From the Departments of Pain Management (J.C., V.S., M.G., O.T.C., F.Z., R.W.R.) Neurosciences (J.C.) Quantitative Health Sciences and Outcomes Research (J.Y., D.Y., E.J.M.), Cleveland Clinic, Cleveland, Ohio Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Palo Alto, California (V.S.).
Anesthesiology. 2019 Oct;131(4):883-893. doi: 10.1097/ALN.0000000000002899.
Sympathetic dysfunction may be present in complex regional pain syndrome, and sympathetic blocks are routinely performed in practice. To investigate the therapeutic and predictive values of sympathetic blocks, the authors test the hypotheses that sympathetic blocks provide analgesic effects that may be associated with the temperature differences between the two extremities before and after the blocks and that the effects of sympathetic blocks may predict the success (defined as achieving more than 50% pain reduction) of spinal cord stimulation trials.
The authors performed a retrospective study of 318 patients who underwent sympathetic blocks in a major academic center (2009 to 2016) to assess the association between pain reduction and preprocedure temperature difference between the involved and contralateral limbs. The primary outcome was pain improvement by more than 50%, and the secondary outcome was duration of more than 50% pain reduction per patient report. The authors assessed the association between pain reduction and the success rate of spinal cord stimulation trials.
Among the 318 patients, 255 were diagnosed with complex regional pain syndrome and others with various sympathetically related disorders. Successful pain reduction (more than 50%) was observed in 155 patients with complex regional pain syndrome (155 of 255, 61%). The majority of patients (132 of 155, 85%) experienced more than 50% pain relief for 1 to 4 weeks or longer. The degree and duration of pain relief were not associated with preprocedure temperature parameters with estimated odds ratio of 1.03 (97.5% CI, 0.95-1.11) or 1.01 (97.5% CI, 0.96-1.06) for one degree decrease (P = 0.459 or 0.809). There was no difference in the success rate of spinal cord stimulation trials between patients with or without more than 50% pain relief after sympathetic blocks (35 of 40, 88% vs. 26 of 29, 90%, P > 0.990).
The authors conclude that sympathetic blocks may be therapeutic in patients with complex regional pain syndrome regardless of preprocedure limb temperatures. The effects of sympathetic blocks do not predict the success of spinal cord stimulation.
交感神经功能障碍可能存在于复杂性区域疼痛综合征中，并且在实践中经常进行交感神经阻滞。为了研究交感神经阻滞的治疗和预测价值，作者检验了以下假设：交感神经阻滞提供的镇痛效果可能与阻滞前后两侧肢体之间的温差有关，并且交感神经阻滞的效果可以预测脊髓刺激试验的成功（定义为疼痛减轻 50%以上）。
作者对 2009 年至 2016 年在一家主要学术中心接受交感神经阻滞的 318 名患者进行了回顾性研究，以评估疼痛减轻与受累和对侧肢体之间术前温差之间的关系。主要结局是疼痛改善超过 50%，次要结局是每位患者报告的疼痛减轻超过 50%的持续时间。作者评估了疼痛减轻与脊髓刺激试验成功率之间的关系。
在 318 名患者中，255 名被诊断为复杂性区域疼痛综合征，其他患者患有各种与交感神经相关的疾病。255 名复杂性区域疼痛综合征患者中有 155 名（61%）出现成功的疼痛减轻（超过 50%）。大多数患者（155 名中的 132 名，85%）在 1 至 4 周或更长时间内经历了超过 50%的疼痛缓解。疼痛缓解的程度和持续时间与术前温度参数无关，估计优势比为 1.03（97.5%CI，0.95-1.11）或 1.01（97.5%CI，0.96-1.06），每降低一度（P=0.459 或 0.809）。在接受交感神经阻滞治疗后疼痛减轻超过 50%的患者与疼痛减轻未超过 50%的患者之间，脊髓刺激试验的成功率没有差异（40 名中的 35 名，88%与 29 名中的 26 名，90%，P>0.990）。
作者得出结论，无论术前肢体温度如何，交感神经阻滞对复杂性区域疼痛综合征患者可能具有治疗作用。交感神经阻滞的效果不能预测脊髓刺激的成功。
