gms | German Medical Science

59th Annual Meeting of the German Society of Neurosurgery (DGNC)
3rd Joint Meeting with the Italian Neurosurgical Society (SINch)

German Society of Neurosurgery (DGNC)

1 - 4 June 2008, Würzburg

Intraoperative changes of brainstem auditory evoked potentials during the trigeminocardiac reflex in cerebellopontine angle surgery

Intraoperative AEP-Veränderungen während des trigemino-kardialen Reflexes in der Kleinhirnbrückenwinkel-Chirurgie

Meeting Abstract

  • corresponding author A. Gharabaghi - Universitätsklinik für Neurochirurgie, Klinikum der Eberhard-Karls-Universität, Tübingen
  • M. A. Acioly - Universitätsklinik für Neurochirurgie, Klinikum der Eberhard-Karls-Universität, Tübingen
  • C. H. Carvalho - Universitätsklinik für Neurochirurgie, Klinikum der Eberhard-Karls-Universität, Tübingen
  • A. Koerbel - Universitätsklinik für Neurochirurgie, Klinikum der Eberhard-Karls-Universität, Tübingen
  • H. Löwenheim - Universitätsklinik für Neurochirurgie, Klinikum der Eberhard-Karls-Universität, Tübingen
  • M. Tatagiba - Universitätsklinik für Neurochirurgie, Klinikum der Eberhard-Karls-Universität, Tübingen

Deutsche Gesellschaft für Neurochirurgie. Società Italiana di Neurochirurgia. 59. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3. Joint Meeting mit der Italienischen Gesellschaft für Neurochirurgie (SINch). Würzburg, 01.-04.06.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocMI.02.02

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgnc2008/08dgnc221.shtml

Published: May 30, 2008

© 2008 Gharabaghi et al.
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Outline

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Objective: The trigeminocardiac reflex (TCR) is known to be a negative prognostic factor for hearing function in cerebellopontine angle (CPA) tumor surgery. The pathophysiological mechanism for this phenomenon is unclear until now. Therefore, this study was conducted to analyze the electrophysiological changes during this reflex in CPA tumor surgery.

Methods: One hundred ten consecutive patients with CPA lesions were studied prospectively for the occurrence of an intraoperative TCR, which was defined as a decrease of the main arterial blood pressure (MABP) by 20% or more, associated with bradycardia lower than 60 beats/min. Brainstem auditory evoked potential (BAEP) were measured continuously during surgery in all patients. Patients were analyzed in respect to preoperative auditory function, baseline BAEP, TCR occurrence, BAEP changes before and after TCR, BAEP at the end of surgery and early postoperative auditory function (7 to 10 days). As soon as a TCR occurred, surgical manipulations were stopped so that the hemodynamic parameters could recover.

Results: Of 58 patients with preoperative functional hearing, 3 (5.1%) patients developed a TCR. In 2 cases an acute intraoperative deterioration of BAEP occurred within 2:04 to 2:40 min (mean, 2:23 min) after the TCR with increased latency, decreased amplitude of the waves, and even wave losses. Intraoperative BAEP was maintained in 1 patient, but the 2 others had significantly deteriorated BAEP waves until the end of the surgery. After the operation, these 2 patients were deaf.

Conclusions: The hemodynamic TCR is followed by BAEP changes. These electrophysiological changes following TCR may also predict postoperative hearing function and may serve as a valuable prognostic tool. Surgical manipulation of the trigeminal pathway and cerebellar retraction were confirmed as risk factors for the TCR occurrence.