Friday, August 26, 2011
Is Spinal Manipulation a Sham?
Many in the spine community have questioned the actual therapeutic benefit of spinal manipulation (SM) in treating low back pain (LBP) despite the publication of multiple randomized controlled trials (RCTs) demonstrating its efficacy. In the August 15 issue, Drs. Senna and Machaly reported their results from a double-blinded, sham-controlled RCT. They utilized an interesting study design in which chronic, non-specific LBP patients were randomized to 12 SM sessions over 1 month, 12 sham manipulation sessions over 1 month, or 12 SM sessions over 1 month followed by 9 months of twice monthly maintenance SM. Such a design allowed them to study both the effect of manipulation and the effect of time on outcomes. They reported that both SM groups improved significantly more than the sham group at 1 month, but the group that did not undergo maintenance SM soon lost their gains and returned to their baseline level of pain and disability. However, the group treated with maintenance SM actually continued to achieve small additional gains over the course of the study. This paper convincingly demonstrated that SM was more effective than placebo and that continued SM could maintain chronic LBP patients’ improvements over time.
While this study demonstrated SM’s effectiveness compared to sham manipulation, the real question is how it compares to other forms of treatment for LBP. It is possible that the sham manipulation used in this study was not convincing, and patients realized they were not getting meaningful treatment. The authors could have addressed this by asking patients after the study whether they believed they received real SM or the sham. The authors did help to improve the blinding of patients by not informing them of the purpose of the study, but if patients were not convinced they were getting effective treatment, the placebo effect was not being controlled for. It would have been interesting to have had a long-term control group in this study, though it would have been logistically difficult to design such a group (i.e. if patients were initially treated with SM followed by sham treatment, it is unlikely they would have remained blinded). What is most impressive about this study is the magnitude of improvement in this population: patients treated with long-term SM improved 19 points on their ODI score. This compares to only a 12 point improvement reported by Fritzell et al. in their study of fusion for chronic, non-specific LBP.[i] This study helps to confirm the efficacy of SM in the chronic LBP population. Hopefully future studies will help to define which subgroups of LBP patients are most appropriate for SM and other forms of therapy so that providers can help individualize treatment for this challenging condition.
Please read Drs. Senna’s and Machaly’s paper. Will this paper change how you utilize SM in the chronic LBP population? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
[i] Fritzell P, Hagg O, Wessberg P, et al. Lumbar fusion versus nonsurgical treatment for chronic low back pain. Spine 2001;26:2521-34.