gms | German Medical Science

64th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

26 - 29 May 2013, Düsseldorf

Evaluation of the predictive value of intraoperative changes in motor evoked potentials of lower cranial nerves for the postoperative functional outcome

Meeting Abstract

  • Marcel Kullmann - Department of Neurosurgery, University Hospital, Tuebingen, Germany
  • Marcos Tatagiba - Department of Neurosurgery, University Hospital, Tuebingen, Germany
  • Marina Liebsch - Department of Neurosurgery, University Hospital, Tuebingen, Germany
  • Günther C. Feigl - Department of Neurosurgery, University Hospital, Tuebingen, Germany; Department of Neurosurgery, Katharinenhospital, Stuttgart, Germany

Deutsche Gesellschaft für Neurochirurgie. 64. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Düsseldorf, 26.-29.05.2013. Düsseldorf: German Medical Science GMS Publishing House; 2013. DocP 084

doi: 10.3205/13dgnc501, urn:nbn:de:0183-13dgnc5017

Published: May 21, 2013

© 2013 Kullmann et al.
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Outline

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Objective: In this study we investigated the predictive value of changes in intraoperatively acquired motor evoked potentials (MEPs) of the lower cranial nerves IX-X (glossopharyngeal nerve and vagus nerve) and XII (hypoglossal nerve) for the postoperative functional outcome.

Method: MEPs of CN IX and CN XII of 63 consecutive patients undergoing posterior fossa surgery were recorded intraoperatively. The collected data included the patients’ age, gender, diagnosis, positioning during surgery, MEP baseline, final and final-to-baseline MEP ratio of the CN IX and CN XII as well as pre- and postoperative nerve function. The MEPs of the contralateral abductor pollicis brevis muscle of the hand were used as a control. We correlated the intraoperative changes of the MEPs to postoperative nerve function such as dysphagia, impairment of the gag reflex, uvula deviation, and tongue deviation.

Results: For the CN IX we found a significant correlation between the amplitude (μV) of the final-to-baseline MEP ratio and uvula deviation (p=0.028) and the amplitude duration (ms) of the final MEP and gag reflex function (p=0.027). The analyses of the risk estimate revealed that patients with an amplitude ≤1.47 V in the final-to-baseline MEP ratio of the CN IX have a 3.4 times increased risk to develop a uvula deviation. Patients with a final MEP of width ≤11.6 ms of the N.IX have a 3.6 times increased risk for their gag reflex to become extinct.

Conclusions: Our study shows for the first time in a large series of patients undergoing posterior fossa surgery the value of intraoperative MEPs as a predictor for postoperative nerve function. We were able to extent previous findings on MEP values of the facial nerve on postoperative nerve function to the caudal cranial nerves. We revealed a significant relationship between the MEP values of the CN IX and X and postoperative function of the uvula and gag reflex.