Immediate effects of spinal manipulation on pain sensitivity and postural stability in individuals with nonspecific chronic low back pain: a randomized placebo-controlled clinical trial

Abstract

Introduction: Low back pain is one of the main public health concerns. Chronic low back pain reduces functional capacity and affects postural stability. Although health professionals widely use spinal manipulation, its immediate effect on painful sensitivity and postural stability is lacking. Objective: This study aims to verify the immediate effects of lumbar spinal manipulation on pressure pain threshold and postural stability in people with chronic low back pain. Secondarily, to verify the immediate effect of lumbar spinal manipulation on pain intensity and the interferences of the patient's beliefs of which treatment was received in pressure pain threshold, postural stability, and pain intensity. Methods: A two-arm, randomised, placebo-controlled, double-blind trial was conducted. Eighty participants with nonspecific chronic low back pain and a minimum score of 3 on the Numeric Pain Rating Scale (NPRS) received one session of lumbar spinal manipulation (n = 40) or simulated lumbar spinal manipulation (n = 40). Primary outcomes were local and remote pressure pain threshold and postural stability. Secondary outcomes were pain intensity and participants’ perceived treatment allocation. Results: Participants had a mean (SD) age of 34.9 (10.5) years, and 50 (62.5%) were women. In the between-group comparison, four body sites had higher PPT scores in the manipulation group, right L5 [Mean difference (MD) = 0.55; 95% CI 0.19, 0.90; p = 0.014], left L1 (MD = 0.57; 95% CI 0.15, 0.99; p =0.033), left deltoid muscle (DT) (MD = 0.35; 95% CI 0.04, 0.65; p = 0.018), and right lateral epicondyle (LE) (MD = 0.34; 95% CI 0.08, 0.60; p = 0.014). Three body sites (right L5, left L5, and left L1) improved more than 15% with the manipulation, suggesting a clinically relevant difference. No significant change was observed for postural stability in either group. Both groups experienced pain relief [F(1,78) = 4.940, p = 0.029], but clinically significant only in the manipulation group. The participant's perceived treatment allocation did not affect the outcomes. Conclusion: One spinal manipulation session reduces lumbar pain sensitivity but does not affect postural stability compared to sham in individuals with chronic low back pain. The participant's belief in having received manipulation did not interfere with the outcomes.