Tissue stapler having a thickness compensator incorporating a hydrophilic agent

1. A staple cartridge assembly for use with a surgical stapler, wherein said staple cartridge assembly is adapted to be used with tissue having a thickness, said staple cartridge assembly comprising:

a cartridge body comprising a support portion, wherein said support portion comprises a plurality of staple cavities, and wherein each said staple cavity comprises an opening;

a plurality of staples, wherein at least a portion of each said staple is removably stored within a said staple cavity, wherein each said staple is movable between an unfired position and a fired position, and wherein each said staple is deformable between an unfired configuration and a fired configuration when each said staple is moved between a said unfired position and a said fired position; and

a compressible tissue thickness compensator configured to be captured within said staples, wherein said compressible tissue thickness compensator at least partially covers said staple cavity openings, wherein said support portion is configured to support said compressible tissue thickness compensator, wherein said compressible tissue thickness compensator is configured to assume a different compressed height within different said staples, and wherein said compressible thickness compensator comprises a bioabsorbable hydrophilic agent embedded therein,

wherein said compressible tissue thickness compensator comprises a dynamic bioabsorbable hydrophilic agent density configured to adaptively respond to tissue having different thicknesses, wherein said dynamic bioabsorbable hydrophilic agent density comprises an uncompressed hydrophilic agent density when said tissue thickness compensator is in an uncompressed state, wherein said dynamic bioabsorbable hydrophilic agent density comprises a first compressed hydrophilic agent density in a first said staple in response to tissue having a first thickness in said first staple, wherein said dynamic bioabsorbable hydrophilic agent density comprises a second compressed hydrophilic agent density in a said second staple in response to tissue having a second thickness in said second staple, wherein the first thickness is different than the second thickness, and wherein said first density is different than said second density.

2. The staple cartridge assembly of claim 1 , wherein said bioabsorbable hydrophilic agent comprises at least one of: fatty acid esters, triglycerides; cholesterol, anionic cholesterol, carboxylates, amphoteric surfactants, amino propionic acids, imido propionic acids and quaterized compounds.

3. The staple cartridge assembly of claim 1 , wherein said compressible tissue thickness compensator comprises an uncompressed thickness which is thicker than the thickness of said tissue.

4. The staple cartridge assembly of claim 1 , wherein said bioabsorbable hydrophilic agent comprises a foam comprising a surfactant.

5. The staple cartridge assembly of claim 1 , wherein said bioabsorbable hydrophilic agent comprises at least one of: fatty acid esters, triglycerides; cholesterol, anionic cholesterol, carboxylates, amphoteric surfactants, amino propionic acids, imido propionic acids and quaterized compounds.

6. The staple cartridge assembly of claim 1 , wherein the first thickness is greater than the second thickness, and wherein said first density is greater than said second density.

7. A staple cartridge assembly for use with a surgical stapler, wherein said staple cartridge assembly is adapted to be used with tissue having a thickness within a range of tissue thicknesses, said staple cartridge assembly comprising:

a cartridge body comprising a support portion, wherein said support portion comprises a plurality of staple cavities, and wherein each said staple cavity comprises an opening;

a plurality of staples, wherein at least a portion of each said staple is removably stored within a said staple cavity, wherein each said staple is movable between an unfired position and a fired position, wherein each said staple is deformable between an unfired configuration and a fired configuration when each said staple is moved between a said unfired position and a said fired position, and wherein each said staple comprises:

a base; and

at least one leg extending from said base, wherein said at least one leg is deformable to capture said tissue between said at least one leg and said base when each said staple is deformed between said unfired configuration and said fired configuration; and

compressible compensation means for dynamically biasing said tissue against at least one of said leg and said base, wherein said compressible compensation means is configured to dynamically assume a different compressed height within different said staples, wherein said compressible thickness compensator comprises a bioabsorbable hydrophilic agent embedded therein,

wherein said compressible compensation means comprises a dynamic bioabsorbable hydrophilic agent density configured to adaptively respond to tissue having different thicknesses, wherein said dynamic bioabsorbable hydrophilic agent density comprises an uncompressed hydrophilic agent density, wherein said dynamic bioabsorbable hydrophilic agent density comprises a first compressed hydrophilic agent density in a first said staple in response to tissue having a first thickness in said first staple, wherein said dynamic bioabsorbable hydrophilic agent density comprises a second compressed hydrophilic agent density in a second said staple in response to tissue having a second thickness in said second staple, wherein the first thickness is different than the second thickness, and wherein said first density is different than said second density.

8. The staple cartridge assembly of claim 7 , wherein said bioabsorbable hydrophilic agent comprises at least one of: fatty acid esters, triglycerides;

cholesterol, anionic cholesterol, carboxylates, amphoteric surfactants, amino propionic acids, imido propionic acids and quaterized compounds.

9. The staple cartridge assembly of claim 7 , wherein said compressible compensation means removably covers said staple cavity openings.

10. The staple cartridge assembly of claim 7 , wherein said compressible compensation means comprises an uncompressed thickness which is thicker than the thickness of said tissue.

11. The staple cartridge assembly of claim 7 , wherein said bioabsorbable hydrophilic agent comprises a foam comprising a surfactant.

12. The staple cartridge assembly of claim 7 , wherein the first thickness is greater than the second thickness, and wherein said first density is greater than said second density.

13. A staple cartridge assembly for use with a surgical stapler, wherein said staple cartridge assembly is adapted to be used with tissue having a thickness within a range of tissue thicknesses, said staple cartridge assembly comprising:

a cartridge body comprising a support portion, wherein said support portion comprises a plurality of staple cavities, and wherein each said staple cavity comprises an opening;

a plurality of staples, wherein at least a portion of each said staple is removably stored within a said staple cavity, wherein each said staple is movable between an unfired position and a fired position, wherein each said staple is deformable between an unfired configuration and a fired configuration when each said staple is moved between a said unfired position and a said fired position, and wherein each said staple comprises:

a base; and

at least one leg extending from said base, wherein said at least one leg is deformable to capture said tissue between said at least one leg and said base when each said staple is deformed between said unfired configuration and said fired configuration, wherein each said staple defines a deformed height in said fired configuration, and wherein said deformed height of at least some of said staples is larger than said tissue thickness whereby a gap distance is defined between said tissue and a portion of each said staple; and

tissue thickness compensation means for resiliently filling each said gap distance, wherein said tissue thickness compensation means is configured to resiliently assume a different compressed height within different said staples, wherein said compressible thickness compensator comprises a bioabsorbable hydrophilic agent embedded therein,

wherein said tissue thickness compensation means comprises a dynamic bioabsorbable hydrophilic agent density configured to adaptively respond to tissue having different thicknesses, wherein said dynamic bioabsorbable hydrophilic agent density comprises an initial hydrophilic agent density, wherein said dynamic bioabsorbable hydrophilic agent density comprises a first compressed hydrophilic agent density in a first said staple in response to tissue having a first thickness in said first staple, wherein said dynamic bioabsorbable hydrophilic agent density comprises a second compressed hydrophilic agent density in a second said staple in response to tissue having a second thickness in said second staple, wherein the first thickness is different than the second thickness, and wherein said first density is different than said second density.

14. The staple cartridge assembly of claim 13 , wherein the first thickness is greater than the second thickness, and wherein said first density is greater than said second density.