Methylene blue-guided retroperitoneoscopy technique: alternative for percutaneous nephrolithotomy in cases with renal access failure

Objective: To present our ‘methylene blue-guided retroperitoneoscopy technique’ that we apply in cases where extravasation develops for various reasons and is complicated as a result in Percutaneous Nephrolithotomy surgery (PNL). Material and Methods: A total of 36 patients, who underwent PNL with the ‘methylene blue technique’ at Bakirkoy Dr. Sadi Konuk Training and Research Hospital between 2014 and 2020, were retrospectively evaluated. The study included only cases in which the ‘methylene blue-guided retroperitoneoscopy technique’ was used due to the inability to advance the Amplatz sheath to the targeted calyx due to renal scarring or a staghorn stone filling the targeted calyx, Amplatz sheath was withdrawn from the kidney with the guidewire due to the inattention of the assistant surgical team or contrast material extravasation. The patients’ demographic, preoperative, perioperative, and postoperative data were recorded, and stone-free and complication rates were noted. Results: The mean age of the patients was 45.1 (36-55) years, the mean body mass index was 27.8±4 kg/m2, the mean stone size was 3.4±0.7 cm, and the mean stone volume was 22.3±10.2 cm3. The mean operation time was calculated as 95.8±30.3 minutes. The stone-free rate was 68% on the postoperative first day and 75% on the third month. Eight patients (22.2%) underwent a secondary procedure (extracorporeal shock wave lithotripsy or flexible ureterorenoscopy). Conclusion: The ‘methylene blue-guided retroperitoneoscopy technique’ we apply under retroperitoneoscopic direct vision is a safe and practical option for re-accessing the kidney by locating the calyx, which is first partially or completely dilated. Keywords: methylene blue, retroperitoneoscopy, renal access failure, percutaneous nephrolithotomy