Anterior transposition of the superior oblique tendon in the treatment of oculomotor nerve palsy and its influence on postoperative hypertropia

Purpose: To determine whether postoperative hypertropia after anterior transposition of the superior oblique tendon without trochleotomy could be avoided with a simplified surgical approach. Methods: Eight patients with oculomotor nerve palsy (one patient was bilaterally affected) were retrospectively identified as having undergone anterior transposition of the superior oblique tendon without trochleotomy or vertical rectus muscle surgery between March 1992 and September 1998. The superior oblique tendon was cut at the medial border of the superior rectus muscle and placed 13.5 mm anterior to the medial insertion of the superior rectus muscle in each of these patients. Resection of the superior oblique tendon was not performed. The lateral rectus muscle was weakened, and no vertical rectus muscles were resected. Results: Preoperative deviations with the uninvolved eye fixating in primary position ranged from 20-90 prism diopters (Δ) of exotropia (mean: 49.3 Δ) and from 0-20 Δ of hypotropia (mean: 11.25 Δ). Postoperative horizontal deviations in the primary gaze position ranged from 12 Δ of exotropia to 20 Δ of esotropia. Six cases were aligned within 10 Δ of exotropia or esotropia. Postoperative vertical deviations in the primary gaze position ranged from 2 Δ of hypertropia to 8 Δ of hypotropia. Six cases were aligned within 2 Δ of deviation. Significant postoperative restrictive hypertropia, or new postoperative paradoxical ocular movements, did not occur in any patient. Patients who underwent follow-up >4 months maintained stable eye alignment. Conclusion: Transposition of the superior oblique tendon without simultaneous resection or trochleotomy, or additional surgery to the vertical rectus muscle simplifies the surgical technique and eliminates subjective decision making regarding the amount of resection.