Comparative study of extracorporeal shock wave lithotripsy (ESWL) between spark gap system and piezoelectric system

We have analyzed the results of the treatment given on 170 cases of cholecystolithiasis, using two different systems of ESWL: Spark Gap System (hereinafter SGS) and Piezoelectric System (hereinafter PES). 1) In the total cases, there were no significant differences in the fragmentation rate between the two systems. PES was, however, superior to SGS in terms of the complete stone free rate. On the other hand, SGS was superior to PES in terms of the average fragmentation rate. 2) We have classified cholecystolithiasis into 4 groups, combining CT and US. PES showed superiority in the ESWL Group 1 (seeming Pure Cholesterol Stone) and Group 2 (seemingly Mixed Stone) in terms of stone free rate. SGS showed superiority in ESWL Group 3 (seemingly Combination Stone) and Group 4 (seemingly Pigment Stone) in terms of fragmentation effect. 3) We have gained good results from both of the system according to Munich Criteria Modified. 4) Concerning the failures of fragmentation and insufficient stone free, further study shall be required to determine whether fragmentation should be repeated, the case should be handled as "beyond adaptability", or the two-system-combined therapy should be applied.