What is extracorporeal shock wave lithotripsy?

Extracorporeal shock wave lithotripsy is a procedure to break up stones inside the urinary tract, bile ducts or pancreatic duct with a series of shock waves generated by a machine called a lithotripter.

The shock waves enter the body and are targeted using an X-ray. The goal of the procedure is to break the stones into smaller pieces that can pass through the body or become easier to extract.

For stones in the kidneys and ureter, fragments will exit with urine. For stones in the bile ducts or pancreatic duct, large fragments may need to be removed by using an endoscope — a flexible tube inserted through the mouth.

Who may need extracorporeal shock wave lithotripsy?

ESWL works differently in various people, and is not always the best choice for someone who has a stone. The following are some of the factors that can affect the procedure’s success.

• Stone composition: Stones composed of cystine and certain types of calcium do not break up well with shock waves.
• Stone location: Stones in very narrow ducts may have trouble passing through or being extracted even after they are broken up.
• Stone size: Large stones may create big fragments that can be difficult to pass or extract.
• Preexisting conditions: Certain conditions, such as chronic infection, may make ESWL less effective.

Some ESWL techniques can make lithotripsy safer and more effective, such as adjusting the power and intervals of the shock waves.

Extracorporeal Shock Wave Therapy for Kidney Stones

Many people who once would have needed major surgery to remove kidney stones can be treated with ESWL without a single incision. ESWL is the main noninvasive treatment for kidney stones. It works well for people with smaller stones that can be easily seen with an X-ray.

ESWL is not recommended for people with chronic kidney infection, because some fragments may not pass and bacteria will not be completely eliminated from the kidney. It may also not work as well for those who have a blockage or scar tissue in the ureter, which may prevent stone fragments from passing.

Because ESWL is a noninvasive procedure, treatments are usually performed in an outpatient setting, meaning you can go home the same day. A mild anesthetic is usually used to numb the kidney area before the procedure.