P.I. nomogram: an exploratory imaging-derived model for predicting early urinary incontinence following ThuLEP.

[BACKGROUND] Early postoperative urinary incontinence (UI) after thulium laser enucleation of the prostate (ThuLEP) can significantly affect postoperative quality of life. Predictive models for UI following ThuLEP are currently lacking. Prostatic apex shape (PAS), initially proposed in prostate cancer research, has shown value in predicting surgical outcomes but remains underexplored in benign prostatic hyperplasia (BPH). This study aimed to develop a nomogram based on PAS and clinical parameters to provide a noninvasive estimate of short-term UI risk after ThuLEP.

[METHODS] Patients who underwent ThuLEP for BPH at a high-volume center were retrospectively included. Inclusion criteria were preoperative BPH diagnosis, mpMRI examination, and complete follow-up data. PAS was classified into four subtypes (A, B, C, D) using a modified MRI-based method. Clinical variables, including intravesical prostatic protrusion (IPP), were collected. Logistic regression analysis was used to identify independent predictors of early postoperative UI, and a nomogram was developed and evaluated using the area under the curve (AUC), calibration analysis, and decision curve analysis.

[RESULTS] A total of 106 patients were included. Early postoperative UI at 1 month occurred in 40 patients (37.7%), with type D showing a significantly lower incidence (p = 0.029). On univariable analysis, PAS (A-C vs. D), IPP > 2.4 cm, and PV > 100 mL were associated with UI. In multivariable models, PAS types A-C (OR 11.721, 95% CI 1.431-85.996; p = 0.022) and IPP > 2.4 cm (OR 11.543, 95% CI 1.350-74.322; p = 0.026) remained independent predictors. P.I. nomogram (PAS, IPP) achieved an AUC of 0.758, demonstrated good calibration (Hosmer-Lemeshow P = 0.993), and showed greater net benefit particularly at threshold probabilities 0.4-0.6.

[CONCLUSION] PAS types A-C and IPP > 2.4 cm were independently associated with 1-month postoperative urinary incontinence after ThuLEP. Our P.I. nomogram showed acceptable discrimination and calibration for short-term UI risk in this exploratory cohort. If confirmed in external populations, this tool may assist preoperative risk stratification and counselling in patients undergoing ThuLEP.