J Neurol Surg A Cent Eur Neurosurg 2024; 85(05): 451-456
DOI: 10.1055/a-2103-7381
Original Article

Anesthetic Fade in Intraoperative Transcranial Motor Evoked Potential Monitoring Is Mainly due to Decreased Synaptic Transmission at the Neuromuscular Junction by Propofol Accumulation

Satoshi Tanaka
1   Department of Neurosurgery, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
,
Kenta Yamamoto
2   Department of Clinical Laboratory, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
,
Shinsuke Yoshida
3   Department of Neurosurgery, Saitama Medical Center, Kawagoe, Saitama, Japan
,
Ryosuke Tomio
4   Department of Neurosurgery, Honjo Neurosurgery & Spinal Surgery Clinic, Honjo, Saitama, Japan
,
Takeshi Fujimoto
1   Department of Neurosurgery, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
,
Misuzu Osaka
1   Department of Neurosurgery, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
,
Toshio Ishikawa
1   Department of Neurosurgery, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
,
Tsunemasa Shimizu
1   Department of Neurosurgery, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
,
Norio Akao
1   Department of Neurosurgery, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
,
Terutaka Nishimatsu
1   Department of Neurosurgery, Numata Neurosurgery & Cardiovascular Hospital, Numata, Gunma, Japan
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Abstract

Background We previously reported that normalization of motor evoked potential (MEP) monitoring amplitude by compound muscle action potential (CMAP) after peripheral nerve stimulation prevented the expression of anesthetic fade (AF), suggesting that AF might be due to reduced synaptic transfer in the neuromuscular junction.

Methods We calculated the time at which AF began for each of craniotomy and spinal cord surgery, and examined whether AF was avoided by CMAP after peripheral nerve stimulation normalization in each. Similar studies were also made with respect to the upper and lower limb muscles.

Results AF was observed in surgery lasting 160 minutes for craniotomy and 260 minutes or more for spinal surgery, and 195 minutes in the upper limb muscles and 135 minutes in the lower limb muscles. In all the series, AF could be avoided by CMAP after peripheral nerve stimulation normalization.

Conclusion AF of MEP occurred in both craniotomy and spinal cord surgery, and it was also corrected by CMAP after peripheral nerve stimulation. AF is considered to be mainly due to a decrease in synaptic transfer of the neuromuscular junction due to the accumulation of propofol because of the avoidance by CMAP normalization. However, it may be partially due to a decrease in the excitability of pyramidal tracts and α-motor neurons, because AF occurred earlier in the lower limb muscles than in the upper limb muscles.



Publikationsverlauf

Eingereicht: 29. November 2022

Angenommen: 30. Mai 2023

Accepted Manuscript online:
31. Mai 2023

Artikel online veröffentlicht:
19. Dezember 2023

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