Extracorporeal shock wave lithotripsy in patients with renal malformations.

Twenty-four consecutive patients with malformed kidneys (21 horseshoe kidneys, 2 crossed ectopic and 1 pelvic kidney) underwent extracorporeal shock wave lithotripsy (ESWL) for nephrolithiasis between 1984 and 1990. No serious complications occurred either during or after treatment. Urinary obstruction was accompanied by fever in 3 patients and by renal colic in 4. Auxiliary measures were required in only 2 cases. Patients with renal anomalies remained in hospital longer than patients with normal kidneys. Fifteen patients were free of stones 3 months after ESWL and 16 after 1 year. Six patients required further ESWL less than 1 year after their first treatment as a result of stone recurrence or regrowth. ESWL is a safe and successful non-invasive procedure for the treatment of nephrolithiasis in patients with malformed kidneys. However, the higher frequency of stone recurrence and regrowth means that these patients must undergo careful monitoring.