Inferior oblique myectomy for upshoots mimicking inferior oblique overaction in Duane retraction syndrome.

PURPOSE

To evaluate the results of inferior oblique myectomy in selected patients with Duane retraction syndrome with upshoot on adduction.

METHODS

This was a prospective, interventional study of consecutive patients with types 1, 2, or 3 Duane syndrome with isolated upshoot in adduction operated on from January 2007 to December 2011. Patients underwent inferior oblique myectomy on the side of the upshooting eye. Only patients with gradual elevation of the eye in adduction in a pattern similar to inferior oblique overaction or patients with hypertropia in the primary position were included. All patients were followed for at least 6 months. Ductions, versions, degree of upshoot, degree of fundus torsion, and pattern of strabismus were analyzed in all patients before and after surgery.

RESULTS

A total of 11 patients were included in the study. Mean patient age at time of surgery was 6.4 ± 5.2 years (range, 3-22 years). Two patients had bilateral inferior oblique myectomy and 4 had simultaneous bilateral medial rectus muscle recession to correct horizontal misalignment. Mean duration of follow-up was 8.6 months (range, 6-36 months). Of the 11 patients, 10 (91%) had complete disappearance of the upshoot at last follow-up. None of the patients developed inferior oblique underaction postoperatively. There was a statistically significant improvement of V pattern after surgery (P < 0.01). Mean vertical misalignment in primary position was 5(Δ) before surgery and 1(Δ) after (P = 0.02). Most patients had no significant fundus torsion before or after surgery.

CONCLUSIONS

Inferior oblique muscle weakening can improve upshoot in selected patients with Duane retraction syndrome without inducing inferior oblique muscle underaction.