US Patent 8257391 Annular support structures

Reinforcing lumen rings are configured and adapted for use in conjunction with a circular endoscopic stapling instrument having a staple cartridge assembly and an anvil assembly. The reinforcing lumen rings maintain anastomotic lumen, e.g. as formed by the circular endoscopic stapling apparatus, in an open condition. The reinforcing lumen rings can include an annular ring having an outer terminal edge and an inner terminal edge, the outer terminal edge having a diameter which is substantially equal to an outer diameter of the staple cartridge assembly and the inner terminal edge having a diameter which is substantially equal to an inner diameter of the staple cartridge assembly.