A staple cartridge assembly for use with a surgical stapling instrument includes a staple cartridge including a plurality of staples and a cartridge deck. The staple cartridge assembly also includes a compressible adjunct positionable against the cartridge deck, wherein the staples are deployable into tissue captured against the compressible adjunct, and wherein the compressible adjunct comprises a first biocompatible layer comprising a first portion, a second biocompatible layer comprising a second portion, and crossed spacer fibers extending between the first portion and the second portion.

Implantable adjuncts for use with a surgical instrument are disclosed. The implantable adjunct includes a first mesh positioned about a first side of the longitudinal knife slot and a second mesh positioned about a second side of the longitudinal knife slot such that the first and second meshes define a gap substantially aligned with the longitudinal knife slot of the staple cartridge body.