[Removal of ureteral calculi transurethrally with special reference to the so-called "indwelling Zeiss loop" (author's transl)].

In 1628 patients with ureteral calculi there were 1511 (92,81%) successful immediate stone extractions (1950--1960) or "delayed" calculi removals by means of the ureteric catheter loop left temporarily in the ureter (1964--1980). 95--98% calculi have been successfully treated since the introduction of the catheter loop designed by Zeiss. Anesthesia, antibiotics and X-ray control were required. Multiple loops were used in 74 patients out of 1408. The procedure is not dangerous if X-ray equipment and instruments are adequate. The immediate stone extraction was successful only in 65% (1965--1960) where as the "delayed" extraction by means of the Zeiss-catheter loop was successful in 95--98%. Less than 5% loop extractions are unsuccessful. The mortality rate was less than 0,15%. The procedure can be repeated without limitation.