Coagulum pyelolithotomy.

In 25 patients undergoing pyelolithotomy a supplementary coagulum technique has been used. Initial difficulties were found in the preparation, instillation and extraction of the coagulum, but with experience a satisfactory technique has been developed. The type of stone situation most likely to benefit from coagulum pyelolithotomy would seem to be where there is a small, mobile stone or stone fragment lying in a calix or in a wide renal pelvis.