Association of Preoperative MRI-Derived Anatomical Parameters with Urinary Continence Recovery After Robot-Assisted...

Objectives: This study evaluated the association of patient age and preoperative prostate MRI-derived anatomical parameters with postoperative urinary incontinence (UI) and urinary continence (UC) recovery after robot-assisted radical prostatectomy (RARP). Methods: We retrospectively included 118 patients who underwent RARP between 2022 and 2024 and had preoperative prostate MRI. Patient age and continence status at 1, 3, 6, and 12 months were obtained from medical records. Levator ani muscle (LAM), obturator internus muscle (OIM), and pubococcygeus muscle thicknesses were measured at their thickest points on axial and coronal T2-weighted images. Membranous urethral width (MUW), length (MUL), and angle (MUA) were measured, and prostate volume was calculated. UC was defined as no pad use or one safety pad per day (used for reassurance or for occasional minimal drops of urine), whereas UI was defined as the use of one or more pads per day that became wet because of urine leakage. Associations were evaluated using group comparisons, Kaplan-Meier analysis, and exploratory Cox and logistic regression models. Results: UC rates at 1, 3, 6, and 12 months were 32.2%, 54.2%, 73.7%, and 91.5%, respectively, while 8.5% of patients remained incontinent at 12 months. At 3 months, patients with UC differed significantly from those with UI in age, MUA, and LAM thickness. Comparisons among patients who achieved UC at different postoperative time points and those with UI at 12 months demonstrated significant differences in LAM thickness, MUL, and MUA (all p < 0.05). In multivariable Cox regression, higher MUA (hazard ratio [HR] 1.43 per 10°), thicker LAM (coronal HR 1.30 and axial HR 1.28 per mm), and younger age (HR 0.85 per 5 years) were associated with earlier continence recovery, whereas MUL was not. Prostate volume, MUW, and pubococcygeus muscle thickness were not associated with continence outcomes. Conclusions: Preoperative MRI-derived anatomical parameters, particularly MUA and LAM thickness, together with patient age, were associated with urinary continence recovery after RARP, and the associations of MUA and LAM thickness remained significant after multivariable adjustment in the time-to-event analysis. These exploratory findings are hypothesis-generating; clinical confounders could not be accounted for, and validation in prospective studies is required before these parameters can be considered for clinical use.