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

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.