Assessment of the axial plane was limited to the segment of the largest disc herniation. Statistical analysis and construction of the nomogramAll statistical analyses were performed using SPSS for Windows (version 17.0; Chicago, IL, USA) and R software (version 4.0.1; https://www.r-project.org/). In the training set, univariate analyses based on clinical characteristics and imaging features were performed using SPSS software. Backward stepwise selection was performed using the likelihood ratio test with Akaike’s information criterion as the stopping rule . To validate risk stratification using our established nomogram in terms of recurrence-free probability scores, we calculated each patient using our nomogram model [0.31583*(hospitalization time.