EFFICACY AND COST-EFFECTIVENESS OF EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY FOR SOLITARY LOWER POLE RENAL CALCULI

Abstract

Purpose We determined the efficacy of extracorporeal shock wave lithotripsy monotherapy and compared its cost-effectiveness with percutaneous nephrolithotomy for the management of lower pole renal calculi. Materials and Methods The efficacy (stone-free rates at 3-months posttreatment) of shock wave lithotripsy with the modified Dornier HM3 * * Dornier Medical Systems, Inc., Marietta, Georgia. machine was determined retrospectively in 114 patients with solitary lower pole renal calculi. Using cost data available from patient billing charges and efficacy data from the literature, the cost-effectiveness for percutaneous nephrolithotomy and shock wave lithotripsy as primary therapy was evaluated. To make this cost-effectiveness comparison, we developed a decision analysis model in which a patient in whom primary therapy failed was rendered stone-free with a secondary percutaneous nephrolithotomy procedure. Results The stone-free rates of solitary lower pole stones with a size range of less than 10, 11 to 20 and greater than 20 mm. were 76, 74 and 33%, respectively, with a single shock wave lithotripsy treatment. Based on average treatment costs for shock wave lithotripsy and percutaneous nephrolithotomy, the model results show that for stone sizes less than 2 cm. primary lithotripsy therapy followed by nephrolithotomy for failed cases is the least costly approach. For stone sizes greater than 2 cm. primary percutaneous nephrolithotomy may be more cost-effective. Conclusions Whereas shock wave lithotripsy with the Dornier HM3 should be considered the initial treatment choice for most lower pole stones less than 2 cm., primary percutaneous nephrolithotomy should be considered for stones larger than 2 cm.