Defining the Rate of Primary Ureteroscopic Failure in Unstented Patients: A Multi-Institutional Study

Purpose: Primary ureteroscopic intervention for kidney or ureteral stones occasionally encounters difficulty with passage of the ureteroscope in the initial procedure. These patients require a second procedure after stenting. We aim to define the contemporary failure rate of primary ureteroscopy (URS) and identify predictive factors that necessitate prestenting. This will assist in preoperative patient counseling, informed consent, and clinical decision-making. Materials and Methods: We conducted a multi-institutional retrospective review of 535 unstented patients undergoing primary URS from August 2011 to August 2013. The primary outcome was gaining access to the unstented ureter. Results: The failure rate for accessing the unstented ureter was 7.7% (41/535). The median age of females with primary ureteroscopic failure was significantly lower than in females who had successful ureteroscopic access (34 vs 52 years; p = 0.0041). There was no difference in the median age of males with access vs failure (58 vs 57 years; p = 0.3683). Proximal ureteral stones had the highest failure rate for ureteral access at 18.28% (p = 0.006). On multivariable logistic regression, proximal ureteral stone location remained a significant predictor of failure when compared to renal stones (odds ratio [OR] 3.14, p = 0.006). When including only ureteral stones in the multivariable analysis, stone location in the proximal ureter compared to the distal ureter remained the only significant predictor of access failure (OR 0.24, p = 0.015). Conclusions: A low overall rate of ureteral access failure in unstented patients is shown. Young female patients and proximal ureteral stones were less likely to be accessed primarily. This study provides information that will help urologists counsel their patients preoperatively regarding their likelihood of failing primary URS necessitating a second procedure. This will also help the patient to make an informed decision during the consent process and may guide urologists on selective prestenting in higher risk patients.