Snare wire structure

A snare wire structure, comprising:

• an operation wire configured to be inserted into a through-passage of a sheath constituting an endoscopic snare;
• and
• a snare loop configured to have both ends connected to a tip end portion of the operation wire and to be formed in a loop shape,
• wherein the snare loop is symmetrically formed, with reference to a center line passing through a continuous portion with respect to the tip end portion of the operation wire, by
• a pair of proximal end portions that are continuous with the tip end portion of the operation wire so as to spread apart from each other at one end portion by forming a proximal end interior angle 2θ0=55° to 80°,
• a pair of first portions that form a first designated interior angle θ1=180°−(θ0+δθ1)(0.5°≤δθ1≤12°) with respect to each of the pair of proximal end portions and that are continuous with an other end portion of each of the pair of proximal end portions, and
• a pair of second portions that form a second designated interior angle θ2=θ1+δθ2 (−8°≤δθ2≤14°) with respect to each of the pair of first portions at one end portion, that are continuous with an other end portion of each of the pair of first portions, and that are continuous at an other end portion, and
• the snare loop includes a first strand made of stainless steel and has a twisted configuration of 1×N1 (N1=3 to 19) and a diameter of 0.2 to 0.35 mm.