Systemic Neuroinflammatory Signatures in Lumbar Spinal Stenosis: An Exploratory Correlation of Serum IL-1β and hs-CRP with Schizas Morphological Grading

Abstract

Introduction: The clinical-radiological paradox in lumbar spinal stenosis (LSS) suggests that anatomical compression alone fails to explain symptom severity. Emerging evidence points to a bio-active stenotic environment driven by chronic neuroinflammation. This study aimed to investigate whether the morphological severity of stenosis, graded by the Schizas classification, correlates with systemic inflammatory biomarkers (Interleukin-1β and high-sensitivity C-reactive protein) after strictly controlling for pharmacological confounders.

Methods: A prospective, cross-sectional exploratory pilot study was conducted on 30 patients with degenerative LSS. To isolate stenosis-induced inflammation, strictly non-obese patients (BMI <30 kg/m²) underwent a verified 7-day NSAID/steroid washout period. Stenosis severity was graded on MRI using the Schizas classification. Due to small sample size in extreme stenosis, Grades C and D were merged into a severe stenosis cohort. Serum IL-1β and hs-CRP were quantified via ELISA. Statistical analysis utilized Kruskal-Wallis tests and bootstrapped multivariate linear regression (1,000 resamples) to control for Age, BMI, and multicollinearity (VIF).

Results: The cohort was stratified into Grade A (n=10), Grade B (n=11), and Severe Grade C/D (n=9). Systemic inflammatory markers demonstrated a significant stepwise elevation corresponding to morphological severity. Median IL-1β levels rose from 5.60 (IQR 4.9–6.4) pg/mL in Grade A to 11.20 (IQR 9.1–13.8) pg/mL in the Severe group (p<0.001). Similarly, hs-CRP increased from 2.15 mg/L to 4.90 mg/L (p=0.003). Bootstrapped regression confirmed that Schizas severity remained a significant independent predictor of IL-1β (β=0.46, p=0.012) and CRP (β=0.49, p=0.009) with acceptable variance inflation factors (VIF < 2.5), validating the model despite age-related correlations.

Conclusion: Morphological severity of the dural sac significantly correlates with systemic inflammatory burden. Severe mechanical compression appears to induce a spillover effect, creating a detectable peripheral inflammatory signature. These biomarkers may serve as objective adjuncts to MRI in conflicting clinical scenarios.