Long-term efficacy of microendoscopic laminotomy for lumbar spinal stenosis in advanced degenerative spondylolisthesis with or without dynamic spinal instability: a propensity score-matching analysis.

OBJECTIVE:In this study, the authors aimed to determine the mid- to long-term outcomes of microendoscopic laminotomy (MEL) for lumbar spinal stenosis (LSS) with degenerative spondylolisthesis (DS) and identify preoperative predictors of poor mid- to long-term outcomes. METHODS:The authors retrospectively reviewed the medical records of 274 patients who underwent spinal MEL for symptomatic LSS. The minimum postoperative follow-up duration was 5 years. Patients were classified into two groups according to DS: those with DS (the DS+ group) and those without DS (the DS- group). The patients were subjected to propensity score matching based on sex, age, BMI, surgical segments, and preoperative leg pain visual analog scale scores. Clinical outcomes were evaluated 1 year and > 5 years after surgery. RESULTS:Surgical outcomes of MEL for LSS were not significantly different between the DS+ and DS- groups at the final follow-up (mean 7.8 years) in terms of Oswestry Disability Index (p = 0.498), satisfaction (p = 0.913), and reoperation rate (p = 0.154). In the multivariate analysis, female sex (standard β -0.260), patients with slip angle > 5° in the forward bending position (standard β -0.313), and those with dynamic progression of Meyerding grade (standard β -0.325) were at a high risk of poor long-term outcomes. CONCLUSIONS:MEL may have good long-term results in patients with DS without dynamic instability. Women with dynamic instability may require additional fusion surgery in approximately 25% of cases for a period of ≥ 5 years.