Journée Henricus L, Berends Hanneke I, Kruyt Moyo C
*Department of Neurosurgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands; †Department of Orthopedics, VU medical center, Amsterdam, the Netherlands; ‡Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands; and §Department of surgery, Sint Maartenskliniek, Nijmegen, the Netherlands.
J Clin Neurophysiol. 2017 Jan;34(1):22-31. doi: 10.1097/WNP.0000000000000338.
Muscle motor evoked potentials (MEPs) from transcranial electrical stimulation (TES) became a standard technique for monitoring the motor functions of the brain and spinal cord at risk during spinal and brain surgery. However, a wide range of criteria based on the percentage of amplitude decrease is used in practice. A survey of the current literature on clinical outcome parameters reveals a variety of percentages in a range of 30% to 100% (50% to 100% spinal procedures) with no consensus. The interpretation of muscle MEPs is hampered by their sensitivity to many interfering factors. Trial-to-trial MEP variations may partly be reduced by controllable parameters of which TES parameters are in the hands of the neuromonitorist. We propose an operational model based on basic neurophysiologic knowledge to interpret the characteristics of MEP-TES voltage curves and predict the influences of the location on the sigmoid voltage curve on spontaneous MEP-variations and influences of factors affecting the voltage curve. The model predicts a correlation between the slope, expressed by a gain, and variations of muscle MEP amplitudes. This complies with two case examples. The limited specificity/sensitivity of warning criteria based on the percentage of amplitude reduction can possibly be improved by developing standards for set-up procedures of TES paradigms. These procedures include strategies for desensitizing MEPs for variations of controllable parameters. The TES voltage or current is a feasible controlling parameter and should be related to the motor threshold and the onset of the supramaximal level being landmarks of MEP-voltage functions. These parameters may offer a valuable addition to multicenter outcome studies.
经颅电刺激（TES）产生的肌肉运动诱发电位（MEP）已成为在脊柱和脑部手术期间监测处于风险中的脑和脊髓运动功能的标准技术。然而，在实践中使用了基于幅度降低百分比的广泛标准。对当前关于临床结果参数的文献调查显示，在30%至100%（脊柱手术为50%至100%）范围内有各种百分比，且未达成共识。肌肉MEP的解释因其对许多干扰因素的敏感性而受到阻碍。通过可控制参数，试验间MEP的变化可能会部分降低，其中TES参数由神经监测人员掌握。我们提出一种基于基本神经生理学知识的操作模型，以解释MEP - TES电压曲线的特征，并预测乙状结肠电压曲线上位置对自发MEP变化的影响以及影响电压曲线的因素的影响。该模型预测由增益表示的斜率与肌肉MEP幅度变化之间的相关性。这与两个案例示例相符。通过制定TES范式设置程序的标准，基于幅度降低百分比的警告标准有限的特异性/敏感性可能会得到改善。这些程序包括使MEP对可控参数变化脱敏的策略。TES电压或电流是一个可行的控制参数，应与运动阈值和超最大水平的起始相关，作为MEP电压功能的标志。这些参数可能会为多中心结果研究提供有价值的补充。
