Surgical Management of Unilateral Superior Oblique Palsy: Thirty Years of Experience

Abstract

Introduction and Purpose We describe the clinical characteristics of 252 patients with unilateral superior oblique palsy who underwent strabismus surgery. We assess if a predetermined surgical strategy, based on preoperative alignment and motility measurements, was effective in treating these patients. On this basis, the patients were divided into three different treatment groups. Methods Two-hundred fifty-two patients were identified retrospectively and classified into three groups according to the performed procedures: 1) inferior oblique weakening; 2) inferior rectus recession; 3) combined inferior oblique weakening and inferior rectus recession. Demographic and clinical data were recorded. Criteria for surgical success included good postoperative alignment (distance, primary position alignment ≤5Δ), and improvement of diplopia and of abnormal head posture. Subgroup analyses of surgical outcome were performed for small (<12Δ) versus large (>20Δ) preoperative hypertropia in the group that underwent inferior oblique weakening, and for inferior oblique disinsertion-myectomy versus inferior oblique recession. Results Mean forced primary position (PP) hypertropia decreased from 14.3Δ (range 3–37Δ) to 4.5Δ (range 0–30Δ) in Group 1, from 13Δ (range 1–30Δ) to 2Δ (range -20–20Δ) in Group 2, and from 25.7Δ (range 6–40Δ) to 1.3Δ (range -12–18Δ) in Group 3. Group 1 had the lowest re-operation rate (7.6%), followed by Group 2 (16%) and Group 3 (25.9%). Final surgical success rates were similar in three groups. Inferior oblique weakening was more predictable for small primary position hypertropia, but still yielded 85% success rate in large deviations. Inferior oblique disinsertion-myectomy resulted in more favorable results than inferior oblique recession (P < 0.05). Conclusion When a predetermined surgical strategy is applied to individual patients with unilateral superior oblique palsy, excellent functional improvement can be achieved in the majority of patients.