Degenerative lumbosacral spondylolisthesis: Instability as the primary pathology and stabilization as definitive treatment. Experience with 28 cases treated by only fixation without any decompression.

Objective: The objective of the study was to evaluate clinical outcomes in patients with degenerative lumbar spondylolisthesis associated with lumbar canal stenosis treated exclusively with multisegmental spinal stabilization, without conventional decompressive procedures involving bone, ligament, or disc resection. This strategy is based on the hypothesis that spinal instability, rather than neural compression, is the primary pathological driver of symptoms. Degenerative lumbar spondylolisthesis is considered part of a broader spectrum of multilevel "vertical" spinal instability, frequently associated with adjacent segment involvement and lumbar canal stenosis. Materials and Methods: Between January 2017 and August 2025, 28 patients with symptomatic lumbar canal stenosis and degenerative spondylolisthesis underwent surgical treatment. Fixation was restricted to the affected listhesis level and adjacent unstable segments. No decompressive bone, ligament, disc, or osteophyte resection was performed. Instability was identified using clinical evaluation, radiological assessment, and intraoperative findings. Stabilization was achieved using transarticular facetal screw fixation. Fixation spanned two segments in 9 patients, three segments in 10 patients, four segments in 8 patients, and five segments in 1 patient. Clinical outcomes were assessed using the Oswestry Disability Index, Visual Analog Scale, and patient-reported satisfaction scores. Results: All patients demonstrated immediate postoperative clinical improvement. At a mean follow-up of 29 months, sustained symptom relief and high patient satisfaction were observed. Solid fixation and successful arthrodesis were achieved in all cases. No patient required reoperation or additional surgical intervention. Conclusions: "Vertical" spinal instability is the principal pathogenic factor in degenerative lumbar spondylolisthesis and associated canal stenosis. Degenerative lumbar spondylolisthesis rarely exists in isolation and commonly involves multisegmental instability. Stabilization of unstable segments alone is the treatment, and decompressive procedures are unnecessary.