New technology in ureteroscopy and percutaneous nephrolithotomy

Abstract

PURPOSE OF REVIEW: New developments of retrograde intrarenal and percutaneous endoscopic surgery for nephrolithiasis have significantly enhanced the indications of endourology compared to extracorporeal shock wave lithotripsy. We want to review the most significant new technologies RECENT FINDINGS: New technology to access the renal collecting system includes marker-based tracking with iPAD, laser-guided puncture on (Uro)Dyna-CT, electromagnetic tracking (only experimental), and optical tracking for ultrasound-guided puncture. Miniaturization percutaneous nephrolithotomy has been further extended and classified to Midi-PCNL (20-22F/L), Mini-PCNL (16-18F/M), Ultra/Super-mini-PCNL (12-14F/S), and Micro-PCNL (8-10F/XS). Knowledge of Ho:YAG-laser lithotripsy including power settings for fragmentation (depending on stone composition), dusting (0.5J/20Hz), and popcorn-effect/laser-burst (1J/30Hz) becomes mandatory. Also hydrodynamic mechanisms for retrieval of fragments (active/passive washout, purging, vacuum-cleaner-effect) have gained importance. Improvements of FURS focus on digital-HD-video-technology with post-processing software (NBI/SPIES) providing better resolution and increased optical field, further miniaturization of endoscopes to fit in smaller access sheath (12/14F), additional tip-less Nitinol baskets and graspers, and introduction of a robotic device (Avicenna Roboflex) to improve ergonomics of the procedure. SUMMARY: Based on recent technical developments, percutaneous nephrolithotomy and particularly flexible ureteroscopy will further gain preference in management of urolithiasis compared to ESWL. Endourology may offer a higher rate of primary success with minimal side-effects which could weigh out the slightly higher degree of invasiveness.