Anterolateral and posterolateral approaches to the foramen magnum: technical description and experience from 97 cases.

Over a 12-year period (1981-1993), 97 lesions located in the foramen magnum area were treated using either the posterolateral or the anterolateral approach. The former is a lateral extent of the midline posterior approach; the latter is the technique of exposure of the cervical vertebral artery applied at the C-1 to C-2 level. The choice between the two types of lateral approaches was made following three modes of localization: anteroposterior attachment, relation to the dura, and relation to the vertebral artery. Both techniques are described in detail, with special attention paid to the bone and dural openings, which vary according to the localization.The treated lesions include 91 tumors, 4 craniocervical junction malformations, 1 synovial cyst, and 1 abcess. A complete resection was realized in 95% of the tumoral cases, with a very limited morbidity and mortality (3%).