US Patent 9844372 Retainer assembly including a tissue thickness compensator

A stapling system for stapling tissue is disclosed. The stapling system comprises a cartridge body, staples removably stored in the cartridge body, and an implantable layer. The implantable layer comprises a first portion comprising a first density, wherein the first portion is comprised of a material. The implantable layer further comprises a lattice comprising a second density, wherein the first density is different than the second density, and wherein the lattice is comprised of the material. The implantable layer further comprises a medicament which promotes tissue ingrowth into the layer in a specified pattern.