Extracorporeal shock wave lithotripsy (ESWL) uses shock waves to break a kidney stone into small pieces that can more easily travel through the urinary tract and pass from the body.

See a picture of ESWL.

• You lie on a water-filled cushion, and the surgeon uses X-rays or ultrasound tests to precisely locate the stone. High-energy sound waves pass through your body without injuring it and break the stone into small pieces. These small pieces move through the urinary tract and out of the body more easily than a large stone.
• The process takes about an hour.
• You may receive sedatives or local anesthesia.
• Your surgeon may use a stent when your stones are larger than 2.5cm. A stent is a small, short tube of flexible plastic mesh that holds the ureter open. This helps the small stone pieces to pass without blocking the ureter.

What To Expect After Treatment

ESWL is usually an outpatient procedure. You go home after the treatment and do not have to spend a night in the hospital.

It may take a few days or weeks for all the stone fragments to pass from your body. You may have mild pain as the small fragments pass through the urinary tract.

Why It Is Done

ESWL may be used on people with a kidney stone that is causing pain or blocking the urine flow. Stones that are between 4mm and 2cm in diameter are most likely to be treated with ESWL.

ESWL may work best for kidney stones in the kidney, not in the ureter. It may be harder for ESWL to break up a stone that has moved into the ureter, although this is still possible. Your surgeon may try to push the stone back into the kidney with a small instrument (ureteroscope) and then use ESWL.

ESWL usually is not used if you:

• Are pregnant. The sound waves and X-rays may be harmful to the fetus.
• Have a bleeding disorder.
• Have a kidney infection, urinary tract infection, or kidney cancer.
• Have kidneys with abnormal structure or function.

How Well It Works

After ESWL, stone fragments usually pass in the urine for a few days and cause mild pain. If you have a larger stone, you may need more ESWL or other treatments.

ESWL machines can be low- or high-energy. Low-energy machines cause less discomfort, but you may need more treatments before the stone is broken into pieces small enough to pass.

For 9 out of every 10 patients with kidney stones smaller than 10mm-either in the kidney or in the ureter-ESWL gets rid of all the stone or leaves only small fragments that don't cause any symptoms.¹

ESWL does not replace the need for the preventive treatment of kidney stones, such as drinking a lot of fluids.

Risks

Complications of ESWL include:

• Pain caused by the passage of stone fragments.
• Blocked urine flow as a result of stone fragments becoming stuck in the urinary tract. The fragments may then need to be removed with a ureteroscope.
• Urinary tract infection.
• Bleeding around the outside of the kidney.

What To Think About

ESWL does not successfully treat cystine kidney stones. These stones do not break up easily.

ESWL is a safe procedure and may be used on children and on individuals with only one working kidney. ESWL should not be used if you have a pacemaker unless a cardiologist has determined it is safe.

Should I use extracorporeal shock wave lithotripsy (ESWL) for my kidney stones?

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Citations

1. Spector DA (2007). Urinary stones. In NH Fiebach et al., eds., Principles of Ambulatory Medicine, 7th ed., pp. 754–766. Philadelphia: Lippincott Williams and Wilkins.