Intraoperative Relaxed Muscle Positioning Technique for Strabismus Repair in Thyroid Eye Disease

Abstract

To describe the outcomes of a relaxed muscle technique for treatment of dysthyroid strabismus. Retrospective consecutive case series. Twenty-four patients with thyroid-related orbitopathy (TRO) underwent strabismus surgery using a novel relaxed muscle technique. Charts of all patients who underwent rectus muscle recession surgery using a relaxed muscle technique between 1997 and 2004 were reviewed. Twenty-four of 28 patients had more than 2 months of follow-up and were included. The extent of recession was determined by marking where the tendon naturally fell while the relaxed muscle rested freely on the globe with the eye in the primary position. The muscle was sutured to the globe at the mark. Linear regression was used to determine the correlation between the degree of strabismus and the amount of recession required to eliminate diplopia. Surgical outcomes were analyzed 2 months, 6 months, and 1 year after strabismus repair. Excellent success was defined as no diplopia in primary and reading gazes without prisms. Good outcome was defined as no diplopia in primary and reading positions with the use of <10 prism diopters. Poor outcome was defined as persistent diplopia in primary or reading positions despite prisms, or the inability of the patient to tolerate the necessary prisms. Twenty-four patients underwent 60 muscle recessions. Nine had diplopia without a history of orbital decompression, 8 had diplopia before decompression, and 7 developed diplopia only after orbital decompression. Twenty-one patients (87.5%) had an excellent final outcome. A clinically acceptable (excellent or good) final outcome was achieved in 24 of 24 patients (100%) after an average of 1.08 surgeries. All 7 patients who developed diplopia only after decompression had an excellent outcome. Linear regression did not show good correlation between the degree of strabismus and the amount of recession required to eliminate diplopia (maximum R2 = 0.7292). There were no complications. The relaxed muscle technique provides excellent ocular alignment and relief from diplopia in a majority of patients with TRO-associated strabismus. Patients who develop diplopia only after orbital decompression may have a higher success rate.