The wire loop of a surgical snare is constructed so as to include a weakened or frangible region. When it is desired to open the loop so as to move it from its entrapped position on a polyp, an additional force is exerted on the loop to draw it further into the sheath. This causes the frangible region...http://www.google.fr/patents/US5462553?utm_source=gb-gplus-shareBrevet US5462553 - Surgical snare with a frangible loop
