Säisänen Laura, Julkunen Petro, Kemppainen Samuli, Danner Nils, Immonen Arto, Mervaala Esa, Määttä Sara, Muraja-Murro Anu, Könönen Mervi
*Institute of Clinical Medicine, Faculty of Health Sciences and §Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; ‡Departments of Clinical Neurophysiology, #Neurosurgery, and **Clinical Radiology, Kuopio University Hospital, Kuopio, Finland; ¶Department of Clinical Neurophysiology, NordLab Kajaani and ‖Kainuu Social and Health Care Joint Authority, Kainuu Central Hospital, Kajaani, Finland.
Neurosurgery. 2015 Sep;77(3):394-405; discussion 405. doi: 10.1227/NEU.0000000000000798.
Navigated transcranial magnetic stimulation (nTMS) has become established as an accurate noninvasive technique for mapping the functional motor cortex for the representation areas of upper and lower limb muscles but not yet for facial musculature.
To characterize the applicability and clinical impact of using nTMS to map cortical motor areas of facial muscles in healthy volunteers and neurosurgical tumor patients.
Eight healthy volunteers and 12 patients with tumor were studied. The motor threshold (MT) was determined for the abductor pollicis brevis and mentalis muscles. The lateral part of the motor cortex was mapped with suprathreshold stimulation intensity, and motor evoked potentials were recorded from several facial muscles. The patient protocol was modified according to the clinical indication.
In all healthy subjects, motor evoked potentials were elicited in the mentalis (mean latency, 13.4 milliseconds) and orbicularis oris (mean latency, 12.6 milliseconds) muscles. At 110% of MT of the mentalis, the motor evoked potentials of facial muscles were elicited mainly in the precentral gyrus but also from one gyrus anterior and posterior to it. The cortical areas applicable for mapping were limited by an artifact attributable to direct peripheral nerve stimulation. The mapping protocol was successful in 10 of 12 tumor patients at locating the representation area of the lower facial muscles. The MT of the facial muscles was significantly higher than that of the abductor pollicis brevis.
nTMS is an applicable and clinically beneficial noninvasive method to preoperatively map the cortical representation areas of the facial muscles in the lower part of the face. Instead of using the MT of the abductor pollicis brevis, the stimulus intensity during mapping should be proportioned to the MT of a facial muscle.
导航经颅磁刺激（nTMS）已成为一种精确的非侵入性技术，用于绘制上肢和下肢肌肉代表区的功能性运动皮层，但尚未用于面部肌肉。
描述使用nTMS绘制健康志愿者和神经外科肿瘤患者面部肌肉皮质运动区的适用性和临床影响。
研究了8名健康志愿者和12名肿瘤患者。测定了拇短展肌和颏肌的运动阈值（MT）。用阈上刺激强度绘制运动皮层的外侧部分，并从几块面部肌肉记录运动诱发电位。根据临床指征修改患者方案。
在所有健康受试者中，颏肌（平均潜伏期13.4毫秒）和口轮匝肌（平均潜伏期12.6毫秒）均引出运动诱发电位。在颏肌MT的110%时，面部肌肉的运动诱发电位主要在前中央回引出，但也可从其前后一个脑回引出。适用于映射的皮质区域受到直接外周神经刺激所致伪迹的限制。在12名肿瘤患者中的10名患者中，映射方案成功定位了面下部肌肉的代表区。面部肌肉的MT显著高于拇短展肌。
nTMS是一种适用于术前绘制面部下部肌肉皮质代表区的非侵入性方法，且具有临床益处。在映射过程中，刺激强度不应使用拇短展肌的MT，而应与面部肌肉的MT成比例。
