## 3 Results
### Diagnostic Performance of the Predictive Models  
The diagnostic performance of each model is provided in Table 5, Table A1 in Appendix B and Figure 2. The AUCs were 0.63 \(\pm\) 0.04 for LR, 0.73 \(\pm\) 0.09 for KNN, 0.73 \(\pm\) 0.09 for DT, 0.72 \(\pm\) 0.03 for SVM, and 0.80 \(\pm\) 0.1 for RF in the internal validation group, representing improved performance from LR over the machine learning model. In the external validation group, four machine learning models had AUCs of 0.60 \(\pm\) 0.08 for KNN, 0.61 \(\pm\) 0.07 for DT, 0.65 \(\pm\) 0.07 for SVM, and 0.61 \(\pm\) 0.08 for RF. Among them, SVM yielded improved discrimination compared with LR (0.59 \(\pm\) 0.07). Chi-squared tests for all models showed that the estimated probability of PPI within 3 months did not differ from the actual observed proportion of recovery from PPI within 3 months (\(p\) > 0.05). \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **PPI Early-Recovery** & **PPI Consistent** & **\(p\)-Value** \\  & **Group (n = 76)** & **Group (n = 90)** & **\(p\)-Value** \\ \hline Age at surgery, year & 70.1 (50, 87) & 72.8 (56, 87) & 0.009 \(\ddagger\) \\ \hline BMI, kg/m\({}^{2}\) & 24.5 (18.6, 32.2) & 23.9 (15.5, 32.7) & 0.208 \(\ddagger\) \\ \hline PSA, ng/mL & 17.1 (1.2, 194.8) & 18.5 (2.7, 426.6) & 0.203 \(\ddagger\) \\ \hline History of TURP, n & 1 (1.3) & 6 (6.7) & 0.087 \(\lx@sectionsign\) \\ \hline \multicolumn{4}{c}{ISUP category and biopsy Gleason score} & 0.596 \(\lx@sectionsign\) \\ \hline
1, 6 (3 + 3) & 11 (14.5) & 12 (13.3) & \\
2, 7 (3 + 4) & 19 (25.0) & 21 (23.3) & \\
3, 7 (4 + 3) & 26 (34.2) & 24 (26.7) & \\
4, 8 & 13 (17.1) & 18 (20.0) & \\
5, 9 & 7 (9.2) & 15 (16.7) & \\ \hline \multicolumn{4}{c}{Surgical approach, n} & 0.191 \(\lx@sectionsign\) \\ \hline Open & 58 (76.3) & 57 (63.3) & \\ Laparoscopic & 12 (15.8) & 21 (23.3) & \\ Robotic & 6 (7.9) & 12 (13.3) & \\ \hline \multicolumn{4}{c}{Anatomic finding on MRI} \\ \hline PV (mm\({}^{3}\)) & 42.4 (19.3, 149.7) & 45.6 (18.7, 120.7) & 0.133 \(\ddagger\) \\ MUL (mm) & 15.7 (8.4, 24.8) & 13.9 (5.1, 24.2) & 0.002 \(\ddagger\) \\ LAM (mm) & 7.9 (4.5, 11.3) & 7.6 (4.3, 11.6) & 0.169 \(\ddagger\) \\ UWT (mm) & 10.2 (7.3, 13.6) & 10.0 (5.2, 13.0) & 0.297 \(\ddagger\) \\ ASM (mm) & 3.2 (1.0, 6.4) & 3.0 (1.2, 5.3) & 0.274 \(\ddagger\) \\ OIM (mm) & 18.2 (9.3, 23.7) & 17.5 (8.4, 49.5) & 0.021 \(\ddagger\) \\ \hline \hline \end{tabular} Note: Unless otherwise specified, data are mean with range. Data are presented as number (%) of patients. \({}^{\dagger}\)\(p\) value was calculated by Student’s \(t\)-test. \({}^{\ddagger}\)\(t\)\(p\) value was calculated by nonparametric Mann–Whitney U test. \({}^{\lx@sectionsign}\)\(p\) value was calculated by Pearson chi-square test. PPI, post-prostectomy incontinence; BMI, body mass index; PSA, prostate-specific antigen; TURP, transurethral resection of the prostate; ISUP, International Society of Urological Pathology; PV, prostate volume; MUL, membranous urethral length; LAM, kevator an muscle; UWT, urethra wall thickness; ASM, anal sphincter muscle; OIM, obturator internal muscle.  
\end{table} 
Table 3: Comparison between PPI early-recovery and consistent groups.