Surgical correction of superior oblique palsy: a case series and guideline for surgical choice

Aim: This paper presents a series of surgical procedures to correct symptomatic superior oblique (SO) palsy. We provide a breakdown of the surgical procedures carried out and provide a simple guideline to aid surgical choice for individual patients. Methods: This is a retrospective study. Patients who had corrective surgery for SO palsy over the past five years were identified from our surgical database. Hospital and orthoptic notes were used to obtain clinical information. 44 patients were included with a total of 50 operations performed. Results: Of the 44 patients, 38 (86.4%) required only one procedure to obtain satisfactory improvement of symptoms. In 6 (13.6%) patients a second surgery was necessary to achieve binocular comfort. The amount of deviation corrected in the primary position from each type of operation was: IO disinsertion: 4 ∆ –20 ∆ (range), median 11 ∆ , SO tuck: 10 ∆ –19 ∆ (range), median 12 ∆ , inverse Knapp: 7 ∆ –28 ∆ (range), median 16 ∆ , contralateral inferior rectus recession: 10 ∆ (only one patient), Harado-Ito: 4–15° of excyclotorsion (range), median 8.5°. Conclusions: Careful pre-operative assessment is essential to recognise which position(s) of gaze has the greatest ocular misalignment or if torsional diplopia is the main barrier to comfortable BSV. A simple grid chart can then be applied to identify suggested surgery to choose. Full prismatic correction of the vertical deviation in the primary position to within normal vertical fusion range of 5 ∆ is not necessary to obtain a satisfactory outcome.