PNEUMATIC NU-ELECTROKINETIC LITHOTRIPSY IN TREATMENT OF URETERAL STONES

Recently, a new device (Combilith(R)) for electrokinetic lithotripsy ( EKL) has become available which is very similar to the well-known devi ce for pneumatic (ballistic) lithotripsy (Swiss Lithoclast(R)), The Li thoclast uses air pressure to push a projectile within the handpiece a gainst the end of a metal probe, which is thereby accelerated and thro wn like a jackhammer against the stone. In principle, the same strokin g movement of a small metal probe is provided by EKL; the difference i s that instead of a projectile, a magnetic core within the handpiece i s accelerated by the electromagnetic principle. This paper compares th e clinical efficacy and the features of the two devices, Testing the d evices on a stone model, taking into account stone propulsion, the sys tems turned out to be equally effective regarding stone disintegration , However, stone displacement was more pronounced with the Lithoclast applied on easily breaking stones. In a second experiment, an optoelec tronic movement-measuring apparatus (Zimmer camera) was employed to me asure the range and velocity of the movement of the probe tip without any contact. The linear acceleration velocity ranged from 5 to a maxim um of 12.5 m/sec with both systems, but the maximum height of the stro ke was 2.5 mm with the Lithoclast and I mm with EKL, After the initial break-up of soft stones, further impact of the probe tip against the stone resulted merely in propulsion; thus, the greater probe stroke he ight is the cause of the stone displacement. In a clinical trial, 22 u reteral stones were treated with the Lithoclast and 35 with the EKL, T he two devices were equally effective in terms of stone disintegration and safety margin. Fixation using a Dormia basket was necessary in 12 cases (8 Lithoclast, 4 EKL), Although a difference in probe stroke he ight was noted when comparing pneumatic and electrokinetic lithotripsy , there were no clinically significant differences in the efficacy of stone fragmentation or stone-free rates. At the current time, EKL is l ess costly.