title: Percutaneous access to upper pole renal stones: role of prone 3-dimensional computerized tomography in inspiratory and expiratory phases.
abstract: OBJECTIVE
  We evaluated the role of noncontrast, prone position, inspiratory and expiratory 3-dimensional spiral computerized tomography (PIE-CT) for preoperative planning of percutaneous treatment in patients with complex upper pole renal calculi.
  
  
  METHODS
  In this pilot study a total of 6 renal units in 4 women and 1 man with complex upper pole calculi who were candidates for percutaneous nephrolithotomy were evaluated with thin section PIE-CT. With the patient imaged in the prone position percutaneous access was simulated under 4 potential access conditions, including subcostal and intercostal, in inspiration and expiration. Each potential access was then deemed transpleural or extrapleural and minimally angulated or severely angulated cephalad.
  
  
  RESULTS
  PIE-CT was performed uneventfully in all patients. Ideal nonangulated extrapleural percutaneous access was deemed possible in 5 of 6 renal units. However, inspiratory plus expiratory phases were necessary to identify the most suitable access site. In 2 renal units only 1 safe access site was identified. No pulmonary complications were noted in any of these patients. In 1 renal unit no suitable access could be identified and this patient was treated with laparoscopic caliceal diverticulectomy.
  
  
  CONCLUSIONS
  Thin section PIE-CT offers 3-dimensionally rendered images that clearly demonstrate anatomical relationships among the kidney, calculi, pleura, diaphragm, ribs and surrounding organs. In this pilot study PIE-CT provided useful data for planning urological intervention for complex upper pole renal stones. This study also suggests that generalizations regarding the safety of upper pole access in the inspiratory or expiratory phase are not warranted.
authors.affiliation: Section of Endourology and Stone Disease, Glickman Urological Institute and Department of Radiology, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ng
authors.forename: Brian R
authors.initials: BR
authors.lastname: Herts
authors.forename: Stevan B
authors.initials: SB
authors.lastname: Streem
mesh_terms: D045853:Exhalation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D001239:Inhalation; D007668:Kidney / Q000000981:diagnostic imaging*; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D008297:Male; D010865:Pilot Projects; D016684:Prone Position; D036542:Tomography, Spiral Computed / Q000379:methods*