The nociceptive withdrawal reflex (NWR) is a spinal withdrawal reflex induced by painful stimulation. It is a measure of spinal hyperexcitability, which is believed to contribute to chronic musculoskeletal pain (MSKP) and headache. Previous syntheses of the evidence for alterations in the NWR in patients with chronic MSKP and headache needed a comprehensive update. This systematic review and meta-analysis was performed after the Preferred Items for Systematic reviews and Meta-Analyses guidelines. Studies examining NWR-related outcome measures in patients with chronic MSKP and headache compared to pain-free controls were identified through electronic database searches and included after screening against predefined eligibility criteria. Standardized mean differences or mean differences and 95% confidence intervals (CI) were calculated. Thirty-one studies were included in the systematic review and 25 in the meta-analysis. Moderate-quality evidence was found indicating lower NWR threshold (-3.68; 95% CI, -4.56 to -2.80; P < 0.001), larger NWR area (standardized mean difference = 0.69; 95% CI, 0.37-1.01; P < 0.001), and shorter NWR latency (mean difference = -13.68; 95% CI, -22.69, -4.67; P = 0.003) in patients compared to controls. These findings remained robust when performing meta-regressions based on subgroups (ie, headache, fibromyalgia, whiplash-associated disorder, and osteoarthritis). Low-quality evidence demonstrated facilitated temporal summation of NWR threshold (-2.48; 95% CI, -3.13 to -1.83; P < 0.001) in patients compared to controls. Spinal hyperexcitability as evidenced by lowered NWR threshold values and temporal summation of the NWR is present in patients with chronic MSKP and headache. No evidence was found for alterations in NWR duration and NWR magnitude. Future research is needed to address the gap in research on NWR-related outcome measures other than NWR threshold.

中文翻译：

---

伤害性撤退反射的改变证明慢性肌肉骨骼疼痛或头痛患者的脊柱过度兴奋：系统评价和荟萃分析。


伤害性撤退反射 （NWR） 是由疼痛刺激引起的脊髓撤退反射。它是衡量脊柱过度兴奋性的指标，据信这会导致慢性肌肉骨骼疼痛 （MSKP） 和头痛。先前对慢性 MSKP 和头痛患者 NWR 改变证据的先前综合需要全面更新。本系统评价和荟萃分析是在系统评价和荟萃分析的首选项目指南之后进行的。通过电子数据库搜索确定了检查慢性 MSKP 和头痛患者与无痛对照相比 NWR 相关结果测量的研究，并在根据预定义的资格标准进行筛选后纳入。计算标准化平均差或平均差和 95% 置信区间 （CI）。系统评价纳入了 31 项研究，荟萃分析纳入了 25 项研究。发现中等质量的证据表明较低的 NWR 阈值 （-3.68;95% CI，-4.56 至 -2.80;P < 0.001），较大的 NWR 面积（标准化平均差 = 0.69;95% CI，0.37-1.01;P < 0.001） 和较短的 NWR 潜伏期 （平均差 = -13.68;95% CI，-22.69，-4.67;P = 0.003）。在进行基于亚组 （即头痛、纤维肌痛、挥鞭伤相关疾病和骨关节炎） 的 meta 回归时，这些发现仍然稳健。低质量证据表明促进了 NWR 阈值的时间总和（-2.48;95% CI，-3.13 至 -1.83;P < 0.001）。慢性 MSKP 和头痛患者存在脊柱过度兴奋，由 NWR 阈值降低和 NWR 的时间总和证明。 没有发现 NWR 持续时间和 NWR 幅度发生变化的证据。需要未来的研究来解决 NWR 阈值以外的 NWR 相关结果测量的研究差距。