Effectiveness of caudal block in patients with spinal stenosis accompanied by redundant nerve root syndrome

OBJECTIVE: Redundant nerve root syndrome (RNRS) is characterized by tortuous, elongated, and enlarged nerve roots in patients with lumbar spinal stenosis. This study was performed to evaluate the effects of caudal block in patients with RNRS and assess factors associated with RNRS. METHODS: Patients with lumbar spinal stenosis who underwent caudal block were retrospectively analyzed. A comparative analysis of pain reduction was conducted between patients with RNRS (Group R) and those without RNRS (Group C). Generalized estimating equation analysis was used to identify factors related to the treatment response. RNRS-associated factors were analyzed using logistic regression analysis. RESULTS: In total, 54 patients were enrolled (Group R, n = 22; Group C, n = 32). Group R had older patients than Group C. The caudal block showed less pain reduction in Group R than in Group C, but the difference was not statistically significant. Generalized estimating equation analysis showed that RNRS was the factor significantly associated with the treatment response. The dural sac anteroposterior diameter and left ligamentum flavum thickness were associated with RNRS in the logistic regression analysis. CONCLUSIONS: Caudal block tended to be less effective in patients with than without RNRS, but the difference was not statistically significant.