POSTEROLATERAL CERVICAL OR THORACIC APPROACH WITH SPINAL-CORD ROTATION FOR VASCULAR MALFORMATIONS OR TUMORS OF THE VENTROLATERAL SPINAL-CORD

This report describes a technique for exposing the ventrolateral quadr ant of the spinal cord through an extended posterolateral approach tha t can be used in both cervical and thoracic regions. The surgical tech nique includes the following: 1) a midline skin incision with a transv erse extension at the level of pathology; 2) unilateral division and r etraction of the paraspinous muscles; 3) laminectomy and unilateral re moval of facets and pedicles; 4) dural incision over the dorsal root e ntry zone; 5) multilevel division of the ipsilateral dentate ligaments ; and 6) elevation and rotation of the spinal cord with dentate tracti on stitches. This technique provides exposure of the ventral root entr y zone, the ipsilateral half of the ventral surface of the cord, and t he anterior spinal artery. The surface of the spinal cord beyond the a nterior spinal artery is not seen. This approach has been used for the treatment of seven ventrolateral spinal cord lesions: five spinal art eriovenous malformations (two Type II, one Type III, two Type TV), one hemangioblastoma, and one cavernous angioma. Ah the lesions were comp letely excised. Two patients had mild new neurological deficit after s urgery, and one adolescent developed mild asymptomatic thoracic kyphos is, but no other spinal instability was observed over a follow-up peri od of 1 to 4 years. This operative approach provides significant advan tages for ventrolateral perimedullary or intramedullary lesions of the cervical or thoracic spinal cord.