Studying the Morbidity and Renal Function Outcome of Missed Internal Ureteral Stents: A Matched Pair Analysis

To investigate the effect of missed internal ureteral stents (IUS) on renal function and to describe different modalities of management and associated morbidity.

A retrospective study included patients with missed IUS (>1 year). The complications of missed IUS were categorized according to the forgotten, encrusted, calcified (FECal) grading system. The estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) equation at time of initial stent placement and time of stent removal. An age- and sex-matched group of patients who had IUS and had available follow-up for the same duration of the study group were used as a control.

A total of 46 missed IUS in 46 patients were included. Complicated stents were reported in 34 (73.9%) patients. FECal grade 1 was reported in 16 (57.2%) patients followed by grade 2 and 4 in 5 (17.8%) patients each. Retrograde removal, visual cystolitholapaxy, ureteroscopy with laser disintegration of encrustations and combined retrograde and antegrade approach have been used in 21, 5, 10, and 9 patients, respectively. In the missed IUS group, the mean±standard deviation (SD) eGFR has declined from 65.5±26.3 mL/min/1.73m(2) to 54.3±30 mL/min/1.73m(2) (P=0.001). While in the control group, the mean±SD eGFR has increased from 57.5±30 mL/min/1.73 m(2) to 66.7±27 mL/min/1.73 m(2) (P=0.001).

Missed IUS were associated with significant complications that necessitated more invasive intervention. In addition, IUS had a negative impact on renal function at time of removal.