MONITORING OF ANTERIOR CERVICAL SPINAL-CORD FUNCTION

Anterior surgery is frequently chosen for treatment of cervical myelop athy. However, intraoperative spinal cord recording has rarely been us ed to monitor the function of the ventral columns. We report a method of monitoring evoked spinal cord potentials useful for detection of mi nor injury of the anterior spinal cord. Evoked spinal cord potentials elicited in cats by thoracic spinal cord and labyrinth stimulation wer e studied. Evoked intraspinal field potentials recorded after labyrint h stimulation were confirmed to originate from the vestibulospinal tra ct in the ventral columns. Low-amplitude potentials were recorded from the posterior epidural space. However, this method has not been used clinically because of difficulty in obtaining selective stimulation in humans. Spinal cord potentials evoked by thoracic stimulation were re corded from the anterior and posterior epidural spaces. The amplitude of the potentials was large enough to permit quantitation of neural fu nction. We confirmed that anterior recording was more sensitive in det ecting ventral column injury than posterior recording was. Based on th ese findings, we used anterior recording from the disc clinically for anterior spinal cord monitoring during anterior cervical surgery.