A circular stapler apparatus and method for stapling tissue include a shaft assembly and an anvil. The anvil is configured to proximally retract toward the shaft assembly, which at least severs or staples tissue based on a single rotary input. The shaft assembly includes a plurality of joint segments, and each joint segment includes a resilient member. The plurality of joint segments are configured to pivot relative to one another in a first, uncompressed position and are configured to lock against one another to prevent pivoting in a second, compressed position. A first plurality of joint segments defines a proximal portion that is attached to a first cable or shaft. A second plurality of joint segments defines a distal portion that is selectively lockable independent of the proximal portion and that is attached to a second cable or shaft.
