Reportedly, tetanic stimulation prior to transcranial electrical stimulation (TES) facilitates elicitation of motor evoked potentials (MEPs) by a mechanism involving increased corticomotoneuronal excitability in response to somatosensory input. However, the posttetanic MEP following stimulation of a pure sensory nerve has never been reported. Furthermore, no previous reports have described posttetanic MEPs in pediatric patients. The aim of this study was to investigate the efficacy of posttetanic MEPs in pediatric neurosurgery patients and to compare the effects on posttetanic MEP after tetanic stimulation of the sensory branch of the pudendal nerve versus the standard median and tibial nerves, which contain a mixture of sensory and motor fibers.

In 31 consecutive pediatric patients with a mean age of 6.0 ± 5.1 years who underwent lumbosacral surgery, MEPs were elicited by TES without tetanic stimulation (conventional MEPs [c-MEPs]) and following tetanic stimulation of the unilateral median and tibial nerves (mt-MEPs) and the sensory branch of the pudendal nerve (p-MEP). Compound muscle action potentials were elicited from abductor pollicis brevis (APB), gastrocnemius (Gc), tibialis anterior (TA), and adductor hallucis (AH) muscles. The success rate of monitoring each MEP and the increases in the ratios of mt-MEP and p-MEP to c-MEP were investigated.

The success rate of monitoring p-MEPs was higher than those of mt-MEPs and c-MEPs (87.5%, 72.6%, and 63.3%, respectively; p < 0.01, adjusted by Bonferroni correction). The mean increase in the ratio of p-MEP to c-MEP for all muscles was significantly higher than that of mt-MEP to c-MEP (3.64 ± 4.03 vs 1.98 ± 2.23, p < 0.01). Subanalysis of individual muscles demonstrated significant differences in the increases in the ratios between p-MEP and mt-MEP in the APB bilaterally, as well as ipsilateral Gc, contralateral TA, and bilateral AH muscles.

Tetanic stimulation prior to TES can augment the amplitude of MEPs during pediatric neurosurgery, the effect being larger with pudendal nerve stimulation than tetanic stimulation of the unilateral median and tibial nerves. TES elicitation of p-MEPs might be useful in pediatric patients in whom it is difficult to elicit c-MEPs.

据报道，经颅电刺激 (TES) 之前的强直刺激通过一种机制促进运动诱发电位 (MEP) 的激发，该机制涉及响应体感输入的皮质运动神经元兴奋性增加。然而，从未报道过刺激纯感觉神经后的强直后 MEP。此外，之前没有报告描述过儿科患者的强直后 MEP。本研究的目的是调查强直后 MEPs 在小儿神经外科患者中的疗效，并比较阴部神经感觉分支与标准正中神经和胫神经的强直刺激后对强直后 MEP 的影响，后者包含感觉混合物和运动纤维。

在 31 名平均年龄为 6.0 ± 5.1 岁、接受腰骶部手术的连续儿科患者中，无强直刺激（传统 MEP [c-MEP]）和单侧正中神经和胫神经（mt- MEP）和阴部神经的感觉分支（p-MEP）。从拇短外展肌 (APB)、腓肠肌 (Gc)、胫骨前肌 (TA) 和拇内收肌 (AH) 肌肉诱发复合肌肉动作电位。研究了监测每个 MEP 的成功率以及 mt-MEP 和 p-MEP 与 c-MEP 比率的增加。

监测 p-MEP 的成功率高于 mt-MEP 和 c-MEP（分别为 87.5%、72.6% 和 63.3%；p < 0.01，经 Bonferroni 校正调整）。所有肌肉的 p-MEP 与 c-MEP 之比的平均增加显着高于 mt-MEP 与 c-MEP（3.64 ± 4.03 对 1.98 ± 2.23，p < 0.01）。对单个肌肉的亚组分析表明，双侧 APB 以及同侧 Gc、对侧 TA 和双侧 AH 肌肉中 p-MEP 和 mt-MEP 之间比率的增加存在显着差异。

TES 之前的强直刺激可以增加小儿神经外科手术过程中 MEP 的幅度，阴部神经刺激的效果比单侧正中和胫神经的强直刺激更大。p-MEP 的 TES 诱发可能对难以诱发 c-MEP 的儿科患者有用。