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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Continuous subcortical motor evoked potential stimulation using the tip of the ultrasonic aspirator for resection of motor eloquent lesions

Meeting Abstract

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  • Ehab Shiban - Neurochirurgische Klinik, Technische Universität München
  • Sandro M. Krieg - Neurochirurgische Klinik, Technische Universität München
  • Thomas Obermueller - Neurochirurgische Klinik, Technische Universität München
  • Maria Wostrack - Neurochirurgische Klinik, Technische Universität München
  • Bernhard Meyer - Neurochirurgische Klinik, Technische Universität München
  • Florian Ringel - Neurochirurgische Klinik, Technische Universität München

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.17.01

doi: 10.3205/15dgnc378, urn:nbn:de:0183-15dgnc3784

Published: June 2, 2015

© 2015 Shiban 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

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Objective: Resection of motor eloquent lesion has become safer due to intraoperative neuromonitoring (IOM). Subcortical stimulation of motor evoked potentials (scMEP) is increasingly used to increase patients' safety even further. So far, scMEP is performed intermittently during resection of eloquently located lesions. The present study assessed the possibility to use a resection instrument for continuous stimulation of scMEP.

Method: An ultrasonic surgical aspirator (SA) was attached to the IOM stimulator and was used as a monopolar subcortical stimulation probe. The influence of SA usage at different ultrasound power levels (0, 25, 50, 75 and 100 %) on stimulation intensity was examined in a saline bath. Afterwards monopolar stimulation with the SA was used during the resection of subcortical lesions in the near vicinity of the corticospinal tract (CST) in 14 cases in comparison to scMEP via a standard stimulation electrode. During resection, the stimulation current at which an MEP response was still measurable with SCS using the SA was compared to the corresponding stimulation current needed using standard monopolar subcortical stimulation probe (MP) at the same location of stimulation.

Results: The use of ultrasound at different energy levels did result in a slight but irrelevant increase of stimulation energy via the tip of the SA in the saline bath. scMEP using SA or MP was successful and almost identical in all patients. One patient developed a new permanent neurological deficit. Transient new postoperative paresis was observed in 28% (4/14) of cases. Gross total resection was achieved in 57% (8/14) and subtotal resection (>80% of tumor mass) in 35% (5/14) of cases.

Conclusions: Continuous motor mapping using subcortical stimulation via SA is a feasible and safe method without any disadvantages in comparison to the sequential use of the standard monopolar stimulation probe. In comparison to the standard probe it offers continuous information on the distance to the corticospinal tract.