[Percutaneous dissolution of uric acid and cystine stones causing acute ureteral obstruction]

Four cases with ureteral obstruction due to uric acid or cystine stones were treated successfully by percutaneous irrigation with sodium bicarbonate or tromethamine-E. These cases underwent percutaneous nephrostomy for the reason of prolonged complete obstruction (case 1), sustained pyelonephritis (case 2) or decreased renal function (case 3 and 4). Two catheters were placed through the nephrostomy tract before irrigation, 6 Fr. ureteral catheter just above the ureteral stone and 10 Fr. pigtail or 12 Fr. Malecot catheter in the renal pelvis. The ureteral stones were markedly reduced in size and passed spontaneously after 6-11 days' duration of irrigation in three cases. In case 2, the remaining stone was removed transurethrally after 14 days' duration of irrigation, and was found to be composed of organic matrix. Percutaneous dissolution is considered to be a safe and reliable method and may be an alternative way of treating uric acid or cystine stone causing acute ureteral obstruction.