title: Aid to percutaneous renal access by virtual projection of the ultrasound puncture tract onto fluoroscopic images.
abstract: OBJECTIVE
  Percutaneous renal access in the context of percutaneous nephrolithotomy (PCNL) is a difficult technique, requiring rapid and precise access to a particular calix. We present a computerized system designed to improve percutaneous renal access by projecting the ultrasound puncture tract onto fluoroscopic images.
  
  
  METHODS
  The system consists of a computer and a localizer allowing spatial localization of the position of the various instruments. Without any human intervention, the ultrasound nephrostomy tract is superimposed in real time onto fluoroscopic images acquired in various views.
  
  
  RESULTS
  We tested our approach by laboratory experiments on a phantom. Also, after approval by our institution's Ethics Committee, we validated this technique in the operating room during PCNL in one patient.
  
  
  CONCLUSIONS
  Our system is reliable, and the absence of image-processing procedures makes it robust. We have initiated a prospective study to validate this technique both for PCNL specialists and as a learning tool.
authors.affiliation: Service d'Urologie, Groupe Hospitalier Pitié-Salpétrière, Paris, France. pierre.mozer@psl.aphp.fr
authors.forename: Pierre
authors.initials: P
authors.lastname: Mozer
authors.forename: Pierre
authors.initials: P
authors.lastname: Conort
authors.forename: Antoine
authors.initials: A
authors.lastname: Leroy
authors.forename: Michael
authors.initials: M
authors.lastname: Baumann
authors.forename: Yohan
authors.initials: Y
authors.lastname: Payan
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Troccaz
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Chartier-Kastler
authors.forename: François
authors.initials: F
authors.lastname: Richard
mesh_terms: D002138:Calibration; D005471:Fluoroscopy / Q000379:methods* / Q000592:standards; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007669:Kidney Calculi / Q000000981:diagnostic imaging / Q000601:surgery; D007670:Kidney Calices / Q000000981:diagnostic imaging / Q000601:surgery; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D019047:Phantoms, Imaging; D010865:Pilot Projects; D015203:Reproducibility of Results; D018084:Ultrasonography, Interventional / Q000379:methods* / Q000592:standards