Is lumbar fusion effective for patients with chronic low back pain?
This trial is a good example of how to do just about everything wrong to get the results you want. The authors did not conceal allocation, did not mask anyone in the study, used an unvalidated and subjective primary outcome, and downplayed the intention-to-treat analysis. Funding for the original study came from industry, and the authors have numerous conflicts of interest. Two other trials in the United Kingdom and Norway found no benefit to lumbar fusion, and the results of this study are consistent with those findings, despite what the authors conclude. (Level of Evidence = 2b)
This is an important question—one not without controversy. This study reports a mean 12.8 years of follow-up from a trial that randomized 294 persons with severe chronic low back pain in a 3:1 ratio to lumbar fusion or physical therapy. This report provides almost no detail about the authors' methods, but a look at their earlier publication reveals that outcome assessors (and, obviously, patients) were not masked to treatment assignment. The earlier report, after two years of follow-up, showed generally favorable results for surgery. Approximately 20% of patients in each group died or were lost to follow-up.
In the long-term results, using intention-to-treat analysis, there is no difference between groups for any outcome, including the patient's global assessment of back pain score, the Oswestry Disability Index score, a visual analog scale for pain score, pain medication use, pain frequency, or employment status. The authors also report an as-treated analysis, which counts the 19 of 72 patients who crossed over to surgery as if they had originally been assigned to surgery (they were not), and they report a per-protocol analysis, which ignores patients who crossed over or were lost to follow-up. Both of these analyses found an improvement in the patient's global assessment score with surgery but failed to find improvement in any other outcomes. On the basis of the single outcome of global assessment score in the more biased analyses, the authors' conclusion is that surgery should be considered effective. An accompanying editorial, which strongly disagrees with the authors, begins with the snide headline: Consensus at last... fusion is no better than nonoperative care in improving pain and disability in chronic low back pain.
Study design: Randomized controlled trial (nonblinded)
Funding source: Industry
Setting: Outpatient (specialty)
Reference: HedlundRJohanssonCHaggOFritzellPTullbergTThe long-term outcome of lumbar fusion in the Swedish lumbar spine study. Spine J2016;16(5):579–587.