Intraoperative Monitoring of Myogenic Motor-Evoked Potentials From the External Anal Sphincter Muscle to Transcranial Electrical Stimulation

Inoue, Satoki; Kawaguchi, Masahiko; Shimoda, Takashi; Kakimoto, Meiko; Sakamoto, T.; Kitaguchi, Katsuyasu; Furuya, Hitoshi; Morimoto, Tetsuya; Sakaki, Toshisuke

doi:10.1097/00007632-200211010-00018

Cited by 24 publications

(8 citation statements)

References 40 publications

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“…In 1953, Floyd and Walls [ 3 ] first reported an electromyogram using a surface electrode placed on the skin of the anus. Monitoring of the EAS with Tc-MsEPs is now widely performed in spinal surgery to prevent intraoperative neurological deficit [ 1 , 4 , 7 - 14 , 16 , 17 ]; in addition, electrophysiological tests for bladder and rectal function have been developed. Many institutions now use monitoring of the EAS with Tc-MsEP to prevent intraoperative paralysis during spinal surgery.…”

Section: Discussionmentioning

confidence: 99%

Efficacy of Anal Needle Electrodes for Intraoperative Spinal Cord Monitoring with Transcranial Muscle Action Potentials

et al. 2018

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Study DesignRetrospective study.PurposeTo examine the relationship between postoperative bowel bladder disorder (BBD) and the efficacy of needle electrodes for the external anal sphincter (EAS) in intraoperative spinal cord monitoring with transcranial muscle action potentials (Tc-MsEP).Overview of LiteratureSpinal surgery for spina bifida, spinal cord tumor, and spinal tethered cord syndrome has a high rate of postoperative BBD. Monitoring of the EAS with Tc-MsEP is frequently performed during spinal surgery. We initially used plug-surface electrodes for this purpose, but have more recently switched to needle electrodes for the monitoring of the EAS. To date, there has been no comparison between the utility of these electrodes.MethodsWaveform derivation, exacerbation of postoperative BBD, and sensitivity and specificity for prediction of BBD by 70% amplitude reduction of EAS activity using needle and plug-surface electrodes were investigated in 239 spine surgeries. The cut-off for the % drop in amplitude for BBD prediction was determined for EAS monitoring using a needle electrode.ResultsThe overall rate of postoperative BBD aggravation was 7.1% (17/239 cases), with the individual rates using needle and plug-surface electrodes being 6.9% (8/116) and 7.3% (9/123), respectively. The waveform derivation rate was significantly higher using needle electrodes (91.3% [106/116] vs. 76.4% [94/123], p <0.01). In patients with baseline waveform detection, the sensitivity and specificity for postoperative BBD were similar in the two groups. With needle electrodes, a cutoff amplitude of Tc-MsEP for the EAS at the end of surgery of 25% of the baseline amplitude had a sensitivity of 89% and specificity of 82% for the prediction of postoperative BBD aggravation.ConclusionsThe significantly higher waveform derivation rate using needle electrodes suggests that these electrodes are effective for monitoring the EAS in spinal surgery in cases with preoperative BBD.

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Section: Discussionmentioning

confidence: 99%

Efficacy of Anal Needle Electrodes for Intraoperative Spinal Cord Monitoring with Transcranial Muscle Action Potentials

et al. 2018

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“…Intraoperative monitoring (IOM) with motor-evoked potentials (MEPs) is a means of assessing corticospinal tract integrity during spinal surgery. 1 Several techniques have been developed to improve the consistency of MEPs in the operating theater, 2,3 usually involving delivery of multiple electrical stimulation pulses.…”

Section: Introductionmentioning

confidence: 99%

Intra-operative monitoring in scoliosis surgery with multi-pulse cortical stimuli and desflurane anesthesia

Dan

Tan

et al. 2004

Spinal Cord

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“…Sedative-hypnotics (e.g., propofol) cause unconsciousness by producing corticocortical inhibition, possibly by GABA-mediated inhibitory interneuron activity within the cerebral cortex [15] with minimal depression of spinal alpha motor neurons [16]. Propofol, like halogenated agents, produces a dose-dependent depression of MEP responses [17, 18]. The influence of propofol is also suggested in this study.…”

Section: Discussionmentioning

confidence: 89%

An evaluation of anesthetic fade in motor evoked potential monitoring in spinal deformity surgeries

et al. 2018

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BackgroundIntraoperative neuromonitoring using motor evoked potentials (MEP) satisfactorily detects motor tract integrity changes during spinal surgery. However, monitoring is affected by “anesthetic fade,” in which the stimulation threshold increases because the waveform amplitude decreases with the accumulation of propofol. Therefore, the purpose of this study was to clarify the effect of anesthetic fade on transcranial MEPs by investigating the time-dependent changes of amplitude during spinal deformity surgeries.MethodsWe retrospectively reviewed medical records of 142 spinal deformity patients (66 patients with idiopathic scoliosis, 28 with adult spinal deformities, 19 with neuromuscular scoliosis, 17 with syndromic scoliosis, and 12 with congenital scoliosis). The average age was 28 years (range, 5 to 81 years). MEPs were recorded bilaterally from the abductor digiti minimi (ADM) and abductor hallucis (AH) muscles during spinal deformity surgeries. The Wilcoxon signed-rank test was used to investigate the time-dependent changes of amplitude after propofol infusion to evaluate anesthetic fade effects.ResultsThe average time to baseline from initial propofol infusion was 113 min (range, 45 to 182 min). In the ADM, the amplitude was 52% at 1 h after initial propofol infusion, 102% at 2 h, 105% at 3 h, 101% at 4 h, 86% at 5 h, and 81% at 6 h. Compared to the 2-h time point, MEP decreased significantly by 16% at 5 h (P < 0.0005) and by 21% at 6 h (P < 0.05). In the AH, the amplitude was 49% at 1 h after initial infusion of propofol, 102% at 2 h, 102% at 3 h, 92% at 4 h, 71% at 5 h, and 63% at 6 h. Compared to the 2-h time point, MEP decreased significantly by 10% at 4 h (P < 0.005), by 31% at 5 h (P < 0.0000005), and by 39% at 6 h (P < 0.05).ConclusionsMEP amplitude significantly decreased in the upper limbs at 5 and 6 h and in the lower limbs at 4, 5, and 6 h after the initial infusion of propofol, respectively. The influence of anesthetic fade could influence false positive MEPs during long spinal surgeries.

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Intraoperative Monitoring of Myogenic Motor-Evoked Potentials From the External Anal Sphincter Muscle to Transcranial Electrical Stimulation

Cited by 24 publications

References 40 publications

Efficacy of Anal Needle Electrodes for Intraoperative Spinal Cord Monitoring with Transcranial Muscle Action Potentials

Efficacy of Anal Needle Electrodes for Intraoperative Spinal Cord Monitoring with Transcranial Muscle Action Potentials

Intra-operative monitoring in scoliosis surgery with multi-pulse cortical stimuli and desflurane anesthesia

An evaluation of anesthetic fade in motor evoked potential monitoring in spinal deformity surgeries

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