Photobiomodulation therapy has a negligible effect as an adjunct to motor control exercise in people with chronic non-specific low back pain: a randomised trial

Question: In adults with chronic non-specific low back pain, does adding photobiomodulation therapy (PBMT) to a program of motor control exercise (MCE) improve pain intensity, disability and circulating prostaglandin E2 (PGE2) concentrations compared with sham PBMT plus MCE? Design: A randomised controlled trial was conducted with concealed allocation, intention-to-treat analysis and blinding of participants, therapists and assessors. Participants: Adults aged 18 to 65 years seeking treatment for chronic non-specific low back pain of ≥ 3 months in duration. Intervention: Participants were randomly allocated to active PBMT plus MCE or sham PBMT plus MCE. Both groups received 12 treatment sessions over 6 weeks. Outcome measures: Assessments were completed at baseline and 6 weeks, with follow-up assessments at 1 month after the end of the intervention period and at 3, 6 and 12 months after randomisation. Primary outcomes were pain intensity (0 to 10 numerical rating scale) and disability (0 to 24 Roland-Morris Disability Questionnaire) at 6 weeks, in which higher scores indicated greater severity. Secondary outcomes were: pain and disability at follow-up timepoints; circulating PGE2 concentrations at 6 weeks; and medication use, concomitant care and adverse events throughout the follow-up period. Results: A total of 148 participants were randomised (74 per group). The intention-to-treat analysis showed that PBMT plus MCE had a negligible effect compared with sham plus MCE at 6 weeks for pain intensity (MD –0.4 points, 95% CI –1.2 to 0.4), disability (MD –0.7 points, 95% CI –2.4 to 0.9) or circulating PGE2 concentrations (MD 31 pg/ml, 95% CI –4 to 66). Negligible between-group differences were observed throughout the 12-month follow-up period, and no treatment-related adverse events occurred. Conclusion: Adding PBMT to MCE did not provide clinically important additional improvements in pain intensity, disability or circulating PGE2 concentrations compared with sham plus the same exercise program. Registration: NCT05487118.