Presented by: Arda Tunc Aydinoglu MD
Istanbul University Faculty of Medicine

Introduction

Recent technological advances in endourology have made retrograde intrarenal surgery (RIRS) a more popular method for the treatment of urolithiasis. Although RIRS is widely used in kidney stones smaller than 2 cm, it has been used with increasing frequency in stones larger than 2 cm. In addition, new instruments such as high-power holmium lasers, thulium fiber lasers and disposable ureteroscopes have been introduced for greater safety, efficiency and comfort for both patients and surgeons. Radiolucent stones, stones in the kidney anatomy that are not suitable for SWL, treatment with anticoagulants, coexistence of kidney and ureteral stones and bleeding disorders are the advantages for this surgery. The aim of RIRS is to achieve stone-free as in other stone surgeries. It is a known fact that the stone-free rate (SFR) is lower in patients undergoing f-URS for upper urinary tract stones compared to percutaneous nephrolithotomy. Some nomograms have been developed to estimate SFR after f-URS to guide the selection of optimal therapy. Various preoperative features have been described, including stone volume and number, presence of lower pole stones or hydronephrosis, and operators experience with f-URS.

Materials

The data of patients who underwent F-URS for proximal ureter and/or renal pelvis stones between January 2018 and February 2023 at the Department of Urology, Istanbul Faculty of Medicine were evaluated retrospectively. Demographic characteristics of the patients, operation time, stone localization, preoperative stone volume, postoperative stone volume and postoperative complications were determined. Stone volumes were calculated using the "3D Slicer image computing" program by using the preoperative and postoperative Computed Tomography (CT) images of the patient, residual fragments of 2 mm and below were considered stone free. When calculating the stone volume in patients with more than one stone, the volume of each stone was calculated and added together. Postoperative KUB of the patients who did not have CT imaging in the postoperative evaluation were was used. Perioperative complications were classified using the modified Clavien system.

Results

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Between January 2018 and February 2023, F-URS procedure was performed on 130 patients due to proximal ureter or kidney stones in the Urology Department of Istanbul Faculty of Medicine. All patients were operated in the standard lithotomy position. The mean age of the patients was 49.2 (12-85). The age of 3 patients was under 18.  38 of the patients were female and 92 were male. 12 patients had multiple stones in the proximal ureter, 5 at the ureteropelvic (UP) junction, 13 at the upper pole, 22 at the middle pole, 19 at the renal pelvis, 34 at the lower pole, and 21 at different calyces. At the end of the operation, JJ stent was placed in all patients. Preoperative and postoperative CT images of 66 (50.7%) people were obtained and stone volumes were calculated. The mean preoperative stone volume was 90 mm3 (11.82 mm3-10534.4 mm3). The mean stone volume of the patients in the first 3 months postoperatively was calculated as 64 mm3 in the CT images. 49 (37.6%) patients were found to be free of calculus postoperatively. The mean operation duration was 97 minutes (20 minutes -269 minutes). Perioperative or postoperative complications were detected in 18 (13.8%) patients. Grade-1 complications were detected in 9 patients, grade-2 complications in 5 patients, and grade-3 complications in 4 patients; Mortality did not occur in any of the patients. The postoperative hospital stay was found to be 1.6 days.

Conclusion

Postoperative stone volume of patients undergoing F-URS for kidney stone disease may be higher than expected when evaluated with unenhanced CT images.

Funding

None

Lead Authors

Resat Aydin, MD
Istanbul University Faculty of Medicine

Yasin Ates, MD
Istanbul University Faculty of Medicine

Ahmet Baris Aydin, MD
Istanbul University Faculty of Medicine

Tzevat Tefik, Associate Professor (Urol) MD
Istanbul

Faruk Ozcan, Professor (Urol) MD
Istanbul University Faculty of Medicine