[A Case of Endoscopic Combined Intrarenal Surgery for Multiple Encrusted Stones on a Forgotten Ureteral Stent Left for 4 Years].

A 43-year-old man underwent extracorporeal shock wave lithotripsy (ESWL) for a left ureteral stone and implantation of a loop stent for the treatment of stone pain in February 2011. However, he was lost to follow-up before the complete removal of the stones and stent. He presented to our hospital with left back pain in March 2015. An abdominal radiograph and a noncontrast computed tomography showed extensive stone formation throughout the stent. A single cystolithotripsy and a double endoscopic combined intrarenal surgery (ECIRS)were performed. All the stones and the encrusted ureteral stent were successfully removed.