 . The retrieval assembly of  claim 41 , wherein at least one filament forms two legs of the retrieval assembly. 
   
   
       45 . The retrieval assembly of  claim 41 , wherein the number of times the ends of the filaments are wound around the grouped filaments and through the lumen is the same as the number of filaments. 
   
   
       46 . The retrieval assembly of  claim 41 , wherein the number of times the ends of the filaments are wound around the grouped filaments and through the lumen is less than the number of filaments. 
   
   
       47 . The retrieval assembly of  claim 41 , wherein the number of times the ends of the filaments are wound around the grouped filaments and through the lumen is greater than the number of filaments.