Microvascular Decompression for Oculomotor Nerve Palsy: A Case Report and Literature Review

BACKGROUND: Oculomotor nerve palsy can result as a manifestation of diabetic mellitus or aneurysmal compression. Vascular loop compression is a very rare etiology of oculomotor nerve palsy. Here, we present a case report of microvascular decompression for oculomotor nerve palsy. CASE DESCRIPTION: We present a 16-year-old male patient, otherwise healthy, who presented with right oculomotor nerve palsy for a period of 1 year. Aneurysmal compression and intracranial lesion were ruled out by cerebral angiogram and magnetic resonance imaging. The presence of vessel loop compression on the nerve was suspected on the basis of features on magnetic resonance imaging. The patient underwent microvascular decompression via a right subtemporal approach. We intraoperatively confirmed vessel loop compression at the exit zone of the nerve from midbrain. Subsequently, the patient's oculomotor palsy has improved gradually over a period of 6 months. CONCLUSIONS: Vascular compression of the oculomotor nerve is a very rare finding in neurosurgical practice. A diagnosis of vascular compression is made by excluding other pathologies and using high-resolution images that visualize the nerve and the offending vessel loop. Microvascular decompression can be an effective treatment method for this condition.