Effectiveness of extracorporeal shockwave lithotripsy in the management of stone-bearing horseshoe kidneys.

Although extracorporeal shockwave lithotripsy (SWL) has dramatically changed the management of urinary tract stone disease, the anatomic abnormalities of horseshoe kidneys cause some difficulties in the use of SWL in this disorder. In this study, 18 patients with stone-bearing horseshoe kidneys were investigated retrospectively in order to determine the effectiveness of SWL. Patients received an average of 11,437 + or - 3062 shocks at an average of 18.8 kV with the Siemens Lithostar. Ten patients were treated in the supine position; stones could be localized in the prone position in eight. Catheterization with a double-J stent was the only adjunctive procedure; it was used in four patients prior to SWL. Adequate stone fragmentation (smaller than 5 mm) was achieved in 14 of the 18 patients (78%). Although 5 of them (28%) became stone free within 6 months after the treatment, residual fragments persisted in 9 patients (50%) during the mean follow-up of 55 months. Stones of 4 patients (22%) were not fragmented adequately. We concluded that although adequate fragmentation can be achieved in stone-bearing horseshoe kidneys, the anatomic abnormalities prevent fragment passage in a substantial number of patients.