Experimental basis for intraoperative calculus localization by ultrasound.

Experiments were conducted in order to prove the usefulness of ultrasound, B-Scan and A-Mode, and A-Mode alone in the localization of small (3 to 10 mm) fragments of foreign materials in renal substance. Clinical experience indicates that stone fragments as small as 3 mm can be localized intraoperatively using A-mode alone, sterilized with gas for use in a surgical field.