Risk Factors for Reoperation after Strabismus Surgery among Patients with Thyroid Eye Disease

PURPOSE To examine risk factors for strabismus surgery reoperation in patients with thyroid eye disease (TED). DESIGN Retrospective cohort study. METHODS An insurance claims database was used to identify patients with TED who underwent at least one strabismus operation between 2003 and 2019. We recorded specific muscles operated on, as well as the timing and frequency of reoperations. Cox regressions were used to estimate associations between time to reoperation and patient and primary surgery characteristics. RESULTS Of the 448 patients who met inclusion criteria, 111 (24.8%) underwent a reoperation. Patients were followed for an average of 5.4 ± 3.0 years after their initial strabismus surgery. The rates of reoperation among patients whose initial surgery involved horizontal muscles only, vertical muscles only, and horizontal and vertical muscles were 29 of 120 (24.2%), 33 of 169 (19.5%), and 49 of 159 (30.8%) respectively (P = .05). The number of muscles operated on initially was the only independent predictor for undergoing a strabismus surgery reoperation (odds ratio, 1.27; 95% confidence interval, 1.03–1.57; P = .03). The number of muscles operated on initially was also associated with shorter time to first reoperation (hazard ratio, 1.22; 95% confidence interval, 1.02–1.46; P = .03). Age at first surgery, time between diagnosis of TED and first strabismus surgery, gender, race, and use of adjustable sutures were not associated with time to reoperation. CONCLUSIONS Approximately 1 in 4 patients with TED require reoperation after strabismus surgery. The number of muscles operated on was the only independent predictor for both undergoing a reoperation and time to first reoperation. To examine risk factors for strabismus surgery reoperation in patients with thyroid eye disease (TED). Retrospective cohort study. An insurance claims database was used to identify patients with TED who underwent at least one strabismus operation between 2003 and 2019. We recorded specific muscles operated on, as well as the timing and frequency of reoperations. Cox regressions were used to estimate associations between time to reoperation and patient and primary surgery characteristics. Of the 448 patients who met inclusion criteria, 111 (24.8%) underwent a reoperation. Patients were followed for an average of 5.4 ± 3.0 years after their initial strabismus surgery. The rates of reoperation among patients whose initial surgery involved horizontal muscles only, vertical muscles only, and horizontal and vertical muscles were 29 of 120 (24.2%), 33 of 169 (19.5%), and 49 of 159 (30.8%) respectively (P = .05). The number of muscles operated on initially was the only independent predictor for undergoing a strabismus surgery reoperation (odds ratio, 1.27; 95% confidence interval, 1.03–1.57; P = .03). The number of muscles operated on initially was also associated with shorter time to first reoperation (hazard ratio, 1.22; 95% confidence interval, 1.02–1.46; P = .03). Age at first surgery, time between diagnosis of TED and first strabismus surgery, gender, race, and use of adjustable sutures were not associated with time to reoperation. Approximately 1 in 4 patients with TED require reoperation after strabismus surgery. The number of muscles operated on was the only independent predictor for both undergoing a reoperation and time to first reoperation.