Biomechanical Effects of Manual Therapy in Patients with Acute Non-specific Low Back Pain – A Feasibility Study.

Abstract

Background: The cause of non-specific low back pain (NSLBP) is unclear; however, mechanical factors are thought to contribute to pain and dysfunction. Manual therapy is a commonly sought treatment for NSLBP and has been demonstrated to be effective in reducing pain and disability, however, some patients respond to manual therapy and others do not. This study aimed to explore the feasibility of conducting a full-scale trial investigating the biomechanical effects of manual therapy. Much of the study was carried out during the Covid-19 pandemic, as such a parallel study was conducted to explore feasibility pre-Covid-19 and within the Covid-19 era. Secondary aims included exploring whether lumbar intervertebral motion changed following a course of manual therapy; and whether those who responded to manual therapy have different intervertebral motion to those who did not. Methods: A Public and Patient Involvement Process assisted in finalising the trial method and development of the trial material, particularly the Home Management Booklet. Sixteen participants with acute NSLBP were recruited from the AECC University College Clinic to the two-armed randomised controlled trial which consisted of a group who received manual therapy and home advice and a group who only received home advice. The home advice consisted of a Home Management Booklet containing information on analgesia, hot and cold packs, and postural advice. Manual therapy consisted of spinal manipulative therapy, mobilisation, and soft tissue therapy. Baseline and follow up measurements included weight bearing and recumbent flexion and extension quantitative fluoroscopy sequences. Continuous intervertebral motion variables included range of motion, disc height, translation, initial attainment rate, motion sharing inequality and variability. Patient Reported Outcomes Measures of Bournemouth Questionnaire and Roland Morris Disability Index-24 were obtained at baseline and follow up to determine responders (at least a minimal clinically important change) and non-responders to manual therapy. The parallel study collected retrospective data from outpatient clinic files to match new patients presented against the trial’s inclusion/ exclusion criteria both pre-Covid-19 and within the Covid-19 era to calculate number of patients who would have been eligible for the trial. The feasibility of a full-scale study was assessed utilising the recruitment and retention data. Sample size for a future full-scale study was calculated. Results: Pre-Covid-19, 9.8% (n=100), and within Covid-19 10.8% (n=59), of low back pain patients would have been eligible for the trial. During the trial, 45 patents were eligible for the trial, of the 28 patients approached, 16 (57%) consented onto the trial. One out of the eight participants in the non-manual therapy group withdrew due to Covid-19, there were no withdrawals in the manual therapy group. Sample size calculated for investigating all biomechanical variables in a future full-scale trial was 83115 participants; for investigating motion share inequality and variability only was 328 participants. Conclusion: A full-scale trial investigating all possible quantitative fluoroscopy intervertebral motion variables is not feasible. Should only motion sharing inequality and variability be utilised a full-scale trial may be feasible as a multi-researcher, multi-site trial, with the addition of additional recruitment centres.