Practical localization of the central sulcus using a video display during surgery by cortical somatosensory evoked potentials and how to discern precentral P20 and central P25

Jun Namiki, Masashi Nakatsukasa, Ikuro Murase, Takayuki Oohira, Masayuki Ishihara, Shigeo Toya

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In patients with lesions around the central sulcus, cortical surface somatosensory evoked potentials (SEPs) have been applied for the purpose of localization of the central sulcus based on the polarity inversion of postcentral N20 to precentral P20 across the central sulcus. We have intraoperatively monitored SEPs to infer the location of the central sulcus in 16 cases since December 1988. Intraoperative localization of the central sulcus has been most useful in patients with frontal lobe gliomas in which the localization of the central sulcus enables the surgeon to extensively resect tumor without postoperative motor weakness. The localization of the central sulcus, however, might be misjudged by using the polarity inversion criterion alone, because central P25 following N20 and P20 complicates SEP waveforms. It is significant that P25, which is recorded also posterior to the central sulcus, is discerned from the precentral P20. In order to solve this matter, we regarded only the positivity in SEP waveforms having the identical peak latency to that of N20 as the precentral P20. Positive potentials having a later peak latency than that of N20 are the superposition of P20 and P25, and might also be recorded posterior to the central sulcus. For the observation of the polarity inversion of N20 to P20 across the central sulcus, a multi-channel SEP should be recorded using a sheet of silicone rubber embedded in a 16-electrode array consisting of a 4 by 4 grid. We projected the exposed cortical surface on the video display through the microscope apparatus and marked the locations of the recording electrodes on the video display. This enabled the location of the recording electrodes to correspond easily and precisely to the cortical surface. Our reliable and simple method of intraoperative localization of the central sulcus by cortical SEPs monitoring is presented in a practical case.

Original languageEnglish
Pages (from-to)123-129
Number of pages7
JournalNeurological Surgery
Volume25
Issue number2
Publication statusPublished - 1997 Feb

Fingerprint

Somatosensory Evoked Potentials
Electrodes
Silicone Elastomers
Frontal Lobe
Glioma
Observation
Neoplasms

Keywords

  • central sulcus
  • intraoperative monitoring
  • median nerve
  • somatosensory evoked potentials

ASJC Scopus subject areas

  • Clinical Neurology

Cite this

Practical localization of the central sulcus using a video display during surgery by cortical somatosensory evoked potentials and how to discern precentral P20 and central P25. / Namiki, Jun; Nakatsukasa, Masashi; Murase, Ikuro; Oohira, Takayuki; Ishihara, Masayuki; Toya, Shigeo.

In: Neurological Surgery, Vol. 25, No. 2, 02.1997, p. 123-129.

Research output: Contribution to journalArticle

@article{527c44540f16470c93457d03f2a1d6c3,
title = "Practical localization of the central sulcus using a video display during surgery by cortical somatosensory evoked potentials and how to discern precentral P20 and central P25",
abstract = "In patients with lesions around the central sulcus, cortical surface somatosensory evoked potentials (SEPs) have been applied for the purpose of localization of the central sulcus based on the polarity inversion of postcentral N20 to precentral P20 across the central sulcus. We have intraoperatively monitored SEPs to infer the location of the central sulcus in 16 cases since December 1988. Intraoperative localization of the central sulcus has been most useful in patients with frontal lobe gliomas in which the localization of the central sulcus enables the surgeon to extensively resect tumor without postoperative motor weakness. The localization of the central sulcus, however, might be misjudged by using the polarity inversion criterion alone, because central P25 following N20 and P20 complicates SEP waveforms. It is significant that P25, which is recorded also posterior to the central sulcus, is discerned from the precentral P20. In order to solve this matter, we regarded only the positivity in SEP waveforms having the identical peak latency to that of N20 as the precentral P20. Positive potentials having a later peak latency than that of N20 are the superposition of P20 and P25, and might also be recorded posterior to the central sulcus. For the observation of the polarity inversion of N20 to P20 across the central sulcus, a multi-channel SEP should be recorded using a sheet of silicone rubber embedded in a 16-electrode array consisting of a 4 by 4 grid. We projected the exposed cortical surface on the video display through the microscope apparatus and marked the locations of the recording electrodes on the video display. This enabled the location of the recording electrodes to correspond easily and precisely to the cortical surface. Our reliable and simple method of intraoperative localization of the central sulcus by cortical SEPs monitoring is presented in a practical case.",
keywords = "central sulcus, intraoperative monitoring, median nerve, somatosensory evoked potentials",
author = "Jun Namiki and Masashi Nakatsukasa and Ikuro Murase and Takayuki Oohira and Masayuki Ishihara and Shigeo Toya",
year = "1997",
month = "2",
language = "English",
volume = "25",
pages = "123--129",
journal = "Neurological Surgery",
issn = "0301-2603",
publisher = "Igaku-Shoin Ltd",
number = "2",

