Comparative in vitro study of the effectiveness of nanosecond electrical pulse and laser lithotripters.

A comparative in vitro research of the efficiency of nanosecond electropulse (Urolit-105M) and Holmium laser (Auriga) lithotripters is presented in this work. Four sizes of BegoStone cement stones of various densities were fabricated for these tests. A comparison of the efficiency of the lithotripters was performed in the experiments on pairs of probes corresponding to a predetermined stone size. The probes and stones sizes that were used simulate an actual clinical situation to some extent. During the execution of the tests, stones of the specified size were placed on a stainless steel grid with the 2×2 mm cells, immersed in a liquid. The distal part of each probe type was placed in contact perpendicularly with regard to the horizontal surface of a stone. The experiment was discontinued when the destroyed particles did not remain on the grid's surface (i.e., when the sample had been shattered into fragments of less than 2 mm). It was ascertained that, for all of the stone samples used in the given experiments the nanosecond electropulse lithotripter demands significantly less cumulative energy and less time for destruction of the stones than the laser lithotripter, that is, according to physical parameters, it is more effective. With that, various dependences from pulse energy and from stones properties at their disintegration for two examined methods of contact lithotripsy are confirmed experimentally. Operation of the compared lithotripters differs according to the mechanism by which the stones are destroyed, accounting for the variable influence of sample density on the received results.