Department of Biomedical Engineering
Repairing Soft Tissue
Headlines from the sports world have taught us the words “rotator cuff injury.” The shoulder’s rotator cuff is not one but a group of tendons that coordinate to lift and rotate the arm. If this cuff is torn, simple actions like stretching, lifting, or moving the arm become difficult and a source of disabling pain, reduced shoulder function, and weakness. Such tears affect not only athletes, but 40% or more of patients over age 60, and some 250,000 rotator cuff repairs are performed each year in the US. Even with improvements in our understanding of this condition and advances in surgical treatment, healing this tendon tissue after the cuff is repaired remains a great challenge. Failure rates of 20%-70% for rotator cuff surgery continue to be reported. The reasons why this repair surgery fails are many, based on patient age, size of the tear and how long the tendons have been torn, how much the muscles have weakened and degenerated, tendon quality, the repair technique itself, and whether the patient progresses or not during post-surgical rehabilitation. Our researchers are investigating how to do better.
In the midriff, the abdominal wall is made up of the soft tissues of the outer skin and underlying fatty and fibrous layers. Hernias, in which the intestines push through weakened parts of the abdominal wall, complicate nearly one third of all surgeries in the abdomen, and an estimated 350,000 hernia repairs, costing $3.2 billion, are performed each year in the US alone. The rate of repeat hernias is very high, with 24%-43% of hernia repairs resulting in failure and the return of the hernia. It is estimated that just a 1% reduction in that rate would mean a cost saving of $32 million each year.
Both of these clinical problems require a way to improve repair of the soft tissues involved in the interaction of muscles and skeleton. Currently, various artificial and natural (“synthetic” and “biologic”) materials have been used to construct scaffolds on which cells can grow to repair soft tissue, but such scaffolds have shown only limited success so far. To address this need, researchers at the Cleveland Clinic have been developing new composite scaffold materials, made from biologic and synthetic materials. These high-tech scaffold materials, tested in the laboratory, have shown promise for improving repair of the tendons of the rotator cuff; now they are ready to be tested in human trials. Laboratory research on the use of these new scaffold materials for repair of the abdominal wall and associated hernias is also ongoing. In the future, we expect to adapt these scaffold materials to help regrow soft tissues in skin, skull and facial bones, and genitourinary organs (organs of reproduction and urine elimination).
Summary: Dr. Derwin is developing a novel hybrid biomaterial that is both strong and biocompatible for repair of soft tissues in the shoulder and abdominal wall.
See also: Derwin Lab