The Impact of Paraspinal Sarcopenia Compared With Generalized Sarcopenia on Conservative Treatment Outcomes in Degenerative Lumbar Spinal Stenosis.

Abstract

Retrospective cohort study. To assess the relationship between generalized and paraspinal sarcopenia in degenerative lumbar spinal stenosis (LSS) and identify risk factors for conservative treatment failure. Sarcopenia, a condition marked by a progressive, age-related decline in skeletal muscle mass, strength, and function, is increasingly being studied in the context of spinal diseases. However, uncertainties remain about the relationship between paraspinal and generalized sarcopenia, and their impact on spinal disease progression and treatment outcomes. A retrospective study of 101 LSS patients who underwent MRI and DXA and received at least 3 months of conservative treatment. Patients were categorized into 2 groups: successful conservative treatment (group A, n=71) and treatment failure requiring surgery (group B, n=30). Paraspinal sarcopenia was evaluated using paraspinal muscle cross-sectional area (PL-CSA/BMI) and fatty infiltration (Goutallier classification). Generalized sarcopenia was assessed using total psoas area (NTPA) and appendicular skeletal muscle mass (ASM/BMI). Logistic regression identified predictive factors for treatment failure. Group A had higher PL-CSA/BMI (143.3±36.0 vs. 123.7±33.4, P=0.001) and lower fatty infiltration (Goutallier 3-4: 19.7% vs. 46.7%, P<0.001) than group B. Generalized sarcopenia parameters showed no significant differences. Lower PL-CSA/BMI was an independent predictor of treatment failure (OR: 0.983, P=0.037). ASM/BMI correlated moderately with PL-CSA/BMI (rho=0.73, P<0.001). Paraspinal sarcopenia, rather than generalized sarcopenia, is a key predictor of conservative treatment failure in LSS. Paraspinal muscle assessment should be emphasized for prognosis and treatment planning.