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

Electric evoked auditory brainstem responses – Importance for functional outcome in auditory brainstem implant (ABI) surgery

Elektrisch evozierte auditorische Hirnstammpotentiale – ihre Bedeutung für das Funktionsergebnis in der Chirurgie des auditorischen Hirnstamm-Implantats

Meeting Abstract

  • corresponding author Cordula Matthies - Department of Neurosurgery, Klinikum Hannover Nordstadt, Hannover
  • K. Kniese - Department of Neurosurgery, Klinikum Hannover Nordstadt, Hannover
  • M. Lenarz - Hannover Medical School, Hannover
  • A. Lesinski-Schiedat - Department of Otorhinolaryngology, Hannover Medical School, Hannover
  • T. Lenarz - Department of Otorhinolaryngology, Hannover Medical School, Hannover
  • M. Samii - Department of Neurosurgery, Klinikum Hannover Nordstadt, Hannover; International Neuroscience Institute, Hannover; 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. DocDI.02.08

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2004/04dgnc0162.shtml

Veröffentlicht: 23. April 2004

© 2004 Matthies et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective

ABI offer a realistic chance to re-establish some useful auditory function in patients with bilateral deafness due to Neurofibromatosis Type 2. Intraoperative functional control of the auditory pathway by neuro-physiological means might be helpful in adequate ABI placement.

Methods

Patient selection is based on NF-2 disease manifestation and psycho-social stability. ABI electrode placement is controlled anatomically and by cranial nerve (VIIth to XIIth) and long tract monitoring. Electrically evoked auditory brainstem responses (EEABR) are evaluated at exposure and stimulation of the cochlear nucleus region. Absence of side effects and reliable EEABR are pre-conditions to definite ABI placement. Postoperative management includes regular control of speech processor programming and audiometric laboratory tests. The quality of auditory function is assigned to classes 1 to 4 based on consonant recognition and speech tracking test at 6 months follow-up.

Results

From 26 patients selected for ABI implantation 24 received an ABI, at tumor surgery (n=20) or thereafter (n=4); all but two experienced auditory sensations and were controlled for at least 6 months follow-up. Two patients showed ABI dislocation and surgical revision was carried out successfully in one and scheduled for the other. Two patterns of EEABR were found, with distinct components III, IV and V in 15 cases and with deformed melted complex in 9 patients. These differences were of predictive importance with regard to functional outcome as class 1 or 2 auditory function were only obtained after distinct EEABR components.

Conclusions

While functional outcome in ABI surgery is dependent on a multitude of pre-existing factors, the only aspect actively to be modified is the adequate microsurgical ABI placement. Obviously, a distinct EEABR recording reflects a useful activation of the cochlear nucleus and hereby allows to predict a sufficient number of electrodes to be activated and to produce good hearing function.