Patent ID: 7559452

Claim:
A surgical instrument, comprising: a handle operably configured to produce closure actuation and opening actuation; an elongate shaft attached to the handle and defining a longitudinal axis; an end effector distally attached to the elongate shaft and comprising a pair of pivoting members opposingly contacting tissue, wherein the lower pivoting member comprises a staple channel and the upper pivoting member comprises an anvil, and each pivoting member including a respective proximally projecting lever constrained to pivot relative to the other lever about a pivot connection, wherein the lever projecting proximally from the staple channel comprises a frame of the elongate shaft attached to the handle and the lever projecting proximally from the anvil comprises an anvil lever; a staple cartridge received in the staple channel; a firing bar slidingly received in the elongate channel and distally movable through the closed end effector to effect severing and stapling of clamped tissue; an outer sheath encompassing the frame of the elongate shaft and the lever of the anvil; and a fluid actuated closure mechanism comprising: a fluid actuator bladder positioned between the levers proximal to the pivot connection to operably engage with one or more of the respective proximal projecting levers of the pair of pivoting members, a fluid conduit communicating fluid with the fluid actuator bladder and extending through the elongate shaft, a fluid reservoir responsive to the closure actuation by the handle to selectively and bi-directionally transfer fluid across the fluid conduit to move at least a portion of the fluid actuator bladder laterally to the longitudinal axis to close and open the end effector, and an opposing fluid actuator bladder positioned between the anvil lever and the outer sheath for opposing the fluid actuator positioned between the proximal projecting levers to close the anvil, the handle further operatively configured to differentially expand and compress the opposing fluid actuator bladder and the fluid actuator bladder to move the anvil open and closed.