The nation's first non-immersion kidney stone lithotripter, the Lithostar, has begun operations at the University of Texas Medical Branch at Galveston.

Lithotripsy uses electromagnetically generated shock waves to disintegrate kidney stones without surgery. The resultant sand-like particles pass out of the body in urine within a few weeks after treatment. Lithotripsy revolutionized kidney stone treatment, which previously had required surgery.Reduction of anesthetics is the Lithostar's primary benefit, according to Dr. Michael M. Warren, chief of the division of urology. The Lithostar's shocks are less powerful than those of water-bath systems. Patients, therefore, feel little pain and usually receive only a local painkiller or intravenous analgesia.

During treatment, the patient lies on a specially designed table. Instead of a water-bath conduit, a gel disk is used to transmit shock waves. The single-use disk, about the size of a salad plate, is placed between the patient and the shock-generating device.

Unlike the water-bath machines, the Lithostar has no limitations on patient weight or height, according to the university. Very heavy, tall or short patients can receive treatment with the device.

"The procedure itself probably costs about the same as the operation," Warren says. "But you spend much less time in the hospital. Plus you go back to work much more quickly. There's a tremendous cost savings, but it's hard to accurately determine money saved by returning the person to the workplace."