Anatomical benchmarks in preoperative magnetic resonance imaging predict early continence recovery following robotic radical prostatectomy.
Urinary incontinence (UI) is one of the most distressful complications of radical prostatectomy. Recently, several variations in the reconstruction technique aimed to change the final anastomosis position and virtual angles between anatomical benchmarks. The aim of the present study is to elucidate anatomical characteristics assessed preoperatively using 3 Tesla magnetic resonance imaging (MRI) that contribute to early recovery of urinary continence (UC) after robotic assisted radical prostatectomy (RARP).
We prospectively analyzed 72 consecutive patients that had undergone for RARP due prostate cancer diagnose and posterior rhabdosphinter reconstruction was performed as the standard technique. All patients underwent 3-T mpMRI (3.0 T Trio® Siemens) before surgery due to the study protocol. Functional outcomes were assessed with EPIC26 questionnaires (1, 6 and 12mo after surgery) and with self-reported first continence date. Membranous urethral length (MUL) and the angle between MUL and prostatic axis (aMUP) were assessed in T2-weighted sagittal preoperative images. Univariate and multivariate analysis were performed with STATA v13.1.
The median age was 63years (47-75), rate of abnormal DRE was 31.94%, and median PSA was 6.5ng/ml (1.5-22.8). UC median assessed with self-reported continence date was 4 weeks after catheter removal (0-32). Date-based UC rates were 81.48% and 90.48% at 6 and 12 months, respectively. When considering UC as need of <=1 PAD/day, those rates were 67.21%, 92.59% and 95.24% at 1, 6 and 12mo respectively. Patients with lower aMUP parameters achieved UC early: 1 month after catheter removal continents had preoperative mean aMUP of 107.21°(95%CI 90.28-124.15), while among those with UI it was 118.53° (95%CI 117.72-133.98); p=0.014. At 6 months aMUP was 114.24° (95%CI 104.62- 123.85) and 141.99° (95%CI 126.49-157.59), respectively; p=0.015. At 12mo, continents had greater preoperative MUL 16.06mm (95%CI 13.85-18.28), while patients with UI had 10.03mm (95%CI 8.72-12.13) p=0.048. No differences in aMUP were found at 12mo, neither in MUL at the 1st or 6th mo according UC status. Multivariate analyses were performed including prostate volume, BMI, clinical stage, imaging stage, aMUP and MUL. Only aMUP was an independent predictor of UC at 6 months OR 0.007 (95%CI: 0.002-0.012), p= 0.012. </p>
Assessment of virtual angles between anatomical benchmarks as aMUP before procedure may help define which patients will recovery UC early, helping in treatment decision make.