Visual Dilatation Technique in Percutaneous Nephrolithotomy: An Initial Clinical Experience

Introduction and Objectives: Tract dilatation is a crucial step in percutaneous nephrolithotomy, which can be guided under fluoroscopy, ultrasound, or combination of both techniques. It can still be difficult to ascertain the optimal depth to prevent overdilation, causing collecting system perforation and vascular injury or underdilation, making the establishment of access tract in a single attempt strenuous.1–7 Here, we present our initial clinical experience in using the novel technique of visual dilator system to obtain real-time visual confirmation of accuracy during percutaneous tract dilatation. Material and Methods: The visual dilator system used consisted of a transparent hollow dilator made of polyvenyl chloride and a 12F mini nephroscope inserted within its lumen. The nephroscope was connected to standard endoscopic camera system. The dilator system backloaded with access sheath was passed over guidewire to dilate percutaneous tract and position the access sheath under visual guidance. Saline was irrigated to maintain clarity during dilatation. Between December 2015 and December 2016, the visual dilator system was used during percutaneous tract dilatation in 13 percutaneous nephrolithotomy (PCNL) cases with mild or above hydronephrosis. Results: All tracts were effectively dilated in a single attempt. The intervening tissue layers, approach into target calix, and the access sheath placement could be visually monitored through the dilator wall to confirm accuracy in dilatation. Mean dilatation time was 3.4 ± 0.9 minutes, hemoglobin drop was 1.4 ± 0.8 g/dL, primary stone-free rate and that after auxiliary treatment were 11/13 (84.6%) and 13/13 (100%), respectively. We experienced overdilatation in one of the initial cases. No complications such as collecting system perforation, loss of access, transfusion, and surrounding organ injury were experienced in rest of the cases. The X-ray exposure time during dilatation was significantly low. Larger number of cases and comparison with other dilatation technique are needed to further prove the efficacy of the technique, which is under study. Conclusion: PCNL access tract dilation using the visual dilatation technique is clinically feasible. It provides a real-time visual monitoring and confirmation of accuracy in dilatation and lower X-ray exposure time during tract creation. It may improve the overall safety and efficacy of the PCNL procedure. No competing financial interests exist. Runtime of video: 4 mins 21 secs An earlier version of this video was presented at the 37th Congress of the Societe Internationale d’Urologic (SIU), October 19–22, 2017, in Lisbon.