Heat shrinkage of extraocular muscle tendon

P. T. Finger, R. Richards, T. Iwamoto, D. B. Myers and F. A. Jakobiec

We have designed and employed a bipolar heating device to shorten extraocular muscles. Treatment involves placing the unidirectional heating device on the sclera with the active surface beneath the tendinous portion of the extraocular-muscle. When power is applied, visible tissue shrinkage occurs. Heat-induced extraocular muscle shrinkage was performed on live rhesus monkeys. Two months later, thermal tendinoplasty-treated extraocular muscles were surgically isolated and evaluated for strength. Biopsies were then performed on these muscles. It was our clinical impression that treated tissues retained their strength, while histologic and electron-microscopic evaluation of heat-treated tendon revealed evidence of shrinkage and compaction of collagen bundles. Thermal tendinoplasty may offer a sutureless method of correcting strabismus by shortening and thereby strengthening extraocular muscles.