Medical Research Unit, Spine Center of Southern Denmark, University Hospital of Southern Denmark, Østrehougvej 55, 5500, Middelfart, Denmark.
Department of Regional Health Research, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
BMC Musculoskelet Disord. 2021 Jan 6;22(1):23. doi: 10.1186/s12891-020-03873-3.
In a prior randomized trial, we demonstrated that participants receiving spinal manipulative therapy at a pain-sensitive segment instead of a stiff segment experienced increased mechanical pressure pain thresholds. We hypothesized that the targeted segment mediated this increase through a segment-dependent neurophysiological reflective pathway. Presently, it is not known if this decrease in pain sensitivity is associated with clinical improvement. Therefore, we performed an explorative analysis to examine if changes in experimental pain sensitivity (mechanical and thermal) and lumbar stiffness were further dependent on clinical improvement in disability and patient-reported low back pain.
This study is a secondary explorative analysis of data from the randomized trial that compared 132 participants with chronic low back pain who received lumbar spinal manipulative therapy applied at either i) the stiffest segment or ii) the segment having the lowest pain threshold (i.e., the most pain-sensitive segment). We collected data at baseline, after the fourth session of spinal manipulation, and at 14-days follow-up. Participants were dichotomized into responders/non-responders using different clinical variables (disability and patient-reported low back pain) with varying threshold values (0, 30, and 50% improvement). Mixed models were used to assess changes in experimental outcomes (stiffness and pain sensitivity). The fixed interaction terms were time, segment allocation, and responder status.
We observed a significant increase in mechanical pressure pain thresholds for the group, which received spinal manipulative therapy at the most pain-sensitive segment independent of whether they improved clinically or not. Those who received spinal manipulation at the stiffest segment also demonstrated increased mechanical pain sensitivity, but only in the subgroup with clinical improvement. We did not observe any changes in lumbar stiffness.
Our results suggest the existence of two different mechanistic pathways associated with the spinal manipulation target. i) A decrease of mechanical pain sensitivity independent of clinical outcome (neurophysiological) and ii) a decrease as a reflection of the clinical outcome. Together, these observations may provide a novel framework that improves our understanding of why some respond to spinal manipulative therapy while others do not.
ClinicalTrials.gov identifier: NCT04086667 registered retrospectively September 11th 2019.
在先前的一项随机试验中，我们证明了在疼痛敏感节段而非僵硬节段接受脊柱手法治疗的患者机械压力痛阈增加。我们假设靶向节段通过节段依赖性神经生理反射途径介导这种增加。目前，尚不清楚这种疼痛敏感性的降低是否与临床改善相关。因此，我们进行了一项探索性分析，以检查实验性疼痛敏感性（机械和热）和腰椎僵硬度的变化是否进一步取决于残疾和患者报告的腰痛的临床改善。
这是一项对比较慢性腰痛患者接受脊柱手法治疗的随机试验的二次探索性分析，这些患者接受了 i）最僵硬节段或 ii）最低疼痛阈值（即最敏感节段）的节段的治疗。我们在基线、第四次脊柱手法治疗后和 14 天随访时收集数据。使用不同的临床变量（残疾和患者报告的腰痛）和不同的阈值（0、30 和 50%改善）将参与者分为反应者/非反应者。使用混合模型评估实验结果（僵硬度和疼痛敏感性）的变化。固定交互项为时间、节段分配和反应者状态。
我们观察到，接受最敏感节段脊柱手法治疗的患者组机械压力痛阈显著增加，无论他们是否有临床改善。那些在最僵硬节段接受脊柱手法治疗的患者也表现出机械疼痛敏感性增加，但仅在临床改善的亚组中。我们没有观察到腰椎僵硬度的任何变化。
我们的结果表明，与脊柱手法治疗靶点相关的存在两种不同的机制途径。i）与临床结果无关的机械疼痛敏感性降低（神经生理学）和 ii）作为临床结果的反映的降低。这些观察结果共同提供了一个新的框架，可增进我们对为什么一些人对脊柱手法治疗有反应而另一些人没有反应的理解。
ClinicalTrials.gov 标识符：NCT04086667 于 2019 年 9 月 11 日回顾性注册。
