Anterior and nasal transposition of the inferior oblique muscle for dissociated vertical deviation associated with inferior oblique muscle overaction.

PURPOSE

To determine outcomes after anterior and nasal transposition of the inferior oblique muscle for dissociated vertical deviation (DVD) associated with inferior oblique overaction.

METHODS

A total of 10 patients who had bilateral DVD with ipsilateral inferior oblique muscle overaction were included in this study. Patients underwent anterior and nasal transposition of the inferior oblique muscles to the medial edge of the inferior rectus muscle insertion; the horizontal rectus muscle was operated on for horizontal strabismus in 2 cases. The primary outcome variables were changes in DVD, inferior oblique muscle action, V pattern, and vertical deviation in primary and side gazes. Patients were evaluated 6 to 10 months (mean, 7.3 months) postoperatively for alignment and oculomotor examination.

RESULTS

Mean age at the time of surgery was 17.5 years. The average preoperative DVD for all eyes was 18.3(Delta) +/- 6.8(Delta), which decreased to 5.0(Delta) +/- 3.1(Delta) (p < 0.001) at 6 months. Mean inferior oblique muscle overaction decreased from +2.1 (range, +1 to +3) to +0.40 (range, -1 to 2). The mean preoperative V pattern was 24.9(Delta). After surgery, the mean correction of the V pattern was 14.8(Delta). Four patients developed 2(Delta) to 5(Delta) postoperative hypotropias in primary position at 6 months.

CONCLUSIONS

Anterior and nasal transposition of the inferior oblique muscle reduces DVD, V pattern, and inferior oblique muscle overaction with minimal complications.