Initial Experience of Simultaneous Combined use of Percutaneous Nephrolithotomy and Flexible Ureteroscopy in Complex Renal Calculi: A Novel Surgical Technique of 'Through-Through' Approach

Background For complex branched renal calculi, the endoscopic combined intrarenal surgery (ECIRS) is worldwide prevalent. This study aimed to present a novel surgical technique of percutaneous nephrolithotomy combined with antegrade flexible ureteroscopy which is named 'Through-through' approach. Methods We retrospectively analyzed the data of 68 patients with complex renal calculi who underwent combined PNL and flexible ureteroscopy surgery using 'Through-through' approach at our center between August 2019 and December 2021. The 'Through-through' approach to surgery was indicated in residual calyceal calculi that neither rigid nephroscope nor retrograde flexible ureteroscope could reach. The brief procedure of this technique involved determining the direction of targeted calyces with the nephroscope first, followed by putting flexible ureteroscope into the targeted calyx through the nephroscope instrument channel and basketing or dusting residual calculi through the flexible ureteroscope instrument channel. Results The mean maximum stone diameter was 4.0 +/- 0.4 cm. The mean operative duration was 100.1 +/- 18.0 minutes, and mean hemoglobin loss was 21.4 +/- 5.1 g/L. In all 68 patients, calculi were cleared in 62 patients, and the stone free rate was 91.2%. Five patients underwent further surgery after 2 weeks because of significant residual calculi. One patient that had a 6 mm residual stone chose observational follow-up. Ten patients emerged with postoperative fever but did not progress to uroseptic shock. There were no Clavien grade >= III complications, and none of the patients required blood transfusion. Conclusion The 'Through-through' approach is safe, feasible and effective for complex renal calculi patients. It is a complementary solution to the failed endoscopic combined intrarenal surgery.