P-5-665 - A case of aneurysmal bone cyst with cranial expansion

Abstract

Vertebral artery (VA) transposition in the extreme-lateral transcondylar approach can minimize the manipulation of the low cranial nerves and the brain stem. The authors describe the surgical technique of VA transposition.From March 2000 to December 2014, 28 of 48 patients underwent VA transposition for anterior foramen magnum meningioma (16 patients) and craniocervical junction (CCJ) tumors (12 patients). Tumor was resected via an extreme-lateral approach with partial condylectomy to expose the anterior portion of the brain stem. For intradural tumors, the VA was mobilized caudomedially after circumferential dural incision around the VA at the level of the foramen magnum. For extradural tumors involving the CCJ, VA was transposed medially from the transverse foramen of C1 without any dural incision.Gross total resection was achieved in 26 of 28 patients (92.9%) with VA transposition. Histologically, meningioma and schwannoma were most common. The origin of the tumors was foramen magnum (57.1%), C1 nerve root (17.9%), clivus (10.7%), jugular foramen (7.1%), posterior skull base (3.6%), and hypoglossal canal (3.6%). VA transposition was performed intradurally in 19 patients (67.9%) and extradurally in 9 patients (32.1%). Surgical morbidity was 17.9% including 4 patients with hypoglossal nerve palsy and 1 patient with quadriparesis. The mean follow-up duration after surgery was 4.2 years (range, 0.1–14.8 years).VA transposition can provide a wide surgical window for anterior foramen magnum meningioma or tumors involving the CCJ with the least manipulation of the neuraxis.