Beňuška J, Čembová N, Naser Y, Žabka M, Pasiar J, Švec A
I. Ortopedicko-traumatologická klinika, Lekárskej fakulty Univerzity Komenského, Slovenskej zdravotníckej Univerzity a Univerzitnej nemocnice Bratislava.
Acta Chir Orthop Traumatol Cech. 2020;87(1):39-47.
PURPOSE OF THE STUDY This retrospective study investigated the significance of a combination of peak latency of waveform amplitude and waveform amplitude in association with spinal deformities. The correlation with postoperative neurologic deficit was evaluated too. MATERIAL AND METHODS Between January 2007 and January 2018, a group of 113 patients was evaluated in the study who underwent spine surgery using intraoperative neurophysiological monitoring (IONM) focusing on transcranial motor evoked potential (tc-MEP) monitoring. The average age of the patients was 30 years. Tc-MEPs were recorded bilaterally from tibialis anterior muscle and the abductor hallucis muscle in 88 patients without neurological deficit and in 25 patients with neurological deficit. The peak latency of waveform amplitude was defined as the period from stimulation until the waveform amplitude reached its peak. The correlation with postoperative neurological deficit was examined separately for latency delays of 5% and 10% or more and in combination with a decrease in amplitude of 70% or more. We used the presence-absence paradigm to evaluate the disappearance of previously present tc-MEPs and amplitude latency delays. The correlation with the deterioration of amplitudes from baseline or the elevation of thresholds was not used. Statistical tests were used to investigate the changes. The cases in our study with significant tc-MEP alerts were reviewed against the evidence-based response checklist. RESULTS Of 113 patients, the decrease in amplitude of 70% or more was identified in the neurological deficit group in 64% vs. 36% in the normal neurological group (p < 0.001). The neurological deficit was observed in 7.96% of patients postoperatively. A decrease in intraoperative amplitude of 70% or more from previously present tc-MEP occurred in 40 cases, with 89% sensitivity, 64% specificity, 36% false positive rate (FPR), and 20% positive predictive value (PPV) for prediction of postoperative neurological deficit. The amplitude latency peak delay of 10% or more was observed in 41 cases from the group of patients with postoperative neurological deficit, with 100% sensitivity, 64% specificity, 36% FPR and 22% PPV. A combination of a decrease in amplitude of 70% or more from the previously present tc-MEP and a delay in amplitude latency peak of 10% or more resulted in 100% sensitivity, 49% specificity, 51% FPR and 10% PPV in the group of postoperative neurological deficit patients. DISCUSSION Intraoperative tc-MEP alarm points have previously focused mainly on waveform amplitude. In our series, a criterion of an amplitude decrease of 70% or more from previously present tc-MEP was set as the alarm point. No alarm criterion for delay of peak latency of waveform amplitude was set before. We set a latency peak delay of 5% or more and 10% or more of waveform amplitude compared with the previously present tc-MEP as alarm criteria. This is the first study exploring the issue. We demonstrated the efficacy of latency peak of waveform amplitude together with the decrease of waveform amplitude. Another study found similarities in the decrease of amplitude of 70 % or more from baseline and the delay in amplitude latency of 10% or more from baseline; with 86% sensitivity, 98% specificity, 2% FPR and 86% PPV (1). CONCLUSIONS In conclusion, we investigated the efficacy of a change of peak latency delay of waveform amplitude in tc-MEP monitoring. The utilizing of the peak latency delay of waveform amplitude value resulted in high sensitivity up to 100 % and allows reduction of the FPR and an increase of the PPV. Further studies should set the alarm criteria more precisely for the waveform amplitude latency peak delay to achieve more effective spinal cord tc-MEP monitoring. Our concept of findings supports the neurophysiological monitoring findings in other studies. Key words: monitoring, IONM, intraoperative neurophysiological monitoring, tc-MEP, motor evoked potential, transcranial, amplitude, latency, peak.
研究目的 本回顾性研究探讨波形幅度峰值潜伏期与波形幅度相结合对于脊柱畸形的意义。同时也评估了其与术后神经功能缺损的相关性。
材料与方法 2007年1月至2018年1月期间，本研究对113例接受脊柱手术的患者进行了评估，这些手术采用术中神经电生理监测（IONM），重点是经颅运动诱发电位（tc-MEP）监测。患者的平均年龄为30岁。在88例无神经功能缺损和25例有神经功能缺损的患者中，双侧记录了胫前肌和拇展肌的tc-MEP。波形幅度峰值潜伏期定义为从刺激到波形幅度达到峰值的时间段。分别针对潜伏期延迟5%及以上、10%及以上，以及与幅度下降70%及以上相结合的情况，研究其与术后神经功能缺损的相关性。我们采用有无范式来评估先前存在的tc-MEP的消失情况以及幅度潜伏期延迟。未使用与基线幅度恶化或阈值升高的相关性。使用统计检验来研究变化情况。我们研究中具有显著tc-MEP警报的病例根据循证反应清单进行了回顾。
结果 在113例患者中，神经功能缺损组中幅度下降70%及以上的情况占64%，而正常神经功能组为36%（p<0.001）。术后7.96%的患者出现神经功能缺损。术中tc-MEP幅度较先前记录下降70%及以上的情况有40例，对术后神经功能缺损预测的敏感性为89%，特异性为64%，假阳性率（FPR）为36%，阳性预测值（PPV）为20%。术后神经功能缺损组中有41例观察到波形幅度潜伏期峰值延迟10%及以上，其敏感性为100%，特异性为64%，FPR为36%，PPV为22%。对于术后神经功能缺损组患者，先前存在的tc-MEP幅度下降70%及以上与波形幅度潜伏期峰值延迟10%及以上相结合，敏感性为100%，特异性为49%，FPR为51%，PPV为10%。
讨论 术中tc-MEP警报点以前主要集中在波形幅度上。在我们的系列研究中，将先前存在的tc-MEP幅度下降70%及以上的标准设定为警报点。以前未设定波形幅度峰值潜伏期延迟的警报标准。我们将与先前存在的tc-MEP相比，波形幅度潜伏期峰值延迟5%及以上和10%及以上设定为警报标准。这是首次探索该问题的研究。我们证明了波形幅度峰值潜伏期与波形幅度下降相结合的有效性。另一项研究发现，与基线相比幅度下降70%及以上和幅度潜伏期延迟10%及以上具有相似性；敏感性为86%，特异性为98%，FPR为2%，PPV为86%（1）。
结论 总之，我们研究了tc-MEP监测中波形幅度峰值潜伏期延迟变化的有效性。利用波形幅度峰值潜伏期延迟值可使敏感性高达100%，并降低FPR，提高PPV。未来的研究应更精确地设定波形幅度潜伏期峰值延迟的警报标准，以实现更有效的脊髓tc-MEP监测。我们的研究结果概念支持其他研究中的神经电生理监测结果。
监测；IONM；术中神经电生理监测；tc-MEP；运动诱发电位；经颅；幅度；潜伏期；峰值
