Surgical results of patients with unilateral superior oblique palsy presenting with large hypertropias.

Purpose: Surgical management of superior oblique palsy (SOP) is challenging because of combined vertical, horizontal, and torsional misalignment. The authors report the surgical results of patients with large primary position hypertropias (> 20 prism diopters [PD]) due to unilateral SOP.

Methods: Criteria for success included correction of the anomalous head posture, primary position alignment between orthotropia and 6 PD of undercorrection, and no reoperation required for residual deviations in any direction of gaze.

Results: Forty-five patients met inclusion criteria. Mean preoperative alignment in primary gaze was 26.5 ± 6.5 PD compared to 3.0 ± 4.4 PD postoperatively (P < .001). Twenty-three (51%) cases met the criteria for success with one operation. Of the patients who had single muscle surgery, 14% had a successful outcome, with a mean 67% (17.3 PD) reduction in hypertropia. Of patients who underwent simultaneous multiple muscle surgery, 58% met the criteria for a successful result, with a mean 92% (24.6 PD) reduction in primary gaze hypertropia. Success was the highest in patients who underwent ipsilateral inferior oblique combined with contralateral inferior rectus recessions with (60% success) or without (65% success) a Harada-Ito procedure.

Conclusion: Undercorrections are frequent following surgery for unilateral SOP with preoperative deviations greater than 20 PD in primary position, especially after single-muscle surgery. Simultaneous multiple muscle surgery rarely results in overcorrection and is recommended in patients with SOP and more than 20 PD of hypertropia in primary position.