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

Abstract

Purpose: To determine the cause of delayed-onset ipsilateral abduction defect associated with aberrant regeneration of the oculomotor nerve.

Methods: 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.

Results: 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.

Conclusion: A late-onset ipsilateral abduction defect caused by failure of relaxation of the medial rectus muscle may be associated with basilar aneurysm.