Extracorporeal shock wave lithotripsy: our experimental and clinical experience with the Direx machine.

The Direx Tripter X-1 is a modular extracorporeal shock wave system that uses underwater spark gaps as its source for lithotripsy. Experience with 712 treatments in 541 patients has given a fragmentation rate of 99%. Of these patients, 27% had stones larger than 2 cm or multiple stones. A stone free situation at 3 months follow-up was achieved in 75% of the cases. Seventeen percent had small fragments less than 4 mm and 8% had fragments greater than 4 mm. Auxiliary procedures following ESWL were required in 7%. No major complications were seen. The advantages of this system are: modularity, mobility, flexibility, and low cost.