Presentation Authors: Brett Johnson, Ryan L Steinberg, Abdulhadi Akhtar, Joseph Crivelli*, Dallas, TX, Igor Sorokin, Worcester, MA, Jodi Antonelli, Margaret Pearle, Dallas, TX
Introduction: Even with aggressive fragment retrieval, ureteroscopy (URS) for upper tract stones yields stone free rates of only approximately 50% when assessed by computed tomography (CT) imaging. We followed a prospective cohort of patients who underwent URS and were imaged with CT at 6-8 weeks to determine the outcome of patient's residual fragments (RFs). Because CT was used, our cohort of patients with RFs is more truly inclusive than previously seen in studies not utilizing early post-operative CT imaging.
Methods: We prospectively evaluated 167 patients (209 renal units) undergoing URS for renal and ureteral calculi between December 2015 and February 2017. CT was obtained at 6-8 weeks post-operatively in all patients. Patients with residual fragments of any size who had at least 12 months of follow-up were included. Patients were evaluated at follow-up office visits with abdominal radiographs and ultrasound, and all patients were contacted by phone to determine if they had experienced any symptomatic stone events attributable to RFs. A stone event was defined as stone passage, need for intervention, symptoms requiring emergency department (ED) visit, or stone growth. Fisher's exact test, Kaplan-Meier method (KM) and multivariable logistic regression was used for statistical analysis.
Results: We identified 67 renal units in 54 patients who had RFs and greater than 12-month follow-up. Median follow-up was 23 months (IQR 18-27). The mean number of RFs per patient was 2.2 Â± 1.5 and the mean size of the largest fragment was 3.7 Â± 2.0 mm. Overall, stone-related events occurred in 48% of renal units (32 of 67). Among the 67 renal units, 12 (18%) required additional surgical intervention. ED visits were required for 10 renal units, and spontaneous RF passage occurred in 11 renal units. Mean time to stone-related event was 15.6 Â± 8.6 months. Multivariable analysis revealed no significant predictors of surgical intervention. By KM analysis, only 27% of renal units remain free of a stone-related event at 30 months post-operatively (Figure).
Conclusions: Rates of stone-related events due to RFs after URS are comparable to those reported after shock wave lithotripsy and percutaneous nephrolithotomy, and RFs of any size pose a risk. Consequently, given the high rate of RFs after URS, efforts to better select patients or to improve stone free rates after URS are necessary.