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.