Materials and Methods
The data of 949 patients, who underwent RIRS for renal and proximal ureteral stones at HSU Izmir Bozyaka Training and Research Hospital and HSU Ankara Diskapi Training and Research Hospital between March 2015 and June 2020, were retrospectively analyzed. Patient data obtained included age, sex, body mass index (BMI), history and physical examination findings, specific comorbidities, and the American Society of Anesthesiologists (ASA) physical status class risk. All patients were evaluated with a detailed history before the operation. Stone parameters, namely number, diameter, location and CT attenuation value of the stone, previous treatments applied for the stone, operative time, fluoroscopy time, and stone burden (length x width x π x 0.25) were recorded. For multiple stones, the sum of each stone’s volume was used. The patients were evaluated preoperatively with complete blood count, serum creatinine, bleeding and clotting times, and urine culture analyses. Those with growth in urine cultures were operated on after antibiotherapy was administered for a sufficient time and the control urine cultures were sterile. Patients with missing data and/or those that did not undergo post-operative first-month non-contrast CT were excluded from the study. Patients who underwent diagnostic ureteroscopy but did not have related data were also not included in the study. Ethics approval was obtained from the Ethics Committee.
All operations were performed under general anesthesia in the dorsal lithotomy position. First, ureteroscopy was performed with a semirigid ureteroscope to provide mechanical dilatation and place a guide wire. Then, according to the surgeon’s preference, a ureteral access sheath (UAS) ( Flexor 9.5/11.5Fr or 12/14Fr, Cook Medical Bloomington, IL, USA, Navigator 11/13Fr, Boston Scientific, Natik, MA, USA) was placed over the guide wire under fluoroscopic control. In cases whereas UAS could not be placed, the operation was performed with a sheath. If the flexible ureteroscope could not reach the kidney over the guide wire, a double-J (DJ) stent was placed and left for passive dilatation, and the operation was postponed. All the RIRS procedures were performed using flexible ureteroscopes (Flex-X2, Karl Storz Endoscope, Tuttligen, Germany), and the stones were fragmented with a Holmium laser using a 6-14 W range. If needed, some fragments were removed with tipless nitinol stone baskets. The procedure was terminated after stone-free status was confirmed by both ureteroscopic inspection and fluoroscopy (leaving only ungraspable gravel or fragments <2mm) or if the surgeon decided to terminate the surgery due to complications, such as bleeding. At the end of the operation, a DJ stent was placed according to the surgeon’s preference.
All patients were evaluated with non-contrast CT at the first month after RIRS to evaluate stone-free status. Residual fragments of <2mm were accepted as insignificant. The results were compared in terms of the predictive capability of stone-free status and complications. Intraoperative complications were assessed using SCC, and postoperative complications were graded according to MCCS [9,10].