Extracorporeal shock wave lithotripsy

Expert reviewer Dr Raj Persad, Consultant Urological Surgeon
Next review due July 2021

Extracorporeal shock wave lithotripsy (ESWL) is a type of treatment for kidney stones. It uses high-energy shock waves to break down the kidney stones into small crystals. After the procedure, the kidney stones should be small enough to pass out of your body in your urine.

About kidney stones

Kidney stones are hard stones that form in your kidneys. Sometimes the stone can move out of your kidney and into the tube that leads to your bladder (ureter). If this happens, it can cause severe pain in your middle or lower back and groin as it moves down the ureter, or if it gets stuck. This is called renal colic. The stone may also cause, or be caused by, a urine infection.

Kidney stones can develop if there’s too much of certain salts or minerals in your urine, and not enough of others. Stones are also more likely to develop if you’re regularly not drinking enough fluid each day.

Kidney stones are often small enough to pass out of your body in your urine without needing any treatment. But if the stone is large or it gets stuck in your ureter, your doctor may suggest extracorporeal shock wave lithotripsy.

Your care may not be quite as we describe here, as it will be designed to meet your individual needs. Kidney stones of different sizes and locations are treated in different ways. You’ll meet the doctor carrying out your procedure beforehand to discuss what will be involved.

See our information about kidney stones for more details.

Deciding on extracorporeal shock wave lithotripsy

It’s important to talk to your doctor about what will happen before, during and after the procedure, and to consider all the pros and cons. You may want to prepare a few questions about the risks and benefits of the procedure, and alternatives to it. This will help you decide whether extracorporeal shock wave lithotripsy is the right choice for you. Here are some of the things to think about.

  • Although extracorporeal shock wave lithotripsy works well for some people, it doesn’t work completely for everyone. You may need to have the procedure done again if the stone doesn’t break down well enough.
  • If you have extracorporeal shock wave lithotripsy rather than other treatments for kidney stones, you’re likely to spend less time in hospital and have fewer complications. But, other treatments may be more likely to get rid of stones, depending on how big and where they are.
  • It’s important to ask your doctor about all the treatments available. There are differences to think about such as recovery time and possible side-effects.

What are the alternatives to extracorporeal shock wave lithotripsy?

There are alternatives to extracorporeal shock wave lithotripsy, and what your doctor suggests will depend on how big your kidney stone is, where it is and what it’s made of. These are the main alternatives.

  • If you have a small kidney stone that’s not causing any other health problems, you can take painkillers and wait for the stone to be passed out in your urine.
  • Medical expulsive therapy (MET). If you have a small stone that’s less than 10mm (1cm), you can take medicines that will speed up the time it takes for the stone to pass in your urine.
  • Ureteroscopic stone removal. This is a type of operation that breaks up the stone using a laser or removes it using special equipment. A long, thin instrument called a ureteroscope is fed into your ureter to break up the stone or take it out. Your surgeon may put a tube called a stent in your ureter, to stop it getting blocked again.
  • Percutaneous nephrolithotomy (PCNL). This is an operation to take out the kidney stone using keyhole surgery. It’s usually used if the stone is large and other treatments haven’t worked. Your surgeon may also use sound waves to break up a large stone during the operation.

    In the rare situation where you have a stone that’s blocking your ureter, so your urine isn’t flowing properly and/or it’s causing a urine infection, this is treated as a medical emergency. It can cause serious illness and even be life-threatening. If this happens, you’ll have an operation called a nephrostomy, where a tube is put in to drain urine straight from your kidney into a bag. Or you might have an operation to put in a tube (stent) that goes around the stone, so urine can drain properly into your bladder. Whether you have the stent or not depends on how big the stone is, where it’s located and how ill you are when the block is found.

Preparing for extracorporeal shock wave lithotripsy

Your doctor will explain how to prepare for your procedure. You’ll often also be given an information sheet by the hospital or unit where you’re having the treatment, giving you extra information about what to expect.

You can usually have extracorporeal shock wave lithotripsy (ESWL) and go home on the same day. It’s usually done without anaesthetic which means you’ll be awake when you have it. You may be given a sedative to help you relax and a painkiller to ease any discomfort.

You can drink fluids without milk, such as water or black coffee, but don’t eat anything two to four hours before the procedure.

If you’re taking any medicines, particularly blood thinning medicines, check with your doctor beforehand whether you should keep taking them.

Your doctor or radiographer will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to understand exactly what will happen. You might find it helpful to prepare some questions to ask about the risks, benefits and alternatives to the procedure. This will help you to inform yourself about the procedure, so you can give your consent for it to go ahead. You’ll be asked to sign a consent form.

An image showing the location of the bladder and surrounding structures

What happens during extracorporeal shock wave lithotripsy?

