title: Perineal noise recording as a non-invasive diagnostic method of urinary bladder outlet obstruction: a study in polyvinyl alcohol and silicone model urethras.
abstract: OBJECTIVE
  At present, an invasive pressure flow study is recommended to diagnose urinary bladder outlet obstruction. This method induces the risk of urinary tract infection and urethral trauma. We studied perineal noise recording as an alternative, non-invasive diagnostic method in three flexible/extensible model urethras and two silicone tubes.
  
  
  METHODS
  The flexible/extensible model urethras were made of a 10% aqueous solution of polyvinyl alcohol (PVA) and differed in wall- stiffness, the silicone tubes differed in diameter and wall-thickness. Three degrees of obstruction were applied by inflating a cuff placed around the PVA-urethras and by compressing the silicone tubes with an adjustable clamp. Noise, produced during flow, was recorded at three positions distal to the obstruction using a piëzoceramic contact microphone.
  
  
  RESULTS
  The average amplitude of the noise and the essential frequency of the power spectrum of each noise recording depended significantly on the degree of obstruction, the position of the microphone and the wall-stiffness in PVA-urethras and the diameter in silicone tubes.
  
  
  CONCLUSIONS
  Based on the results of this study perineal noise recording shows good potential as an alternative method for diagnosing bladder outlet obstruction.
authors.affiliation: Department of Urology, Sector Furore, Erasmus MC, Rotterdam, The Netherlands. t.idzenga@erasmusmc.nl
authors.forename: Tim
authors.initials: T
authors.lastname: Idzenga
authors.forename: Johan J M
authors.initials: JJ
authors.lastname: Pel
authors.forename: Radj A
authors.initials: RA
authors.lastname: Baldewsing
authors.forename: Ron
authors.initials: R
authors.lastname: van Mastrigt
mesh_terms: D003627:Data Interpretation, Statistical; D008953:Models, Anatomic; D010502:Perineum / Q000473:pathology*; D011142:Polyvinyl Alcohol; D012828:Silicones; D001748:Urinary Bladder Neck Obstruction / Q000473:pathology*
chemical_list: D012828:Silicones; D011142:Polyvinyl Alcohol