LAUSR

PurposeTo present patients who suffered damage to the inferior oblique muscle branch of the oculomotor nerve during orbital fat decompression.MethodsThis study was a retrospective chart review of all patients who underwent orbital decompression surgery between April 2009 and June 2016 by the authors.ResultsAmong 414 sides from 226 consecutive patients who underwent orbital decompression, the inferior oblique muscle branch was injured in two sides (0.5%) of two patients. Both patients showed hypotropia and incyclotropia immediately after surgery. Within 6 months of injury, ocular deviation on primary gaze had mostly resolved after conservative treatment. None of the patients underwent strabismus surgery. Postoperative computed tomographic images demonstrated that the affected branch was indistinct 3–4 mm posterior to the inferior oblique muscle.ConclusionsThis report indicates that injury to the inferior oblique muscle nerve branch can occur at a point posterior to the inferior oblique muscle during orbital fat decompression; however, the resulting ocular deviation improves considerably within 6 months of injury.