Fate of clinically insignificant residual fragments after extracorporeal shock wave lithotripsy with EDAP LT-01 lithotripter.

The stone-free rate of 248 cases of clinically insignificant residual fragments (CIRF) was 32.7% by 1 month, 73.0% by 3 months, and 92.7% by 6 months of follow-up. The stone-free rate decreased but not remarkably in accordance with the increment of the caliceal dilatation (92.9%, 94.9%, 85.7%, and 83.3% for no, mild, moderate, and severe dilatation, respectively) by 6 months of follow-up. The clearance of the CIRF was not influenced by their location, the pelviocaliceal angle, the infundibular length, or the number of the lower calices. Of 16 patients who had residual stone fragments at 6 months and underwent an additional session of extracorporeal shock wave lithotripsy (SWL), 12 became stone free by another 6 months of follow-up. Therefore, it is desirable to wait for clearance of CIRF for at least 6 months before offering further treatment, regardless of their location and anatomic variation of the calices containing CIRF. Repeated SWL, even for stone fragments of 3 to 4 mm in diameter found initially 1 month after the last session of SWL, might promote clearance of the CIRF, and additional SWL for persistent CIRF could be an appropriate adjunctive measure.