Differences in Urodynamic Findings of Robot-Assisted Radical Prostatectomy Before and 2 Years After Surgery

Numerous studies have investigated changes in urinary function following robot-assisted radical prostatectomy (RARP); however, most studies have primarily focused on identifying predictors of postoperative urinary incontinence. This study aimed to evaluate bladder function and lower urinary tract symptoms through urodynamics examined before and 2 years after RARP.

This single-center, retrospective study included patients who underwent RARP for prostate cancer between April 2014 and April 2022. All participants who met our criteria completed questionnaires and underwent uroflowmetry (UFM) and pressure-flow study (PFS) both preoperatively and 2 years postoperatively.

Of the 376 patients, 141 were included in the analysis. Their median age was 68 years. The median prostate volume (PV) was 34.5 mL, and the median PSA level was 6.17 ng/mL. Postoperative evaluations revealed significant reductions in International Prostate Symptom Score (IPSS) items Q1, Q3, Q5, and the total score, while overactive bladder symptom score (OABSS) item Q4 increased significantly. UFM findings demonstrated significant improvements in maximum and average flow rates, flow time, and residual urine volume. PFS results showed significant improvements in voiding phase parameters and the bladder outlet obstruction (BOO) index. However, the bladder contractility index (BCI) significantly declined. Higher preoperative BCI and BOOI, advanced age, and smaller prostate volume were identified as independent risk factors for greater postoperative decline in BCI. Patients with 3-4 risk factors exhibited a significantly greater decline in BCI than those with 0-2 risk factors (median changes in BCI: -28.8 [IQR, -43.8 to -10.6] vs. 2.1 [IQR, -23.7 to 16.2], p < 0.001).

RARP was associated with improving urinary symptoms and objective urodynamic parameters, including UFM and PFS outcomes. Nevertheless, a decline in the BCI was observed at 2 years postoperatively among older patients. These findings suggest that increased age at the time of surgery might be associated with postoperative deterioration of detrusor function, although causality remains unclear.