Metro Pain Group, Melbourne, VIC, Australia.
Abbott Laboratories, Sunnyvale, CA, USA.
Neuromodulation. 2019 Dec;22(8):937-942. doi: 10.1111/ner.12921. Epub 2019 Jan 30.
Neuromodulation is an important tool for achieving pain relief in otherwise-intractable neuropathic pain conditions. Dorsal root ganglion (DRG) stimulation, in which primary sensory neurons are stimulated prior to their entry into the spinal canal, provides treatment with high levels of dermatomal specificity and can provide advantages compared to conventional spinal cord stimulation. Although DRG stimulation can produce perceptible paresthesias, many patients operate their systems at subthreshold amplitudes that do not elicit this sensation. Pain relief both with and without paresthesia was investigated in this retrospective analysis.
A retrospective review of all qualifying permanent DRG stimulation systems at a single center over more than a three-year period was completed. Pain (0-10 numeric rating scale) was assessed at baseline, at the end of the trial, and after three, six, and twelve months of treatment. Patients were categorized based on their usage of the stimulator at amplitudes that either did or did not produce paresthesias.
Of the 39 patients, 34 (87%) reported having no-paresthesias at any of the follow-up visits. Average pain relief was 73.9% after the trial period and 63.1% after 12 months of treatment. The responder rate (50% or better pain relief) after three months of treatment was more than 80%. Exploratory subgroup analyses showed that similar degrees of pain relief were achieved in numerous body regions and with various pain etiologies. The five patients who reported paresthesias during treatment had pain relief similar to those of the group that did not experience paresthesias.
Clinically significant and sustained pain relief over more than a period of 12 months was achieved with DRG stimulation programmed at amplitudes below the perceptual level. Thus, the reported analgesia was paresthesia-independent. That good clinical outcomes were observed independent of the generation of paresthesia in DRG stimulation suggests several mechanisms of action, including the inhibition of supraspinal regions involved in somatic paresthesia sensation. The retrospective results presented here posit that future prospective study of DRG stimulation delivered at below the threshold of perceptible paresthesias is warranted.
神经调节是缓解其他难以治疗的神经性疼痛的重要手段。背根神经节（DRG）刺激是在初级感觉神经元进入椎管之前对其进行刺激，这种治疗方法具有很高的皮节特异性，可以与传统的脊髓刺激相比具有优势。虽然 DRG 刺激可以产生可感知的感觉异常，但许多患者以不引起这种感觉的亚阈值幅度运行其系统。本回顾性分析研究了有和没有感觉异常的疼痛缓解情况。
对一个中心超过三年的所有合格的永久性 DRG 刺激系统进行了回顾性审查。在基线、试验结束时以及治疗 3、6 和 12 个月后评估疼痛（0-10 数字评分量表）。根据患者在产生或不产生感觉异常的刺激器幅度下的使用情况对患者进行分类。
39 例患者中，34 例（87%）在所有随访中均无感觉异常。试验期后平均疼痛缓解率为 73.9%，治疗 12 个月后为 63.1%。治疗 3 个月后的应答率（疼痛缓解 50%或以上）超过 80%。探索性亚组分析表明，在许多身体部位和各种疼痛病因中都达到了相似程度的疼痛缓解。在治疗过程中报告有感觉异常的 5 名患者的疼痛缓解与未经历感觉异常的组相似。
在超过 12 个月的时间内，以低于感知水平的幅度编程的 DRG 刺激实现了临床显著且持续的疼痛缓解。因此，报告的镇痛与感觉异常无关。在 DRG 刺激中观察到的良好临床结果独立于感觉异常的产生，表明存在几种作用机制，包括抑制涉及躯体感觉异常感觉的脊髓上区域。这里提出的回顾性结果表明，有必要对低于可感知感觉异常阈值的 DRG 刺激进行未来的前瞻性研究。
