Intrarenal arteriovenous malformation following flexible ureterorenoscopy and holmium laser stone fragmentation: Report of a case

Background: Flexible ureterorenoscopy (FURS) and holmium laser lithotripsy is currently considered as one of the treatment options for large renal calculi. It has been shown to be safer than percutaneous nephrolithotomy. The latter can sometimes be complicated by the formation of intrarenal arteriovenous malformation (AVM). AVM is extremely rare following FURS and laser lithotripsy. Indeed only one case has been reported on reviewing the literature up to June 2018. We report on the second case illustrating the possibility of developing this major complication following this procedure. Case presentation: A 79 years old diabetic and hypertensive male with stage-4 chronic kidney disease who previously had left extracorporeal shockwave lithotripsy and FURS with Holmium laser lithotripsy, presented with bilateral large renal calculi. He underwent simultaneous bilateral FURS and Holmium laser lithotripsy and was discharged home the following day with almost clear urine. Four days post-discharge, he presented with gross hematuria for which he required hospitalization and blood transfusion. CT scan demonstrated left subcapsular, perinephric and retroperitoneal hematoma. Angiography showed contrast extravasation from pseudoaneurysms in two small branches of left renal artery. Both were selectively embolized with micro-coils and this led to the cessation of the hematuria. Conclusions: Despite the relative safety of FURS and Holmium laser lithotripsy, it can be associated with major complications like intrarenal AVM. This can probably be prevented by careful and judicious use of laser energy in patients with large stone burden and premorbid conditions.