How to assess the long-term recovery outcomes of patients with cauda equina syndrome before surgery: a retrospective cohort study

Background: Factors influencing recovery after decompression surgery for cauda equina syndrome (CES) are not completely identified. The authors aimed to investigate the most valuable predictors (MVPs) of poor postoperative recovery (PPR) in patients with CES and construct a nomogram for discerning those who will experience PPR. Methods: Three hundred fifty-six patients with CES secondary to lumbar degenerative diseases treated at Xijing Hospital were randomly divided into training ( N =238) and validation ( N =118) cohorts at a 2:1 ratio. Moreover, 92 patients from the 970 th Hospital composed the testing cohort. Least Absolute Shrinkage and Selection Operator regression (LASSO) was used for selecting MVPs. The nomogram was developed by integrating coefficients of MVPs in the logistic regression, and its discrimination, calibration, and clinical utility were validated in all three cohorts. Results: After 3 to 5 years of follow-up, the residual rates of bladder dysfunction, bowel dysfunction, sexual dysfunction, and saddle anesthesia were 41.9, 44.1, 63.7, and 29.0%, respectively. MVPs included stress urinary incontinence, overactive bladder, low stream, difficult defecation, fecal incontinence, and saddle anesthesia in order. The discriminatory ability of the nomogram was up to 0.896, 0.919, and 0.848 in the training, validation, and testing cohorts, respectively. Besides, the nomogram showed good calibration and clinical utility in all cohorts. Furthermore, the optimal cutoff value of the nomogram score for distinguishing those who will experience PPR was 148.02, above which postoperative outcomes tend to be poor. Conclusion: The first pretreatment nomogram for discerning CES patients who will experience PPR was developed and validated, which will aid clinicians in clinical decision-making.