-
J Neurosurg Anesthesiol · Apr 2012
High-frequency stimulation restored motor-evoked potentials to the baseline level in the upper extremities but not in the lower extremities under sevoflurane anesthesia in spine surgery.
- Yoshiteru Shida, Chikami Shida, Norihiko Hiratsuka, Kozo Kaji, and Junichi Ogata.
- Department of Orthopedics, Kyushu Rosai Hospital, Kitakyushu, Japan. teru0805leo@yahoo.co.jp
- J Neurosurg Anesthesiol. 2012 Apr 1;24(2):113-20.
BackgroundVolatile anesthetics attenuate medium-frequency (250 to 500 Hz) pulse train transcranial electrical stimulation (TES) motor-evoked potentials (MEPs) better than propofol. High-frequency (1000 Hz) TES may restore hand MEP amplitude under volatile anesthesia, but its effect on leg MEPs critical for spine surgery monitoring is unknown.MethodsThe effects of sevoflurane and propofol and modulation of the stimulation frequencies on MEPs elicited by TES in the anterior tibial, abductor hallucis, and abductor pollicic brevis muscles were investigated in 31 patients undergoing spine surgery. MEPs elicited by transcranial magnetic stimulation were also obtained before the surgeries and compared with the TES MEPs.ResultsSevoflurane attenuated the MEP amplitudes significantly. The MEP amplitudes increased with the TES frequency in the case of the arms, but not the legs, under sevoflurane anesthesia. The MEPs recorded under propofol anesthesia did not differ from those elicited by transcranial magnetic stimulation before the surgery (control).ConclusionsSevoflurane is inadvisable for MEP monitoring in the legs during spine surgery as modulation of the TES frequency did not eliminate the suppressive effect of sevoflurane on the MEPs in the legs. Clinicians should be forewarned of the greater risk of unmonitorable MEPs, especially in the legs, under sevoflurane anesthesia.
Notes
Knowledge, pearl, summary or comment to share?You can also include formatting, links, images and footnotes in your notes
- Simple formatting can be added to notes, such as
*italics*
,_underline_
or**bold**
. - Superscript can be denoted by
<sup>text</sup>
and subscript<sub>text</sub>
. - Numbered or bulleted lists can be created using either numbered lines
1. 2. 3.
, hyphens-
or asterisks*
. - Links can be included with:
[my link to pubmed](http://pubmed.com)
- Images can be included with:
![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
- For footnotes use
[^1](This is a footnote.)
inline. - Or use an inline reference
[^1]
to refer to a longer footnote elseweher in the document[^1]: This is a long footnote.
.