Physiotherapy, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.
Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.
Phys Ther. 2021 Mar 3;101(3). doi: 10.1093/ptj/pzaa223.
Evidence suggests altered pronociceptive and antinociceptive mechanisms in many chronic pain conditions. Knowledge about these mechanisms in nonspecific chronic neck pain (NSNP) would improve understanding of the causes and the design of more effective treatments. Pressure pain threshold (PPT) is often used to assess presence of altered nociceptive processing in NSNP; however, its usefulness to detect this is yet to be established. The purpose of this study was to determine the functional status of temporal summation of second pain (TSSP) and conditioned pain modulation (CPM) in NSNP and to characterize the association of both measures with PPT and clinical features of NSNP.
Thirty-two participants with NSNP (mean [SD] age = 44 [11] years; 27 female) and 32 age- and sex-matched healthy controls were recruited. TSSP was assessed using an electrical stimulus at the dorsum of the hand, and CPM was evaluated with the Cold Pressor Test. PPT was assessed bilaterally at the neck and tibialis anterior muscles.
Participants with NSNP showed greater TSPP (mean difference = 0.23; 95% CI = 0.46-0.01; Cohen d = 0.51) and lower CPM (mean difference = 19.44; 95% CI = 10.42-28.46; Cohen d = 1.09). Pooled data from all participants showed lower PPTs at the neck than the tibialis anterior. However, PPT measures did not differ between groups at either location. PPT measures were not correlated with CPM and TSP.
NSNP is associated with enhanced pronociceptive and impaired antinociceptive mechanisms, which may explain long-lasting pain and failure of some treatments to resolve symptoms. However, due to the observational nature of this study, a clear cause-effect relationship cannot be established. Normal PPT values in the clinic should not be interpreted as absence of altered nociceptive processing.
This study fills in some gaps in knowledge. Changes in central nociceptive processing may explain persistent and recurrent symptoms in NSNP and failure of treatments to obtain long-lasting relief. Further research is required to ascertain if TSSP and CPM assessment in the clinic may help predict physical therapy treatment outcome. Whether symptomatic relief with physical therapy is mediated by an improvement in TSSP and CPM should also be explored. PPTs were unaltered in participants with NSNP despite evidence of impairment in the central pain modulatory systems. Normal PPTs should not be interpreted as evidence of unaltered central pain-related processing.
有证据表明，在许多慢性疼痛病症中，伤害感受和抗伤害感受机制发生了改变。了解非特异性慢性颈痛（NSNP）中的这些机制将有助于更好地理解其病因，并设计更有效的治疗方法。压痛阈（PPT）常用于评估 NSNP 中伤害感受处理的改变情况；然而，其检测的有效性尚待确定。本研究旨在确定 NSNP 中第二痛的时间总和（TSSP）和条件性疼痛调制（CPM）的功能状态，并描述这两种测量方法与 PPT 以及 NSNP 的临床特征之间的关联。
招募了 32 名 NSNP 患者（平均[标准差]年龄=44[11]岁；27 名女性）和 32 名年龄和性别匹配的健康对照者。通过手部背侧的电刺激评估 TSSP，通过冷加压试验评估 CPM。双侧颈部和胫骨前肌均行 PPT 评估。
NSNP 患者的 TSPP 更高（平均差异=0.23；95%置信区间=0.46-0.01；Cohen d=0.51），CPM 更低（平均差异=19.44；95%置信区间=10.42-28.46；Cohen d=1.09）。所有参与者的汇总数据显示，颈部的 PPT 低于胫骨前肌。然而，两组在任何部位的 PPT 测量值均无差异。PPT 测量值与 CPM 和 TSP 均无相关性。
NSNP 与伤害感受增强和抗伤害感受受损机制相关，这可能解释了长期疼痛和某些治疗方法失败无法缓解症状的原因。然而，由于本研究为观察性研究，因此无法确定明确的因果关系。临床上正常的 PPT 值不应被解释为不存在伤害感受处理改变。
本研究填补了一些知识空白。中枢伤害感受处理的改变可能解释了 NSNP 中的持续性和复发性症状以及治疗方法无法获得长期缓解的原因。需要进一步研究以确定在临床上评估 TSSP 和 CPM 是否有助于预测物理治疗的治疗效果。物理治疗的症状缓解是否通过 TSSP 和 CPM 的改善来介导也应进行探讨。尽管中枢疼痛调制系统受损，但 NSNP 患者的 PPT 并未改变。正常的 PPT 值不应被解释为中枢疼痛相关处理未改变的证据。
