Localization of stereotactic targets by microrecording of thalamic somatosensory evoked potentials

F. Shima, T. Morioka, Shozo Tobimatsu, O. Kavaklis, M. Kato, M. Fukui

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

To improve the localization of stereotactic targets, somatosensory evoked potentials (SEPs) were recorded from the thalamus and subthalamic area using a specially designed semimicroelectrode in 61 patients and a conventional ''macroelectrode'' in 17 patients. By means of the semimicroelectrode, median nerve stimulation evoked two distinct SEPs, consisting of a diphasic wave with a huge positivity restricted to the nucleus ventrocaudalis (Vc) and a triphasic wave of lower amplitude with a major negativity in the ventral part of the nucleus ventrointermedius (Vim) and nucleus ventrooralis posterior (Vop) as well as the subthalamic lemniscal pathway. The Vim-Vc junction could thus be clearly delineated by an abrupt transition of SEPs from one type to the other with a precision of 1 mm. The parvicellular part of the Vc (Vcpc), situated in its basal region, was distinguishable from the Vc proper by a significant reduction of the positivity elicited by stimulation of the median nerve and by a rapid growth of a diphasic SEPs to stimulation of the posterior tibial nerve. In the other thalamic nuclei, stimulation of the median nerve elicited triphasic SEPs of a very small amplitude, suggesting a volume conduction current from the lemniscal pathway. With the macroelectrode, the positivity in the Vc was sensitive to electrode manipulation and the thalamic nuclei could not be distinctly outlined. SEP monitoring using the semimicroelectrode significantly improved the precision of target localization, which allowed minimizing of the volume of the therapeutic lesion without losing surgical effectiveness, while avoiding complications associated with increased penetration of the coagulating electrode. It is suggested that recording serial thalamic SEPs with the semimicroelectrode is a practical method to refine stereotactic targets in the thalamus.

Original languageEnglish
Pages (from-to)223-230
Number of pages8
JournalNeurosurgery
Volume28
Issue number2
DOIs
Publication statusPublished - 1991

Fingerprint

Somatosensory Evoked Potentials
Median Nerve
Thalamic Nuclei
Thalamus
Electrodes
Tibial Nerve
Growth

All Science Journal Classification (ASJC) codes

  • Surgery
  • Clinical Neurology

Cite this

Localization of stereotactic targets by microrecording of thalamic somatosensory evoked potentials. / Shima, F.; Morioka, T.; Tobimatsu, Shozo; Kavaklis, O.; Kato, M.; Fukui, M.

In: Neurosurgery, Vol. 28, No. 2, 1991, p. 223-230.

Research output: Contribution to journalArticle

Shima, F. ; Morioka, T. ; Tobimatsu, Shozo ; Kavaklis, O. ; Kato, M. ; Fukui, M. / Localization of stereotactic targets by microrecording of thalamic somatosensory evoked potentials. In: Neurosurgery. 1991 ; Vol. 28, No. 2. pp. 223-230.
@article{9a37c4e65285426389d59958ad389824,
title = "Localization of stereotactic targets by microrecording of thalamic somatosensory evoked potentials",
abstract = "To improve the localization of stereotactic targets, somatosensory evoked potentials (SEPs) were recorded from the thalamus and subthalamic area using a specially designed semimicroelectrode in 61 patients and a conventional ''macroelectrode'' in 17 patients. By means of the semimicroelectrode, median nerve stimulation evoked two distinct SEPs, consisting of a diphasic wave with a huge positivity restricted to the nucleus ventrocaudalis (Vc) and a triphasic wave of lower amplitude with a major negativity in the ventral part of the nucleus ventrointermedius (Vim) and nucleus ventrooralis posterior (Vop) as well as the subthalamic lemniscal pathway. The Vim-Vc junction could thus be clearly delineated by an abrupt transition of SEPs from one type to the other with a precision of 1 mm. The parvicellular part of the Vc (Vcpc), situated in its basal region, was distinguishable from the Vc proper by a significant reduction of the positivity elicited by stimulation of the median nerve and by a rapid growth of a diphasic SEPs to stimulation of the posterior tibial nerve. In the other thalamic nuclei, stimulation of the median nerve elicited triphasic SEPs of a very small amplitude, suggesting a volume conduction current from the lemniscal pathway. With the macroelectrode, the positivity in the Vc was sensitive to electrode manipulation and the thalamic nuclei could not be distinctly outlined. SEP monitoring using the semimicroelectrode significantly improved the precision of target localization, which allowed minimizing of the volume of the therapeutic lesion without losing surgical effectiveness, while avoiding complications associated with increased penetration of the coagulating electrode. It is suggested that recording serial thalamic SEPs with the semimicroelectrode is a practical method to refine stereotactic targets in the thalamus.",
author = "F. Shima and T. Morioka and Shozo Tobimatsu and O. Kavaklis and M. Kato and M. Fukui",
year = "1991",
doi = "10.1227/00006123-199102000-00008",
language = "English",
volume = "28",
pages = "223--230",
journal = "Neurosurgery",
issn = "0148-396X",
publisher = "Lippincott Williams and Wilkins",
number = "2",

}

TY - JOUR

T1 - Localization of stereotactic targets by microrecording of thalamic somatosensory evoked potentials

AU - Shima, F.

