Abducens Nerve Palsy Due to Neurovascular Compression

Neurovascular compression (NVC) as the cause of abducens nerve palsy is an infrequent event. Only a small number of cases have been reported in the literature, and the efficacy of microvascular decompression (MVD) for abducens nerve palsy remains unclear. We reviewed previously reported cases of abducens nerve palsy caused by NVC and added our own cases. We analyzed the clinical characteristics of vascular compression abducens nerve palsy and assessed the indication for MVD. Twenty-two patients with isolated abducens nerve palsy due to vascular compression were confirmed in total, consisting of 20 patients (19 publications) from the literature search and 2 cases from our experienced cases. All patients had no possible causes for isolated abducens nerve palsy except the NVC on the nerve root. Unlike the sudden onset in the typical abducens nerve palsy, all patients demonstrated gradual development of the symptom in NVC-related abducens palsy. Careful observation was the most common strategy in most patients; however, no noticeable improvement was reported in the conservative treatment. Surgical intervention was performed in 6 patients after observation for several months and showed favorable outcomes in all cases. Vascular compression could be a potential cause of abducens nerve palsy. Gradual onset or episodic symptom of abducens palsy with a definitive radiological finding of vascular compression deserves considering MVD for abducens nerve palsy.