Development and validation of a nomogram to predict the achievement of minimal clinically important difference following percutaneous endoscopic lumbar discectomy

BACKGROUND: This study is devoted to developing a nomogram predicting the achievement of minimal clinically important difference (MCID) in patients with lumbar disc herniation (LDH) following percutaneous endoscopic lumbar discectomy (PELD). METHODS: The patients involved were followed up for at least 2 years. Univariate logistic analysis and multivariable logistic regression were applied for identifying factors significantly influencing the achievement of MCID. Based on the selected factors, a nomogram was developed using R (v4.4.2). Discriminative ability, calibration, and clinical utility of the nomogram were evaluated by receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA), respectively. RESULTS: The study involved 442 patients, of which 23 (5.20%) failed to achieve the MCID. The statistical analysis identified the baseline Visual Analog Scale (VAS) score, presence of Lasegue's sign, and fat infiltration rate (FIR) of the multifidus muscle as independent risk factors. The nomogram showed good discrimination in development (AUC 0.84, 95% CI 0.73-0.95) and internal validation (AUC 0.88, 95% CI 0.69-0.98). Calibration was assessed by Hosmer-Lemeshow test and calibration curves, with p-values of 0.536 (development) and 0.369 (internal validation), and mean absolute errors (MAE) found (development) and 0.026 (internal validation). Decision curve analysis suggested positive net benefit across threshold probabilities of ~ 52-98% (development) and > 68% (internal validation). CONCLUSIONS: Baseline VAS scores, presence of Lasegue's sign, and FIR of multifidus muscles are predictive factors for achieving the MCID in patients undergoing PELD. SIGNIFICANCE: The study developed and validated a nomogram that can predict the achievement of MCID following PELD by assessing preoperative risk factors in patients with lumbar disc herniation.