title: [Bladder wall tension with physiological bladder emptying in patients with detrusor hyperactivity and infravesical obstruction].
abstract: OBJECTIVE
  The range of maximum bladder smooth muscle tension in the published literature varies between 1.3 and 59 N/cm (2) depending on the experimental setup. Based on own animal trials, we attempted to determine bladder wall tension during detrusor contraction in physiological and obstructed voiding and during detrusor instabilities in our patient collective.
  
  
  METHODS
  In 24 patients (mean age 56 +/- 8.4 years), bladder wall tension as detrusor force per cross sectional area of bladder tissue [in N/cm (2)] was calculated following urodynamic evaluation and ultrasound determination of bladder wall thickness. The patients were divided into 3 groups with 8 patients per group as follows: group I: patients with bladder outlet obstruction in accordance with the Abrams-Griffiths nomogramme; group II: patients with detrusor instabilities; group III: patients with normal bladder emptying.
  
  
  RESULTS
  Maximum bladder wall tension in group I was 9.8 +/- 3.9 N/cm (2). During bladder instabilities (group II), maximum bladder wall tension was 11.7 +/- 2.6 N/cm (2). Maximum bladder wall tension was 2.8 +/- 0.5 N/cm (2) in group III, which was significantly lower (p < 0.05, Mann-Whitney U-Test) than that of groups I and II.
  
  
  CONCLUSIONS
  We conclude that bladder wall tension is distinctly lower in patients with normal voiding than in those with obstructed micturition or detrusor instabilities. Furthermore, our results suggest that the detrusor is not fully activated during normal voiding and is thus capable of compensating for to a greater stress situation with more effective contractions.
authors.affiliation: Urologische Klinik, Klinikum Mannheim gGmbH, Universitätsklinikum Mannheim. stephan.bross@uro.ma.uni-geidelberg.de
authors.forename: S
authors.initials: S
authors.lastname: Bross
authors.forename: P M
authors.initials: PM
authors.lastname: Braun
authors.forename: M S
authors.initials: MS
authors.lastname: Michel
authors.forename: T
authors.initials: T
authors.lastname: Knoll
authors.forename: F J
authors.initials: FJ
authors.lastname: Martinez Portillo
authors.forename: K-P
authors.initials: KP
authors.lastname: Jünemann
authors.forename: P
authors.initials: P
authors.lastname: Alken
mesh_terms: D000328:Adult; D000368:Aged; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000502:physiology; D001743:Urinary Bladder / Q000502:physiology* / Q000503:physiopathology; D014550:Urinary Incontinence, Stress / Q000503:physiopathology; D014554:Urination / Q000502:physiology*; D014555:Urination Disorders / Q000503:physiopathology*; D014563:Urodynamics