US Patent 6945444 Surgical stapling device for performing circular anastomoses

This application is directed to a surgical stapling device for performing circular anastomoses. The stapling device includes a retractable trocar which is slidably supported by an anvil retainer and movable from a retracted position located within the anvil retainer to an advanced position extending from the anvil retainer. The trocar defines a sensor and is operatively connected to an indicator assembly. The indicator assembly is operatively associated with an anvil assembly such that the indicator will not move from a fire-not ready position to a fire-ready position until an anvil assembly has been mounted to the anvil retainer.