Somatosensory and cortico-spinal tract monitoring during spinal cord surgery

33 patients with disease at cervical or thoracic (above Th11) level were operated on with the assistance of intraoperative neurophysiological monitoring (IOM). The IOM protocol included: 1 - somatosensory potentials (SEP) recorded from the epidural spinal space and from the scalp; 2 - motor potentials evoked by transcranial electrical stimulation and recorded From spinal epidural electrodes. Regarding baseline potentials, in 12/33 patients, SEPs were absent or very poor quality, and in 4 of them, MEPs were absent as well. Therefore, IOM was impossible in these 4 patients. During surgery, no modifications of the potentials were recorded in 16 cases. Permanent changes occurred in 10 cases, and temporary changes in 3. The analysis of our series indicates that SEPs alone are not sufficient for IOM in spinal cord surgery; an integration with MEP monitoring is mandatory.