Manual therapy is a commonly recommended treatment of low back pain (LBP), yet few studies have directly compared the effectiveness of thrust (spinal manipulation) vs non-thrust (spinal mobilization) techniques. This study evaluated the comparative effectiveness of spinal manipulation and spinal mobilization at reducing pain and disability compared with a placebo control group (sham cold laser) in a cohort of young adults with chronic LBP.
This single-blinded (investigator-blinded), placebo-controlled randomized clinical trial with 3 treatment groups was conducted at the Ohio Musculoskeletal and Neurological Institute at Ohio University from June 1, 2013, to August 31, 2017. Of 4903 adult patients assessed for eligibility, 4741 did not meet inclusion criteria, and 162 patients with chronic LBP qualified for randomization to 1 of 3 treatment groups. Participants received 6 treatment sessions of (1) spinal manipulation, (2) spinal mobilization, or (3) sham cold laser therapy (placebo) during a 3-week period. Licensed clinicians (either a doctor of osteopathic medicine or physical therapist), with at least 3 years of clinical experience using manipulative therapies provided all treatments.
Primary outcome measures were the change from baseline in Numerical Pain Rating Scale (NPRS) score over the last 7 days and the change in disability assessed with the Roland-Morris Disability Questionnaire (scores range from 0 to 24, with higher scores indicating greater disability) 48 to 72 hours after completion of the 6 treatments.
A total of 162 participants (mean [SD] age, 25.0 [6.2] years; 92 women [57%]) with chronic LBP (mean [SD] NPRS score, 4.3 [2.6] on a 1-10 scale, with higher scores indicating greater pain) were randomized.
- 54 participants were randomized to the spinal manipulation group,
- 54 to the spinal mobilization group,
- 54 to the placebo group.
There were no significant group differences for sex, age, body mass index, duration of LBP symptoms, depression, fear avoidance, current pain, average pain over the last 7 days, and self-reported disability. At the primary end point, there was no significant difference in change in pain scores between spinal manipulation and spinal mobilization (0.24 [95% CI, -0.38 to 0.86]; P = .45), spinal manipulation and placebo (-0.03 [95% CI, -0.65 to 0.59]; P = .92), or spinal mobilization and placebo (-0.26 [95% CI, -0.38 to 0.85]; P = .39). There was no significant difference in change in self-reported disability scores between spinal manipulation and spinal mobilization (-1.00 [95% CI, -2.27 to 0.36]; P = .14), spinal manipulation and placebo (-0.07 [95% CI, -1.43 to 1.29]; P = .92) or spinal mobilization and placebo (0.93 [95% CI, -0.41 to 2.29]; P = .17). A comparison of treatment credibility and expectancy ratings across groups was not statistically significant (F2,151 = 1.70, P = .19), indicating that, on average, participants in each group had similar expectations regarding the likely benefit of their assigned treatment.
The authors concluded that in this randomized clinical trial, neither spinal manipulation nor spinal mobilization appeared to be effective treatments for mild to moderate chronic LBP.
This is an exceptionally well-reported study. Yet, one might raise a few points of criticism:
- The comparison of two active treatments makes this an equivalence study, and much larger sample sizes are required or such trials (this does not mean that the comparisons are not valid, however).
- The patients had rather mild symptoms; one could argue that patients with severe pain might respond differently.
- Chiropractors could argue that the therapists were not as expert at spinal manipulation as they are; had they employed chiropractic therapists, the results might have been different.
- A placebo control group makes more sense, if it allows patients to be blinded; this was not possible in this instance, and a better placebo might have produced different findings.
Despite these limitations, this study certainly is a valuable addition to the evidence. It casts more doubt on spinal manipulation and mobilisation as an effective therapy for LBP and confirms my often-voiced view that these treatments are not the best we can offer to LBP-patients.