The procedure takes between 30 minutes and an hour, depending on how big your kidney stone is.

You’ll be asked to lie down on a couch. An ultrasound scanner is usually used to pinpoint the exact position of your kidney stone and then the machine is positioned where the stone is. You’ll have water or gel put on your skin to make sure there is good contact between you and the machine. When the machine is turned on, sound waves go through your skin to the stone. Keep as still as you can during the treatment. This is because the sound waves will have been carefully set up to break up the stone and cause you the least discomfort. Because the treatment uses sound waves, there’s no harmful radiation involved.

You might get a stinging pain on the skin on your back from the shock waves. Some people say it’s a bit like having an elastic band flicked on your skin. Some people get pain deeper in their body too. If you’re uncomfortable, you can ask for more painkillers.

What to expect afterwards

You should be able to go home a couple of hours after the procedure when you’re ready. If you’ve had a sedative, the medicines can stay in your body for a while. Because of this it’s safest not to drive, drink alcohol, operate machinery or make important decisions for 24 hours after sedation. Make sure someone can take you home.

There are medicines available to ease any pain or discomfort you may have. The doctor treating you will consider how well your kidney is functioning before prescribing any medicines, as certain medicines can cause kidney damage. If you need a follow-up appointment, your nurse will tell you before you go home.

Recovering from extracorporeal shock wave lithotripsy

Once you get home, it's best to take it easy for the rest of the day. Most people feel able to get back to their normal activities within a few days, but this can depend on how big the stones are and how the procedure went. For larger stones it may take around a week to get back to normal.

If you need pain relief, you can take over-the-counter painkillers such as paracetamol, or ibuprofen if your doctor says you can. Always read the patient information leaflet that comes with your medicine and, if you have any questions, ask your pharmacist for advice.

You may be given antibiotics to take to treat or prevent an infection, and it’s important to make sure you finish these as prescribed.

Drink plenty of fluids – around twice as much as you would usually drink. This helps to prevent bleeding and infection.

Side-effects of extracorporeal shock wave lithotripsy

As with every procedure, there are some risks associated with extracorporeal shock wave lithotripsy (ESWL). We haven’t included the chance of these happening as they are specific to you and differ for every person. Ask your doctor to explain how these risks apply to you.

Side-effects are the unwanted but mostly temporary effects you may get after having the procedure. Side-effects of ESWL include:

  • pain and discomfort
  • a small amount of blood and fragments of stone in your urine – the fragments can cause renal colic, which may need further treatment
  • bruising and broken blood vessels under your skin where your treatment was given

Complications of extracorporeal shock wave lithotripsy

Complications are when problems occur during or after the treatment. The complications of extracorporeal shock wave lithotripsy (ESWL) include the following.
  • Infection – you may need antibiotics to treat this. If you have the symptoms of infection, such as a fever, pain and problems passing urine, speak to your GP.
  • Heavy bleeding, such as lots of blood in your urine or blood clots. If this happens, speak to the hospital unit where you were treated.
  • A blockage in your ureter. Sometimes pieces of broken stone pile up inside the tube that leads to your bladder and this may need treatment.

Frequently asked questions

  • Yes, you may need more treatment. Sometimes ESWL doesn’t work completely the first time you have it and if that happens, you may need to have it again to get rid of any remaining stones. ESWL usually works best if a stone is smaller than 2 centimetres.

    If you’ve had kidney stones, then you’re also likely to get them again later in life. Around half of people with a kidney stone will have developed another one within five years of treatment and around eight in 10 people will have one again within 10 years.

    After you’ve had treatment, your doctor may do some tests to see whether you’re likely to develop more kidney stones in future. You may be asked to have some blood tests and collect your urine for 24 hours. This can help to show what’s causing the stones to develop.

    Depending on your test results, your doctor may suggest some changes to your lifestyle to help prevent stones forming. This includes making sure you drink around 2 litres of fluid a day and eat a healthy balanced diet. You may also need some specific advice from your doctor or a dietitian about certain foods you should eat less of.

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Related information

    • Extracorporeal shock wave lithotripsy. Medscape., updated April 2018
    • Nephrolithiasis. BMJ Best Practice., last updated November 2017
    • I think I might have kidney stones. British Association of Urological Surgeons., accessed April 2018
    • Srisubat A, Potisat S, Lojanapiwat B, et al. Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones. Cochrane Database of Systematic Reviews 2014, Issue 11. Art. No.: CD007044. DOI: 10.1002/14651858.CD007044.pub3
    • Extracorporeal shock wave lithotripsy for stones. British Association of Urological Surgeons. 2017

  • Reviewed by Graham Pembrey, Lead Health Editor, Bupa Health Content Team, July 2018
    Expert reviewer Dr Raj Persad, Consultant Urological Surgeon
    Next review due, July 2021