To study the clinical characteristics, treatment and outcome of patients with aneurysmal third nerve palsy. Eleven patients with isolated third nerve palsy from an intracranial aneurysm from 1998 to 2002 at Ramathibodi Hospital were reviewed retrospectively. The average age was 60 years. Ipsilateral headache and/or retroorbital pain occured in 80 percent of the patients. Ten patients had unilateral disease, whereas one patient had bilateral involvement. The most common site of aneurysm was at the origin of the posterior
communicating artery. Endovascular treatment with coil embolization provided successful occlusion as well as neurosurgical clipping. Recovery of third nerve function was found in all patients but had variable degrees. Patients who received early treatment, especially within 10 days after onset of oculomotor dysfunction appeared to have the best chance of recovery. Aberrant regeneration developed in 5 cases. The commonest sign was lid retraction during adduction and downward gaze.

Keywords : Aneurysm, Third nerve palsy, Aberrant regeneration