title: Detrusor underactivity is prevalent after radical prostatectomy: A urodynamic study including risk factors.
abstract: BACKGROUND
  The objective was to determine the prevalence of, and factors that predict, detrusor underactivity (DU) in patients presenting with incontinence or lower urinary tract symptoms (LUTS) following radical prostatectomy (RP). We also determined the prevalence of bladder outlet obstruction (BOO) and detrusor overactivity (DO) in this population.
  
  
  METHODS
  Patients who underwent urodynamics post-RP were identified. Detrusor underactivity was defined as a maximum flow rate (Qmax) of ≤15 mL/s and detrusor pressure (Pdet) Qmax <20 cmH20 or maximum Pdet <20 cmH20 during attempted voiding. Abdominal voiding (AV) was defined as sustained increase in abdominal pressure during voiding. Bladder outlet obstruction and DO were identified using the Abrams-Griffiths nomogram and the International Continence Society criteria. Univariate logistic regression was used to determine factors predicting DU. The following factors were analyzed: age, year of RP, procedure type (minimally-invasive surgery [MIS] or open), postoperative radiation, nerve-sparing, clinical stage, biopsy Gleason grade and interval between RP and evaluation.
  
  
  RESULTS
  Between 2005 and 2008, 264 patients underwent urodynamics post-RP. Detrusor underactivity was observed in 108 patients (41%; 95% CI 35%, 47%), of whom 48% demonstrated AV. Overall, BOO and DO were present in 17% (95% CI 12%, 22%) and 27% (95% CI 22%, 33%), respectively. On univariate analysis, only MIS RP was predictive of DU (univariate odds ratio 2.05 for MIS vs. open; p = 0.009).
  
  
  CONCLUSIONS
  Detrusor underactivity and AV are common in patients presenting for evaluation of incontinence or LUTS following RP. The etiology of DU in this setting is likely related to the surgical approach. Because DU may affect the success of male incontinence treatment with the male sling or artificial urinary sphincter, it is useful to document its presence prior to treatment. More studies are needed to elucidate the influence of DU on treatment success for male urinary incontinence following RP.
authors.affiliation: Sidney Kimmel Center for Prostate and Urologic Cancers, Division of Urology, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY; ; Section of Urology, University of Chicago Mount Sinai Hospital, Chicago, IL.
authors.forename: Doreen E
authors.initials: DE
authors.lastname: Chung
authors.affiliation: Department of Urology, The Mount Sinai Medical Center, New York, NY;
authors.forename: Benjamin
authors.initials: B
authors.lastname: Dillon
authors.affiliation: Department of Urology, The University of Tennessee Health Sciences Center, Memphis, TN;
authors.forename: Jordan
authors.initials: J
authors.lastname: Kurta
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY;
authors.forename: Alexandra
authors.initials: A
authors.lastname: Maschino
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY;
authors.forename: Angel
authors.initials: A
authors.lastname: Cronin
authors.affiliation: Sidney Kimmel Center for Prostate and Urologic Cancers, Division of Urology, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY; ; James Buchanan Brady Foundation, Department of Urology, Weill Medical College of Cornell University, New York, NY;
authors.forename: Jaspreet S
authors.initials: JS
authors.lastname: Sandhu