title: MRI factors to predict urinary incontinence after retropubic/laparoscopic radical prostatectomy.
abstract: OBJECTIVE
  Prostate cancer can be treated by radical prostatectomy (RP) and provoke a troublesome side effect: urinary incontinence (UI). We propose a verification of the usefulness of MRI and an identification of which structures are involved in UI after RP.
  
  
  METHODS
  Between September 2002 and December 2011, 550 patients underwent RP. We performed MRI to evaluate extraprostatic disease before surgery. To evaluate patient status, we measured the following structures: length (LP), width (WP), height (HP) and volume (PV) of the prostate, membranous urethral length (MUL), urethral wall thickness (UWT), levator ani muscle (LAM) and obturator internus muscle (OIM) thickness, ratio of levator ani muscle/prostate volume (LAM/PV), volume of the urethra (VU). UI was defined according to ICS definition as the complaint of any involuntary leakage of urine and evaluated 1 year after surgery. Analyses were performed by mean comparisons, univariate and multivariate logistic regression with a 1000-resample bootstrapping.
  
  
  RESULTS
  Means of measurements were: LP 4.46 cm, WP 5.15 cm, HP 3.9 cm, PV 49.3 cc; LAM 0.51 cm, OIM 1.46 cm; MUL 1.43 cm, UWT 1.38 cm; and LAM/PV 0.013 cm/cc, VU 2.33 cc. One hundred and twenty-two (22.2 %) patients complained of urine leakage. Univariate obtained differences in PV, OIM, MUL, and UWT. After adjusting by confounders, multivariate analysis showed: MUL: [OR 0.134; CI 95 % (0.022-0.493); P 0.006]; PV: [OR 1.016; CI 95 % (1.004-1.029); P 0.005]; UWT: [OR 6.03; CI 95 % (1.068-44.1); P 0.033].
  
  
  CONCLUSIONS
  MRI is a useful tool to predict UI after RP. The MUL and PV are well-identified structures that are involved in UI. Our study shows that UWT also influences UI.
authors.affiliation: Department of Urology, Clinica Universidad de Navarra, Pio XII, 36, 31008, Pamplona, Spain, atienza@unav.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Tienza
authors.forename: Mateo
authors.initials: M
authors.lastname: Hevia
authors.forename: Alberto
authors.initials: A
authors.lastname: Benito
authors.forename: Juan I
authors.initials: JI
authors.lastname: Pascual
authors.forename: Juan Javier
authors.initials: JJ
authors.lastname: Zudaire
authors.forename: Jose Enrique
authors.initials: JE
authors.lastname: Robles
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006801:Humans; D010535:Laparoscopy; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017773:Pelvic Floor / Q000473:pathology*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000209:etiology; D011237:Predictive Value of Tests; D011467:Prostate / Q000473:pathology; D011468:Prostatectomy / Q000009:adverse effects / Q000379:methods*; D011471:Prostatic Neoplasms / Q000601:surgery*; D012189:Retrospective Studies; D014549:Urinary Incontinence / Q000175:diagnosis* / Q000209:etiology