Most spine surgeons agree that stenosis patients with predominant low back pain (LBP) have worse surgical outcomes than patients with predominant leg pain, and this has been shown rather conclusively in at least two previous studies.1,2 In the February 1 issue, Dr. Sigmundsson and his colleagues from Sweden report their data from the Swedish Spine Register comparing surgical outcomes between lumbar stenosis patients with predominant back pain and predominant leg pain and between those treated with decompression alone and decompression and fusion. Similar to the prior studies, they reported generally worse outcomes for the patients with predominant LBP (defined as LBP greater than or equal to leg pain) compared to those with predominant leg pain. Controlling for potential confounders lessened the differences to some degree, though they still remained significant on the Oswestry Disability Index (ODI) and EQ-5D. Less clear was the effect of fusion on outcomes. Approximately 13% of patients underwent a fusion in addition to decompression, and fusion patients were younger, included a higher proportion of females, and had worse baseline scores on the ODI and EQ-5D. In the patients with predominant leg pain, fusion had no obvious effect on outcomes other than some trends towards increased leg pain in the fusion group. In the predominant LBP group, fusion was associated with marginally better SF-36 physical function scores and EQ-5D scores. The fused patients also reported significantly better self-estimated walking distance and patient satisfaction. Among the predominant LBP patients, there were no significant differences between the fused and unfused groups on the other outcome measures. The authors concluded that for stenosis patients with predominant LBP, fusion may offer some small but real benefits.
The authors and the Swedish spine surgery community should be congratulated on maintaining such a high quality spine surgery register that allows for studies of this kind. While the Spine Patient Outcomes Research Trial (SPORT) allowed for comparison of outcomes among stenosis patients with predominant LBP and predominant leg pain, so few stenosis patients underwent fusion that the effect of fusion could not be evaluated. The Swedish register includes a very large number of patients, allowing for analysis of the effect of fusion even though it was used in only one of eight patients. This paper represents a good first step in determining which stenosis patients benefit from fusion in addition to decompression. The authors wisely excluded those with spondylolisthesis, though we do not know if those with degenerative scoliosis were included or not. Not surprisingly, the patients with predominant leg pain did not seem to benefit from fusion. Conversely, those with predominant LBP did seem to get at least some marginal benefit from fusion on some outcome measures. What this likely indicates is that there is a subgroup of patients with predominant back pain who benefit from fusion, but this and other prior studies have not been able to determine which characteristics can be used to identify this group. The authors suggest an RCT comparing decompression to decompression plus fusion in stenosis patients with predominant LBP. If consistent with the current data, such a study would likely show a small benefit to fusion for the group overall, but, if the study population is large enough, it would also allow for the identification of characteristics that predict a greater benefit from fusion. Until such a study is done—and it is unclear if it ever will be done—surgeons are left to their judgment about which stenosis patients to fuse. While those with sagittal or coronal plane deformities likely benefit from fusion in addition to decompression, the indications for fusion in the absence of deformity remain obscure. This study takes a nice first step in this line of research and suggests that the subgroup that benefits from fusion will be found among those with predominant LBP, and spine researchers should focus their attention on that group rather than those with predominant leg pain.
Please read Dr. Sigmundsson’s article on this topic in the February 1 issue. Does this paper change your approach to treating stenosis patients with predominant LBP? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
Associate Web Editor
1. Kleinstuck FS, Grob D, Lattig F, et al. The influence of preoperative back pain on the outcome of lumbar decompression surgery. Spine (Phila Pa 1976) 2009;34:1198-203.
2. Pearson A, Blood E, Lurie J, et al. Predominant leg pain is associated with better surgical outcomes in degenerative spondylolisthesis and spinal stenosis: results from the Spine Patient Outcomes Research Trial (SPORT). Spine (Phila Pa 1976) 2011;36:219-29.