Reusable circular stapler handle with open assembly architecture

A circular stapling instrument comprising:

• a reciprocating drive shaft having an engagement member at a tip of the reciprocating drive shaft and a threaded adjustment member at a base of the reciprocating drive shaft;
• a firing bar forming an engagement groove and having an engagement shaft that forms an opening through which the tip of the reciprocating drive shaft is received;
• a handle having a firing trigger and forming a cavity which receives the firing bar and the reciprocating drive shaft, wherein an upper end of the firing trigger engages the engagement groove and detachably secures the firing bar and the reciprocating drive shaft within the cavity of the handle;
• a carrier cover covering a portion of the firing bar and the reciprocating drive shaft;
• a shaft assembly detachably coupled with the handle;
• and
• a stapling reload assembly detachably coupled to the shaft assembly, the reload assembly comprising:
• a casing,
• a staple holder attached to the casing,
• a staple driver comprising a driver alignment surface, the staple driver receivable within the casing and configured to move within the casing from a pre-fired position to a fired position, and
• an anvil assembly comprising an anvil base surface, an anvil alignment surface, and a staple forming surface, the anvil base surface configured to move from an open position away from the casing to a closed position adjacent the casing, wherein the anvil alignment surface is configured to mate with the driver alignment surface, to rotationally align the staple forming surface with the staple holder, when the anvil base surface is in the closed position.