V1722: Percutaneous access under direct endoscopic visualization: A modified approach for percutaneous neph

V1722: Percutaneous access under direct endoscopic visualization: A modified approach for percutaneous nephrolithotomy


Introduction and Objectives
Percutaneous nephrolithotomy has replaced the need for open surgery in the vast majority of kidney stone cases. Evolved from retrograde contrast approaches, we employ an endoscopic assisted procedure. Using flexible ureteroscopy (URS) for calyx selection with concurrent fluoroscopy, we can be very specific with positioning our access. Comparing this method to completely fluoroscopic access, we have noted several key benefits.

Proned cystoscopy is performed, allowing safety and working wires to be inserted. A ureteric re-entry sheath is placed for the duration of the case, and flexible ureteroscopy is performed. The optimal calyx is visualized, and the scope tip is held in that position. Fluoroscopically a Chiba needle is placed in line with the angulation of the calyx, using the bulls-eye technique to achieve the correct trajectory. Once oriented, the C-arm is rotated 50 off axis to judge depth of penetration, and the needle is advanced (while endoscopically observing the papilla). When the needle and URS tips meet fluoroscopically, the assistant sees the needle tip emerge from the papilla. The trocar is removed from the needle, and a Benston wire is passed, and pulled to the meatus using a preloaded URS basket. The Benston is exchanged for a superstiff wire through an open ended catheter, which then becomes a through-and-through safety/working wire.

Balloon dilation and sheath placement are performed under URS minimizes the risk of not being in the collecting system. If fragmentation is required, flexible nephroscopy/ureteroscopy are performed at the end of the procedure to ensure no residual stones. A double J stent and skin stitch are placed, without leaving any nephrostomy tubes. Post op CXR is ordered for all supra-costal accesses.

To date we have performed several hundred consecutive cases using this approach. Comparing 160 patients, (fluoroscopic PCNL vs. endoscopic assisted PCNL) we had significantly decreased fluoroscopy time by 87.5% (20min vs 2.5min), decreased the need for secondary procedures by 80% (14 vs 3), and reduced the number of cases terminated due to bleeding (6 vs 0 cases).

Endoscopic guidance for percutaneous access is an easy modification, allowing for an added degree of selectivity and accuracy. With benefits seen in fluoroscopy time, reducing the need for secondary procedures, and bleeding risk, we have now employed this method as our standard of care.

Funding: none