Neuroimaging Approaches to Deconstructing Acupuncuture for Chronic Pain

最近几项针灸治疗慢性疼痛的荟萃分析表明，真针并不优于假针灸/安慰剂针灸。然而，这些相同的荟萃分析也指出，在不同的试验中，针灸方法存在显著的异质性，这使得综合结果变得复杂。例如，虽然电针(EA)在缓解纤维肌痛(FM)的疼痛方面优于假针刺，但手法针刺(MA)则不是。就生理作用而言，电针和电针是非常不同的过程。它们作用于不同的外周靶点，诱导不同的心理物理知觉，体现在不同的大脑反应中。事实上，躯体感觉传入可能是针刺镇痛的一个关键变量，一些假针刺工具(如Streitberger针(SN))的使用也受到了批评，因为它们也产生躯体感觉。此外，躯体感觉可能是FM的一个特别重要的变量，因为这种慢性疼痛障碍显示出感觉和伤害性放大的改变。因此，我们假设电针对FM更有效，因为它作为一种脱敏疗法，当在多次治疗过程中重复应用时，逐渐使神经系统习惯于持续的内源性疼痛和躯体感觉信号。我们的总体目标是评估针刺诱导的躯体感觉传入对FM神经生物学改变和镇痛的影响。为了验证我们的假设，我们将在FM中将神经成像纳入一项随机、盲目、纵向的试验，使用具有显著不同体感传入的针灸干预：(1)电针和(2)模拟激光(ML)针灸-一种相对较新的假针灸形式，不会诱导任何体感传入。我们的第一个目标将在基线上描述FM慢性疼痛潜在的与躯体感觉相关的改变的神经回路。目的2将评估电针和模拟激光针刺对FM慢性疼痛的神经回路的纵向脱敏作用。然后，目标3将评估基线时改变的神经回路预测电针和模拟激光针灸的临床反应的能力。这些分析将提供急需的信息，即哪些患者可能从哪些针灸干预中受益最多。

Several recent meta-analyses of acupuncture for chronic pain have shown that verum acupuncture is not superior to sham/placebo acupuncture. However, these same meta-analyses have also noted significant heterogeneity in acupuncture methods across trials, which complicates combining results. For example, while electro-acupuncture (EA) was superior to sham acupuncture in relieving pain for fibromyalgia (FM), manual acupuncture (MA) was not. In terms of physiologic action, EA and MA are very different procedures. They effect different peripheral targets and induce different psychophysical perceptions, manifest in different brain response. In fact, somatosensory afference may be a key variable in acupuncture analgesia, and the use of some sham needling devices (e.g. Streitberger Needle (SN)) has been criticized since they also produce somatosensation. Moreover, somatosensation may be a particularly important variable for FM, as this chronic pain disorder is known to display altered sensory and nociceptive amplification. Thus, we hypothesize that EA has been more effective for FM because it functions as a desensitization therapy, which when applied repeatedly over multiple treatment sessions, gradually habituates the nervous system to continuing endogenous pain and somatosensory signaling. Our overall goal is to evaluate the impact of acupuncture-induced somatosensory afference on altered neurobiology and analgesia in FM. To test our hypotheses, we will incorporate neuroimaging into a randomized, blinded, longitudinal trial in FM using acupuncture interventions with significantly different amounts of somatosensory afference: (1) EA and (2) mock laser (ML) acupuncture - a relatively new form of sham acupuncture that does not induce any somatosensory afference. Our first Aim will characterize, at baseline, the altered somatosensory-related neurocircuitry underlying chronic pain in FM. Aim 2 will evaluate longitudinal desensitization effects of electro- and mock laser acupuncture on the neurocircuitry underlying chronic pain in FM. Aim 3 will then evaluate the ability of altered neurocircuitry at baseline to predict clinical response to both electro- and mock laser acupuncture. These analyses will provide much needed information about which patients might benefit most from which acupuncture interventions.