Symptomatic patients with lumbar isthmic spondylolisthesis are traditionally treated with a variety of fusion surgeries.
Compared with normative controls, patients with IS suffer selective atrophy of their multifidus (MF) muscle, whereas their erector spinae (ES) muscle undergoes a compensatory hypertrophy. Advancing age has a detrimental effect on the areas of the lumbar paraspinal muscles (PSMs), whereas female sex predisposes to a decreased psoas muscle area. Multifidus muscle atrophy correlates with PSC, indicating the role of this deep stabilizer in the biomechanical stability of spondylolisthetic spines. This may be of clinical significance in targeted physiotherapy programs during the conservative management of isthmic spondylolisthesis (IS) 1).
Spoor et al. present a novel noninstrumented surgical approach for patients with isthmic spondylolisthesis, with clinical and radiographic results.
Charts of patients who underwent this technique were reviewed. The procedure consisted of nerve root decompression by reconstruction of the intervertebral foramen. This was achieved by removal of the pedicle followed by noninstrumented posterolateral fusion in which autologous bone graft from the right iliac crest was used. Outcomes regarding radicular complaints, bony fusion, progression of the slip, and complications were evaluated using patient history and radiographs obtained at follow-up intervals of 3-18 months after surgery. RESULTS A total of 58 patients with a mean age of 47 years were treated with this method. Partial removal of the pedicle was performed in 93.1% of the cases, whereas in 6.9% of the cases the entire pedicle was removed. The mean duration of surgery was 216.5 ± 54.5 minutes (range 91-340 minutes). The mean (± SD) duration of hospitalization was 10.1 ± 2.9 days (range 5-18 days). After 3 months of follow-up, 86% of the patients reported no leg pain, and this dropped to 81% at last follow-up. Radiographic follow-up showed bony fusion in 87.7% of the patients. At 1 year, 5 patients showed progression of the slip, which in 1 patient prompted a second operation within 1 year. No major complications occurred. CONCLUSIONS Treatment of isthmic spondylolisthesis by reconstruction of the intervertebral neuroforamen and posterolateral fusion in situ is a safe procedure and has comparable results with the existing techniques. Cost-effectiveness research comparing this technique to conventional instrumented fusion techniques is necessary to evaluate the merits for both patients and society 2).
Lumbar laminectomy plus lumbar spinal fusion: may be indicated for patients with degenerative lumbar spondylolisthesis, lumbar spinal stenosis and radiculopathy, adult degenerative scoliosis (ADS), or instability.
Surgery for lumbar spondylolisthesis is indicated if symptoms are disabling and interfere with work, if the condition is progressive, or if there is a significant neurological deficit. The ideal surgical treatment remains controversial 3).
Lumbar fusion for spondylolisthesis tends to yield more consistent outcomes than fusion for degenerative disc disease and discogenic low back pain.
The optimal surgical management of lumbar spinal stenosis patients with spondylolisthesis remains controversial.
The best medical evidence available in the literature confirms the utility of fusion for improving patient outcomes following decompression for stenosis associated with spondylolisthesis. The majority of evidence from other studies comparing outcomes after decompression alone or decompression combined with PLF in patients with stenosis and spondylolisthesis also favors the performance of PLF. The medical evidence regarding the use of pedicle screw fixation in this patient population is rated as Class III and is inconsistent. A consistent benefit associated with the use of pedicle screw fixation has been reported in patients with preoperative instability or kyphosis. Iatrogenic instability following decompression is associated with poor outcomes and may also be treated with PLF involving supplemental instrumentation. The precise definition of instability or kyphosis has varied among researchers and requires further study 4).
Surgery is widely used and has recently been shown to be more effective than nonoperative treatment when the results were followed over two years. Questions remain regarding the long-term effects of surgical treatment compared with those of nonoperative treatment.
The standard surgical treatment for degenerative spondylolisthesis with lumbar stenosis is lumbar fusion following standard laminectomy. Although this strategy is widely adopted, it is not supported by class I evidence. This strategy assumes that degenerative spondylolisthesis worsens the outcome of laminectomy by causing postoperative instability. However, instability may be reduced or prevented by the use of less invasive decompression techniques.
In 165 consecutive patients who underwent unilateral laminotomy with bilateral decompression (ULBD), the patients were prospectively followed with a standardized questionnaire, short-form 36 (SF-36), and standing lumbar x-rays for a maximum follow-up period of 5 years. According to the presence or absence of degenerative spondylolisthesis, the patients were divided into two groups: an olisthesis group and a non-olisthesis group.
The average SF-36 physical score and bodily pain score improved substantially immediately after surgery. This improvement was maintained up to 5 years postoperatively. Progression of slippage was uncommon in both groups, with an overall incidence of 8% at 5 years follow-up. There was no significant difference in the average physical score, the bodily pain score, or the rate of progression of slippage between the olisthesis and non-olisthesis groups.
It indicates that preoperative degenerative spondylolisthesis does not worsen the outcome of patients with lumbar stenosis undergoing ULBD. These results suggest that lumbar fusion is often unnecessary in patients with degenerative spondylolisthesis and lumbar stenosis if the posterior decompression technique is ULBD 5).
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 6).
The favorable outcome of surgical treatment for degenerative lumbar spondylolisthesis (DS) is widely recognized, but some patients require reoperation because of complications, such as pseudoarthrosis, persistent pain, infection, and progressive degenerative changes. Among these changes, adjacent segment disease (ASD) and same segmental disease (SSD) are common reasons for reoperation. However, the relative risks of the various factors and their interactions are unclear.
The role of arthrodesis in the surgical management of lumbar spondylolisthesis remains controversial. Azad et al., hypothesized that practice patterns and outcomes for this patient population may vary widely.
They calculated arthrodesis rates, inpatient and long term costs, and key quality indicators (e.g. reoperation rates). Using linear and logistic regression models, they then calculated expected quality indicator values, adjusting for patient-level demographic factors, and compared these values to the observed values, to assess quality variation apart from differences in patient populations.
They identified a cohort of 67,077 patients (60.7% female, mean age of 59.8 years (SD, 12.0) with lumbar spondylolisthesis who received either laminectomy or laminectomy with arthrodesis. The majority of patients received arthrodesis (91.8%). Actual rates of arthrodesis varied from 97.5% in South Dakota to 81.5% in Oregon. Geography remained a significant predictor of arthrodesis even after adjusting for demographic factors (p<0.001). Marked geographic variation was also observed in initial costs ($32,485 in Alabama to $78,433 in Colorado), two-year post-operative costs ($15,612 in Arkansas to $34,096 in New Jersey), length of hospital stay (2.6 days in Arkansas to 4.5 in Washington, D.C.), 30-day complication rates (9.5% in South Dakota to 22.4% in Maryland), 30-day readmission rates (2.5% in South Dakota to 13.6% in Connecticut), and reoperation rates (1.8% in Maine to 12.7% in Alabama).
There is marked geographic variation in the rates of arthrodesis in treatment of spondylolisthesis within the United States. This variation remains pronounced after accounting for patient-level demographic differences. Costs of surgery and quality outcomes also vary widely. Further study is necessary to understand the drivers of this variation 8).