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Fusion offered no potential benefit in decompressive surgery for spinal stenosis
When fusion was combined with decompression in a study, it resulted in more complications and revision surgeries compared with decompression alone.
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The addition of concomitant fusion to decompression surgery for lumbar spinal stenosis added no benefit to outcomes, according to 2-year results of a multcenter, randomized, controlled study.
The presence of preoperative degenerative spondylolisthesis (DS) also made no difference in the outcomes between the two groups, Peter Försth, MD, said when he presented the results.
“The addition of fusion in decompressive surgery for lumbar spinal stenosis (LSS) did not lead to a better outcome compared to decompression only. This was true even among the 133 patients where a preoperative DS was present. The DS patients did not have more back pain or disability preoperatively. DS has been considered as an indication for additional fusion in LSS, but in our view, the importance of DS has been overestimated,” Försth told Orthopaedics Today Europe.
ODI compared for procedures
From 2006 to 2012, 233 patients between 50 years and 80 years of age with LSS at one level or two adjacent levels, with symptom duration longer than 6 months, were enrolled in the study. A computerized randomization was performed to place patients in groups to receive either decompression alone or decompression with concomitant fusion. The patients were further stratified for the existence of preoperative DS, which occurred in 58% of patients.
The primary outcome assessed was the Oswestry Disability Index (ODI) score.
During the course of the study, five patients were lost to postoperative followup for a 97% follow up rate. At final follow up, the average ODI score of patients who underwent decompression alone was 24 points, and it was 26 points for patients who underwent decompression with fusion (P = .35). In the group with preoperative DS, those who underwent decompression had an average ODI of 22 points and those who underwent decompression with fusion had an average ODI of 26 points (P = .31), according to the results.
No differences were found in the EuroQol-5D scores or the Zürich Claudication Questionnaire among patients with and without preoperative DS. Walking distance improved in all patients regardless of preoperative DS from 307 m in 6 minutes to 400 m in 6 minutes at 2-year follow-up, according to Försth.
Figure 1. This MRI of lumbar spinal stenosis with degenerative spondylolisthesis was taken from one of the patients included in the study.
Source: Forsth P
“At follow-up, there is no significant difference between treatment groups. The same was true in the subgroup with DS at follow-up, with no significant differences between the two groups. With all outcome measures, there was a significant improvement compared to preoperative,” he said.
Fewer infections with decompression
Postoperatively five patients in the decompression group developed an infection and 13 patients in the fusion and decompression group developed an infection. Seventeen patients in the decompression and fusion group had subsequent lumbar surgery compared with 12 patients in the decompression only group, Försth said.
Eighty percent of patients showed improvement in back and leg pain at follow-up. More than 80% of patients showed improvement in walking ability; however, there were no differences between the two treatment groups in these findings.
The less-invasive decompression surgery should be used in the elderly population with LSS to decrease complications and infections that may come with decompression paired with fusion, Försth said. – by Robert Linnehan
- Reference:
- Försth P, et al. Paper #68. Presented at: EuroSpine Annual Meeting; Oct. 1-3, 2014; Lyon, France.
- For more information:
- Peter Försth, MD, can be reached at Stockholm Spine Center, 194 89 Upplands Väsby, Stockholm, Sweden; email: peter.forsth@spinecenter.se.
Disclosure: Försth reports no relevant financial disclosures.
Perspective
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David A Wong, MD, MSc, FRCS(C)
The conclusions from this study must be viewed with a healthy skepticism due to issues in the methodology and length of follow-up. This paper is an excellent example of the utility, but also the limitations of registry data especially in regard to the usefulness of conclusions for comparative effectiveness research and insurance coverage decisions.
Previous randomized, controlled trials (RCT) (eg Herkowitz 1991, Fischgrund 1997) had the opposite conclusion, where addition of a fusion did improve clinical outcome in lumbar spinal stenosis. However, whether the fusion was solid or not made no clinical difference at their initial 2-to 3-year follow-up. Registry data allow collection of outcomes in a relatively larger patient population. However, the strength of evidence is not considered as powerful as an RCT.
When there are contradictory papers on both sides of the experimental question, additional studies give the most useful information when they look at a subgroup analysis trying to identify factors which separate responders from non-responders. This often requires data that are not included in the basic data set of a registry. For example, this methodology does not specify data, such as the degree of instability on flexion extension radiographs, which might allow identification of factors which are common to responders. Other factors not included in the analysis in this study might be degree of disc space narrowing, facet orientation and presence of facet synovial cysts.
Although 2-year follow-up is generally considered the standard follow-up for clinical studies, this may be too short a time frame for a paper to be considered sufficiently definitive to be useful in comparative effectiveness research and a basis for insurance coverage decisions. Recall that it was only at the 8-year follow-up of the Herkowitz and Fischgrund patients (Kornblum 2004) that the long-term clinical benefit to a solid fusion was recognized (and thus the usefulness of instrumentation, which improved the fusion rate).
This study continues to reinforce the impression that more refined protocols/subgroup analysis methodologies are necessary to truly gain a clear clinical picture of factors separating responders and non-responders to the inclusion of a fusion to a lumbar spinal stenosis decompression.
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