Experimental laboratory lithotripter: design, construction, and operation

A laboratory lithotripter has been constructed and used to comminute (crush to a powder) both kidney stones and gallstones. The stones are placed in the second focus (f2) of an ellipse of revolution whose linear eccentricity is 4.7 cm and then acoustically shocked an average of 200 times by an underwater spark discharge at the first focus (f1). The energy levels available from the capacitors (3 to 52 joules) of this unit extend below and above the range of commercially available clinical devices. The electrical and mechanical design of this unit is presented. At a relatively low cost (approximately $15,000) the unit appears to have considerable application in non-clinical research in lithotripsy. Quantitative results of the application of this device to the comminution of human kidney stones are presented.