Ultrasonic scanning during operation for renal calculi.

Real-time B-mode ultrasound scanning was used during operations for nephrolithiasis. Scanning was done before pyelotomy or nephrotomy to confirm the presence of calculi. For stones in an intrarenal position, requiring an incision through renal parenchyma for extraction, ultrasound permitted guidance for an exploratory needle to localize the calculi precisely. Once the needle tip was in the proximity of the stone a nephrotomy incision was made along the needle track. This procedure enabled the use of relatively small nephrotomy incisions and reduced search time and tissue manipulation. After calculi were extracted ultrasonography was used to make certain that all stone fragments were removed. Ultrasound was considered helpful in 15 of 16 operations.