Small diameter linear surgical stapling apparatus

A surgical stapling apparatus, comprising:

• a housing assembly;
• an elongated shaft assembly defining a longitudinal axis and having a distal end portion and a proximal end portion, the proximal end portion selectively attached to the housing assembly;
• an anvil assembly supported on the distal end portion of the elongated shaft assembly;
• a cartridge assembly selectively attached to the anvil assembly to secure the cartridge assembly to the elongated shaft assembly;
• and
• a firing drive screw coupled to a firing nut, the firing nut coupled to a firing tube, the firing tube coupled to a firing rod, the firing rod positioned to advance a drive beam assembly through the cartridge assembly.

An adapter assembly of a surgical stapling apparatus, the adapter assembly comprising:

• a proximal housing;
• an elongated shaft assembly coupled to the proximal housing and defining a longitudinal axis, the elongated shaft assembly having a proximal end portion and a distal end portion;
• an end effector supported on the distal end portion of the elongated shaft assembly, the end effector including an anvil assembly and a cartridge assembly selectively attached to the anvil assembly;
• and
• a firing assembly including a firing drive screw threadedly coupled to a firing nut, the firing nut coupled to a firing tube, the firing nut positioned to translate when the firing drive screw rotates to cause the firing tube to translate for firing the end effector.