Velasco Francisco, Argüelles Carlos, Carrillo-Ruiz José D, Castro Guillermo, Velasco Ana Luisa, Jiménez Fiacro, Velasco Marcos
Unit for Stereotactic Functional Neurosurgery and Radiosurgery, Service of Neurology and Neurosurgery, Mexico General Hospital, Mexico City, Mexico.
J Neurosurg. 2008 Apr;108(4):698-706. doi: 10.3171/JNS/2008/108/4/0698.
In this study the authors used a double-blind protocol to assess the efficacy of motor cortex stimulation (MCS) for treating neuropathic pain.
Eleven patients with unilateral neuropathic pain (visual analog scale [VAS] score 8-10) of different origins and topography were selected for MCS. A 20-contact grid was implanted through a craniotomy centered over the motor cortex contralateral to the painful area. The motor cortex strip was identified using neuroimages, somatosensory evoked potentials, acute electrical stimulation, and corticocortical evoked potentials. Subacute therapeutic stimulation trials allowed the authors to determine the most efficient pair of contacts to use for long-term MCS. The grid was replaced with a 4-contact electrode connected to an internalized stimulator. Bipolar stimulation at a 40-Hz frequency, 90-micro sec pulse width, amplitude 2-7 V, and 1 hour in "ON" and 4 hours in "OFF" mode was used. Pain was evaluated using the VAS, Bourhis, and McGill pain scales applied each month for 1 year. At Day 60 or 90, the stimulators were turned to OFF mode for 30 days in a randomized, double-blind fashion. The statistical tool used was the Wilcoxon test.
Three patients did not report improvement in the subacute trial and were excluded from long-term MCS; the remaining patients underwent long-term stimulation. Significant improvement of pain was induced by MCS (p < 0.01); this persisted during the follow-up period. Turning stimulation to OFF mode increased pain significantly (p < 0.05). Improvement at 1 year was >or= 40% (40-86%) in all cases.
Motor cortex stimulation is an efficient treatment for neuropathic pain, according to an evaluation facilitated by a double-blind maneuver. Subacute stimulation trials are recommended to determine the optimum motor cortex area to be stimulated and to identify nonresponders.
在本研究中，作者采用双盲方案评估运动皮层刺激（MCS）治疗神经性疼痛的疗效。
选取11例不同病因和部位的单侧神经性疼痛患者（视觉模拟量表[VAS]评分8 - 10）接受MCS治疗。通过在疼痛区域对侧运动皮层上方进行开颅手术，植入一个20触点的电极格栅。利用神经影像、体感诱发电位、急性电刺激和皮质皮质诱发电位来识别运动皮层条带。亚急性治疗性刺激试验使作者能够确定用于长期MCS的最有效触点对。将电极格栅替换为连接到植入式刺激器的4触点电极。采用40赫兹频率、90微秒脉冲宽度、2 - 7伏幅度的双极刺激，“开”模式持续1小时，“关”模式持续4小时。使用VAS、布尔希斯和麦吉尔疼痛量表，在1年的时间里每月对疼痛进行评估。在第60天或第90天，以随机、双盲的方式将刺激器切换到“关”模式30天。使用的统计工具是威尔科克森检验。
3例患者在亚急性试验中未报告疼痛改善，被排除在长期MCS治疗之外；其余患者接受长期刺激。MCS可显著改善疼痛（p < 0.01）；这种改善在随访期间持续存在。将刺激切换到“关”模式会使疼痛显著增加（p < 0.05）。所有病例在1年时的改善率均≥40%（40 - 86%）。
根据双盲操作辅助评估，运动皮层刺激是治疗神经性疼痛的有效方法。建议进行亚急性刺激试验，以确定最佳的运动皮层刺激区域并识别无反应者。
