A new technique for intraoperative monitoring of spinal cord function: multichannel recording of spinal cord and subcortical evoked potentials.

A new technique for intraoperative monitoring of spinal cord function is described. Evoked potentials to peripheral nerve stimulation are recorded with interspinous ligament needles from below and from two or more levels above the surgery. Simultaneously subcortical potentials are recorded with scalp electrodes from cervical-scalp derivations. Simultaneous recordings from multiple levels (below and above the surgical procedure) permit reliable differentiation between technical problems and alteration of cord function due to the surgical procedure. The interspinous ligament technique for recording of spinal potentials has significant advantages over previous monitoring techniques. One case in which monitoring during surgery detected a reversible acute spinal cord dysfunction is described.