title: The Locator: novel percutaneous nephrolithotomy apparatus to aid collecting system puncture--a preliminary report.
abstract: OBJECTIVE
  Precise needle puncture of the renal collecting system is an essential step for successful percutaneous nephrolithotomy (PCNL). Puncture is technically challenging and has many pitfalls for the urologic surgeon. We describe the development of a novel navigation system, the Locator, to assist accurate percutaneous needle placement and compare this with conventional manual techniques.
  
  
  METHODS
  The essence of the device is that it stabilizes the needle for PCNL puncture. It relies on an adjustable lockable multidirectional head that is securely fixed to the operating table. The radiolucent head holds a 10F metal guide that allows renal collecting system puncture. The system uses the traditional fluoroscopic "bull's-eye sign" to achieve precise and fixed alignment. Objective assessment was obtained by in vitro testing using simulated PCNL puncture with and without using the Locator. Time to successful puncture and fluoroscopy screening time (FST) was assessed.
  
  
  RESULTS
  Six urologic trainees were recruited to test the Locator. Simulated PCNL puncture was quicker and with reduced fluoroscopy when the apparatus was used. The mean FST for traditional hand vs Locator puncture was 46 vs. 16 seconds (P  =  0.03), and the mean time to puncture was 225 vs. 118 seconds (P  =  0.26).
  
  
  CONCLUSIONS
  The Locator is a simple, cheap, and novel assistant to achieving successful PCNL puncture. It achieves this by stabilizing the needle during puncture. Preliminary in vitro testing suggests that the device may reduce fluoroscopy exposure and be quicker. The device warrants further evaluation in the clinical setting.
authors.affiliation: Division of Urology, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa. j.lazarus@uct.ac.za
authors.forename: John
authors.initials: J
authors.lastname: Lazarus
authors.forename: John
authors.initials: J
authors.lastname: Williams
mesh_terms: D005471:Fluoroscopy; D006801:Humans; D007685:Kidney Tubules, Collecting / Q000601:surgery*; D009339:Needles; D009403:Nephrostomy, Percutaneous / Q000295:instrumentation* / Q000379:methods*; D011677:Punctures / Q000295:instrumentation* / Q000379:methods*