Katayama Y, Fukaya C, Yamamoto T
Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, Japan.
J Neurosurg. 1998 Oct;89(4):585-91. doi: 10.3171/jns.1998.89.4.0585.
The goal of this study was to identify the neurological characteristics of patients with poststroke pain who show a favorable response to motor cortex (MC) stimulation used to control their pain.
The neurological characteristics of 31 patients treated by MC stimulation were analyzed. In 15 patients (48%), excellent or good pain control (pain reduction > 60%) was achieved for follow-up periods of more than 2 years by using MC stimulation at intensities below the threshold for muscle contraction. Satisfactory pain control was achieved in 13 (73%) of 18 patients in whom motor weakness in the painful area was virtually absent or mild, but in only two (15%) of the 13 patients who demonstrated moderate or severe weakness in the painful area (p < 0.01). Muscle contraction was inducible in the painful area in 20 patients when stimulated at a higher intensity. No such muscle response was inducible in the remaining 11 patients, no matter how extensively the authors attempted to determine appropriate stimulation sites. Satisfactory pain control was achieved in 14 (70%) of the 20 patients in whom muscle contraction was inducible, but in only one (9%) of the 11 patients in whom muscle contraction was not inducible (p < 0.01). No significant relationship was observed between pain control and various sensory symptoms, including the presence of hypesthesia, spontaneous dysesthesia, hyperpathia, and allodynia, or the disappearance of the N20 component of the median nerve-evoked somatosensory scalp potential. No significant relationship existed between the effect of MC stimulation on the pain and stimulation-induced phenomena, including paresthesia, improvement in motor performance, and attenuation of involuntary movements.
These findings suggest that the pain control afforded by MC stimulation requires neuronal circuits that are maintained by the presence of intact corticospinal tract neurons originating from the MC. Preoperative evaluation of motor weakness of the painful area appears to be useful for predicting a favorable response to MC stimulation in the control of poststroke pain.
本研究的目的是确定对用于控制疼痛的运动皮层（MC）刺激有良好反应的中风后疼痛患者的神经学特征。
分析了31例接受MC刺激治疗的患者的神经学特征。15例患者（48%）通过使用低于肌肉收缩阈值的强度进行MC刺激，在超过2年的随访期内实现了优秀或良好的疼痛控制（疼痛减轻>60%）。在疼痛区域几乎没有或仅有轻微运动无力的18例患者中，13例（73%）实现了满意的疼痛控制，但在疼痛区域表现为中度或重度无力的13例患者中，只有2例（15%）实现了满意的疼痛控制（p<0.01）。20例患者在更高强度刺激时，疼痛区域可诱导肌肉收缩。其余11例患者无论作者多么广泛地尝试确定合适的刺激部位，均未诱导出这种肌肉反应。在可诱导肌肉收缩的20例患者中，14例（70%）实现了满意的疼痛控制，但在不可诱导肌肉收缩的11例患者中，只有1例（9%）实现了满意的疼痛控制（p<0.01）。在疼痛控制与各种感觉症状之间未观察到显著关系，包括感觉减退、自发感觉异常、痛觉过敏和感觉异常，或正中神经诱发的体感头皮电位N20成分的消失。MC刺激对疼痛的影响与刺激诱发现象之间不存在显著关系，包括感觉异常、运动性能改善和不自主运动减弱。
这些发现表明，MC刺激提供的疼痛控制需要由源自MC的完整皮质脊髓束神经元维持的神经回路。术前评估疼痛区域的运动无力似乎有助于预测MC刺激在控制中风后疼痛方面的良好反应。
