Radiology and treatment of urinary tract stone disease

Renal and ureteral calculi are treated primarily using extracorporeal lithotripsy, with percutaneous nephrostolithotomy retaining an important role for the treatment of large stones and complex situations. Aspects of pretherapy evaluation are reviewed. The vast majority of calculi 5 mm or less in diameter in the mid and lower ureter will pass spontaneously; in patients with acute ureteral obstruction, lower-osmolar nonionic contrast for urography caused as much discomfort as conventional high-osmolar contrast. Treatment planning for extracorporeal lithotripsy has changed in that internal stenting is no longer routinely recommended. Milk-of-calcium and calyceal diverticular stones respond poorly to extracorporeal lithotripsy. The access route used for percutaneous stone removal varies among investigators. Some advocate an intercostal approach for up to one third of patients; substantial complications occur with placement of a track above the 11th rib. Sepsis develops after percutaneous nephrostomy in up to 21% of patients, but the risk of sepsis can be decreased significantly by the administration of antibiotics during and after the procedure. Complications of extracorporeal lithotripsy include renal hematoma (especially if the patient is hypertensive or is taking aspirin), regional organ injury, and bacteremia. Although originally feared to occur frequently, hypertension occurring after or caused by extracorporeal lithotripsy was not confirmed to be a major problem. The incidence in a 2-year postlithotripsy follow-up was no greater than that for control subjects.