Background: An estimated 0.2% of the population may have a unilateral nonfunctional kidney. This pre-existing condition may lead to the mistaken presumption that a ureteral injury has occurred when performing cystoscopy after hysterectomy.
Cases: Two cases are presented in which cystoscopy to confirm ureteral patency after hysterectomy was performed in patients with pre-existing unknown nonfunctional kidneys. These false-positive findings resulted in additional operative time, additional cost, and unnecessary surgical exploration.
Conclusion: Cystoscopy to confirm ureteral patency after hysterectomy may lead to an incorrect presumption of a ureteral injury in patients with a pre-existing nonfunctional kidney.