Does Previous Extracorporeal Shock Wave Lithotripsy Affect the Performance and Outcome of Percutaneous Nephrolithotomy?

PURPOSE: ESWL and percutaneous nephrolithotomy are the primary treatment modalities for kidney stones. Furthermore, percutaneous nephrolithotomy is first line treatment when ESWL fails. We assessed how previous ESWL affects the performance and outcome of percutaneous nephrolithotomy. MATERIALS AND METHODS: A total of 1,008 patients underwent percutaneous nephrolithotomy between 2002 and 2007, of whom 230 (22.8%) had a recent history of failed ESWL. Patient characteristics, operative findings, success and complication rates in patients with and without a history of ESWL were analyzed and compared. RESULTS: In the post-ESWL group mean stone size was significantly lower and the mean +/- SD interval between the last ESWL session and percutaneous nephrolithotomy was 3.4 +/- 2.1 months (range 1 to 12). Mean operative time and fluoroscopic screening time were similar in the 2 groups (p >0.05). However, mean operative time per cm(2) stone and fluoroscopic screening time per cm(2) stone were significantly prolonged in the post-ESWL group (p <0.05). At a mean followup of 5.6 +/- 1.2 months (range 3 to 6) an overall success rate of 89% was achieved. Success and complication rates were comparable in the 2 groups. CONCLUSIONS: Although similar success and complication rates were achieved with percutaneous nephrolithotomy after failed ESWL, percutaneous nephrolithotomy is usually more difficult with prolonged operative time and fluoroscopic screening time per cm(2) stone due to the tissue effects of ESWL and scattered stone fragments in the pelvicaliceal system.