Retaining pin mechanism for a surgical cutter stapler

A surgical instrument adapted for applying a plurality of surgical fasteners to body tissue, the surgical instrument comprising: a frame having a proximal end and a distal end, with a handle positioned at the proximal end and an end effector positioned at the distal end;the end effector being shaped and dimensioned for supporting a cartridge housing and an anvil, the cartridge housing and anvil being relatively movable between a first spaced apart position and a second position in close approximation with one another;a firing mechanism associated with the end effector and the cartridge housing for selective actuation of the fastening elements for treatment of an individual; anda retaining pin for enclosing tissue between the anvil and the cartridge housing, the retaining pin being movable relative to the cartridge housing under the control of a retaining pin actuation mechanism;the retaining pin actuation mechanism includes a lever rotationally connected to the handle for facilitating both manual and automatic advancement of the retaining pin and requiring manual retraction of the retaining pin.