The spine and spinal cord during neurosurgical operations: real-time ultrasonography.

Intraoperative ultrasound scanning of the spinal cord and spine was performed during 36 operations in 35 patients. The technique allows neurosurgeons to evaluate an operative procedure during the operation. Effectiveness of shunt placement in syringomyelia can be detected and the completeness of tumor or disk removal can be determined. Precise locations for biopsy of intramedullary lesions can be made. Periodic motion of the spinal cord at the cardiac rate was also detected. This motion was usually due to transmitted pulsations from the anterior spinal artery and appeared to be most pronounced when the artery was compressed between a mass and the spinal cord. This finding refutes the commonly held idea that spinal cord motion implies that the cord is free within the thecal sac.