Reversible somatosensory evoked potential changes with neodymium: yttrium-aluminum-garnet laser use

Reversible prolongation and dissolution of the tibial somatosensory evoked potential (SEP) was observed with operative use of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser during extirpation of a foramen magnum meningioma. Rapid normalization of the SEP followed irrigation with cool saline. The absence of postoperative dorsal column deficit suggests that heat-related physiological changes occurred before the point of irreversible tissue injury. Should intraoperative SEP monitoring prove a reliable index of tissue temperature, it could enable safer use of the Nd:YAG laser in the vicinity of the spinal cord and brain stem.