Kidney Stones Health Center
Extracorporeal Shock Wave Lithotripsy (ESWL) for Kidney Stones
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 .
Understanding Kidney Stones -- the Basics
Kidney stones are created when certain substances in urine -- including calcium, oxalate, and sometimes uric acid -- crystallize. These minerals and salts form crystals, which can then join together and form a kidney stone. Kidney stones usually form within the kidney, where urine collects before flowing into the ureter, the tube that leads to the bladder. Small kidney stones are able to pass out of the body in the urine -- and may go completely unnoticed by you. But larger stones irritate...
Read the Understanding Kidney Stones -- the Basics article > >
- 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 if you have a large stone. 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.
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.
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 4 mm (0.16 in.) and 2 cm (0.8 in.) in diameter are most likely to be treated with ESWL.
ESWL may work best for kidney stones in the kidney or in the part of the ureter close to the kidney. Your surgeon may try to push the stone back into the kidney with a small instrument (ureteroscope) and then use ESWL.
ESWL is usually 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
For 9 out of 10 patients who have kidney stones smaller than 10 mm (0.4 in.)-either in the kidney or in the ureter-ESWL gets rid of all of the stone or leaves only small fragments that don't cause any symptoms.1
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 replace the need for the preventive treatment of kidney stones, such as drinking enough fluids so that you don't get dehydrated.
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.
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WebMD Medical Reference from Healthwise
