Recent evidence published in Journal of Neurology Neurosurgery and Psychiatry suggests no benefits of adding instrumented fusion to decompression for treating degenerative spondylolisthesis (DS). Isolated decompression seems sufficient for most patients.
Degenerative spondylolisthesis is a widespread spinal pathology with prevalence reaching 25%–43% in women and 19%–31% in men over 65 years. Ventral shift of the cranial vertebra compared with the more caudal vertebra is caused by arthritis of the facet joints, malfunction of the stabilising ligaments and disc degeneration. All these changes contribute to the compromise of the canal and lumbar spinal stenosis (LSS). DS is one of the most common causes of progressive lower back or leg pain (neurogenic claudication or radiculopathy). It is a common indication for spinal surgery in adults, generally leading to better results than conservative therapy.

The least invasive, safest and least costly procedure to treat DS is non-destabilising decompression of the spinal canal with resection of hypertrophic facet joints and ligamentum flavum. There is an ongoing debate on whether fusion of the altered lumbar segment should be added to decompression to decrease the risk of further progression of the pathology.
Over the past decades, there has been an upward trend in the total number of lumbar fusion procedures worldwide. A study found 62.3% increase in elective lumbar fusion surgery between 2004 and 2015. Patients with DS accounted for most elective fusion procedures in the USA (45·2% in 2015).
However, it is a much more invasive and expensive procedure with a higher incidence of complications than isolated decompression. It is also associated with the development of degeneration or even symptomatic stenosis or instability of the adjacent spinal segment (ASD, adjacent segment disease). The incidence of ASD following lumbar fusion is 9% with a reoperation rate of 6.2% at 5 years postoperatively.
LSS associated with DS makes surgical management more complex and controversial. The resection of the posterior vertebral structures carries a potential risk of developing iatrogenic instability after isolated decompression. This risk is probably comparable to developing ASD after fusion as our results show a similar reoperation rate in both interventions. Evidence shows that symptomatic progression of the slip in patients after decompression without solid fusion becomes apparent only in long-term follow-ups.
The meta-analysis done by Kaiser et al shows that spinal fusion may not be necessary in most cases of DS. At 2 years after surgery, the results for ODI, leg pain, reoperation rate and QoL were comparable between both groups (decompression with and without fusion), and omitting fusion reduced back pain slightly more compared with decompression with fusion. Isolated decompression was linked with fewer perioperative complications. Fusion was associated with a notable increase in the duration of surgery, blood loss and extended hospital stay. Their results also indicated a higher risk of complications after spinal fusion.
According to the latest recommendations of The North American Spine Society from 2016 based on older observational data, simple decompression may be considered for symptomatic DS with low-grade (up to 20% anteroposterior caudal vertebral body) slip unresponsive to conservative treatment. The authors noted that in the case of preserving medial structures, it leads to equivalent results as instrumented decompression. A consensus has been reached on the need to fuse an unstable spinal segment, regardless of aetiology.
“Our findings provide clinicians and healthcare policy makers with a comprehensive assessment and high-quality evidence on the safety and efficacy of simple decompression as a superior option for patients with stable DS”,they said. This conclusion might be especially useful for patients in higher age groups who are likely to be better served by the lower morbidity associated with decompression alone.
Reference
Decompression alone versus decompression with instrumented fusion in the treatment of lumbar degenerative spondylolisthesis: a systematic review and meta-analysis of randomised trials
Radek Kaiser, Lucia Kantorová, Alena Langaufová et al
Journal of Neurology, Neurosurgery& Psychiatry
http://dx.doi.org/10.1136/jnnp-2022-330158