[Intraoperative monitoring of spinal interventions with evoked potentials]

Monitoring the spinal cord can improve the safety margin during spinal surgery. This technique requires a stimulus source, transmitted through filters and amplifiers, and resulting in an enhanced signal that is recorded. Several techniques are now available, both non-invasive and invasive. We have carried out intraoperative monitoring during 178 spinal operations to correct deformities. Cortical somatosensory evoked potentials (CSEP) were obtained with Fz-Cz' recording sites, following bilateral posterior tibial nerve stimulation. In addition, unilateral median nerve stimulation was performed as a control. Six cases with an intraoperative alteration in waveform are described.