Intraoperative neuromonitoring for function-guided resection differs for supratentorial motor eloquent gliomas and metastases.
BACKGROUND
Recent data show differences in intraoperative neuromonitoring (IOM) in relation to the operated brain lesion. Due to the recently shown infiltrative nature of cerebral metastases, this work investigates the differences of IOM for cerebral metastases and glioma resection concerning sensitivity, specificity, and predictive values when aiming on preservation of motor function.


METHODS
Between 2006 and 2011 we resected 171 eloquently located tumors (56 metastases, 115 gliomas) associated with the rolandic cortex or the pyramidal tract using IOM via direct cortical motor evoked potentials (MEPs). Postoperatively, MEP data were re-analyzed with respect to surgery-related paresis, residual tumor, and postoperative MRI with two different thresholds for MEP decline (50 and 80 % below baseline).


RESULTS
MEP monitoring was successful in 158 cases (92.4 %). MEPs were stable in 54.7 % of all metastases cases and in 65.2 % of all glioma cases (p < 0.0001). After metastases resection, 21.4 % of patients improved and 21.9 % deteriorated in motor function. Glioma patients improved in only 5.4 % and worsened in 31.3 % of cases (p < 0.05). Resection was stopped due to MEP decline in 8.0 % (metastases) and 34.8 % of cases (gliomas) (p < 0.0002).


CONCLUSIONS
There is significant difference between glioma and metastases resection. Post-hoc, metastases show more stable MEPs but a surprisingly high rate of surgery-related paresis and therefore a higher rate of false negative IOM.
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Thomas.Obermueller@lrz.tum.de.
Thomas
T
Obermueller
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. M-Schaeffner@gmx.de.
Michael
M
Schaeffner
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Ehab.Shiban@lrz.tum.de.
Ehab
E
Shiban
Department of Anesthesiology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. D.Droese@lrz.tum.de.
Doris
D
Droese
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Chiara.Negwer@lrz.tum.de.
Chiara
C
Negwer
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Bernhard.Meyer@lrz.tum.de.
Bernhard
B
Meyer
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Florian.Ringel@lrz.tum.de.
Florian
F
Ringel
Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. Sandro.Krieg@lrz.tum.de.
Sandro M
SM
Krieg
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000473:pathology / Q000503:physiopathology / Q000556:secondary / Q000601:surgery*; D015331:Cohort Studies; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005910:Glioma / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009044:Motor Cortex / Q000503:physiopathology / Q000601:surgery*; D018365:Neoplasm, Residual; D010291:Paresis / Q000503:physiopathology*; D011183:Postoperative Complications / Q000503:physiopathology*; D011712:Pyramidal Tracts / Q000503:physiopathology / Q000601:surgery*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult