Background: Retrograde intrarenal surgery (RIRS) has become the preferred treatment option for selected renal stones <20 mm. However, laser fragmentation of stones often results in residual small fragments that may prompt subsequent stone events. We describe a simple technique to facilitate removal of these fragments. Case Presentation: A 68-year-old woman underwent elective RIRS for a 13 mm right renal pelvic stone. After laser fragmentation of the stone there were numerous <2 mm fragments too small to allow removal by a standard retrieval basket (i.e., NCircle^® and NCompass^® Nitinol Stone Extractors, Cook Medical, Bloomington, IN). A smaller ureteral access sheath (UAS) was advanced into the kidney within the preexisting larger UAS and, using a connecting piece from a Foley catheter, stone fragments were suctioned out through the smaller sheath. Stone-free status was corroborated endoscopically and with postoperative CT. Conclusion: Stone fragments were flushed from the kidney using a simple irrigation technique through a coaxial UAS.

Background: Renal collecting system injuries are a rare occurrence during percutaneous nephrolithotomy (PCNL). However, when they do happen, the potential for complications rises exponentially the longer the injury goes undetected. This case highlights a possible higher rate of injury when using continuous flow sheaths. Case Presentation: A 65-year-old woman with history of large volume obstructing left-sided renal pelvis stone had an emergent ureteral stent placed for infection and was referred for interval management. Patient was taken for PCNL in the prone split-leg position where a continuous flow ureteral access sheath and a continuous flow nephrostomy sheath was used. Puncture and dilatation were performed under endoscopic guidance to avoid collecting system injury during access. The anesthesiologist discovered abnormalities in the patient's pulmonary ventilation settings. This allowed the surgical team to quickly halt the procedure and place the patient supine where a distended abdomen was discovered consistent with irrigation fluid extravasation into the abdominal cavity. Given concern for abdominal compartment syndrome, interventional radiology was then called to assist in placing a drain in the right lower quadrant of the patient to evacuate the irrigation fluid. This is the second such occurrence in a span of 6 months when using continuous flow ureteral access and nephrostomy sheaths. Conclusion: Renal collecting systems injuries are infrequent when access is obtained under endoscopic guidance. Prompt recognition of physiologic breathing abnormalities allowed the surgical team to quickly treat the injury, preventing further complications from arising in the setting of a diagnosis where time to detection plays an important role in prognosis. However, given that this is the second such injury, the usage of continuous flow sheaths and their rate of associated complications and injuries must be thoroughly examined.