title: The "all-seeing needle": initial results of an optical puncture system confirming access in percutaneous nephrolithotomy.
abstract: BACKGROUND
  In percutaneous nephrolithotomy (PNL), the best possible way to access the collecting system is still a matter of debate. There is little possibility of correcting a suboptimal access.
  
  
  OBJECTIVE
  To describe our initial experience using a micro-optical system through a specific puncture needle to confirm the quality of the chosen access prior to dilatation of the operating tract.
  
  
  METHODS
  Micro-optics of 0.9- and 0.6-mm diameter were used. The micro-optic with integrated light lead was inserted through the working sheath of the puncture needle. The modified needle had a 1.6-mm (4.85-Fr) outer diameter. The optical fiber was connected via a zoom ocular and light adapter to a standard endoscopic camera system. For sufficient intraoperative sight, an irrigation system was connected.
  
  
  METHODS
  The optical puncture needle was used in 15 patients for renal access prior to standard PNL procedures.
  
  
  METHODS
  The optical assessment included determination of the distortion, resolution, angle, and field of view. The irrigation flow was assessed in an ex vivo setting, with the puncture stylet or the needle shaft either empty or with a 0.018-in guidewire inserted.
  
  
  CONCLUSIONS
  In all cases, visualization of the punctured kidney calyces was successful and the presence of the target calculi could be confirmed prior to guidewire placement and tract dilation. The 0.9-mm optic was found to be significantly superior in all optical parameters in contrast to the 0.6-mm optic. No significant complications were observed.
  
  
  CONCLUSIONS
  The optical puncture needle for PNL appears to be most helpful for confirming the optimal percutaneous access to the kidney prior to dilation of the nephrostomy tract, improving the safety of the technique.
authors.affiliation: Department of Urology, Ludwig Maximilians Universität München, Campus Grosshadern, Munich, Germany.
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Bader
authors.forename: Christian
authors.initials: C
authors.lastname: Gratzke
authors.forename: Michael
authors.initials: M
authors.lastname: Seitz
authors.forename: Rajan
authors.initials: R
authors.lastname: Sharma
authors.forename: Christian G
authors.initials: CG
authors.lastname: Stief
authors.forename: Mahesh
authors.initials: M
authors.lastname: Desai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004106:Dilatation; D019723:Endoscopes; D004867:Equipment Design; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000473:pathology / Q000628:therapy*; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D008904:Miniaturization; D009339:Needles; D009403:Nephrostomy, Percutaneous / Q000295:instrumentation*; D055100:Optical Fibers; D011677:Punctures; D007507:Therapeutic Irrigation / Q000295:instrumentation; D016896:Treatment Outcome; D055815:Young Adult