Importance Chronic back pain (CBP) is a leading cause of disability, and treatment is often ineffective. Approximately 85% of cases are primary CBP, for which peripheral etiology cannot be identified, and maintenance factors include fear, avoidance, and beliefs that pain indicates injury. Objective To test whether a psychological treatment (pain reprocessing therapy [PRT]) aiming to shift patients' beliefs about the causes and threat value of pain provides substantial and durable pain relief from primary CBP and to investigate treatment mechanisms. Design, Setting, and Participants This randomized clinical trial with longitudinal functional magnetic resonance imaging (fMRI) and 1-year follow-up assessment was conducted in a university research setting from November 2017 to August 2018, with 1-year follow-up completed by November 2019. Clinical and fMRI data were analyzed from January 2019 to August 2020. The study compared PRT with an open-label placebo treatment and with usual care in a community sample. Interventions Participants randomized to PRT participated in 1 telehealth session with a physician and 8 psychological treatment sessions over 4 weeks. Treatment aimed to help patients reconceptualize their pain as due to nondangerous brain activity rather than peripheral tissue injury, using a combination of cognitive, somatic, and exposure-based techniques. Participants randomized to placebo received an open-label subcutaneous saline injection in the back; participants randomized to usual care continued their routine, ongoing care. Main Outcomes and Measures One-week mean back pain intensity score (0 to 10) at posttreatment, pain beliefs, and fMRI measures of evoked pain and resting connectivity. Results At baseline, 151 adults (54% female; mean [SD] age, 41.1 [15.6] years) reported mean (SD) pain of low to moderate severity (mean [SD] pain intensity, 4.10 [1.26] of 10; mean [SD] disability, 23.34 [10.12] of 100) and mean (SD) pain duration of 10.0 (8.9) years. Large group differences in pain were observed at posttreatment, with a mean (SD) pain score of 1.18 (1.24) in the PRT group, 2.84 (1.64) in the placebo group, and 3.13 (1.45) in the usual care group. Hedges g was -1.14 for PRT vs placebo and -1.74 for PRT vs usual care (P < .001). Of 151 total participants, 33 of 50 participants (66%) randomized to PRT were pain-free or nearly pain-free at posttreatment (reporting a pain intensity score of 0 or 1 of 10), compared with 10 of 51 participants (20%) randomized to placebo and 5 of 50 participants (10%) randomized to usual care. Treatment effects were maintained at 1-year follow-up, with a mean (SD) pain score of 1.51 (1.59) in the PRT group, 2.79 (1.78) in the placebo group, and 3.00 (1.77) in the usual care group. Hedges g was -0.70 for PRT vs placebo (P = .001) and -1.05 for PRT vs usual care (P < .001) at 1-year follow-up. Longitudinal fMRI showed (1) reduced responses to evoked back pain in the anterior midcingulate and the anterior prefrontal cortex for PRT vs placebo; (2) reduced responses in the anterior insula for PRT vs usual care; (3) increased resting connectivity from the anterior prefrontal cortex and the anterior insula to the primary somatosensory cortex for PRT vs both control groups; and (4) increased connectivity from the anterior midcingulate to the precuneus for PRT vs usual care. Conclusions and Relevance Psychological treatment centered on changing patients' beliefs about the causes and threat value of pain may provide substantial and durable pain relief for people with CBP. Trial Registration ClinicalTrials.gov Identifier: NCT03294148.

中文翻译：

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疼痛再处理疗法与安慰剂和常规护理对慢性背痛患者的影响：一项随机临床试验。

重要性 慢性背痛 (CBP) 是导致残疾的主要原因，治疗通常无效。大约 85% 的病例是原发性 CBP，其外周病因无法确定，维持因素包括恐惧、回避和认为疼痛表明受伤的信念。目的 测试旨在改变患者对疼痛的原因和威胁价值的信念的心理治疗（疼痛再处理疗法 [PRT]）是否能够从原发性 CBP 中提供实质性和持久的疼痛缓解，并研究治疗机制。设计、设置和参与者这项具有纵向功能磁共振成像 (fMRI) 和 1 年随访评估的随机临床试验于 2017 年 11 月至 2018 年 8 月在大学研究环境中进行，1 年随访由2019 年 11 月。对 2019 年 1 月至 2020 年 8 月的临床和 fMRI 数据进行了分析。该研究将 PRT 与开放标签安慰剂治疗以及社区样本中的常规护理进行了比较。干预 随机分配到 PRT 的参与者在 4 周内参加了 1 次与医生的远程医疗会议和 8 次心理治疗会议。治疗旨在帮助患者重新定义他们的疼痛是由于非危险的大脑活动而不是外周组织损伤，使用认知、躯体和基于暴露的技术相结合。随机分配到安慰剂的参与者在背部接受了开放标签的皮下盐水注射；随机接受常规护理的参与者继续他们的日常护理。主要结果和措施 治疗后一周平均背痛强度评分（0 至 10）、疼痛信念、和 fMRI 测量诱发疼痛和静息连接性。结果 在基线时，151 名成年人（54% 女性；平均 [SD] 年龄，41.1 [15.6] 岁）报告了平均 (SD) 低至中度疼痛（平均 [SD] 疼痛强度，4.10 [1.26] of 10；平均[SD] 残疾，23.34 [10.12] of 100) 平均 (SD) 疼痛持续时间为 10.0 (8.9) 年。在治疗后观察到较大的组间疼痛差异，PRT 组的平均 (SD) 疼痛评分为 1.18 (1.24)，安慰剂组为 2.84 (1.64)，常规护理组为 3.13 (1.45)。PRT 与安慰剂的对冲 g 为 -1.14，PRT 与常规护理的对冲 g 为 -1.74 (P < .001)。在 151 名参与者中，随机接受 PRT 的 50 名参与者中有 33 名（66%）在治疗后无痛或几乎无痛（报告疼痛强度评分为 0 分或 10 分），相比之下，51 名参与者中有 10 名（20%）被随机分配到安慰剂组，50 名参与者中有 5 名（10%）被随机分配到常规护理组。治疗效果在 1 年的随访中保持不变，PRT 组的平均 (SD) 疼痛评分为 1.51 (1.59)，安慰剂组为 2.79 (1.78)，常规护理组为 3.00 (1.77)。在 1 年的随访中，PRT 与安慰剂的 Hedges g 为 -0.70（P = .001），PRT 与常规护理的 Hedges g 为 -1.05（P < .001）。纵向 fMRI 显示 (1) PRT 与安慰剂相比，对前扣带回和前额叶皮层诱发背痛的反应降低；(2) 与常规护理相比，PRT 前岛叶的反应减少；(3) PRT 与两个对照组相比，增加了从前前额叶皮层和前岛叶到初级体感皮层的静息连接；(4) PRT 与常规护理相比，增加了从前扣带回到楔前叶的连接。结论和相关性 以改变患者对疼痛原因和威胁价值的信念为中心的心理治疗可以为 CBP 患者提供实质性和持久的疼痛缓解。试验注册 ClinicalTrials.gov 标识符：NCT03294148。