Abstract
BACKGROUND: Lumbar canal stenosis (LCS) limits walking capacity through neurogenic claudication, yet the relationship between dural sac canal diameter and functional distance remains incompletely defined. This study aimed to evaluate the relationship between the narrowest dural sac diameter, patient-reported disability, and claudication distance. METHODS: A prospective, observational study was conducted from December 2024 to June 2025. Adults presenting with neurogenic claudication secondary to LCS were consecutively enrolled. Demographics, Oswestry Disability Index (ODI), visual-analog score (VAS), and claudication distance were recorded. MRI measurements comprised depth of the lateral recess and anteroposterior (AP) dural sac diameters at L3-L4, L4-L5, L5-S1, with the narrowest value designated the "narrowest diameter." Pearson correlations and multivariable linear regression (dependent variable: claudication distance) were performed (α = 0.05). RESULTS: Seventy-one patients (mean ± SD age 60.5 ± 8.5 years; 54.9 % male) were analyzed. Mean claudication distance was 408.6 ± 193.6 m; mean narrowest dural sac diameter, 6.44 ± 1.63 mm. Claudication distance correlated moderately with ODI (r = -0.65, p < 0.001) and fairly with the narrowest dural sac diameter (r = 0.24, p = 0.041); age, symptom duration, and lateral-recess depths were not significant. Regression revealed ODI (β = -0.62, p < 0.001) and narrowest diameter (β = 0.21, p = 0.021) as independent predictors, while BMI lost significance. The model equation was: Claudication distance (m) = 1058.86 - 9.20 × ODI + 25.03 × narrowest diameter (mm). CONCLUSIONS: Functional walking capacity was significantly associated with ODI and the narrowest dural sac diameter within this cohort; however, walking performance remains a multifactorial outcome influenced by several systemic variables. Integrating ODI with precise MRI measurements may enhance prognostication and treatment planning. LEVEL OF EVIDENCE: Prospective observational study, Level III.