Surgical stapler with rotary cam drive and return

A surgical circular stapler has a body, shaft, a stapling assembly, a motor, a cam assembly, and a firing assembly. The shaft extends distally from the body. The stapling assembly is secured to a distal end of the shaft. Longitudinal translation of the firing assembly causes the stapling assembly to drive a plurality of staples in a circular array to secure two lumens of tissue together. The stapling assembly may further drive a blade to sever any excess tissue interior of the circular array of staples. The motor is operable to rotate the cam assembly. Rotation of the cam assembly causes longitudinal translation of the firing assembly. A single rotation of the cam assembly is operable to drive the firing assembly from a proximal position to a distal position and back to a proximal position.