[Significance of "clinically insignificant residual fragments" (CIRF) after ESWL]

Almost 75% of all urinary calculi can be treated by extracorporeal shock wave lithotripsy (ESWL). In contrast to endoscopic and open-surgical procedures the patients are not immediately free of stones. The residual fragments after ESWL are called clinically insignificant residual fragments (CIRF), if the fragments are less than 5 mm in size and if there is the possibility of a spontaneous passage. But CIRF can cause ureteral obstruction. In addition, CIRF play an important role for the risk of stone growth and stone recurrence. The metaanalysis shows that it is not advisable to classify the CIRF only by their size. The morphological conditions of the urinary tract also have to be evaluated. Therefore, stone patients with CIRF after ESWL require a close follow-up and timely adjuvant therapy. All aspects mentioned lead to the conclusion to use the term "CIRF" with caution.