Abstract: A surgical snare having a wire which forms the snare loop made from a shape memory effect metallic alloy which exhibits superelasticity at room temperature. The wire is trained so that it assumes an intermediate snare loop size in an unrestrained free state. From this trained free state configuration, the loop can be expanded to a large loop and contracted to a very small loop without permanent deformation from the trained intermediate state. This range of movement enables an expanded range of applicability for snares in general, and also enables reducing the instrument tip size with improved loop configuration.

Abstract: An improved surgical snare apparatus includes an elongated tubular tip extending from a control handle. The ends of a single U-formed snare wire extend through the tip and out of its proximal end where they are secured to a control element in the handle that enables moving of the wire. The distal end is modified from conventional snares to allow the contracted snare loop to be substantially nested within the tip. In the fully contracted nested position, the wire substantially closes the modified distal end so that the sharp cutting edges of the distal end are not exposed to contact with body tissue during insertion into an incision or opening. Thus, the combination of the modified distal end and the single wire nested within presented a tip the minimizes trauma during insertion.The configuration of the expanded single wire loop is modified from conventional dual wire snare loops into a more rounded form which is easier to manipulate around tissue to be severed, a polyp for example.