Endourology & Stone Disease(구연) (E-170) Experience of Laparoscopic or Robotic ureterolithotomy with Concomitant Flexible ureterorenoscopic intrarenal stone removal for Large Upper Ureter Stone and Renal Calyceal Stones Urology, Soonchunhyang University Bucheon Hospital, Urology, Soonchunhyang University Bucheon Hospital, Urology, Soonchunhyang University Bucheon Hospital, Urology, Soonchunhyang University Bucheon Hospital, Urology, Soonchunhyang University Bucheon Hospital, Urology, Soonchunhyang University Bucheon Hospital Ji Kang Yun, Woong Bin Kim, Sang Wook Lee, Kwang Woo Lee, Jun Mo Kim, Young Ho Kim Background: Recently, retrograde intrarenal surgery (RIRS) has been widely performed due to the remarkable development of endoscopic instruments and techniques. However, it is still challenging when the large upper ureter stone is present with renal calyceal stones. / Objectives: The objective of this study was to evaluate the feasibility and safety new procedures. We applied laparoscopic or robotic ureterolithotomy with concomitant flexible ureterorenoscopic intrarenal stone removal in such cases. / Materials and Methods: We reviewed the records of 10 cases of laparoscopic or robotic ureterolithotomy with concomitant flexible ureterenoscopic intrarenal stone removal performed by single surgeon from March 2019 to April 2020. Under general anesthesia, patients were in semi lateral position. One camera port and two additional working ports were installed. After exposing the ureter where the stone is located, the stone was removed by longitudinal cold incision. After removing the ureter stone, the flexible ureterorenoscope(fURS) was inserted through the lowest working port. Guided by laparoscope, fURS was introduced into the ureterotomy site, and renal stones were removed with a stone basket (Nitinol tipless stone extractor). Because the size of ureterotomies were enough to stone extraction, no ureteral access sheath or lithotriptor was required in all cases. / Results and Conclusion: The average of preoperative ureter and renal stone size were 2.01cm (1.5-2.5cm) and 0.69cm (0.3-1.3cm), respectively. Mean stone density was 1240HU (707-1686HU). The average operating time was 99min (75-123min) for ureterolithotomy including 24min (7-40min) for flexible ureteroscopy. The average number of removed kidney stones were 2.1. Double J stent was inserted in all cases. No intraoperative complications were noted. The average length of hospital stay was 8 days (5-11days), and the average visual pain scale was measured at 4 points (2-8points). The stone free rate was 100% in all patients except one who was confirmed to remain 0.6 cm renal stone and additional ESWL was performed later. Transient urinary retention occurred in one patient but was immediately recovered. One patient required re-admission because of occurring ipsilateral acute pyelonephritis on 20 days after surgery. Two patients complained of mild stent irritation and removed the stent on the 14th day of surgery. The mean stent indwelling period was 33.7 days (14-55 days). Among the treatment options that can be performed in patients with large-sized upper ureteral stones with simultaneous renal calyceal stones, laparoscopic or robotic ureterolithotomy with concomitant flexible ureterenoscopic intrarenal stone removal can be safely performed and high stone free rate can be achieved. keywords : Robotics, Laparoscopy, Urolithiasis