title: Artificial urinary sphincter AMS 800™ in males--can we explain residual leaks when sitting?
abstract: OBJECTIVE
  Some patients fitted with an AMS 800™ type artificial urinary sphincter report urinary leaks in the sitting position whose mechanism remains unclear. In this experimental study we explain these residual leaks by characterizing fluid transfer and pressure variations in the device during cuff compression.
  
  
  METHODS
  Two complete sets of AMS 800 devices were tested on an original test bench. A qualitative study using methylene blue dye was performed to assess fluid transfer within the device during manual cuff compression. After estimating the pressures exerted on the perineal floor in the sitting position, pressure variations in the AMS 800 components were measured in real time using the pressure sensors of a urodynamic workstation.
  
  
  RESULTS
  When the AMS 800 cuff was compressed between 2 fingers, reflux of the blue dye into the balloon through the pump resistor was observed. After the cuff was compressed for 5, 10, 15 and 20 seconds at a pressure of 150 cm H2O, the minimal pressure measurements in the cuff were 37, 25, 14 and 12 cm H2O, respectively. Furthermore, the time required for cuff re-pressurization was 68, 87, 101 and 117 seconds, respectively.
  
  
  CONCLUSIONS
  Urinary leaks reported in sitting position by patients fitted with an AMS 800 may be explained by compression of the urethral cuff between the pelvic floor and the chair, which causes emptying of the cuff into the balloon. Patients should be reassured that there is no implant dysfunction and may adopt simple lifestyle strategies to circumvent these leaks.
authors.affiliation: Department of Urology, Pitié-Salpétrière Academic Hospital, Pierre et Marie Curie University, Paris, France. Electronic address: aurel.beaugerie@wanadoo.fr.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Beaugerie
authors.affiliation: Department of Urology, Pitié-Salpétrière Academic Hospital, Pierre et Marie Curie University, Paris, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Phé
authors.affiliation: Department of Urology, Pitié-Salpétrière Academic Hospital, Pierre et Marie Curie University, Paris, France.
authors.forename: Gavishsing
authors.initials: G
authors.lastname: Munbauhal
authors.affiliation: Department of Urology, Pitié-Salpétrière Academic Hospital, Pierre et Marie Curie University, Paris, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Chartier-Kastler
authors.affiliation: Department of Urology, Pitié-Salpétrière Academic Hospital, Pierre et Marie Curie University, Paris, France; Institut des Systèmes Intelligents et de Robotique, Équipe AGATHE, Pierre et Marie Curie University, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Mozer
mesh_terms: D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000209:etiology*; D011187:Posture; D011312:Pressure; D011474:Prosthesis Design; D014549:Urinary Incontinence / Q000209:etiology*; D016741:Urinary Sphincter, Artificial
keywords: artificial; equipment and supplies; suburethral slings; urinary incontinence; urinary sphincter