Medical Health Encyclopedia

Most procedures are more effective for calcium and uric acid stones and less effective for struvite and cystine stones, although new techniques may be improving their effects on all stones.

Extracorporeal Shock Wave Lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is the most frequently used procedure for destroying and removing simple stones located in the kidney or upper urinary tract, including struvite stones. ESWL is not used for cystine stones. It is generally not successful for stones larger than three centimeters in diameter (which is slightly over an inch).

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All ESWL procedures deliver shock waves from outside the body to break the stones. ("Extracorporeal" means "outside the body" and "lithotripsy" means stone-breaking.) There are several variations. The following is a typical procedure:

• Most ESWL procedures use some anesthesia, although they are often done on an outpatient basis.
• The patient is positioned in a water bath. (In some procedures the patient lies on a soft cushion.)
• The procedure uses ultrasound to generate shock waves that travel through the skin and body tissues until they hit the dense stones. (X-rays or ultrasound are used to help the surgeon pinpoint the stone during treatment.)
• The stones are crushed into tiny sand-like pieces that usually pass easily through the urinary tract.
• The shattered stone fragments may cause discomfort as they pass through the urinary tract. In such cases, the doctor may insert a small tube called a stent through the bladder into the ureter to help the fragments pass. This practice, however, has not proved to speed up passage of the stones in most cases and is not used routinely.

Extracorporeal shock wave lithotripsy (ESWL) is a procedure used to shatter simple stones in the kidney or upper urinary tract. Ultrasonic waves are passed through the body until they strike the dense stones. Pulses of sonic waves pulverize the stones, which are then more easily passed through the ureter and out of the body in the urine.