}

TY - JOUR

T1 - Practical localization of the central sulcus using a video display during surgery by cortical somatosensory evoked potentials and how to discern precentral P20 and central P25

AU - Namiki, Jun

AU - Nakatsukasa, Masashi

AU - Murase, Ikuro

AU - Oohira, Takayuki

AU - Ishihara, Masayuki

AU - Toya, Shigeo

PY - 1997/2

Y1 - 1997/2

N2 - In patients with lesions around the central sulcus, cortical surface somatosensory evoked potentials (SEPs) have been applied for the purpose of localization of the central sulcus based on the polarity inversion of postcentral N20 to precentral P20 across the central sulcus. We have intraoperatively monitored SEPs to infer the location of the central sulcus in 16 cases since December 1988. Intraoperative localization of the central sulcus has been most useful in patients with frontal lobe gliomas in which the localization of the central sulcus enables the surgeon to extensively resect tumor without postoperative motor weakness. The localization of the central sulcus, however, might be misjudged by using the polarity inversion criterion alone, because central P25 following N20 and P20 complicates SEP waveforms. It is significant that P25, which is recorded also posterior to the central sulcus, is discerned from the precentral P20. In order to solve this matter, we regarded only the positivity in SEP waveforms having the identical peak latency to that of N20 as the precentral P20. Positive potentials having a later peak latency than that of N20 are the superposition of P20 and P25, and might also be recorded posterior to the central sulcus. For the observation of the polarity inversion of N20 to P20 across the central sulcus, a multi-channel SEP should be recorded using a sheet of silicone rubber embedded in a 16-electrode array consisting of a 4 by 4 grid. We projected the exposed cortical surface on the video display through the microscope apparatus and marked the locations of the recording electrodes on the video display. This enabled the location of the recording electrodes to correspond easily and precisely to the cortical surface. Our reliable and simple method of intraoperative localization of the central sulcus by cortical SEPs monitoring is presented in a practical case.

AB - In patients with lesions around the central sulcus, cortical surface somatosensory evoked potentials (SEPs) have been applied for the purpose of localization of the central sulcus based on the polarity inversion of postcentral N20 to precentral P20 across the central sulcus. We have intraoperatively monitored SEPs to infer the location of the central sulcus in 16 cases since December 1988. Intraoperative localization of the central sulcus has been most useful in patients with frontal lobe gliomas in which the localization of the central sulcus enables the surgeon to extensively resect tumor without postoperative motor weakness. The localization of the central sulcus, however, might be misjudged by using the polarity inversion criterion alone, because central P25 following N20 and P20 complicates SEP waveforms. It is significant that P25, which is recorded also posterior to the central sulcus, is discerned from the precentral P20. In order to solve this matter, we regarded only the positivity in SEP waveforms having the identical peak latency to that of N20 as the precentral P20. Positive potentials having a later peak latency than that of N20 are the superposition of P20 and P25, and might also be recorded posterior to the central sulcus. For the observation of the polarity inversion of N20 to P20 across the central sulcus, a multi-channel SEP should be recorded using a sheet of silicone rubber embedded in a 16-electrode array consisting of a 4 by 4 grid. We projected the exposed cortical surface on the video display through the microscope apparatus and marked the locations of the recording electrodes on the video display. This enabled the location of the recording electrodes to correspond easily and precisely to the cortical surface. Our reliable and simple method of intraoperative localization of the central sulcus by cortical SEPs monitoring is presented in a practical case.

KW - central sulcus

KW - intraoperative monitoring

KW - median nerve

KW - somatosensory evoked potentials

UR - http://www.scopus.com/inward/record.url?scp=12644251970&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=12644251970&partnerID=8YFLogxK

M3 - Article

C2 - 9027888

AN - SCOPUS:12644251970

VL - 25

SP - 123

EP - 129

JO - Neurological Surgery

JF - Neurological Surgery

SN - 0301-2603

IS - 2

ER -