Extracorporeal shockwave lithotripsy for stones in abnormal urinary tracts: Analysis of results and comparison with normal urinary tracts

Purpose: We reviewed our experience with SWL for stones in abnormal urinary tracts and compared the results with those in normal urinary tracts. Patients and Methods: The study group was composed of 2566 renal units (RU) treated on the Siemens Lithostar lithotripter at our SWL unit whose treatm ent and follow-up at 10 to 12 weeks were completed. Sixty-eight RUs (2.7%) belonged to 52 patients who had congenital upper urinary tract abnormalitie s. Logistic regression analysis was performed to analyze the impact of age, stone size, location, and the type of abnormality on the outcome of the SW L in the abnormal RU. The student t-, chi-square, and Fisher's exact tests were used for the comparison of stone load, number of treatment sessions, c atheter placement, and success rates of the patients with normal and abnorm al RU. Results of long-term follow-up for available patients (38 RU; 56%) w ere also evaluated. Results: Age, stone load, stone location, and the type of abnormality did n ot have a statistically significant impact on the outcome of SWL for abnorm al RU. The average stone load was 2.1 +/- 2.8 cm(2) in the abnormal and 1.4 +/- 1.3 cm(2) in the normal RU. Thus, the stone load was significantly hig her in the abnormal RU (P < 0.05). In the abnormal group, 56% of the RU bec ame stone free, 37% had nonobstructive and noninfectious clinically insigni ficant residual fragments less than or equal to4 mm (CIRF), and SWL failed in 7%. In the normal group, 78% of the RU became stone-free, 18.5% had CIRF , and SWL failed in 4%. There was no significant difference in the success rates in the groups if success was defined as stone free and CIRF together (P > 0.05). However, there was significant a difference when stone-free, CI RF, and failure rates were evaluated separately (P < 0.05). Recurrence, reg rowth, and retreatment rates in abnormal RU were 50%, 37%, and 34%, respect ively. Conclusions: Although the fragmentation rates were similar, clearance of th e fragments was hampered in abnormal urinary tracts. Thus, especially for l arge stones, other endourologic treatment options should be considered. Hig h recurrence and regrowth rates warrant careful monitoring and consideratio n for medical treatment during follow-up.