What is shock wave lithotripsy?

Shock wave lithotripsy is a common treatment for kidney stones. Providers sometimes call this procedure extracorporeal shock wave lithotripsy (ESWL).

Shock wave lithotripsy uses high-energy shock (pressure) waves to break up stones. Tiny pieces of kidney stones can then move through the urinary tract more easily.

Shock wave lithotripsy may help reduce your symptoms (such as pain) and allow you to pass the kidney stones on your own. It may help you avoid more invasive surgery to remove kidney stones.

What are kidney stones?

Kidney stones are composed of substances (like calcium) that are present in the urine. A kidney stone forms when high levels of these substances crystallize into a mass.

Most kidney stones form inside the kidney but may move into the ureter (the tube that carries urine to the bladder).

When does a kidney stone need to be treated?

Most kidney stones pass on their own. But sometimes, a kidney stone becomes too big to move through (or gets stuck inside) the urinary tract. Pain during a ‘kidney stone attack’ is typically due to a stone getting stuck in the ureter and blocking drainage of urine from the kidney. Kidney stones may cause health issues, such as kidney damage, blood in the urine or a severe infection. In these cases, treatment can help you safely get rid of kidney stones and feel better.

When is shock wave lithotripsy needed?

Shock wave lithotripsy usually works best to treat smaller stones inside the kidney or upper part of the ureter (urine tube). Your provider will consider a stone’s size, your medical problems (including medications) and your body structure before deciding what’s best for you.

Providers often use shock wave lithotripsy to treat kidney stones that:

• Are too large to pass on their own (larger than 5 millimeters in diameter — about the size of a pencil eraser).
• Block urine flow.
• Are very painful.

When is shock wave lithotripsy not recommended to treat kidney stones?

Your provider needs to know a stone’s exact location. Typically a CT scan is performed to identify your stone location and size. Sometimes an X-ray and/or ultrasound can be used as well.

You may not be a candidate for shock wave lithotripsy if you have:

• Hard stones: Kidney stones made up of certain substances (like cystine or certain types of calcium stones) may be more difficult to break up with shock wave lithotripsy.
• Pregnancy: People who are or could be pregnant should not have lithotripsy. The shock waves may harm a fetus.
• Infected kidney stone: An infected kidney stone that is stuck in the ureter and causing fevers or chills is a medical emergency and should not be treated with shock wave lithotripsy.
• Special medical needs: Shock wave lithotripsy should not be used in medical conditions that result in increased risk of bleeding, such as use of blood thinners, due to increased risk of severe bleeding from the kidney.
• Very large kidney stones: Shock wave lithotripsy works best on small kidney stones. Your provider may recommend another treatment for kidney stones over 1-2 centimeters in diameter.

How common is shock wave lithotripsy?

Shock wave lithotripsy is very common. It is the second most common way in which kidney stones are surgically treated in the US.

What can I expect before a shock wave lithotripsy procedure?

Your healthcare provider will explain how to prepare for your procedure. You may need to:

• Complete lab work: You may have blood tests to check your kidney function and blood counts, as well as urine tests to check for infection in your urine.
• Review your medications with your provider: Keep taking all medications unless your provider tells you otherwise. You may need to stop taking warfarin or other blood-thinning medications. These medications could increase the risk of bleeding related to the procedure.
• Follow a specific diet: You will need to stop eating and drinking for a few hours before your procedure.

Who performs shock wave lithotripsy?

Urologists usually perform shock wave lithotripsy. Urologists are highly trained doctors who specialize in treating complex problems of the kidney and other urinary organs.

What can I expect during a shock wave lithotripsy procedure?

Your provider will not need to make any incisions during a shock wave lithotripsy procedure. But you’ll still need some form of anesthesia (pain relief) to keep you comfortable. You may be awake but drowsy or asleep during the procedure.

During a shock wave lithotripsy procedure:

1. You lie on a padded table on top of a water-filled cushion. Less commonly, you may sit in a large tub of water.
2. Providers use X-rays or ultrasound to pinpoint a kidney stone’s location. These images help providers aim shock waves precisely to make treatment more effective.
3. Your care team may move you slightly to line up your body with the energy beams.
4. A shock wave lithotripsy machine sends powerful energy waves through the water and into your body. If you’re awake for the procedure, you may hear a popping sound or feel a tapping sensation along your side.
5. Thousands of shock waves are aimed at the kidney stone, breaking the stone into many pieces. Smaller pieces can then pass more easily through the urinary tract.

How long does a shock wave lithotripsy procedure take?

Shock wave lithotripsy typically takes about one hour. Your procedure may take more or less time, depending on the size and number of kidney stones you have and your overall health.

