Advancing Endoscopic Decompression in Degenerative Lumbar Spondylolisthesis – A Commentary on “Biportal Endoscopic Decompression for Degenerative Lumbar Spondylolisthesis With Stenosis”
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Introduction: The Evolving Landscape of Degenerative Lumbar Spondylolisthesis Treatment
Degenerative lumbar spondylolisthesis (DLS) management has traditionally centered on the debate between decompression alone versus decompression with fusion [1-3]. While fusion aims to prevent further slippage, it carries concerns regarding increased operative time, costs, and adjacent segment disease. Conversely, decompression alone raises concerns about iatrogenic instability.
In this context, the authors’ recent study on ‘Biportal endoscopic decompression for DLS with stenosis’ emerges as a timely and valuable contribution to the literature. This commentary aims to highlight the study’s commendable aspects and discuss its broader implications within the evolving landscape of DLS treatment, particularly considering recent high-level evidence supporting decompression alone and the burgeoning potential of endoscopic spinal surgery techniques.
Key Insights From the Current Paper: Evidence for Endoscopic Decompression
The authors [4] investigate the impact of biportal endoscopic spinal surgery (BESS) on DLS with stenosis, and the study offers several noteworthy strengths. The study employed a clear methodological approach by categorizing patients into group A (68 patients with central stenosis and low-grade DLS, Meyerding grade I) and group B (102 patients with central stenosis alone). This stratification allowed for focused analysis of outcomes within the DLS cohort, using validated clinical measures such as the visual analogue scale (VAS) for pain, Oswestry Disability Index (ODI) for functional status, and Modified Macnab criteria for patient satisfaction, alongside crucial radiological assessments of sagittal translation on dynamic flexion-extension radiographs.
The study demonstrated substantial and clinically meaningful improvements in pain and functional disability across all validated outcome measures.
Most critically for the DLS population, the study provides crucial evidence regarding preservation of spinal stability following BESS unilateral laminotomy for bilateral decompression (ULBD). Radiological evaluation revealed no significant changes in sagittal translation postoperatively, directly addressing one of the primary concerns that often leads surgeons to opt for fusion in DLS cases: the fear of inducing or exacerbating segmental instability after decompression-alone procedures. The study’s focus on low-grade DLS with confirmed preoperative segmental stability likely contributed to these favorable outcomes. The absence of major complications further underscores the safety of this endoscopic technique in appropriately selected patients. However, certain limitations warrant consideration. The relatively short follow-up duration may not capture potential long-term complications or delayed instability that could develop over years. Additionally, the study’s broad classification of grade I DLS lacks detailed morphological subtyping, which could influence surgical outcomes and potentially limit the generalizability of the findings across the heterogeneous DLS population.
The Growing Evidence for Decompression Alone
Recent high-level evidence has significantly influenced the debate surrounding fusion necessity in DLS surgery. The landmark Nordsten Degenerative Spondylolisthesis (Nordsten-DS) trial stands as pivotal evidence in this debate. The 5-year followup results by Austevoll et al. [2] demonstrated that decompression alone was noninferior to decompression with instrumented fusion in DLS patients. Specifically, the proportion of patients achieving ≥30% reduction in ODI scores at 5 years was identical at 63% for both groups, with mean ODI change of -17.8 for both decompression alone and fusion groups. Importantly, rates of subsequent lumbar surgeries were not significantly different between groups.
These findings are particularly compelling because the decompression group predominantly underwent conventional open laminectomy—a more invasive procedure than endoscopic techniques. If open decompression achieves comparable longterm outcomes to fusion, it strongly challenges the routine addition of fusion for DLS.
This paradigm is supported by other key randomized controlled trials (RCTs). Försth et al. [3] found that adding fusion to decompression for lumbar spinal stenosis, with or without DLS, did not result in better clinical outcomes at 2 or 5 years but led to longer hospital stays, increased operative times, greater blood loss, and higher surgical costs. Secondary analyses from the Nordsten trial have questioned traditional patient selection criteria. Hellum et al. [5] found that pre-specified baseline variables, including commonly used radiological instability criteria, did not predict better outcomes with fusion surgery. Additionally, Solvang et al. [6] reported that surgeons’ preoperative recommendations for fusion were not associated with better clinical outcomes than random allocation, suggesting that clinical judgment in selecting patients for fusion may not be as reliable as previously assumed (Tables 1-2).
