US Patent 10575847 Circular surgical stapler with mating anvil and shell assembly

A surgical stapler comprising a handle assembly, an elongated body portion extending distally from the handle assembly, and a head portion disposed adjacent a distal portion of the elongated body portion and including an anvil assembly and a shell assembly. The anvil assembly is movable in relation to the shell assembly between spaced and approximated positions. The anvil assembly has an anvil head and a plurality of projections extending proximally of the anvil head, the projections engageable with a portion of the shell assembly.