Lithostar: An Electromagnetic Acoustic Shock Wave Unit for Extracorporeal Lithotripsy

The Lithostar electromagnetic acoustic shock wave (EMAS) lithotripter eliminates the need for a waterbath or disposable electrodes while providing hard-copy radiograph capabilities within a multipurpose uroradiologic table. Herein, treatment experience with 266 patients is presented. Three-month follow-up abdominal radiographs were available for review in 122 patients. The majority of patients were treated on an outpatient basis using a combination of intravenous sedation and a transcutaneous nerve stimulator unit. Initial fragmentation occurred in 89% of patients. The stone-free rate at 3 months (70%), incidence of shock wave retreatment (7%), and the need for post-shock wave auxiliary procedures (16%) were dependent on stone size and stone location. The concept of an effectiveness quotient is introduced, enabling clinicians to compare the performance of a variety of lithotripters for any given set of conditions (i.e., stone size, location, composition). From these data, the effectiveness of EMAS lithotripsy is equivalent to or better than other second-generation lithotripters for all types of renal calculi, and it is as effective as the Dornier HM3 for stones smaller than 1 cm in diameter.