gms | German Medical Science

55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

25. bis 28.04.2004, Köln

Monitoring of facial nerve function

Monitoring der Facialisfunktion

Meeting Abstract

  • corresponding author Katja Kniese - Dept. of Neurosurgery, Klinikum Hannover Nordstadt and Hannover Medical School, Hannover
  • K. Aufschnaiter - Dept. of Neurosurgery, Klinikum Hannover Nordstadt and Hannover Medical School, Hannover
  • M. Gaab - Dept. of Neurosurgery, Klinikum Hannover Nordstadt and Hannover Medical School, Hannover
  • M. Samii - International Neuroscience Institute, Hannover
  • C. Matthies - Dept. of Neurosurgery, Klinikum Hannover Nordstadt and Hannover Medical School, Hannover

Deutsche Gesellschaft für Neurochirurgie. Ungarische Gesellschaft für Neurochirurgie. 55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie. Köln, 25.-28.04.2004. Düsseldorf, Köln: German Medical Science; 2004. DocMO.05.05

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgnc2004/04dgnc0057.shtml

Published: April 23, 2004

© 2004 Kniese et al.
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Outline

Text

Objective

Intraoperative monitoring of the facial nerve has been designed to early identify the facial nerve and control its functional integrity. However, little consensus has been found on the technique nor on the interpretation of findings and their correlation with postoperative outcome.

Methods

In a series of 200 patients operated for vestibular schwannomas, facial monitoring was performed using bipolar facial EMG recording at the orbicularis oculi and oris muscles. During tumor resection and at final facial nerve testing the two parameters of investigation were the reactivity to slight mechanic stimulation and the reactivity to electrical stimulation. Intraoperative EMG findings were correlated with the facial nerve function post-surgery at 0 and 12 to 24 months follow-up according to the House-Brackmann-Scale.

Results

In 4 patients (2%) the facial nerve activity subsided during surgery because of anatomical nerve discontinuity. In the remaining patients the facial nerve was preserved in anatomical continuity. 26 patients (12.5%) showed a severe facial nerve palsy after surgery; all these patients have meanwhile presented with some facial nerve recovery, to HB2 to HB3 in 20 patients and HB4 in 4 and HB5 in 2 patients. All patients with intraoperative discontinuity showed intraoperative disappearance of the mechanic and the electric facial nerve reactivity. Of those patients with severe facial palsy, 4 patients showed a loss of mechanic facial nerve reactivity and all the others exhibited significant reduction in mechanic reactivity, usually with loss of reactivity in one facial branch and reduction in the other. Electrical reactivity was preserved in these cases.

Conclusions

Electric reactivity of the facial nerve is a reliable parameter of axonal continuity, though it may not identify partial axon block. The potential for recovery of the facial nerve may be ideally proven by contained electrical reactivity; therefore it is most relevant in predicting the long-term functional outcome. Mechanical reactivity and its changes are parameters superior in identifying significant temporary facial palsies. Contained mechanic reactivity is a useful sign of a potential for fast and complete functional recovery.