Mini-endoscopic guided access: a simple principle for relocating the guidewire into the pelvicalyceal system for safe percutaneous nephrolithotomy

Abstract Objective To report our initial experience using a simple principle that helps mini-endoscopic relocation of the guidewire into renal pelvis, ureter or upper calyx to improve percutaneous nephrolithotomy (PNL) puncture efficacy and enable safe dilatation. Methods A hydrophilic guidewire (sensor) was introduced through the access needle to calyx with a casting stone. 8 F Alken guide rod was passed over the guidewire followed by serial dilatation until the 4th Alken dilator (18F). Mini-perc outer sheath (18 F) was passed over under fluoroscopic guidance. A 8/11 Fr semirigid ureteroscope was progressed through the mini-perc sheath. A second sensor guidewire was passed, negotiated at the side of the stone to run through the infundibulum and renal pelvis down to the ureter or up to upper calyx under direct ureteroscopic vision. Routine tract dilatation by sequential rigid Alken metal dilators was done to enlarge the tract to 30 Fr. Results Our technique was employed on 14 (23%) out of 61 cases of PNL. Mean patient age was 47.5 yrs. Average stone size was 4.3 cm. Mean mini-endoscopic time taken to relocate the guidewire into the ureter or upper calyx was 63 s. Mini-endoscopic fluoroscopy time from introduction of ureteroscope to passage of sensor guidewire into ureter or upper calyx was 7.7 s. No mini-endoscopic access complication reported. Conclusion The mini-endoscopic access directs and facilitates initial percutaneous access and dilatation safely with reducing radiation exposure. Technique novelty is due to being a simple, safe, effective, economic and benefit in simplifying the early learning curve of PNL.