Biomaterials for Adhesion-Free Tendon Repair

DESCRIPTION (provided by applicant): The formation of adhesions following flexor tendon surgery in the hand is a common post-operative complication. Adhesions can severely impair the function and range of motion of the affected digit and can cause the partial loss of hand function. Injection of hyaluronan (HA) or insertion of barriers prepared from chemically-modified HA are currently used to reduce adhesions, but the short half-lives of injected HA or HA barriers compromises their efficacy in preventing adhesions. To address this problem, we recently developed a novel in situ crosslinkable HA hydrogel that can contain the antiproliferative drug mitomycin C (MMC) via a covalent linkage. In preliminary results, film barriers and injectable forms of this HA-MMC hydrogel prevented the formation of intraperitoneal adhesions in a rat uterine horn model. We now propose to establish the feasibility of using this material to address the important unmet surgical need in tendon surgery. The ultimate goal of this program is to demonstrate that post-operative tendon adhesions can be reduced or eliminated by a composite material that promotes the healing of the surgically repaired tendon while simultaneously preventing adhesion formation to surrounding tissues. This goal will be addressed experimentally through four specific aims. First, we will prepare crosslinked gels with different MMC concentrations and determine the rate of MMC release from the films. Second, we will determine the biocompatibility in vivo by subcutaneous injection of the in situ crosslinkable gels in rodents. Third, we will fabricate films and tubes using the HA-MMC materials. Finally, we will determine the efficacy of these HA-MMC devices in a rabbit digital flexor tendon model using functional, biomechanical, and histological criteria.