Transperineal Ultrasound for Preoperative Pelvic Floor Assessment Prior to Radical Prostatectomy: Inter-Operator...

Post-prostatectomy urinary incontinence (UI) is a major functional complication of radical prostatectomy (RP), and preoperative membranous urethral length (MUL) has been established as an independent predictor of recovery. Magnetic resonance imaging (MRI) remains the standard for MUL measurement; however, access constraints and operator dependency limit its applicability. Transperineal ultrasound (TPUS) represents a promising alternative. This study aimed to evaluate the inter-operator reliability of TPUS-based pelvic floor measurements performed by urologists and their concordance with preoperative MRI in patients scheduled for robot-assisted radical prostatectomy (RARP).

A prospective observational cohort study was conducted. Fifty-one patients scheduled for RARP underwent preoperative TPUS performed by two urologists, blinded to each other's measurements. Eight pelvic floor parameters were recorded: MUL, prostatic height (PH), prostatic width (PW), prostatic depth (PD), urethral width (UW), urethra-prostate angle (UPA), prostatic urethral length (PUL), and total urethral length (TUL). Preoperative MRI served as the reference standard. Interoperator reliability and transperineal ultrasound-magnetic resonance imaging (TPUS-MRI) concordance were assessed.

Inter-operator reliability for TPUS ranged from moderate to substantial across all variables (intraclass correlation coefficient (ICC) range 0.57 to 0.74), with the strongest agreement observed for PD (ICC 0.74; 95% confidence interval (CI) 0.59 to 0.84) and MUL (ICC 0.73; 95% CI 0.57 to 0.84). Concordance between TPUS and MRI was strongest for MUL (ICC 0.47; 95% CI 0.23 to 0.66) and PH (ICC 0.47; 95% CI 0.22 to 0.66), both in the moderate range; UW and TUL showed statistically significant but only fair concordance, whereas the remaining four parameters showed no significant concordance.

TPUS performed by urologists demonstrates reproducible inter-operator agreement for pelvic floor parameters, particularly MUL. Significant, though modest, concordance with MRI (moderate for MUL and PH and fair for UW and TUL) together with small absolute mean differences for the key parameters, suggests that TPUS provides clinically reasonable estimates despite limited individual-level interchangeability with MRI. TPUS is a reproducible tool with acceptable inter-operator reliability for key pelvic floor parameters, particularly MUL, and may serve as a complement to MRI or an accessible alternative. However, its individual-level interchangeability with MRI remains limited, and its predictive value for post-prostatectomy urinary continence has not yet been established and requires confirmation in prospective studies.