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 overclepression in adduction (+2 to 3) and an A pattern of 10(Delta) to 40(Delta) 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(Delta) 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(Delta) (range, 0(Delta)-32.5(Delta)). 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. (J AAPOS 2012;16:342-344)