ABSTRACT

Permanent or transient neurological impairments are reported with a frequency of 1 % and 3.5 % after spinal surgeries. In modern spine surgery units, intraoperative neurophysiological monitoring (IONM) techniques are used during the operation to prevent or minimize complications.

In this article, early results of the IONM which has been initiated in Gazi University Medical Faculty are reviewed.

Recordings were obtained (Nicolet CR Endeavor) before the operation and as necessary during the operation. Templates were developed for recording both motor evoked potentials from the extremities in response to transcranial electrical stimulation and also the somatosensorial evoked potentials from the scalp in response to bilateral tibial and median nerve stimulation. Surface electrodes were used for stimulating the peripheral nerves, needle electrodes were used for recording from the muscles and cork-screw electrodes were preferred over the scalp. Multimodal spinal cord monitoring was performed during surgery of 39 cases. No responses could be elicited in the first two cases due to technical difficulties and inappropriate anesthetic agents. Neurohysiological monitoring was generally succesful in the subsequent cases.

In 10 cases it was necessary to alert the surgery and anaesthesia teams due to significant response changes and the situation of each case was reevaluated jointly. In 8 of these cases, the response changes were reversed completely during the surgery. Postoperative neurological deficits occured in one of these cases in whom the responses recovered during the surgery and in one of the two cases in whom the motor evoked potentials did not recover at all.

By implementing the neurophysiological monitoring techniques to replace the Stagnara Wake-up test which carries several pitfalls and uncertinities, this study aimed to prevent irreversible neural injuries which may develop during spinal surgery. Stagnara Wake-up test was abandoned after the initial five cases. We conclude that optimal intraoperative neurophysiological monitoring can be achieved only by appropriate collaboration between the surgery, anaesthesia and the neurophysiological monitoring teams.