Long surgical waiting list times are associated with an increased rate of negative ureteroscopies

Introduction: Negative ureteroscopy (NURS) is “a ureteroscopy in which no stone is found during the procedure.” We aimed to determine the association between the surgical waiting list time (WLT) and the NURS rate. Methods: We retrospectively analyzed all patients scheduled for ureteroscopy in our center between January 2017 and July 2019. The inclusion criterion was unilateral semirigid ureteroscopy for a single ureteral stone; exclusion criteria were renal-only stones, incomplete ureteroscopy, and stones >10 mm. We analyzed age, gender, body mass index, stone size, density and location, presence of a temporary double-J (DJ) stent, use of medical expulsive therapy, and WLT. Complications while waiting for surgery were also collected and analyzed. Results: We included 219 patients, 41 (18.7%) of whom had NURS. The median WLT was 74 days (interquartile range [IQR] 45–127). Variables protective against NURS were large stone size (odds ratio [OR] 0.78, 95% confidence interval [CI] 0.66–0.93), presence of a temporary DJ stent (OR 0.43, 95% CI 0.2–0.8), and radiopaque stones (OR 0.44, 95% CI 0.21–0.88). A long WLT (>60 days) increased the risk of NURS (OR 2.18, 95% CI 1.02–4.61). Complications requiring emergency department visits while waiting for surgery were documented in 58/137 (42.3%) patients with indwelling DJ stents; nonetheless, a WLT greater than the median was not associated with an increased risk of complications (p=0.38). Conclusions: Long WLT has an independent, direct, and linear correlation with NURS rates. Patients at higher risk of NURS, may be offered preoperative re-evaluation with a computed tomography scan in a resource-limited setting.