Intraoperative monopolar mapping during 5-ALA-guided resections of glioblastomas adjacent to motor eloquent areas: evaluation of resection rates and neurological outcome.

Schucht, Philippe; Seidel, Kathleen; Beck, Jürgen; Murek, Michael; Jilch, Astrid; Wiest, Roland; Fung, Christian; Raabe, Andreas (2014). Intraoperative monopolar mapping during 5-ALA-guided resections of glioblastomas adjacent to motor eloquent areas: evaluation of resection rates and neurological outcome. Neurosurgical focus, 37(6), E16. American Association of Neurological Surgeons 10.3171/2014.10.FOCUS14524

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Resection of glioblastoma adjacent to motor cortex or subcortical motor pathways carries a high risk of both incomplete resection and postoperative motor deficits. Although the strategy of maximum safe resection is widely accepted, the rates of complete resection of enhancing tumor (CRET) and the exact causes for motor deficits (mechanical vs vascular) are not always known. The authors report the results of their concept of combining monopolar mapping and 5-aminolevulinic acid (5-ALA)-guided surgery in patients with glioblastoma adjacent to eloquent tissue.


The authors prospectively studied 72 consecutive patients who underwent 5-ALA-guided surgery for a glioblastoma adjacent to the corticospinal tract (CST; < 10 mm) with continuous dynamic monopolar motor mapping (short-train interstimulus interval 4.0 msec, pulse duration 500 μsec) coupled to an acoustic motor evoked potential (MEP) alarm. The extent of resection was determined based on early (< 48 hours) postoperative MRI findings. Motor function was assessed 1 day after surgery, at discharge, and at 3 months.


Five patients were excluded because of nonadherence to protocol; thus, 67 patients were evaluated. The lowest motor threshold reached during individual surgery was as follows (motor threshold, number of patients): > 20 mA, n = 8; 11-20 mA, n = 13; 6-10 mA, n = 10; 4-5 mA, n = 13; and 1-3 mA, n = 23. Motor deterioration at postsurgical Day 1 and at discharge occurred in 30% (n = 20) and 10% (n = 7) of patients, respectively. At 3 months, 3 patients (4%) had a persisting postoperative motor deficit, 2 caused by vascular injury and 1 by mechanical injury. The rates of intra- and postoperative seizures were 1% and 0%, respectively. Complete resection of enhancing tumor was achieved in 73% of patients (49/67) despite proximity to the CST.


A rather high rate of CRET can be achieved in glioblastomas in motor eloquent areas via a combination of 5-ALA for tumor identification and intraoperative mapping for distinguishing between presumed and actual motor eloquent tissues. Continuous dynamic mapping was found to be a very ergonomic technique that localizes the motor tissue early and reliably.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurosurgery
04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic and Interventional Neuroradiology

UniBE Contributor:

Schucht, Philippe; Beck, Jürgen; Wiest, Roland; Fung, Christian and Raabe, Andreas


600 Technology > 610 Medicine & health




American Association of Neurological Surgeons




Martin Zbinden

Date Deposited:

22 Jan 2015 09:51

Last Modified:

23 Jan 2015 03:59

Publisher DOI:


PubMed ID:


Additional Information:

5-ALA = 5-aminolevulinic acid CRET = complete resection of enhancing tumor CST = corticospinal tract CUSA = Cavitron Ultrasonic Surgical Aspirator DCS = direct cortical stimulation EEG = electroencephalography GTR = gross-total resection KPS = Karnofsky Performance Scale MEP = motor evoked potential MRC = Medical Research Council MT = motor threshold SSEP = somatosensory evoked potential STR = subtotal resection TES = transcranial electrical stimulation TOF = train of five corticospinal tract glioblastoma intraoperative neuromonitoring motor evoked potential subcortical mapping tumor surgery




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