Pitfalls in Cortical Localization by Intraoperative Recording of Cortical Somatosensory Evoked Potenmtials Toshikazu KUWAFIIA 1 , Kazuyoshi FUNAHASHI 1 , Daisuke NAKA 1 , Mitsuhiro OGURA 1 , Natsuhiko YOSHIDA 1 , Naoki TSUJI 1 , Seiji HAYASHI 1 , Norihiko KOMAI 1 1Department of Neurological Surgery,Wakayama Medical College Keyword: Central sulcus , Cortical localization , Intraoperative monitoring , Somatosensory evoked potential pp.223-228
Published Date 1992/3/10
DOI https://doi.org/10.11477/mf.1436900410
  • Abstract
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Cortical somatosensory evoked potential (SEP) re-cordings were made in 11 patients who had lesions lo-cated in or near the somatosensory or motor gyri to localize the central sulcus and sensorimotor cortex dur-ing neurosurgical operations. Cortical localization was successful in 7 of the 11 patients by recording phase re-versal waveforms of N20 and P20 at electrode sites in the hand area on opposite sides of the central sulcus. There were 4 cases in which the cortical localization failed. Locations of craniotomy were far distant from the central sulcus retrospectively in 2 of the 4 patients. Cortical SEPs couldn't be recorded despite probable ex-posure of the hand area and apparently adequate sti-mulation and recording conditions in 2 patients who had showed no or low amplitude scalp SEP preoper-atively. In one of these 2 patients only low amplitude negative waves were recorded at the cortex which was thought far field potentials originated from subcortical structures. In 2 patients cortical SEP was monitored during the removal of the tumors and was useful to estimate the effects of the operative procedures on the sensorimotor cortex.

It is concluded that the localization of cortical func-tions using cortical SEP is useful for reducing risk associated with intracranial surgery. However, we must be aware that there are some pitfalls in this method.

Copyright © 1992, Igaku-Shoin Ltd. All rights reserved.


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