Combined resection and anterior transposition of the inferior oblique muscle for treatment of large primary position hypertropia caused by unilateral superior oblique muscle palsy.

Purpose: To evaluate the efficacy of combined resection and anterior transposition of the inferior oblique muscle for treatment of unilateral superior oblique muscle palsy with hypertropia from 20(Δ) to 25(Δ) in primary position.

Methods: The medical records of consecutive patients operated on for unilateral superior oblique muscle palsy and hypertropia from 20(Δ) to 25(Δ) in primary position were retrospectively reviewed. All patients had overaction of the inferior oblique muscle. The inferior oblique muscle was disinserted and 4 mm of its distal end was resected and transposed to the lateral border of the inferior rectus muscle insertion. The prism and alternate cover test was used to measure hypertropia. Surgical results were evaluated at 6 months' follow-up.

Results: A total of 27 patients were included. The mean hypertropia in primary position was 22.6 ± 0.4(Δ) preoperatively, which decreased to 1.4 ± 0.6(Δ) after surgery. None of the patients developed hypotropia in primary position. Mild limitation of elevation was recorded in 1 patient, and 4 patients developed lower eyelid fullness.

Conclusions: In this patient cohort, combined resection and anterior transposition of the inferior oblique muscle effectively treated unilateral superior oblique muscle palsy with hypertropia from 20(Δ) to 25(Δ) in primary position.