STONE DISEASE

Endoscopically Guided Percutaneous Renal Access: “Seeing is Believing”
Khan F, Borin JF, Pearle MS, McDougall EM, Clayman RV
Department of Urology, University of California, Irvine, Orange, California 92868, USA
J Endourol. 2006; 20: 451-5

• Image-guided percutaneous nephrostomy tube placement can be a challenging procedure, particularly in a nondilated system or in the morbidly obese patient. Herein, we report the routine use of ureteroscopy-guided percutaneous renal access. With this method, rapid, accurate creation and dilation of the nephrostomy tract is assured in all patients regardless of body habitus or stone burden.
  
  
• Editorial Comment
  Access is everything when it comes to percutaneous nephrolithotomy. Selecting the appropriate calyx, entering on the papillae, avoiding the infundibulum, gaining guidewire access down to the bladder, or better yet through-and-through from flank to urethral meatus are key steps that make or break the procedure. Traditionally we have relied on ultrasound or biplanar fluoroscopy to help guide renal access, and then experience, manipulation, torque catheters and a pinch of luck to get the guidewire down to the bladder.
  The technique described in this study emphasizes the endoscopic skills inherent to urologists rather than the imaging skills more commonly found with radiologists. By observing the angle of entry of the access needle and advancement of the guidewire into the collecting system one can limit the opportunity for inaccurate or unsuccessful renal access. When we have utilized this technique, we grasp the guidewire with a 3-prong Triceps grasper (Boston Scientific) and pull it through the ureteral access sheath to gain through-and-through access.
  When weighing the advantage of this technique against the added cost of flexible ureteroscopy with a ureteral access sheath, it is clear that this may not be needed for all cases; rather it may play a more important role in complex cases where ureteroscopic management or displacement of some of the stones may be needed. It may also be of particular important for a novice on the learning curve of gaining renal access. Also important to note is that it requires two experienced endoscopists – one at each end of the patient, therefore it may be a technique more suited for teaching environments.

Dr. Manoj Monga
Professor, Department of Urology
University of Minnesota
Edina, Minnesota, USA