Impact of Pre-operative MRI-measured Membranous Urethral Length on Urinary Continence after Radical Cystectomy and Orthotopic Substitution: Clinical and Urodynamic Evaluation

Abstract

We aimed to determine the impact of membranous urethral length as measured by preoperative magnetic resonance imaging (MRI) upon continence following radical cystectomy and orthotopic substitution. A total of 40 male patients (mean age 55.7 +/- 7 years) were subjected to radical cystectomy and orthotopic ileal substitution for bladder cancer. Membranous urethral length was measured by preoperative MRI utilizing coronal oblique high resolution T2 weighted images. In all evaluable patients, day and night continence statuses as well as time to stable continence were recorded. Urodynamic assessment included medium fill pouchometry and urethral pressure profilometry. Of all patients 10 were non-evaluable. Mean follow-up period was 8.1 +/- 1.9 months. All the evaluable patients were continent by daytime. On the other hand, 13 were continent by night (43.3%), 13 showed occasional enuresis (43.3%) and 4 were nightly enuretic (13.4%). Mean membranous urethral lengths were 14 +/- 1.9, 13.8 +/- 1.9 and 12.8 +/- 1.7 mm in the three groups, respectively (P = 0.51). Mean time to reach stable postoperative daytime continence was 5.4 +/- 4.6 whilst it was 12.5 +/- 7.4 weeks for nighttime continence. There was no significant correlation between preoperative membranous urethral length and time to stable day or night continence (R = -0.11, -0.08, respectively). Moreover, such correlation was not observed with postoperative urethral pressure profilometry parameters including maximum urethral pressure, maximum urethral closure pressure or functional urethral length (R = -0.33, -0.38, -0.16, respectively). Preoperative MRI-measured membranous urethral length has no value for judgment of postoperative continence status following radical cystectomy and ileal bladder substitution.