Description
Purpose: Precise needle puncture of the renal collecting system is an essential
but challenging step for successful percutaneous nephrolithotomy. We evaluated
the efficiency of a new real-time electromagnetic tracking system for in vivo
kidney puncture.
Materials and Methods: Six anesthetized female pigs underwent ureterorenoscopy
to place a catheter with an electromagnetic tracking sensor into the
desired puncture site and ascertain puncture success. A tracked needle with a
similar electromagnetic tracking sensor was subsequently navigated into the
sensor in the catheter. Four punctures were performed by each of 2 surgeons in
each pig, including 1 each in the kidney, middle ureter, and right and left sides.
Outcome measurements were the number of attempts and the time needed to
evaluate the virtual trajectory and perform percutaneous puncture.
Results: A total of 24 punctures were easily performed without complication.
Surgeons required more time to evaluate the trajectory during ureteral than
kidney puncture (median 15 seconds, range 14 to 18 vs 13, range 11 to 16,
p ¼ 0.1). Median renal and ureteral puncture time was 19 (range 14 to 45) and 51
seconds (range 45 to 67), respectively (p ¼ 0.003). Two attempts were needed to
achieve a successful ureteral puncture. The technique requires the presence of a
renal stone for testing.
Conclusions: The proposed electromagnetic tracking solution for renal collecting
system puncture proved to be highly accurate, simple and quick. This method
might represent a paradigm shift in percutaneous kidney access techniques
; Vilaça, João L. 
