Vogel Simon, Magerl Walter, Treede Rolf-Detlef, Schilder Andreas
Mannheim Center for Translational Neuroscience (MCTN), Department of Neurophysiology, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany.
Department of Experimental Orthopedics and Trauma Surgery, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
Life (Basel). 2022 Feb 25;12(3):340. doi: 10.3390/life12030340.
Acute low back pain can be experimentally induced by injections of hypertonic saline into deep tissues of the back, such as fascia and muscle. The current study investigated the dose-dependency of peak-pain and spatial extent of concomitant radiating pain following 50, 200 and 800 μL bolus injections of hypertonic saline (5.8%) into the thoracolumbar fascia and multifidus muscle, since data on dose-dependency is lacking in humans. Sixteen healthy subjects rated (11 female, 5 male; 23.3 ± 3.1 years, mean ± SD) intensity and spatial extent of pain. Injections into the fascia resulted in significantly higher peak-pain (+86%, p < 0.001), longer pain durations (p < 0.05), and larger pain areas (+65%, p < 0.02) and were less variable than intramuscular injections. Peak-pain ratings and pain areas were 2−3-fold higher/larger for 200 μL vs. 50 μL. In contrast, peak pain increased only marginally at 800 μL by additional 20%, while pain areas did not increase further at all in both, fascia and muscle. Thus, higher injection volumes did also not compensate the lower sensitivity of muscle. Peak-pain ratings and pain areas correlated between fascia and muscle (r = 0.530, p < 0.001 and r = 0.337, p < 0.02, respectively). Peak-pain ratings and pain areas correlated overall (r = 0.490, p < 0.0001), but a weak correlation remained when the impact of between-tissue differences and different injection volumes were singled out (partial r = 0.261, p < 0.01). This study shows dose-dependent pain responses of deep tissues where an injection volume of 200 μL of hypertonic saline is deemed an adequate stimulus for tissue differentiation. We suggest that pain radiation is not simply an effect of increased peripheral input but may afford an individual disposition for the pain radiation response. Substantially higher pain-sensitivity and wider pain areas support fascia as an important contributor to non-specific low back pain.
急性下背痛可通过向背部深层组织（如筋膜和肌肉）注射高渗盐水进行实验诱导。由于人类缺乏剂量依赖性的数据，本研究调查了向胸腰筋膜和多裂肌注射50、200和800微升高渗盐水（5.8%）后，峰值疼痛的剂量依赖性以及伴随的放射痛的空间范围。16名健康受试者（11名女性，5名男性；平均年龄23.3±3.1岁）对疼痛强度和空间范围进行了评分。向筋膜内注射导致峰值疼痛显著更高（+86%，p<0.001）、疼痛持续时间更长（p<0.05）、疼痛区域更大（+65%，p<0.02），并且比肌肉内注射的变异性更小。200微升注射量与50微升相比，峰值疼痛评分和疼痛区域高/大2至3倍。相比之下，800微升时峰值疼痛仅略微增加20%，而在筋膜和肌肉中，疼痛区域均未进一步增加。因此，更高的注射量也无法弥补肌肉较低的敏感性。筋膜和肌肉之间的峰值疼痛评分和疼痛区域具有相关性（分别为r=0.530，p<0.001和r=0.337，p<0.02）。峰值疼痛评分和疼痛区域总体具有相关性（r=0.490，p<0.0001），但当区分组织间差异和不同注射量的影响时，相关性较弱（偏相关r=0.261，p<0.01）。本研究显示了深部组织的剂量依赖性疼痛反应，其中200微升高渗盐水的注射量被认为是组织分化的适当刺激。我们认为疼痛放射不仅仅是外周输入增加的结果，可能还与个体对疼痛放射反应的倾向有关。显著更高的疼痛敏感性和更广泛的疼痛区域支持筋膜是导致非特异性下背痛的重要因素。
