Different exposure times of flexion distraction technique in the L5-S1 distance and local pain of patients with chronic low back pain: A feasibility study

Background: Low back pain (LBP) is a worldwide public health problem. The flexion -distraction technique (FDT) has been considered to treat LBP. However, the adequate dosage and the treatment effects are not clearly understood. This feasibility study aimed to assess the effects of different exposure times with 5 and 10 min of the FDT on the L5 -S1 distance and pressure pain threshold (PPT) of patients with chronic LBP. Methods: A two -arm, examiner -blinded, randomized controlled feasibility trial with participants with chronic LBP enrolled in an outpatient clinic. Participants were randomly assigned to FDT-T5 (5 min) or FDT-T10 (10 min). The distance between the L5 lamina and the sacral promontory, and the PPT at the L5 spinous process was measured before and immediately after FDT. Ultrasound imaging was used to measure L5 -S1 distance, and the pressure algometry examined the PPT. Pre- and post -intervention data were compared between two groups by two-way analysis of variance (ANOVA) for repeated measures. We also calculated the intra- and inter -rater reliability of the L5 -S1 measurement. Results: Seventeen participants [10 (58.8 %) females, mean age 45 (+/- 12) years] completed all procedures. Improvements in the intervertebral space [FDT-T5 mean change = 2.65 (95 %CI 1.45, 3.85) mm; FDT-T10 mean change = 1.88 (95 %CI -1.86, 5.63) mm] and decreases in PPT values [FDT-T5 mean change = -0.55 (95 %CI -1.35, 0.26) Kgf; FDT-T10 mean change = -0.79 (95 %CI -1.92, 0.34) Kgf] were observed, although there was no significant difference between the two groups for the distance between the L5 lamina and the sacral promontory (p = 0.595) or the spinous process L5 PPT (p = 0.672) after the intervention. Good reliability values were found for inter- and intra-rater measurements ranging between ICC = 0.81 to ICC = 0.88). Conclusion: In this feasibility trial, both groups showed an increased distance between L5 -S1 and decreased the PPT in the L5 spinous process, indicating greater pain sensitivity after the intervention. These quantitative methods may measure distance and pain in definitive studies. Implications for practice: