The Impact of Ureteral Access Sheath Use on the Development of Abnormal Postoperative Upper Tract Imaging after Ureteroscopy.

INTRODUCTION Ureteral access sheaths (UAS) are commonly utilized during ureteroscopy (URS) to facilitate stone removal, improve visibility and maintain low intrarenal pressures. However, the use of a UAS can cause ureteral wall ischemia and ureteral tears, potentially increasing the risk of postoperative ureteral stricture and obstruction. The primary objective of this study was to study the impact that UAS use has on postoperative imaging studies. Secondary objectives included studying the impact of other intraoperative parameters on postoperative imaging studies. METHODS A retrospective chart review was conducted of cases that underwent URS for nephroureterolithiasis across two high volume institutions between January 2012 and September 2016. Patient demographics, cumulative stone size, operative time, use of UAS, laser lithotripsy, basket extraction, preoperative ureteral stent, and postoperative ureteral stent placement were extracted from the electronic medical record. Findings of follow-up renal ultrasound, KUB, and/or CT at approximately eight weeks after surgery were recorded. RESULTS A total of 1,332 URS were performed, with 1,060 cases (79.6%) returning for routine upper tract imaging after URS. Postoperative hydronephrosis was noted following 127 cases (12.0%). Factors predicting presence of hydronephrosis after URS include lower BMI (p=0.0016), greater cumulative stone size (p=0.0003), increased operative time (p<0.0001), preoperative ureteral stent (OR=1.49, p=0.0299) and postoperative ureteral stent placement (OR=6.43, p=0.0031). Postoperative hydronephrosis was not associated with use of UAS, age, laser lithotripsy, or basket extraction. CONCLUSIONS Use of UAS did not have a significant impact on development of postoperative hydronephrosis, suggesting UAS is safe for use during URS. Ureteral strictures remain very rare following URS, seen in only 1.0% of our cohort. With an observed prevalence of hydronephrosis of 12.0% on follow-up imaging at eight weeks, routine upper tract imaging after URS remains a valuable prognostic tool.