gms | German Medical Science

63rd Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Japanese Neurosurgical Society (JNS)

German Society of Neurosurgery (DGNC)

13 - 16 June 2012, Leipzig

Multimodal non-invasive functional brain mapping for surgery in eloquent areas

Meeting Abstract

  • M.T. Leao - Klinik für Neurochirurgie, Universitätsklinikum Tübingen
  • A.P. Pauli-Forster - Klinik für Neurochirurgie, Universitätsklinikum Tübingen
  • M. Liebsch - Klinik für Neurochirurgie, Universitätsklinikum Tübingen
  • M. Schuhmann - Klinik für Neurochirurgie, Universitätsklinikum Tübingen
  • A. Gharabaghi - Klinik für Neurochirurgie, Universitätsklinikum Tübingen
  • M. Tatagiba - Klinik für Neurochirurgie, Universitätsklinikum Tübingen

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 63. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie (JNS). Leipzig, 13.-16.06.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. DocDO.11.06

doi: 10.3205/12dgnc104, urn:nbn:de:0183-12dgnc1040

Published: June 4, 2012

© 2012 Leao et al.
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Outline

Text

Objective: Pre-surgical access to locate the motor areas of the brain cortex represents a great advantage for successful neurosurgical functional preservation. Traditionally, functional magnetic resonance imaging (fMRI) with diffusion tensor imaging (DTI) technique has been used to study cortical motor areas. Combining different modalities of imaging and electrophysiology methods such as navigated transcranial magnetic stimulation (nTMS), and intraoperative monitoring (IOM), allows precise location of cortical motor areas while respecting functional cortical individuality and plasticity. Moreover, nTMS overcomes the usual limitations of traditional fMRI studies like task-dependency, patient’s response, and regional blood flow.

Methods: A prospective study was carried out since July 2010. A total of 80 full brain mappings were performed using nTMS equipment with eXimia Software. Stimulation was applied by biphasic coil in a single pulse mode over the lesioned hemisphere and motor evoked potentials (MEP) were recorded from 6 EMG channels/muscles: Abductor Pollicis Brevis, First Dorsal Interosseous, Flexor Carpi Radialis, Extensor Digitorum Communis, Biceps and Tibialis. Mapping performed with 110% of APB motor threshold (MT) and TA MT for arm and leg regions respectively (50 uV filter). Cortical activation area was analysed and the resultant positive functional grid was introduced in the surgery 3D navigation tool. Amplitudes and latencies of the MEPs for each muscle were compared between pre-operative and intraoperative responses, using a monopolar probe for cortical stimulation and recording the MEPs on muscles with needle electrodes, exactly position over the same locations as pre-operative skin electrodes were placed.

Results: The results of the IOM are 100% compatible with the pre-surgery TMS maps, both in terms of dimension and location of functional area, and of amplitudes and latencies of MEPs obtained. The correlation between the functional area obtained by IOM and the preoperative fMRI is not 100%, and the functional area generated is less precise (in extension and location). Interestingly, nTMS preoperative maps leaded to a change in the original surgical approach, and the motor function remained intact after surgery in all cases.

Conclusions: Combining nTMs to preoperative fMRI and IOM, allows more precise location of cortical motor areas and, consequently, preservation of motor function in surgeries of the central region.