Abstract: A surgical stapling instrument for performing a circular anastomosis stapling operation is provided. The surgical instrument includes a stapling head assembly mounted by a curved shaft to an actuator handle assembly and incorporates an improved actuator mechanism for transmitting the required operating forces and movements from the actuator handle assembly through the curved shaft to an anvil and staple driver of the stapling head assembly. The stapling head assembly includes a longitudinally movable trocar detachably secured by one or more retainer clips on a hollow shaft of the anvil. When the trocar is retracted, the anvil shaft slides into a central support tube which aligns the anvil axially and circumferentially with a staple holder on the stapling head assembly. The retainer clips are locked against the trocar by the support tube and transmit tension from the trocar to the anvil with no tension load on the anvil shaft.

Abstract: An endoscopic clip applying system as described which contains a venting system and a clip applying support system which prevents closure of the mechanism before firing. The applier's jaws are spaced apart no further than the width of the applier shaft, even when holding a clip. Also, the system ensures proper loading of the clips and prevents them from falling out during loading. Further, the system describes an easily manufacturable, positively opening system which has minimized size requirements. Furthermore, a lock-out mechanism is provided so that the mechanism may not be inadvertently fired. The shaft resists excessive torque as well as holds the clip in place during firing. There are provisions for sealant and non back-up of the clips, as well as features which make the clip properly placed for closure. In an alternate embodiment, the clip applier shaft rotates about its handle mechanism.