gms | German Medical Science

57th Annual Meeting of the German Society of Neurosurgery
Joint Meeting with the Japanese Neurosurgical Society

German Society of Neurosurgery (DGNC)

11 - 14 May, Essen

Motor monitoring during surgery for intrinsic tumors of the insula

Motorisches Monitoring bei Operationen intrinsischer Inseltumoren

Meeting Abstract

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  • corresponding author G. Neuloh - Klinik und Poliklinik für Neurochirurgie, Universität Bonn
  • J. Schramm - Klinik und Poliklinik für Neurochirurgie, Universität Bonn

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 57. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie. Essen, 11.-14.05.2006. Düsseldorf, Köln: German Medical Science; 2006. DocSA.10.07

The electronic version of this article is the complete one and can be found online at:

Published: May 8, 2006

© 2006 Neuloh et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: To assess the feasibility, validity and clinical usefulness of motor evoked potential (MEP) monitoring during surgery for intrinsic tumors of the insula. Such procedures carry a high risk for new motor deficit, due to the close relation of the tumors with the corona radiata and the internal capsule, as well as their vascular supply. MEP recording allows nearly continuous assessment of motor function in the anesthesized patient.

Methods: MEPs were successfully recorded during 60 procedures in 58 patients (29 female, 40.3 (9-73) years) with insular tumors (26 low-grade; 12 insulo-opercular, 48 insulo-paralimbic/limbic). In another 11 cases MEP recordings were unsuccessful (positioning of stimulating electrode).

Results: Stable MEPs (52%) always precluded new deficit. MEP deterioration during resection (43%) triggered intervention (stop resection, retractor, papaverine). Reversible deterioration (33%) indicated unimpaired function or transient deficit. Irreversible deterioration indicated in 6/9 cases (10% of all cases) permanent, otherwise transient new paresis. Severe permanent pareses (KPS<70, n=2) were due to postresectional ischemia. In 11 patients without successful monitoring, permant pareses occurred in 27%. An extent of resection of >90% was achieved in 55% and of <70% in 13% for monitored cases, and in 27% each for unmonitored cases.

Conclusions: MEP monitoring is feasible for insular tumors. It is a valid indicator of motor function. MEP deterioration is mostly reversible after early intervention, and indicates unimpaired function or transient new deficit. Permanent new pareses are always indicated by irreversible MEP deterioration or loss, severe new deficit is typically caused by postresectional ischemia. With MEP-Monitoring, the extent of resection appears to be higher, and the rate of new deficit appears to be lower.