EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY OF MIDDLE URETERAL STONES - AREURETERAL STENTS NECESSARY

Objectives. To ascertain whether insertion of a ureteral stent improve s the outcome of middle ureteral (overlying the pelvic bone) stones tr eated with extracorporeal shock-wave lithotripsy (ESWL). Methods. Thir ty-three patients with middle ureteral stones were treated with ESWL a t our institution between October 1991 and October 1994, Twenty-six pa tients were available for follow-up; 14 patients were treated with ste nt bypass, 8 were treated in situ, and 4 patients were treated after p ercutaneous nephrostomy (PCN), All patients were treated initially on an unmodified Dornier HM-3, and all but 4 patients were treated in the prone position on a modified Stryker frame. Follow-up consisted of a plain abdominal radiograph, intravenous urogram, occasionally a retrog rade urogram, and a telephone interview. Results. The overall stone-fr ee rate for ESWL alone was 73%, and the efficiency quotient was 69. Th e stone-free rates after a single treatment for the stent bypass, in s itu, and PCN groups were 71%, 65%, and 75%, respectively. Overall, 4% of patients required retreatment, 19% of patients required an auxiliar y procedure, and 8% of the patients required hospital or emergency roo m admissions for renal colic. For stones 10 mm or greater (9), stone-f ree rates after one treatment for the stent bypass, in situ, and PCN g roups were 33%, 33%, and 67%, respectively; for stones less than 10 mm (17), success rates were 82%, 80%, and 100%, respectively. Conclusion s. Pretreatment stinting provides no advantage over in situ ESWL for m iddle ureteral calculi (Fisher's exact test, P = 1.0), ESWL is a reaso nable initial therapy for middle ureteral stones less than 10 mm.