Absorbable tissue dressing assemblies, systems, and methods formed from hydrophilic polymer sponge structures such as chitosan

1. An absorbable tissue dressing assembly comprising

a tissue dressing matrix including an absorbable hydrophilic polymer material;

a flexible absorbable polymer film or mesh backing layer including at least one of absorbable aliphatic polyesters, aliphatic polyurethanes, hyaluronic acid, a hyaluronate, and a poly-hydroxyl butyrate material; and

wherein the backing layer includes at least one of a woven nano-fiber material and a woven micro-fiber material.

2. An assembly according to claim 1

wherein the absorbable hydrophilic polymer material comprises a chitosan material.

3. An assembly according to claim 2

wherein the backing layer is bonded by direct adhesion with a top layer of the absorbable hydrophilic polymer material.

4. An assembly according to claim 1

wherein the tissue dressing matrix includes spherulitic nucleated structures within a lamella structure.

5. A method of manufacturing an absorbable tissue dressing assembly as defined in claim 4 comprising the following steps:

subjecting a solution of a chitosan hydrophilic polymer to phase separation by a controlled freezing process that includes a delay interval, followed by a controlled freeze-drying or lyophilization water removal step that occurs at a temperature below the collapse temperature to create the tissue dressing matrix; and

subjecting the tissue dressing matrix, after freeze-drying or lyophilization to a densification process.

6. An assembly according to claim 1

wherein the backing layer presents an increased surface area that can accelerate biodegradation.

7. An assembly according to claim 1

wherein the tissue dressing matrix is sized and configured to define a perimeter edge, and the backing layer is sized and configured to extend beyond the perimeter edge to present a skirt of material to receive suture material or staples.

8. An assembly according to claim 1

wherein the tissue dressing matrix is sized and configured to define an elongated strip having opposite ends, so that the elongated strip can be wrapped around a site, and wherein the backing layer is placed at one opposite end of the elongated strip.

9. An assembly according to claim 8

wherein the site is a blood vessel and the elongated strip can be wrapped around the blood vessel without collapsing the vessel on itself.

10. A method comprising

providing an absorbable tissue dressing assembly as defined in claim 1 ; and

performing a laparoscopic procedure using the absorbable tissue dressing assembly.

11. A method according to claim 10

wherein the laparoscopic procedure includes at least one of an abdominal aortic aneurysmectomy; spleen, liver, kidney, or gallbladder surgeries; open heart and bypass procedures; hysterectomies; total joint arthoplasties, burns and face lifts; radical neck dissections; trauma such as gun shot, knife wounds, wound debridement; spinal fusions and laminectomies; bowel and colon resections; radial prostatectomies; vascular anastomoses; and laparoscopic nephrectomies.