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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

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Electrooculography with adhesive surface electrodes for localizing cranial nerves III, IV and VI during skull-base surgery

Elektrookulographie durch Oberflächenelektroden zur intraoperativen Auffindung der Hirnnerven III, IV und VI bei Schädelbasiseingriffen

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  • corresponding author P. Slotty - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf
  • H. J. Steiger - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf
  • W. Stummer - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf

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. DocMO.11.07

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgnc2008/08dgnc113.shtml

Published: May 30, 2008

© 2008 Slotty 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.

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Objective: Monitoring of cranial nerves III, IV and VI during skull-base surgery has until now been carried out with electromyography. Because of the invasive character of electrode placement and methodical uncertainties, this technique is not commonly used. We investigated the use of adhesive surface electrodes for electrooculography (EOG) in order to localize and monitor the cranial nerves III, IV and VI.

Methods: Patients undergoing skull-base surgery were monitored by EOG using three surface electrodes adjacent to each eye at fixed locations (below and above the pupil, upper left corner of the eye on the left eye, lower right corner of the eye on the right eye). During the operation, the oculomotor nerves were localized anatomically and stimulated using a bipolar electrode with a 200 µs square-pulse at an amperage of 0.1 to 1.0 mA. Reactions of the external eye muscles were detected by monitoring directional fluctuations of the orbital dipole, which were triggered by stimulation.

Results: 10 patients have been investigated so far (5x N III, 2x NIV, 3x NIV). Stimulation of cranial nerves III and VI elicited a change in EOG in all cases, indicating a clear response. Direction of EOG changes and latency between stimulation and answer corresponded to the expected values. During stimulation of N. IV clear changes in EOG could only be detected in one out of three patients. For control purposes, stimulations were also performed in adjacent structures (skull base/ dura mater) without eliciting any detectable reactions.

Conclusions: EOG using non-invasive surface electrodes is a safe and simple technique for localizing cranial nerves III and VI, with limited use for detecting NIV during skull base surgery. Further study will elucidate, whether prolongations in latency can predict imminent nerve damage or whether surgical manipulations of the oculomotor nerves elicit eye movements, as detected by EOG.