Types of Surgery Performed and Reoperation Rate for Congenital Superior Oblique Palsy: a Claims Database Study

Purpose To investigate types of surgeries performed to treat a presumed congenital superior oblique palsy (SOP) and the reoperation rate. Methods This was a population-based retrospective cohort study using claims data from the United States. Patients who underwent strabismus surgery for a presumed congenital SOP with >= 3 months of continuous enrolment after the initial surgery were included. We investigated age, surgical methods and the time interval between the initial surgery and reoperation. The hazard ratios for reoperation were estimated according to the surgical methods using Cox regression analysis. Results A total of 3,998 patients underwent surgery for presumed congenital SOP; 2,981 (74.6%) on only one vertical muscle (excluding superior oblique). Reoperation was performed on 427 patients (10.7%). Compared to patients who underwent unilateral surgery on one vertical muscle (excluding superior oblique muscle), patients who underwent surgery that included the superior oblique muscle (unilateral 2.08; 95% CI, 1.61-2.67, p < 0.001; bilateral 2.44; 95% CI, 1.40-4.28, p = 0.002) and two or more vertical muscles (excluding the superior oblique muscle) (unilateral 2.99; 95% CI, 2.00-4.49, p < 0.001; bilateral 1.68; 95% CI, 1.23-2.28, p = 0.001) had increased hazard ratios for reoperation. The median period between the initial surgery and reoperation was 168.0 [Q1-Q3 84.0-407.8] days and negatively correlated with patient age at initial surgery (r = -0.199, p < 0.001). Conclusion The reoperation rate for presumed congenital SOP was 10.7%. Patients who underwent surgery on two or more vertical muscles or the superior oblique muscle had an increased risk of reoperation.