Incidence of Deflux® calcification masquerading as distal ureteric calculi on ultrasound

Abstract Objective Dextranomer-hyaluronic acid (Deflux ® ), the most widely used compound in the endoscopic treatment of vesico-ureteric reflux (VUR) today, is believed to provoke only minimal inflammation. Reports of calcification of Deflux ® are increasing. We ascertain the incidence of Deflux ® calcification appearing as distal ureteric calculi on ultrasound. Methods Three cases (2 external patients) of ureteroscopy for calcified submucosal Deflux ® prompted a retrospective review of the notes and imaging of all children treated with Deflux ® for VUR between December 2000 and January 2011 at Great Ormond Street Hospital. Results 232 children ( M : F  = 5:3) received Deflux ® for VUR at median age 2 years (range 2 months–12 years). Follow-up annual ultrasound, performed in all, identified calcification in 2. The interval between Deflux ® injection and presentation of its calcification was 4 years. 104 of the 232 children had been followed up for 4–10 years. Considering the observed lag-period, after 4 years the incidence of calcification of Deflux ® on ultrasound was 2% (2/104). Conclusions Patients should be warned that calcification of Deflux ® can occur. Misinterpretation as ureteric stones is common and may lead to unnecessary ureteroscopy. In this series, the incidence of calcification of Deflux ® on ultrasound after 4 years was 2%.