Kishima Haruhiko, Saitoh Youichi, Osaki Yasuhiro, Nishimura Hiroshi, Kato Amami, Hatazawa Jun, Yoshimine Toshiki
Department of Neurosurgery, Osaka University Medical School, Suita, Osaka, Japan.
J Neurosurg. 2007 Jul;107(1):43-8. doi: 10.3171/JNS-07/07/0043.
The mechanisms underlying deafferentation pain are not well understood. Motor cortex stimulation (MCS) is useful in the treatment of this kind of chronic pain, but the detailed mechanisms underlying its effects are unknown.
Six patients with intractable deafferentation pain in the left hand were included in this study. All were righthanded and had a subdural electrode placed over the right precentral gyrus. The pain was associated with brainstem injury in one patient, cervical spine injury in one patient, thalamic hemorrhage in one patient, and brachial plexus avulsion in three patients. Treatment with MCS reduced pain; visual analog scale (VAS) values for pain were 82 +/- 20 before MCS and 39 +/- 20 after MCS (mean +/- standard error). Regional cerebral blood flow (rCBF) was measured by positron emission tomography with H2(15)O before and after MCS. The obtained images were analyzed with statistical parametric mapping software (SPM99).
Significant rCBF increases were identified after MCS in the left posterior thalamus and left insula. In the early post-MCS phase, the left posterior insula and right orbitofrontal cortex showed significant rCBF increases, and the right precentral gyrus showed an rCBF decrease. In the late post-MCS phase, a significant rCBF increase was detected in the left caudal part of the anterior cingulate cortex (ACC).
These results suggest that MCS modulates the pathways from the posterior insula and orbitofrontal cortex to the posterior thalamus to upregulate the pain threshold and pathways from the posterior insula to the caudal ACC to control emotional perception. This modulation results in decreased VAS scores for deafferentation pain.
去传入性疼痛的潜在机制尚未完全明确。运动皮层刺激（MCS）对这类慢性疼痛的治疗有效，但其作用的详细机制尚不清楚。
本研究纳入6例左手顽固性去传入性疼痛患者。所有患者均为右利手，在右侧中央前回上方放置硬膜下电极。疼痛与1例脑干损伤、1例颈椎损伤、1例丘脑出血及3例臂丛神经撕脱有关。MCS治疗使疼痛减轻；疼痛的视觉模拟量表（VAS）值在MCS前为82±20，MCS后为39±20（平均值±标准误）。在MCS前后，用H2(15)O正电子发射断层扫描测量局部脑血流量（rCBF）。用统计参数映射软件（SPM99）分析所得图像。
MCS后，左侧丘脑后部和左侧岛叶的rCBF显著增加。在MCS后的早期阶段，左侧岛叶后部和右侧眶额皮质的rCBF显著增加，而右侧中央前回的rCBF减少。在MCS后的晚期阶段，在前扣带回皮质（ACC）的左侧尾部检测到rCBF显著增加。
这些结果表明，MCS调节从岛叶后部和眶额皮质到丘脑后部的通路以上调疼痛阈值，以及从岛叶后部到ACC尾部的通路以控制情绪感知。这种调节导致去传入性疼痛的VAS评分降低。
