Patent ID: 8663168

Claim:
An endoscopic instrument, comprising: a first flexible insertion member sized for insertion through a body lumen to a target site and having a first flexibility; a second flexible insertion member sized for insertion through a first lumen of the first flexible insertion member; and a needle including a proximal portion received within a distal portion of the second flexible insertion member and including a distal portion extending distally beyond a distal end of the second flexible insertion member for penetration of tissue, the needle including a plurality of flexibility enhancing grooves formed therein along at least a portion of the length of the needle so that a second flexibility of the needle is greater than the first flexibility, the distal portion of the needle including at least one of the flexibility enhancing grooves, a size and a spacing of each of the flexibility enhancing grooves being selected to maintain a predetermined degree of axial strength, wherein at least one of the grooves comprises a first needle wall thickness that is less than a second needle wall thickness at a portion of the needle in which the grooves are absent, and wherein the flexibility enhancing grooves disposed at the proximal portion of the needle increase a mechanical lock between an outer wall of the proximal portion of the needle and an inner wall of the distal portion of the second flexible insertion member.