Abduction defect associated with aberrant regeneration of the oculomotor nerve after intracranial aneurysm.

Abstract

To determine the cause of delayed-onset ipsilateral abduction defect associated with aberrant regeneration of the oculomotor nerve. Isolated oculomotor palsy was noted after successful basilar artery aneurysm surgery in a 35-year-old patient. Several months later, aberrant regeneration of the oculomotor nerve and an ipsilateral abduction defect were first detected. Ocular electromyography demonstrated failure of relaxation of the ipsilateral medial rectus muscle on attempted abduction, suggesting cocontraction of horizontal recti muscles as the origin of the abduction defect. A late-onset ipsilateral abduction defect caused by failure of relaxation of the medial rectus muscle may be associated with basilar aneurysm.