The efficacy of superior oblique Z-tenotomy in the treatment of overdepression in adduction (superior oblique overaction).

INTRODUCTION

To evaluate the efficacy of superior oblique Z-tenotomy in the treatment of overdepression in adduction (superior oblique overaction) with respect to collapse of A-pattern strabismus and normalization of versions.

METHODS

The medical records of patients who underwent bilateral superior oblique Z-tenotomy for mild to moderate overdepression in adduction and A-pattern strabismus between June 2004 and August 2010 were retrospectively reviewed. Surgical indications included mild to moderate overdepression in adduction (+2 to 3) and an A pattern of 10(Δ) to 40(Δ) between upgaze and downgaze. A monopolar electrode microdissection needle was used to make two tenotomies, 60% to 80% in width and 8 mm apart, perpendicular to the axes of the tendon in opposite directions. Surgical success included a postoperative A pattern of ≤10(Δ) and overdepression in adduction of ≤1.

RESULTS

A total of 20 patients (mean age, 9.8 years; age range, 3-34) underwent bilateral superior oblique Z-tenotomy during the study period: 2 patients (10%) with esotropia and 18 with exotropia (90%). Average decrease in pattern was 16(Δ) (range, 0(Δ)-32.5(Δ)). Success rate for pattern collapse was 78%, with resolution of overdepression in adduction of 90%.

CONCLUSIONS

Z-tenotomy of the superior oblique tendon collapsed A-pattern strabismus and normalized versions.