gms | German Medical Science

63rd Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Japanese Neurosurgical Society (JNS)

German Society of Neurosurgery (DGNC)

13 - 16 June 2012, Leipzig

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Nerve crush but not displacement-induced stretch of the intra-arachnoidal facial trunk promotes facial palsy after cerebellopontine angle surgery in a rat model

Meeting Abstract

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  • H. Bendella - Institut für Anatomie I, Klinikum der Universität zu Köln, Köln, Deutschland
  • M. Timmer - Klinik für Allgemeine Neurochirurgie, Klinikum der Universität zu Köln, Köln, Deutschland
  • R. Goldbrunner - Klinik für Allgemeine Neurochirurgie, Klinikum der Universität zu Köln, Köln, Deutschland
  • D.N. Angelov - Institut für Anatomie I, Klinikum der Universität zu Köln, Köln, Deutschland

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 63. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie (JNS). Leipzig, 13.-16.06.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. DocP 025

doi: 10.3205/12dgnc412, urn:nbn:de:0183-12dgnc4125

Published: June 4, 2012

© 2012 Bendella et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

Text

Objective: Post-operative peripheral facial nerve palsy (immediate or delayed) occurs in 20–40 % of the patients with cerebellopontine angle (CPA) tumors. Since the intra-arachnoidal portion of the facial nerve is very vulnerable and even the slightest tension may result in ruptured axons, we tested whether a displacement of the brainstem during CPA-surgery (e.g. removal of a vestibular schwannoma) would affect the post-operative motor performance of the facial (vibrissal) muscle in rats. Aim of the present study was to establish a model for further studies.

Methods: Twelve male adult Wistar rats, divided in two groups (each of 6 animals) were used. Under inhalation anesthesia (0.6 l/min Oxygen +1.2 l/min Laughing gas +1.8 Vol.% Isoflurane) the occipital squama was opened, the cerebellum gently retracted and the intra-arachnoidal segment of the right facial nerve exposed. An intensive mechanical displacement of the brainstem towards the midline (group 1) or a crush of the facial nerve close to the internal acoustic porus with watchmaker forceps for 5 sec (group 2) were applied. On the next day, the facial motor performance (amplitude of vibrissal bouts during explorative whisking) was determined in all rats (Motus 5, PEAK Performance Technologies).

Results: Our results show that the intensive mechanical displacement of the brainstem towards the midline had no effect (control group) of the function of the facial muscles: the amplitude of the vibrissal hairs was in the normal range of 50–60 degrees. On the other hand, 5 sec of nerve crush resulted in completely paralysed vibrissal hairs. At present, we modify the intensity of the crush and perform longer observation periods.

Conclusions: Providing the first controlled experimental setting for both brainstem displacement and crush of the facial nerve trunk, our model could be helpful to investigate questions concerning cranial basis surgery.