Patent ID: 8877233

Claim:
A method for preparing a medical device, comprising: forming a three-dimensionally stable sponge structure including collagen, said forming including crosslinking the collagen with a chemical crosslinking agent, and drying the sponge structure to form a dried three-dimensionally stable sponge structure; wetting the dried three-dimensionally stable sponge structure to form a wetted three-dimensionally stable sponge structure; radially compacting the wetted three-dimensionally stable sponge structure by subjecting the three-dimensionally stable sponge structure to radial compaction force, wherein said radial compaction force compacts the sponge structure radially so as to provide a generally cylindrical shape to the sponge structure and to provide a compacted volume to pores of the sponge structure; drying the wetted three-dimensionally stable sponge structure by lyophilization during said compacting to provide said sponge structure in a dried, compacted state having said generally cylindrical shape and having a density; wherein upon removal of said compaction force, said sponge structure is structurally stable and remains in said dried, compacted state having said generally cylindrical shape and having said pores stably retained at said compacted volume until said sponge structure in said dried, compacted state is contacted with a liquid susceptible to absorption by said sponge structure; and wherein said sponge structure in said dried, compacted state is expansible at least 100% by volume when saturated with deionized water.