Minimally invasive surgery for degenerative lumbar spondylolisthesis
The objective of this study was to compare the cost-effectiveness of minimally invasive surgery (MIS) for patients with degenerative lumbar spondylolisthesis (DLS) relative to failed medical management with the cost-effectiveness of hip and knee arthroplasty for matched cohorts of patients with osteoarthritis.
Methods: A cohort of patients with DLS undergoing MIS procedures with decompression alone or decompression and instrumented fusion between 2008 and 2014 was matched to cohorts of patients with hip osteoarthritis (OA) and knee OA undergoing total joint replacement. Incremental cost-utility ratios (ICURs) were calculated from the perspective of the Ontario Ministry of Health, using prospectively collected Short Form-6 Dimension utility data. Costs and quality-adjusted life-years (QALYs) were discounted at 3% and sensitivity analyses were performed.
Results: Sixty-six patients met the inclusion criteria for the DLS cohort (n = 35 for decompression alone), with a minimum follow-up time of 1 year (mean 1.7 yr). The mean age of patients in the DLS cohort was 64.76 years, and 45 patients (68.2%) were female. For each cohort, utility scores improved from baseline to follow-up and the magnitude of the gain did not differ by group. Lifetime ICURs comparing surgical with nonsurgical care were Can$7946/QALY, Can$7104/QALY and Can$5098/QALY for the DLS, knee OA and hip OA cohorts, respectively. Subgroup analysis yielded an increased ICUR for the patients with DLS who underwent decompression and fusion (Can$9870/QALY) compared with that for the patients with DLS who underwent decompression alone (Can$5045/QALY). The rank order of the ICURs by group did not change with deterministic or probabilistic sensitivity analyses.
Conclusion: Lifetime ICURs for MIS procedures for DLS are similar to those for total joint replacement. Future research should adopt a societal perspective and potentially capture further economic benefits of MIS procedures 1).
There is some moderate evidence that decompression alone may be a feasible Degenerative Lumbar Spondylolisthesis treatment with lower surgical morbidity and similar outcomes to lumbar spinal fusion when performed in a select population with a low-grade slip. Similarly, the addition of interbody fusion may be best suited to a subset of patients with high-grade degenerative spondylolisthesis, although this remains controversial. Minimally invasive techniques are increasingly being utilized for both decompression and fusion surgeries with more and more studies showing similar outcomes and lower postoperative morbidity for patients. This will likely be an area of continued intense research. Finally, the role of spondylolisthesis reduction will likely be determined as further investigation into optimal sagittal balance and spinopelvic parameters is conducted. Future identification of ideal thresholds for the sagittal vertical axis and slip angle that will prevent progression and reoperation will play an important role in surgical treatment planning. Current evidence supports the surgical treatment of degenerative spondylolisthesis. While posterolateral spinal fusion remains the treatment of choice, the use of interbodies and decompressions without fusion may be efficacious in certain populations. However, additional high-quality evidence is needed, especially in newer areas of practice such as minimally invasive techniques and sagittal balance correction 2).
There are reports that fusion is the standard treatment of choice for cases of lumbar degenerative spondylolisthesis (LDS) associated with lumbar spinal canal stenosis with a large degree of slippage. The reasons why, however, have not been clarified. On the other hand, it is known that the progress of slippage decreases and restabilization occurs over the natural course of LDS. Therefore, if minimally invasive decompression could be performed, there would be little possibility of it influencing the natural course of LDS, so it would not be necessary to include preoperative percentage slip in the criteria for the selection of fusion. This study examined the course of LDS cases more than 5 years after treatment with minimally invasive decompression to determine whether pre- and postoperative slippage and disc changes influence the clinical results.
A total of 51 intervertebral segments in 51 cases with the chief complaint of radicular or cauda equina symptoms due to lumbar spinal canal stenosis were examined after prospective treatment with minimally invasive decompression for LDS. The mean age of the patients at the time of surgery was 66.7 years and the mean follow-up period was 7 years 4 months. Minimally invasive decompression was performed regardless of the degree of low-back pain or percentage slip. The outcome variables were clinical results and changes in imaging findings.
Over the follow-up period, postoperative percentage slip increased and disc height decreased, but the Japanese Orthopaedic Association score improved. Regardless of the preoperative percentage slip, disc height, or degree of intervertebral disc degeneration or segmental instability, the clinical results were favorable. In the high preoperative percentage slip group, low disc height group, and progressive disc degeneration group, there was little postoperative progress of slippage. In the group with a postoperative slippage increase of more than 5%, slippage increased significantly at postoperative year 2, but no significant difference was observed at the final follow-up.
When minimally invasive decompression was performed to treat LDS, the postoperative change in slippage was no different from that during the natural course. Furthermore, regardless of the degree of preoperative slippage or intervertebral disc degeneration, the clinical results were favorable. Also, the higher the preoperative percentage slip and the more that disc degeneration progressed, the more the progress of postoperative slippage decreased. Because the postoperative progress of slippage decreased, it is believed that even after minimally invasive decompression, restabilization occurs as it would during the natural course. If minimally invasive decompression can be performed to treat LDS, it is believed that preoperative percentage slip and intervertebral disc degeneration do not have to be included in the appropriateness criteria for fusion 3).