title: Evaluation of the Predictive Value of Intraoperative Changes in Motor-Evoked Potentials of Caudal Cranial Nerves for the Postoperative Functional Outcome.
abstract: OBJECTIVE
  The predictive value of changes in intraoperatively acquired motor-evoked potentials (MEPs) of the lower cranial nerves (LCN) IX-X (glossopharyngeal-vagus nerve) and CN XII (hypoglossal nerve) on operative outcomes was investigated.
  
  
  METHODS
  MEPs of CN IX-X and CN XII were recorded intraoperatively in 63 patients undergoing surgery of the posterior cranial fossa. We correlated the changes of the MEPs with postoperative nerve function.
  
  
  RESULTS
  For CN IX-X, we found a correlation between the amplitude of the MEP ratio and uvula deviation (P = 0.028) and the amplitude duration of the MEP and gag reflex function (P = 0.027). Patients with an MEP ratio of the glossopharyngeal-vagus amplitude ≤1.47 μV had a 3.4 times increased risk of developing a uvula deviation. Patients with a final MEP duration of the CN IX-X ≤11.6 milliseconds had a 3.6 times increased risk for their gag reflex to become extinct.
  
  
  CONCLUSIONS
  Our study greatly contributes to the current knowledge of intraoperative MEPs as a predictor for postoperative cranial nerve function. We were able to extent previous findings on MEP values of the facial nerve on postoperative nerve function to 3 additional cranial nerves. Finding reliable predictors for postoperative nerve function is of great importance to the overall quality of life for a patient undergoing surgery of the posterior cranial fossa.
authors.affiliation: Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany. Electronic address: marcel.kullmann@med.uni-tuebingen.de.
authors.forename: Marcel
authors.initials: M
authors.lastname: Kullmann
authors.affiliation: Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany.
authors.forename: Marcos
authors.initials: M
authors.lastname: Tatagiba
authors.affiliation: Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Liebsch
authors.affiliation: Department of Neurosurgery, Eberhard-Karls University, Tuebingen, Germany; Department of Neurosurgery, Sozialstiftung Bamberg, Bamberg, Germany.
authors.forename: Guenther C
authors.initials: GC
authors.lastname: Feigl
mesh_terms: D000328:Adult; D003391:Cranial Nerves / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005930:Glossopharyngeal Nerve / Q000502:physiology; D006801:Humans; D007002:Hypoglossal Nerve / Q000502:physiology; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000502:physiology
keywords: Glossopharyngeal-vagus nerve; Hypoglossal nerve; Intraoperative neuromonitoring; Motor-evoked potentials; Posterior fossa tumors; Postoperative nerve function