Summary of key randomized controlled trials: decompression alone versus decompression with fusion for degenerative lumbar spondylolisthesis
Summary of key randomized controlled trials: endoscopic decompression alone versus open or microscopic decompression for DLS
Endoscopic Decompression: Optimizing the Technique
If robust RCTs demonstrate that decompression alone, even via conventional open laminectomy, is noninferior to fusion for DLS, the clinical focus logically shifts towards optimizing the decompression procedure itself. Endoscopic spinal surgery techniques have emerged with the promise of achieving adequate neural decompression while significantly minimizing iatrogenic injury to paraspinal muscles, ligaments, and bony stabilizing structures [7-9].
Supporting evidence comes from Kim et al. [10], who reported an RCT comparing full-endoscopic laminectomy (FEL) to standard tubular laminectomy, revealing contrasting effects on spondylolisthesis progression. While spondylolisthesis was exacerbated or newly developed in 24% of patients in the standard technique group, the endoscopic group demonstrated improvement in spondylolisthesis in 8% of patients, providing Level I evidence that endoscopic approaches may reduce the risk of postoperative iatrogenic spondylolisthesis compared to conventional technique.
Additional observational evidence from Choi et al. [11] reported that radiological instability actually decreased postoperatively following full-endoscopic ULBD for grade I DLS, from 51.2% at baseline to 27.9% at final follow-up, suggesting potential “restabilization” phenomenon with endoscopic techniques.
The core argument emerges: if upcoming RCTs demonstrate that endoscopic decompression techniques yield outcomes superior or equivalent to those of conventional laminectomy for DLS, the evidence landscape would be profoundly altered. Endoscopic decompression offers established neural decompression benefits combined with inherent minimally invasive advantages: reduced soft tissue trauma, potentially faster recovery, and excellent stability preservation.
Anticipating Definitive Evidence
While the current study titled Biportal Endoscopic Decompression for Degenerative Lumbar Spondylolisthesis With Stenosis provides promising data, Level I evidence from large, well-designed RCTs is paramount for definitively establishing the role of endoscopic decompression in DLS management. The spinal community awaits results from ongoing RCTs comparing endoscopic techniques to conventional approaches, including the ENDO-F trial comparing interlaminar FEL versus open de-compressive laminectomy [12], and the ENDO-B trial evaluating biportal endoscopic versus conventional microscopic decompressive laminectomy [13].
DLS-specific data from these trials would provide crucial evidence addressing unique biomechanical considerations compared to stenosis without spondylolisthesis. Should these RCTs demonstrate endoscopic decompression’s noninferiority to conventional techniques, particularly with maintained stability in DLS patients, a powerful evidence cascade would emerge: endoscopic decompression ≥conventional decompression, and conventional decompression ≈ fusion for DLS. This would strongly position endoscopic decompression as a highly favorable, evidence-backed option for DLS.
Conclusion: Toward a Paradigm Shift
This study provides commendable evidence supporting biportal endoscopic ULBD as safe, effective, and stability-preserving surgical treatment for carefully selected patients with low-grade DLS and concomitant stenosis. The work serves as an important stepping stone toward potential paradigm shift in DLS treatment.
The future appears poised for transformation driven by: robust long-term evidence from RCTs like Nordsten-DS supporting decompression alone over fusion; promising clinical and radiological outcomes from endoscopic studies highlighting minimal invasiveness and stability preservation; and anticipated high-level evidence from ongoing RCTs comparing endoscopic versus conventional techniques. Should these trials confirm the benefits of endoscopic approaches, particularly with DLS-specific data, minimally invasive endoscopic decompression is likely to emerge as a leading, evidence-backed primary surgical option for a significant proportion of DLS patients. Lumbar fusion would then be more selectively reserved for cases with definite preoperative instability, prominent axial pain, or DLS that demonstrates significant progression within a relatively short timeframe. The authors’ contribution plays a valuable role in paving the way for this more nuanced and patient-centered future in DLS management.
Notes
Conflict of Interest
The author has nothing to disclose.