Extracorporeal shock-wave lithotripsy of middle ureteral stones: Are ureteral stents necessary?

Objectives: To ascertain whether insertion of a ureteral stent improves the outcome of middle ureteral (overlying the pelvic bone) stones treated with extracorporeal shock-wave lithotripsy (ESWL). Methods: Thirty-three patients with middle ureteral stones were treated with ESWL at our institution between October 1991 and October 1994. Twenty-six patients were available for follow-up; 14 patients were treated with stent bypass, 8 were treated in situ, and 4 patients were treated after percutaneous 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 retrograde urogram, and a telephone interview. Results: The overall stone-free rate for ESWL alone was 73%, and the efficiency quotient was 69. The stonefree rates after a single treatment for the stent bypass, in situ, and PCN groups were 71%, 63%, and 75%, respectively. Overall, 4% of patients required retreatment, 19% of patients required an auxiliary procedure, and 8% of the patients required hospital or emergency room admissions for renal colic. For stones 10 mm or greater (9), stone-free rates after one treatment for the stent bypass, in situ, and PCN groups were 33%, 33%, and 67%, respectively; for stones less than 10 mm (17), success rates were 82%, 80%, and 100%, respectively. Conclusions: Pretreatment stinting provides no advantage over in situ ESWL for middle ureteral calculi (Fisher's exact test, P = 1.0). ESWL is a reasonable initial therapy for middle ureteral stones less than 10 mm.