An apparatus comprising: (a) a body; (b) a shaft assembly extending distally from the body, wherein the shaft assembly has a distal end; (c) a stapling head assembly located at the distal end of the shaft assembly, wherein the stapling head assembly comprises: (i) a deck member, wherein the deck member comprises: a deck surface, an outer annular array of staple openings formed through the deck surface, an inner annular array of staple openings formed through the deck surface, and a plurality of recesses (560, 570) formed in the deck surface, wherein at least a portion of the recesses are positioned between at least some of the staple openings, (ii) a plurality of staples, and (iii) a driver operable to drive the staples through the staple openings; and (d) an anvil, wherein the anvil is operable to compress tissue against the deck surface, characterised in that the plurality of recesses comprises an inner plurality of recesses, wherein the recesses of the inner plurality of recesses are positioned between the staple openings of the inner annular array of staple openings, and wherein the recesses of the inner plurality of recesses are in communication with each other via channels. (a) a body; (b) a shaft assembly extending distally from the body, wherein the shaft assembly has a distal end; (c) a stapling head assembly located at the distal end of the shaft assembly, wherein the stapling head assembly comprises: (i) a deck member, wherein the deck member comprises: a deck surface, an outer annular array of staple openings formed through the deck surface, an inner annular array of staple openings formed through the deck surface, and a plurality of recesses (560, 570) formed in the deck surface, wherein at least a portion of the recesses are positioned between at least some of the staple openings, (ii) a plurality of staples, and (iii) a driver operable to drive the staples through the staple openings; and (i) a deck member, wherein the deck member comprises: a deck surface, an outer annular array of staple openings formed through the deck surface, an inner annular array of staple openings formed through the deck surface, and a plurality of recesses (560, 570) formed in the deck surface, wherein at least a portion of the recesses are positioned between at least some of the staple openings, a deck surface, an outer annular array of staple openings formed through the deck surface, an inner annular array of staple openings formed through the deck surface, and a plurality of recesses (560, 570) formed in the deck surface, wherein at least a portion of the recesses are positioned between at least some of the staple openings, (ii) a plurality of staples, and (iii) a driver operable to drive the staples through the staple openings; and (d) an anvil, wherein the anvil is operable to compress tissue against the deck surface, characterised in that the plurality of recesses comprises an inner plurality of recesses, wherein the recesses of the inner plurality of recesses are positioned between the staple openings of the inner annular array of staple openings, and wherein the recesses of the inner plurality of recesses are in communication with each other via channels.