What can I expect right after a shock wave lithotripsy procedure?

Shock wave lithotripsy is typically an outpatient procedure. While you should go home the same day, expect to spend a few hours in the recovery room. Because you’ll receive sedation, someone will need to drive you home.

How long does it take to pass stones after shock wave lithotripsy?

You can expect to pass kidney stone fragments in your urine for several days to weeks after the procedure. Stone pieces may look like sand, gravel or dust.

Passing stone fragments (even tiny ones) can still hurt. Over-the-counter pain medication can keep you comfortable until you’ve passed all the stone fragments.

How effective is shock wave lithotripsy at treating kidney stones?

The success rate of shock wave lithotripsy varies. It depends on the size, location, and type of kidney stone and your body type.

Overall, 70% to 90% of people who are good candidates for shock wave lithotripsy are stone-free (as seen on follow-up X-rays) three months after treatment. You have a higher chance of success if the kidney stone is inside certain parts of the kidney or in the upper part of the ureter.

What if shock wave lithotripsy doesn’t work?

In some cases, shock wave lithotripsy doesn’t break up a stone enough for all pieces to pass on their own. If that happens, you may need another procedure.

Depending on your situation, your provider may recommend a second shock wave lithotripsy. Or your provider may suggest clearing any remaining stones through a minimally invasive procedure called ureteroscopy. Talk to your healthcare provider about the different types of kidney stone treatments.

What are the potential risks or complications after shock wave lithotripsy?

Potential risks of shock wave lithotripsy include, but are not limited to:

• Blockage in the ureter.
• Blood in the urine or bleeding around the kidney.
• Infection.
• Mild discomfort or bruising on the back (near the treated area).
• Painful urination.

Who is ineligible for shock wave lithotripsy?

Certain medical conditions could make shock wave lithotripsy less effective or riskier. For that reason, your healthcare provider may recommend against shock wave lithotripsy if you have:

• Abdominal aortic aneurysm.
• Bleeding disorders, such as hemophilia.
• Conditions that require blood thinner medications.
• Obesity.
• Cardiac pacemaker or defibrillator.
• Kidney infection or other type of urinary tract infection.
• Kidney cancer or decreased kidney function.
• Pregnancy.
• Spinal deformities, such as scoliosis.
• Uncontrolled high blood pressure.

What does recovery after shock wave lithotripsy look like?

As you recover from shock wave lithotripsy, you can expect to:

• Feel sore for a day or two: Right after shock wave lithotripsy, you may feel sore or stiff near the treatment area. Some people notice slight bruising along their side.
• See blood in your urine: It’s common to see small amounts of blood in your urine. (Your pee may look pink.) It may hurt to urinate. These symptoms usually go away after a few days.
• Collect stone pieces that you pass: Testing the stone may tell your provider what caused your kidney stones (and how to prevent new stones). Your provider may give you a urine strainer. It looks like a funnel with mesh at the bottom. It collects stone fragments when you pee.
• Drop off the stone sample for testing: You can store the stone fragments you collect in a specimen cup your provider gives you or a plastic bag. Follow your provider’s instructions. You may need to take it to your next follow-up visit or drop the sample off at a lab.
• Drink plenty of water: Staying hydrated helps stone fragments move through your body. Drinking water may also help you avoid constipation (a common side effect of certain pain medications).

How long does it take to recover from shock wave lithotripsy?

Most people get back to their usual routines within a few days. But you may have lingering side effects until your body has passed the last of the stone fragments.

When should I call my healthcare provider?

Call your doctor if you have sudden, severe belly or back pain that doesn’t go away, or persistent nausea or vomiting. If you have these symptoms, go straight to the emergency room.

These symptoms are signs that a kidney stone may be blocking urine flow. Rarely, a blockage can lead to a serious infection (that causes fevers or chills) that may pose a danger to your health.

Call your provider anytime you have concerns, especially if you have:

• Blood clots in your urine.
• Fever.
• Pain that gets worse, even after taking pain medication.
• Problems peeing (you feel the urge to pee but can’t).
• Nausea or vomiting.
• Dizziness or light-headedness.

A note from Cleveland Clinic

Shock wave lithotripsy is a safe treatment to get rid of kidney stones. Passing even tiny kidney stone fragments can hurt — sometimes a lot. If you have shock wave lithotripsy, expect to feel some discomfort as stone fragments pass in the days and weeks after treatment. Pain may come and go until all the kidney stone pieces have worked their way out of your body. If you have other health issues, such as uncontrolled high blood pressure, shock wave lithotripsy may pose extra risks to you. Talk with your doctor about what to expect and whether shock wave lithotripsy is the right kidney stone treatment for your needs.