Objective: to compare the severity of the urinary tract wall damage from direct electroimpulse and electrohydraulic application.

Materials and methods. Tissues were collected during the open operations. Electroimpulse lithotripter “Urolith 150M” and electrohydraulic lithotripter “Combilith” were under investigation. Impulse energy for “Urolith 150 M” was 0.4-1.0 J, probe diameters – 2.7-6.0 Fr. Impulse energy for “Combilith” was 0.36-0.96 J, probe diameter – 3.0-7.0 Fr.

Results. Electrohydraulic action at the calyx wall with a power of 0.36 J resulted in the calyx wall full depth perforation with a diameter of 2.5 mm and depth of 1 mm, which led also to the parenchyma injury. Electroimpulse action with a power of 0.4 J resulted in the superficial injuries of the calyx wall. With power of 1 J visible injuries of the wall were evident. With maximal power and 900 contact to the ureter wall with a probe of smallest (3.0 Fr) diameter “Combilith” caused a crater-like perforation of the ureter. Under the same conditions “Urolith 150M” caused only superficial laceration of the mucosa without wall perforation. In the bladder wall “Combilith” application with a probe 7.0 Fr and power 0.96 J resulted in the perforation of all bladder layers. “Urolith 150 M” under same conditions caused a dotty mucosal injury. Conclusions. Electrohydraulic action led to more pronounced injuries to the urinary tract, when compared to electroimpulse. e safest application of the electrohydraulic lithotripsy is in the bladder, the more proximal is the application, the more severe could be the injuries. Calyx location of stones is a contraindication for the application of “Combilith”. Electroimpulse lithotripsy could be applied at all locations in the urinary tract.