AU - Morioka, T.

AU - Tobimatsu, Shozo

AU - Kavaklis, O.

AU - Kato, M.

AU - Fukui, M.

PY - 1991

Y1 - 1991

N2 - To improve the localization of stereotactic targets, somatosensory evoked potentials (SEPs) were recorded from the thalamus and subthalamic area using a specially designed semimicroelectrode in 61 patients and a conventional ''macroelectrode'' in 17 patients. By means of the semimicroelectrode, median nerve stimulation evoked two distinct SEPs, consisting of a diphasic wave with a huge positivity restricted to the nucleus ventrocaudalis (Vc) and a triphasic wave of lower amplitude with a major negativity in the ventral part of the nucleus ventrointermedius (Vim) and nucleus ventrooralis posterior (Vop) as well as the subthalamic lemniscal pathway. The Vim-Vc junction could thus be clearly delineated by an abrupt transition of SEPs from one type to the other with a precision of 1 mm. The parvicellular part of the Vc (Vcpc), situated in its basal region, was distinguishable from the Vc proper by a significant reduction of the positivity elicited by stimulation of the median nerve and by a rapid growth of a diphasic SEPs to stimulation of the posterior tibial nerve. In the other thalamic nuclei, stimulation of the median nerve elicited triphasic SEPs of a very small amplitude, suggesting a volume conduction current from the lemniscal pathway. With the macroelectrode, the positivity in the Vc was sensitive to electrode manipulation and the thalamic nuclei could not be distinctly outlined. SEP monitoring using the semimicroelectrode significantly improved the precision of target localization, which allowed minimizing of the volume of the therapeutic lesion without losing surgical effectiveness, while avoiding complications associated with increased penetration of the coagulating electrode. It is suggested that recording serial thalamic SEPs with the semimicroelectrode is a practical method to refine stereotactic targets in the thalamus.

AB - To improve the localization of stereotactic targets, somatosensory evoked potentials (SEPs) were recorded from the thalamus and subthalamic area using a specially designed semimicroelectrode in 61 patients and a conventional ''macroelectrode'' in 17 patients. By means of the semimicroelectrode, median nerve stimulation evoked two distinct SEPs, consisting of a diphasic wave with a huge positivity restricted to the nucleus ventrocaudalis (Vc) and a triphasic wave of lower amplitude with a major negativity in the ventral part of the nucleus ventrointermedius (Vim) and nucleus ventrooralis posterior (Vop) as well as the subthalamic lemniscal pathway. The Vim-Vc junction could thus be clearly delineated by an abrupt transition of SEPs from one type to the other with a precision of 1 mm. The parvicellular part of the Vc (Vcpc), situated in its basal region, was distinguishable from the Vc proper by a significant reduction of the positivity elicited by stimulation of the median nerve and by a rapid growth of a diphasic SEPs to stimulation of the posterior tibial nerve. In the other thalamic nuclei, stimulation of the median nerve elicited triphasic SEPs of a very small amplitude, suggesting a volume conduction current from the lemniscal pathway. With the macroelectrode, the positivity in the Vc was sensitive to electrode manipulation and the thalamic nuclei could not be distinctly outlined. SEP monitoring using the semimicroelectrode significantly improved the precision of target localization, which allowed minimizing of the volume of the therapeutic lesion without losing surgical effectiveness, while avoiding complications associated with increased penetration of the coagulating electrode. It is suggested that recording serial thalamic SEPs with the semimicroelectrode is a practical method to refine stereotactic targets in the thalamus.

UR - http://www.scopus.com/inward/record.url?scp=0026071423&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0026071423&partnerID=8YFLogxK

U2 - 10.1227/00006123-199102000-00008

DO - 10.1227/00006123-199102000-00008

M3 - Article

C2 - 1997890

AN - SCOPUS:0026071423

VL - 28

SP - 223

EP - 230

JO - Neurosurgery

JF - Neurosurgery

SN - 0148-396X

IS - 2

ER -