Edward G. Parent

DRY FILM MADE OF HYLAN TO PREVENT ADHESION BETWEEN TWO HEALING TISSUE SURFACES

ABSTRACT When the epithelial cell layer covering two adjacent tissues is removed accidentally or intentionally during surgical procedures, the underlying connective tissue will grow together during the wound- healing process. Similarly, when two connective tissue surfaces not covered by endothelium but separated by elastoviscous fluid containing high molecular weight hyaluronan are wounded by trauma or during surgical procedures, they can grow together during the healing process. Such adhesion between two tissue surfaces may interfere with function and the excessive new connective tissue formed (scar tissue) may exert pressure on adjacent nerves, causing chronic pain. This paper describes the use of new formulations of dry films containing only hylan. In animal models, this film prevented adhesion formation between two tissue surfaces denuded from their mesothelial or epithelial cell cover. The most important property of this film after it is hydrated by tissue fluids was that it still adhered to the tissue surface, ensuring its stay in place. Thus, it functions as a barrier material, separating the healing tissues. The films do not cause inflammation or foreign body reaction and they do not interfere with the healing of adjacent tissues. These films successfully prevented adhesions between tissue surfaces in liver and cecal abrasion models in rat and uterine horn abrasion models in rabbits. Such films can also be used as delivery vehicles for various drugs, influencing them by combining their physical barrier effect with regulation effects on the healing process.