A Transcondylar Approach to the Arteriovenous Malformation at the Ventral Cervicomedullary Junction

ARTERIOVENOUS MALFORMATION AT the cervicomedullary junction is a rare disorder, usually presenting with subarachnoid hemorrhage. The diagnosis is difficult because of its anatomical location. In addition, the ventral location of these arteriovenous malformations makes surgical treatment difficult. We describe three cases surgically treated with a transcondylar approach. The usefulness of digital subtraction angiography and magnetic resonance imaging is discussed. The technique of the transcondylar approach is also described, including C1 hemilaminectomy, unroofing of the transverse foramen of C1 to obtain control of the vertebral artery, and partial resection of the occipital condyle and lateral atlantal mass by extradural drilling. This approach provides direct access to the ventral portion of the cervicomedullary junction.