Predicting failed access in unstented ureteroscopy

The risk of failed access (FA) in unstented ureteroscopy ranges from 7.7 to 16%, with young females and those with prior ipsilateral stone surgery, narrow ureteral anatomy, and proximal ureteral stone location carrying higher risk. We aim to determine the rate of failed access at our institution and analyze demographic, clinical, and operative variables associated with FA. We conducted a review of all unstented ureteroscopy procedures at our institution between January 2018 and June 2022. Ureteroscopy for stone, stricture, and neoplasm were included. The primary endpoint was rate of FA, when the unstented ureter failed to accommodate the ureteroscope distal to the target lesion. Demographic, clinical, and operative variables were analyzed to determine if there was an association with FA. Of the 562 ureteroscopies cases reviewed, 221 unstented ureteroscopies fit our inclusion criteria. FA occurred in 34 (15.4%). Previous stone passage (p = 0.039) and distal ureteral location (p = 0.042) were associated with successful access (SA). Proximal ureteral location was associated with FA (p = 0.008). These variables remained statistically significant when analyzed with multivariable logistic regression. There was no association with other demographic, clinical and operative variables. FA occurred at a rate of 15.4% at our institution. Previous stone passage and distal ureteral location were associated with SA, while proximal ureteral location was associated with FA. Prospective studies are needed to better determine predictors of FA.