Extracorporeal Shock Wave Lithotripsy (ESWL) is a non-invasive procedure that uses shock waves to break up kidney stones so they can easily pass through the urinary tract. The shock waves, which are created outside the body by a machine (lithotripter), travel through the skin until they reach the kidney stones. After the stones have been hit, they will break down into sand-like particles.
Understanding the Procedure
General anesthesia, to ensure the person remains unconscious and relaxed during the procedure, local anesthetic, to numb the area, or a sedative may be given. The choice depends on the technique, the type of stone and the patient. The body is positioned so that the stone can be targeted precisely with the shock wave.
Using x-ray guidance (fluoroscopy), the location of the stone within the kidney is identified. Then, the physician directs high-intensity sound waves using a special instrument (lithotripter) at the stone. During treatment, it is extremely important to remain very still to keep the stones in focus. The number of shocks waves and treatments needed depends upon the size and hardness of the stones.
It is possible that some stones may not break or may break into large pieces that are difficult to pass. In these instances, the surgeon may insert a small tube (stent) through the bladder into the tube that connects the kidney and bladder (ureter) to help the fragments pass.
Indications for the Procedure
Extracorporeal shock wave lithotripsy is well suited to patients with small kidney stones that can be easily seen by x-ray.