Immediate effect of mechanical lumbar traction in patients with chronic low back pain: A crossover, repeated measures, randomized controlled trial.

BACKGROUND: Lumbar traction is a treatment method traditionally used for chronic low back pain (CLBP) in many countries. However, its clinical effectiveness has not been proven in medical practice. The purpose is to conduct a multi-center, crossover, randomized controlled trial (RCT) to prove the efficacy and safety of traction on CLBP patients, using equipment capable of precise traction force control and of reproducibility of the condition based on the previous biomechanical and pre-clinical studies. METHODS: Ninety-five patients with non-specific CLBP from 28 clinics and hospitals were randomly assigned to either the intermittent traction with vibration (ITV) first group (A: sequence ITV to ITO) or the intermittent traction only (ITO) first group (B: sequence ITO to ITV); the former was treated with repeated traction and vibration force added to preload. All patients were followed up weekly for 2 periods after study-initiation. The primary outcome measures were disability level including pain and quality of life (based on Japan Low back pain Evaluation Questionnaire; JLEQ), and JLEQ was measured repeatedly. Statistical analysis was performed using linear mixed model. RESULTS: Comparing to pre-traction data, both traction modes significant improvement except the first intervention of ITO treatment. The differences in JLEQ scores over time showed significant improvements in the treatment to which vibrational force was added in contrast to the conventional traction treatment; Mean difference was significant to compare ITV treatment and ITO treatment (-1.75 (p = 0.001), 95% CI; -2.69 to -0.80). However, neither difference between the two sequences (p = 0.884) nor carryover effect (p = 0.527) was observed. CONCLUSIONS: Altogether, the results indicate that lumbar traction was able to improve the pain and functional status immediately in patients with CLBP. This study contributes to add some evidence of the efficacy of lumbar traction.