Impact of Concomitant Grade I Degenerative Spondylolisthesis on Clinical and Radiographic Outcomes

Abstract

Dear Editor, we read the publication “Impact of Concomitant Grade I Degenerative Spondylolisthesis on Clinical and Radiographic Outcomes Following Biportal Endoscopic versus Microscopic Laminectomy for Lumbar Spinal Stenosis: A Post Hoc Analysis of a Multicenter Randomized Clinical Trial. 1 ” This article presents a clinically significant issue, as degenerative spondylolisthesis grade I often complicates the decision-making process for decompression in patients with lumbar spinal stenosis. Analysis found that the presence of DS1 did not significantly alter 12-month clinical outcomes between biportal endoscopic laminectomy and microscopic laminectomy. However, interpretation should be cautious, as this study was a post hoc analysis and reduced the sample size from 120 randomized trial participants to only 101. Segmenting patients by DS1 status also resulted in relatively small sample sizes within each subgroup, which may reduce the statistical power to detect small but clinically significant differences. Therefore, the absence of a difference should not automatically be interpreted as evidence of equivalence between the two techniques. Another limitation is that the 12-month assessment may be too short for degenerative disease with ongoing biomechanical changes, particularly since the study found increased slip percentage and instability ratio in both groups, although not significantly different between techniques. Importantly, such increases may simply be radiographic progressions unrelated to short-term symptoms. However, this can have more significant implications over several years, such as recurrent stenosis, mechanical back pain, or the need for future fusion. Future studies should therefore define repeat surgery or conversion to fusion as a key clinical endpoint, rather than merely evaluating radiographic parameters. Furthermore, the distinction between “stable DS1” and DS1 with clear dynamic instability should be considered, as these two patient groups may have significantly different post-decompression risks.