gms | German Medical Science

66th Annual Meeting of the German Society of Neurosurgery (DGNC)
Friendship Meeting with the Italian Society of Neurosurgery (SINch)

German Society of Neurosurgery (DGNC)

7 - 10 June 2015, Karlsruhe

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Intraoperative neurophysiological monitoring during resection of infratentorial lesions with particular emphasis on long tract functions

Meeting Abstract

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  • Philipp J. Slotty - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf
  • Amre Abdulazim - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf
  • Kunihiko Kodama - Department of Neurosurgery Shinshu University School of Medicine, Matsumoto, Japan
  • Mani Javadi - Klinik für Neurochirurgie, Universitätsklinikum Frankfurt am Main
  • Daniel Hänggi - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf
  • Volker Seifert - Klinik für Neurochirurgie, Universitätsklinikum Frankfurt am Main
  • Andrea Szelényi - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf; Klinik für Neurochirurgie, Universitätsklinikum Frankfurt am Main

Deutsche Gesellschaft für Neurochirurgie. 66. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Karlsruhe, 07.-10.06.2015. Düsseldorf: German Medical Science GMS Publishing House; 2015. DocMI.17.05

doi: 10.3205/15dgnc382, urn:nbn:de:0183-15dgnc3826

Published: June 2, 2015

© 2015 Slotty et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

Text

Objective: Methods of choice for intraoperative neurophysiological monitoring (IOM) within the infratentorial compartment are mostly early brainstem auditory evoked potentials (BAEPs), free running electromyogram (EMG) and direct nerve stimulation (DNS) of cranial nerves (CN-IOM). Long tract monitoring with Somatosensory Evoked Potentials (SEPs) and Motor Evoked Potentials (SEPMEP-IOM) might be considered in brainstem pathologies. Reports about simultaneous use are scarce. Simultaneous use of CN- and SEPMEP-IOM was analyzed for IOM-alterations with regard to lesion location and type.

Method: Standardized CN- and SEPMEP-IOM was performed in 305 patients (50.6 ± 14.1 years, 166 female) being treated for various posterior fossa pathologies. Significant IOM alterations were > 50% decrement in EPs and A-Train activity in CN and new conduction block CN-DNS. Data on IOM alterations and corresponding early post-operative neurologic deficits were analyzed.

Results: IOM alterations were observed in 158/305 cases (51.8%) (CN-IOM alterations 115/305 (37.7%), SEPMEP-IOM alterations 43/305 (14.0%)). IOM alterations were followed by neurological sequelae in 98/305 cases (32.1%), 62% of IOM alterations resulted in neurologic deficits.

Sensitivity and specificity for detection of CN deficits were 98% and 84% respectively, and 44% and 99% for long tract deficits.

The likelihood of CN-IOM alterations is highest in schwannomas (74.6% of surgeries) and the detection rate of CN deficits in schwannoma surgery is 85.5%. SEPMEP-IOM alterations indicating long tract hazard are most frequently observed in intramedullary cavernomas (50.0%) and hemangioblastomas (36.4%), correctly predicting postoperative deficits in (81.2%). Regarding localization brainstem and petroclival lesions were closely associated with concurrent CN- and SEPMEP-IOM alterations, whereas the incidence of alterations affecting CN- and SEPMEP-IOM was significantly lower in other regions.

Conclusions: The incidence of IOM alterations during surgery in the posterior fossa varies widely between different entities and localizations. This analysis provides crucial information not only on the necessity of IOM in different surgical settings but also on intraoperative interpretation of IOM alteration regarding their potential neurologic sequelae. As numerous localizations and lesions types were associated with MEPSEP and CN-IOM alterations we recommend the simultaneous use of both modalities.