There has been a long-standing debate about the need for fusion in addition to decompression for patients with lumbar degenerative spondylolisthesis (DS). Since the 1991 publication of Herkowitz and Kurz’s seminal publication demonstrating better outcomes for patients treated with decompression and fusion vs. decompression alone, the pendulum has swung in favor of decompression and fusion. However, as less invasive decompression techniques have been developed, surgeons have considered the possibility that a less destabilizing decompression technique might obviate the need for fusion. In the March 1 issue, Dr. Chang and his colleagues from Japan compared outcomes between stenosis patients with and without DS who were treated with a unilateral laminotomy with bilateral decompression without fusion. About one third of patients had DS, with 139 patients followed for one year and 56 patients for five years. In comparing SF-36 physical function and bodily pain scores, they found no significant differences between the two groups at any time point. Additionally, they also reviewed follow-up radiographs to determine the rate of slip development or progression and found that 2 patients in each group (6% in the DS group, 2% in the non-DS group, difference not significant) developed or had progression of listhesis. They reported an 8% rate of slip development or progression for the entire cohort over 5 years, but they did not present the data stratified by presence or absence of DS. Based on these data, the authors concluded that no fusion was necessary when using their less invasive decompression technique even in the presence of DS.
The authors did well gathering data prospectively on over 100 patients undergoing less invasive lumbar decompression and demonstrated that the presence of listhesis did not negatively affect outcomes. Unfortunately, the most pressing question facing surgeons is whether adding a fusion to decompression in DS improves outcomes, and that question remains unanswered. Multiple studies have demonstrated better outcomes for DS patients when they undergo decompression and fusion vs. decompression alone,1-3 though these studies employed a traditional open laminectomy. No studies have compared a less invasive decompression alone to decompression and fusion in DS patients, which is the study design necessary to answer the question. The authors suggested that since outcomes were similar for the patients with and without DS, fusion is unlikely to improve outcomes. However, the Spine Patient Outcomes Research Trial (SPORT) demonstrated significantly better outcomes on the SF-36 physical function and bodily pain scores in the DS cohort—most of whom were treated with decompression and fusion-- compared to the spinal stenosis without listhesis cohort—most of whom were treated with decompression alone.4 Given this finding, it certainly is possible that the DS patients in the current study would have done better with the addition of fusion. While the rate of listhesis development or progression was not significantly different between the two groups, the authors did not provide separate survival curves for the two groups over the five year follow-up, making it more difficult to understand this phenomenon. Given the good outcomes and low rate of listhesis progression reported in the DS patients in this study, it certainly raises the possibility that fusion may not be necessary in all DS patients. However, due to the design of this study, the question remains unanswered. Hopefully this paper will serve as an impetus to perform an RCT comparing less invasive decompression alone to decompression and fusion in DS patients.
Please read Dr. Chang’s article in the March 1 issue. Does this change your approach to treating DS patients? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
Associate Web Editor
1. Ghogawala Z, Benzel EC, Amin-Hanjani S, et al. Prospective outcomes evaluation after decompression with or without instrumented fusion for lumbar stenosis and degenerative Grade I spondylolisthesis. J Neurosurg Spine 2004;1:267-72.
2. Herkowitz HN, Kurz LT. Degenerative lumbar spondylolisthesis with spinal stenosis. A prospective study comparing decompression with decompression and intertransverse process arthrodesis. The Journal of bone and joint surgery 1991;73:802-8.
3. Kleinstueck FS, Fekete TF, Mannion AF, et al. To fuse or not to fuse in lumbar degenerative spondylolisthesis: do baseline symptoms help provide the answer? European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society 2012;21:268-75.
4. Pearson A, Blood E, Lurie J, et al. Degenerative spondylolisthesis versus spinal stenosis: does a slip matter? Comparison of baseline characteristics and outcomes (SPORT). Spine (Phila Pa 1976) 2010;35:298-305.