title: The influence of membranous stretched urethral length and urethral circumference on postoperative recovery of continence after radical prostatectomy: A pilot study.
abstract: BACKGROUND
  We investigate the influence of stretched membranous urethral length (SUL) and urethral circumference (UC) on postoperative recovery of continence after radical prostatectomy (RP).
  
  
  METHODS
  To evaluate the distal continence zone intraoperatively, we individually measured and recorded stretched membranous urethral length (distance between the urogenital diaphragm and the prostate apex with cephalad retraction, SUL) and urethral circumference (UC) after exposure of the urethra. We analyzed the association between magnetic resonance imaging-measured membranous urethral length (MRIL) and urethral diameter (MRID) and intraoperative SUL and UC and influence on return to continence.
  
  
  RESULTS
  The mean patient age, SUL and UC were 66.5 ± 6.0 years, 24.2 ± 3.3 mm, and 27.5 ± 4.4 mm, respectively. MRIL and MRID were 11.3 ± 1.6 mm and 10.6 ± 1.9mm, respectively. In the bivariate correlation analysis, there was no statistically significant correlation between SUL and MRIL (p = 0.201) and between UC and MRID (p = 0.124). In the Kaplan-Meier curve analysis, cumulative continence rates between the two groups dichotomized at the median value according to age (p = 0.0519), SUL (p = 0.6583), UC (p = 0.4031), MRIL (p = 0.4042), and MRID (p = 0.8191) were not significantly different. High SUL-to-MRIL ratio (>2.2) was the only significant predictor of lower cumulative continence rate (p = 0.0457).
  
  
  CONCLUSIONS
  MRIL measured during surgery was not associated with postoperative continence recovery after RP. We observed that an excessively long membranous urethra compared to the urethral length on preoperative MRI is predictive of poorer postoperative continence recovery. However, small sample size and potential confounding surgical factors limit the significance of this study.
authors.affiliation: Department of Urology, Bundang Jesaeng General Hospital, Bundang-gu, Seongnam-si, Gyeonggi-do, South Korea;
authors.forename: Dae Sung
authors.initials: DS
authors.lastname: Cho
authors.affiliation: Department of Radiology, Ajou University School of Medicine, Yeongtong-gu, Suwon-si, Gyeonggi-do, South Korea;
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Department of Urology, Bundang Jesaeng General Hospital, Bundang-gu, Seongnam-si, Gyeonggi-do, South Korea;
authors.forename: Se Joong
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Urology, Ajou University School of Medicine, Yeongtong-gu, Suwon-si, Gyeonggi-do, South Korea.
authors.forename: Sun Il
authors.initials: SI
authors.lastname: Kim