title: Detrusor after-contraction: a new insight.
abstract: OBJECTIVE
  Detrusor after-contractions (DAC) are non-common in adults. Both definition (nothing in ICS reports) and significance (artefact, link with detrusor overactivity (DO) or bladder outlet obstruction (BOO)) remain discussed. Our purpose was to carry out an analysis of the urodynamic parameters during voidings with DAC and, using the VBN model, to simulate pathophysiological conditions able to explain both voiding phase and DAC.
  
  
  METHODS
  From large urodynamic database of patients referred for evaluation of lower urinary tract dysfunction, DAC were observed in 60 patients (5.7%). Criteria for DAC were post-void residual <30mL and increase of detrusor pressure >10cmH(2)O. VBN model was used for analysis of both pressure and flow curves, and simulations of pathophysiological conditions.
  
  
  RESULTS
  Onset of DAC (ODAC) occurred when Q=7.3±5.7mL/s and bladder volume=17.9±15.4mL. Urgency-frequency syndrome and urodynamic diagnosis of DO were the more frequent scenarios associated with DAC. ODAC was associated to an inversion of the slope of detrusor pressure curve without any perturbation in flow curve. Among tested pathophysiological hypothesis (great, abnormal, detrusor force, sphincter contraction), none allowed restoring all recorded curves (flow rate, voiding pressure and DAC).
  
  
  CONCLUSIONS
  No urodynamic characteristic of the first part of voiding is an index of occurrence of DAC. ODAC is a significant phenomenon linked with the bladder collapse. DAC is not associated with BOO but more probably with DO and appears as the result of local conditions in an almost empty bladder (concentration of stresses around a transducer); thus DAC seems of weak clinical significance.
authors.affiliation: ER6 - Université Pierre & Marie Curie (Paris 06), Paris, France.|Service de Rééducation Neurologique, Hôpital Rothschild, Paris, France.
authors.forename: Francoise A
authors.initials: FA
authors.lastname: Valentini
authors.affiliation: Service de Rééducation, Hôpital Saint Antoine, Paris, France.
authors.forename: Brigitte G
authors.initials: BG
authors.lastname: Marti
authors.affiliation: ER6 - Université Pierre & Marie Curie (Paris 06), Paris, France.|Service de Rééducation Neurologique, Hôpital Rothschild, Paris, France.
authors.forename: Gilberte
authors.initials: G
authors.lastname: Robain
authors.affiliation: ER6 - Université Pierre & Marie Curie (Paris 06), Paris, France.
authors.forename: Pierre P
authors.initials: PP
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016477:Artifacts; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D011312:Pressure; D012016:Reference Values; D012189:Retrospective Studies; D012212:Rheology; D012737:Sex Factors; D014521:Urethra / Q000503:physiopathology; D001743:Urinary Bladder / Q000503:physiopathology*; D053201:Urinary Bladder, Overactive / Q000503:physiopathology*; D014555:Urination Disorders / Q000503:physiopathology; D014563:Urodynamics / Q000502:physiology*; D055815:Young Adult