title: Positional variation in the Whitaker test.
abstract: OBJECTIVE
  To describe positional variation in the outcome of the Whitaker test.
  
  
  METHODS
  The authors retrospectively reviewed the cases of six patients in whom the pressure gradient during Whitaker testing varied by at least 10 cm of water and changed from normal ( < or = 13 cm of water) to abnormal ( > 13 cm of water) when patients were placed in different positions.
  
  
  RESULTS
  Four patients had obstruction only in nonstandard positions. All had intermittent symptoms, and three had ureteral kinks at fluoroscopy. Two patients with ileal conduits had abnormal results in the standard position but normal results at repositioning related to compression of the conduits (seen as conduit distention at fluoroscopy). All six had undergone urinary tract surgery. Gradient differences with positional change ranged from 10 to > 38 cm of water.
  
  
  CONCLUSIONS
  Whitaker testing in different positions may help identify intermittent obstructions that might otherwise go undetected or prevent inappropriate diagnosis of obstruction. Intermittent or unexplained symptoms, tortuous ureters, malpositioned kidneys, or previous surgery are indications for provocative positional testing.
authors.affiliation: Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0030, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Ellis
authors.forename: R P
authors.initials: RP
authors.lastname: Campo
authors.forename: M V
authors.initials: MV
authors.lastname: Marx
authors.forename: R H
authors.initials: RH
authors.lastname: Cohan
authors.forename: J F
authors.initials: JF
authors.lastname: Platt
authors.forename: L P
authors.initials: LP
authors.lastname: Sonda
authors.forename: G J
authors.initials: GJ
authors.lastname: Faerber
authors.forename: D H
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008722:Methods; D008875:Middle Aged; D011187:Posture; D012189:Retrospective Studies; D014524:Urethral Obstruction / Q000175:diagnosis*