Do ureteral stent diameter and length or patient demographics play a role in stent encrustation?

Retained ureteral stents may constitute a technical challenge. The purpose of this study was to analyze the patient population with retained ureteral stents with regards to stent sizes to better understand if these factors could play a pivotal role in their encrustation.Methods: After institutional review board approval, we retrospectively analyzed the data of patients who underwent multimodal surgical procedures for the removal of retained ureteral stents from 2010–2018. The primary outcomes analyzed were ureteral stent length and diameter, location of stent placement, and patients’ demographics as potential etiologies for encrustation.Results: We included 30 patients with 32 encrusted ureteral stents and 37 patients with 46 forgotten non-retained ureteral stents. Indications for stenting included urolithiasis, malignancy, pregnancy, ureteral stricture, and ureteropelvic junction obstruction. Stent diameters ranged from 6 Fr. to 8.5 Fr. Stent lengths ranged from 22 to 30 cm, and multilength stents were used too. Smaller diameter stents were less likely to be retained when compared to larger diameter stents (>6 Fr.) (p=0.002). Overall stent length was not found to be significant (p=0.251); however, the difference in stent surface area differed by over 1cm (p<0.001). Patients who were uninsured were more likely to have retained stents (p=0.003). Patients who reside with longer commuting distance to the main academic medical center were more likely to have retained stents (p=0.010).Conclusions: Retained ureteral stents could be avoided. Taking into consideration ureteral anatomical variation among patients, smaller diameter stents and smaller surface area may prevent encrustation. Uninsured patients, with farther distance to seek medical care, and females are the most at risk.