What is ESWL?
Extracorporeal shock wave lithotripsy (ESWL) uses shock waves to break the kidney stone into small pieces that can pass from the body more easily than one large stone. Stone fragments usually pass within a few weeks. Depending on the size of the stone, you may need only one treatment. The larger the stone, the more likely it is that you will need more than one treatment. See an illustration of ESWL. ESWL is only one method used to break up kidney stones, but it is the most commonly used method because it does not require surgery. Other options include percutaneous nephrolithotomy or nephrolithotripsy, ureteroscopy, and open surgery.
In the past, treatment of large urinary stones required invasive surgery. Since the early 1980’s, extracorporeal shock wave lithotripsy (ESWL) obviated surgery for over 90% of these patients. As with any new medical technology, the goals and efficacy of ESWL must be compared to those of previous methods. Shock wave phenomena were studied during the 1960s with the advent of high velocity air and space travel, and shock wave effects on biologic materials began in the 1970’s. As little difference exists in acoustic impedance between body tissues and water, shock waves generated in water are transmitted through biologic tissues without significant energy loss. Acoustic impedance exists between a kidney stone (solid) and surrounding kidney tissue with urine (water density). Experiments demonstrated disintegration of the crystalline structure of stones when shock wave energy was focused on this acoustic interface. Shock waves are generated from a spark-plug apparatus with opposing electrodes
Extracorporeal Shock Wave Lithotripsy (ESWL) is a non-invasive medical procedure designed to help eliminate renal and biliary calculi, otherwise known as kidney stones and gallbladder stones, respectively. The procedure is generally painless and usually conducted on an outpatient basis without the need for anesthesia. However, ESWL patients are often given a sedative, most likely due to the simple fact that the procedure can take up to an hour to complete and the recipient must lie reasonably still. In some cases, the patient is kept occupied by being permitted to watch the entire process on an ultrasound monitor. ESWL is accomplished through the use of a lithotriptor, a device that emits electrical impulses (shockwaves) initiated via an electrohydraulic, piezoelectric, or electromagnetic generator. The first lithotriptor introduced in the U.S. was the electrohydraulic Dornier HM3 in the early 1980s, which was originally designed to test components of supersonic aircraft. Its design is
