Patent ID: 7300445

Claim:
A method of performing intralumenal full thickness resection of tissue, comprising the steps of: inserting into a body lumen via a naturally occurring body orifice an operating head slidably received around a distal end of a flexible insertion tube, wherein the operating head includes: a proximal-facing abutting surface; a first optical device disposed on a distal portion of the operating head, the first optical device having a viewing area extending distally of the distal portion; a working chamber extending within an exterior wall of the operating head, a first portion of the exterior wall being moveable with respect to a second portion thereof to selectively open the working chamber to an exterior of the operating head; and a second optical device mounted within the working chamber with a viewing area extending distally therefrom; sliding an insertion sheath over the flexible tube until a distal end of the insertion sheath contacts the abutting surface; and moving the insertion sheath further into the body lumen to drive the operating head distally relative to the flexible insertion tube until the operating head is in a desired position relative to a distal end of the flexible insertion tube.