Prospective Evaluation and Classification of Ureteral Wall Injuries Resulting from Insertion of a Ureteral Access Sheath During Retrograde Intrarenal Surgery

Purpose: The safety of using a ureteral access sheath during retrograde intrarenal surgery remains controversial. Using a novel classification, we prospectively evaluated the incidence and severity of ureteral access sheath driven ureteral wall injury after flexible ureteroscopy for retrograde intrarenal surgery. Materials and Methods: Data on a total of 359 consecutive patients who underwent retrograde intrarenal surgery for kidney stone were prospectively collected at 2 academic centers. We propose what is to our knowledge a novel endoscopic classification of iatrogenic ureteral wall injury. Ureteral injuries after retrograde intrarenal surgery were assessed visually with a digital flexible ureterorenoscope. The primary outcome measure was the incidence and nature of ureteral injuries. We sought factors predisposing to such injuries. Results: Ureteral wall injury was found in 167 patients (46.5%). Severe injury involving the smooth muscle layers was observed in 48 patients (13.3%). Males vs females (p = 0.024) and older vs younger patients (p = 0.018) were at higher risk for severe ureteral access sheath related ureteral injury. The most significant predictor of severe injury was absent ureteral Double-J (R) stenting before retrograde intrarenal surgery (p < 0.0001). Pre-stenting vs no pre-stenting decreased the risk of severe injury by sevenfold. Body mass index, a history of diabetes mellitus, vascular disease or abdominopelvic radiation therapy and operative time were not associated with severe ureteral injury. Conclusions: Ureteral access sheath use for retrograde intrarenal surgery should involve systematic visual assessment of the entire ureter to recognize severe ureteral injury. The incidence of severe ureteral injury is largely decreased by preoperative Double-J stenting.