Intracorporeal or extracorporeal lithotripsy for distal ureteral calculi? Effect of stone size and multiplicity on success rates

Abstract

Over a period of 57 months, 404 patients with distal ureteral calculi were treated by in situ SWL on a Storz Modulith SL 20 lithotripter and 163 by ureteroscopy (URS) and Swiss Lithoclast stone fragmentation. The case notes on these patients were reviewed for comparison of the initial stone number and individual length and for the calculation of the stone-free, treatment, retreatment, secondary procedure, and complication rates. Complete data were available on 447 patients. The median stone length was 7.0 (range 4-25) mm in the SWL group and 8.0 (range 5-13) mm in the URS group. The single-treatment stone-free rates for the SWL and URS groups were 74.8% and 89.7%, respectively, for single stones and 50.0% and 88.9%, respectively, for multiple (>1) stones. The mean treatment rates for the SWL and URS groups were 1.97 and 1.03, respectively, for single stones and 2.83 and 1.00, respectively, for multiple stones. The mean treatment rate for single stones subjected to SWL increased with increasing stone length (1.57 for stones <8 mm and 2.38 for stones >8 mm), whereas this was not the case for patients submitted to URS (1.20 and 1.27, respectively). The re-treatment rate for each group showed a reciprocal trend. Of the SWL group, 25.9% of the patients eventually required URS to render them stone-free. Nearly all (96%) of the patients undergoing SWL were treated as outpatients. The mean hospitalization in the URS group was 1.1 days. Three patients who underwent URS sustained a ureteral perforation, which was managed successfully by double-J stent insertion. The ideal primary treatment for small (<8 mm) distal ureteral calculi is in situ SWL, with URS plus Lithoclast fragmentation being reserved for failed SWL, single stones >8 mm in length, and multiple stones.