Osteopathic visceral manipulation for constipation and chronic nonspecific low back pain

This trial investigated the effect of osteopathic visceral manipulation (OVM) on disability and pain intensity in individuals with functional constipation and chronic nonspecific low back pain. It was designed as a randomized controlled trial with a blinded assessor. Seventy-six volunteers with functional constipation and chronic nonspecific low back pain were randomized to two groups: OVM and sham OVM. The primary clinical outcome was pain intensity measured using a numeric rating scale (NRS) and disability measured using the Oswestry Disability Index (ODI). The secondary outcomes were electromyographic signals measured during the flexion-extension cycle, the finger-to-floor distance during complete flexion of the trunk, and the Fear-Avoidance Beliefs Questionnaire (FABQ). All outcomes were determined after six weeks of treatment as well as three months after randomization.

The OVM group reported a reduction in pain intensity after six weeks of treatment and at the three-month evaluation (p < .0002) and the sham group reported a reduction in pain intensity after three-month evaluation (p < .007). For the ODI was also found in the OVM group six weeks after the end of treatment (treatment effect = -6.59, 95% CI: -12.01 to -1.17, p = .01) and at the three-month evaluation (treatment effect = -6.02, 95% CI: -11.55 to -0.49, p = .03). Significant differences were also found for paravertebral muscle activity during the dynamic phases (flexion and extension) six-week evaluations.

The authors concluded that the OVM group demonstrated a reduction in pain intensity and improvement in disability after six-weeks and three-month follow-up while the sham group reduction in pain three-month follow-up.

I have no access to the full paper (if someone can send me the paper, I would update my post accordingly), but from reading the abstract, it seems the reported findings are based on within-group changes. The whole point of having a control group is to compare verum and control. The other point of importance is that it would have been crucial to verify whether patients were able to tell the verum from the sham intervention. If patients were able to tell, they would no longer be blinded and the placebo effect would have not been accounted for. A third point of relevance might be that the study seems tiny and far too small for drawing general conclusions about the value of OVM.

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I have now seen the protocol of the paper – thanks for making it available – and might add the following points to the discussion:

• The sham treatment consisted of  “light touches over the different parts of the abdomen, without any deep mobilization or movement. The osteopath applied her hands over the same points with the
  same duration as in OVM to give the patient the perception of being treated.” It is likely that patients in the control group could have guessed that they were sham-treated.
• The stats issue cannot be resolved on the basis of just the protocol.
• “To assess patients’ blinding to treatment allocation, patients are asked post treatment (six weeks after
  the start of treatment) to report which study treatment they think that they received (OVM/SOVM). The effect of their reports on outcome will be examined in explorative analysis.” As I have no

access to the results, I still do not know whether blinding was successful.