Naseff Specialty Center, United Neurosurgery Associates, St. Paul, MN, USA.
Neuromodulation. 2014 Jan;17(1):22-6; discussion 26-7. doi: 10.1111/ner.12033. Epub 2013 Feb 21.
Development of effective chronic pain treatment strategies has been hampered by the lack of an objective pain biomarker. Magnetoencephalography (MEG) has demonstrated cortical disorganization corresponding to the affected limb of complex regional pain syndrome (CRPS) patients and spinal cord stimulation (SCS) can acutely treat CRPS in a reversible and adjustable fashion. In order to better define a potential MEG-sensitive biomarker for chronic pain, our goal was to study the effects of therapeutic SCS on cortical disorganization in patients with unilateral limb CRPS.
Two patients treated with either thoracic or cervical SCS with leg or arm CRPS were studied with MEG. Baseline and tactile-evoked responses were recorded with and without effective SCS therapy.
All MEG recordings were obtained with minimal interference. In the patient with arm CRPS, with the stimulator off, first and fifth digit primary somatosensory (SI) cortical representations (D1/D5) were significantly disorganized and spatially inverted as compared with the opposite unaffected limb. Effective SCS therapy was then able to acutely normalize or restore hand cortical organization in the affected CRPS limb. This restoration of cortical organization was partially maintained with lingering pain relief when the stimulator was subsequently turned off.
This is the first report of a MEG study showing D1/D5 cortical disorganization and its apparent reversal or restoration with cervical SCS therapy. Ours also is the first report of an apparent acute reversible interchange in the cortical representations of D1 and D5. Our limited data demonstrate that disorganization of SI cortex might be a neurophysiologic marker of chronic pain as shown with instantaneous normalization of SI disorganization or restoration of SI organization with therapeutic SCS. As a clinically proven tool for functional mapping, MEG might be shown to provide an objective measure of chronic pain. More data are required to further investigate this possibility.
由于缺乏客观的疼痛生物标志物，有效的慢性疼痛治疗策略的发展受到了阻碍。脑磁图（MEG）已经证明了复杂区域疼痛综合征（CRPS）患者受影响肢体的皮质紊乱，脊髓刺激（SCS）可以以可逆和可调节的方式急性治疗 CRPS。为了更好地定义慢性疼痛的潜在 MEG 敏感生物标志物，我们的目标是研究治疗性 SCS 对单侧肢体 CRPS 患者皮质紊乱的影响。
对接受胸椎或颈椎 SCS 治疗的腿部或手臂 CRPS 的 2 名患者进行 MEG 研究。在有效 SCS 治疗存在和不存在的情况下，记录基线和触觉诱发反应。
所有 MEG 记录都在最小干扰下获得。在手臂 CRPS 患者中，当刺激器关闭时，第一和第五指初级体感（SI）皮质代表（D1/D5）明显紊乱，空间倒置，与对侧未受影响的肢体相比。有效的 SCS 治疗随后能够急性使受影响的 CRPS 肢体的手部皮质组织正常化或恢复。当随后关闭刺激器时，皮质组织的这种恢复部分保持了持续的疼痛缓解。
这是第一项显示 D1/D5 皮质紊乱及其与颈椎 SCS 治疗的明显逆转或恢复的 MEG 研究报告。我们也是第一项报告 D1 和 D5 的皮质代表出现明显急性可逆交换的报告。我们有限的数据表明，SI 皮质的紊乱可能是慢性疼痛的神经生理标志物，如 SI 紊乱的瞬时正常化或治疗性 SCS 恢复 SI 组织。作为一种经过临床验证的功能映射工具，MEG 可能被证明提供慢性疼痛的客观测量。需要更多的数据来进一步研究这种可能性。
