Extracorporeal shock wave lithrotripsy (ESWL)

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

Why do I need extracorporeal shock wave lithotripsy?

Your doctor may offer you extracorporeal shock wave lithotripsy (ESWL) if you have kidney stone(s) that are causing you severe and ongoing pain.

Kidney stones are often small enough to pass out of your body in your urine without needing any treatment. You may just need to take painkillers while you wait for the stone to pass. Sometimes, your Doctor may also give you medicine to help the stone pass more quickly. If a kidney stone is causing severe pain that you can’t manage at home, your Doctor  may refer you to hospital for further investigation and treatment. They will suggest you go straight to hospital if you have signs of infection, such as a fever. 

If you’re referred to hospital because of kidney stones, you’ll usually have a CT scan or ultrasound, and then be seen by an urologist. This is a doctor specialising in conditions affecting the urinary system. ESWL is one of the treatments to remove your kidney stone that you may be offered.

Alternatives to extracorporeal shock wave lithotripsy

There are alternative treatments to extracorporeal shock wave lithotripsy (ESWL). Which ones your doctor suggests will depend on a number of things. These include how big your kidney stone is, where it is, your age and general health, and if you’ve already had any other treatments.

These are the main alternatives.

• Watchful waiting. 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), your doctor may give you medicines that will speed up the time it takes for the stone to pass in your urine. 
• Ureteroscopy. This is an operation that involves using a laser to break up the stones. Your surgeon may put a tube called a stent in your ureter, to stop it getting blocked by the stone fragments.
• 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 use ultrasound to break up a large stone during the operation.

Deciding on extracorporeal shock wave lithotripsy

When you see a urologist for kidney stone treatment, they will talk through all the treatment options that may be possible for you. If your urologist suggests extracorporeal shock wave lithotripsy (ESWL) as an option, they’ll talk through exactly what will happen before, during and after the procedure. They will also tell you about the potential risks and benefits involved. Here are some of the things to think about.

• ESWL is non-invasive, which means it doesn’t involve cutting or putting anything into your body – the treatment is given through your skin. This means you’re likely to spend less time in hospital than for more invasive procedures, and there may be less chance of developing complications.
• Although ESWL works well for many people, there is a chance that it may not work for you and that you may need further treatment. Other procedures may have a greater success rate, although they are more invasive.
• It’s important to be aware of the potential side-effects and complications associated with ESWL. These include pain and bleeding after the procedure, and a risk of infection and needing further treatment. See our sections on side-effects and complications for more information.
• It may be that your kidney stones would clear if you left them, without the need for any medical or surgical treatment. 

Do ask your doctor if you have any questions or need any further explanation about the procedure. You’ll be asked to sign a consent form if you choose to have ESWL, so it’s important to make sure you feel properly informed.

Preparing for extracorporeal shock wave lithotripsy

Your doctor will explain how to prepare for your procedure, and you may be given some printed information about what to expect. If you smoke, it’s a good idea to stop before your procedure because smoking can put you at greater risk of complications.

You can usually have extracorporeal shock wave lithotripsy (ESWL) and go home on the same day. You won’t be able to drive yourself though, so make sure you have made arrangements for someone to take you home. You won’t usually need an anaesthetic for ESWL, which means you’ll be awake when you have it. You may be given a sedative to help you relax, which can make you sleepy. You’ll also be given a painkiller to ease any discomfort and an injection of antibiotics before the procedure.

You’ll usually need to stop eating two to four hours before the procedure, but you can still drink clear fluids, such as water or black tea and coffee. If you’re taking any medicines, particularly blood-thinning medicines, check with your doctor beforehand whether you should stop or keep taking them.

What happens during extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is usually carried out by a specialist doctor called a urologist, or by a lithotripsy technician. They use a machine called a shock wave generator to deliver the treatment. 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 the treatment couch on your side with your lower back towards the generator. Your doctor or technician will apply water or gel to your skin. This is to make sure the shock waves are transmitted effectively through your skin. Your doctor or technician will pinpoint the exact position of your kidney stone using  or . When the shock wave generator is turned on, it will fire pulses of shock waves through your skin and onto the stone to break it up.

Keep as still as you can during the treatment to make sure the shock waves are being targeted at the right position. You might get a stinging pain on the skin of your back from the shock waves – like having an elastic band flicked on your skin.

Some people may feel a deeper pain in their kidney too. If you’re uncomfortable, do let your doctor or technician know because they may be able to give you more painkillers or sedation.

For larger stones, you may need more than one session to break the stones into small enough fragments to pass down your ureter.

What to expect afterwards

You should be able to go home a couple of hours after the procedure. If you’ve had a sedative, you might feel a bit groggy for a while. Because of this, it’s safest not to drive, drink alcohol, operate machinery or make any important decisions for 24 hours after sedation. Make sure someone can take you home.

Before you leave, your doctor or nurse will give you some advice about your recovery and information about follow-up appointments. You may be prescribed painkillers to ease any pain or discomfort, and antibiotics to prevent an infection. 

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 straightaway, but this can depend on how big the stones are and how the procedure went. 

You’ll need to wait for the fragments of kidney stone to pass out of your body in your urine. This can take several days or even weeks. Drink plenty of fluids – around twice as much as you usually drink – to help flush your system through and reduce risk of bleeding and infection. Your doctor may ask you to collect your urine for 24 hours for analysis in a laboratory.

It can be painful when the stones pass. Take any painkillers that your doctor has prescribed or [PC1]  if your doctor has advised this is ok. If you experience severe pain, a high temperature, increasing bleeding or inability to pass urine, you should contact the hospital straightaway.

You’ll usually see your doctor for a follow-up appointment after around six weeks. They may ask you to have an X-ray to check that the fragments of kidney stone have disappeared. If any are still left behind, you may need further treatment. See our FAQs for more information. 

Side-effects of extracorporeal shock wave lithotripsy

Side-effects are unwanted but mostly temporary effects you may get from having the procedure. Side-effects of extracorporeal shock wave lithotripsy include:

• pain and discomfort as the fragments of stone descend your urinary tract
• a small amount of blood and fragments of stone in your urine – this can last for several days
• bruising and blistering of your skin where your treatment was given – this usually goes away within about seven days

Complications of extracorporeal shock wave lithotripsy

Complications are problems that can happen during or after the treatment. The most common complications of extracorporeal shock wave lithotripsy include the following.

• Infection in your urinary tract. This can develop as the stone breaks up. If you have the symptoms of infection, such as a fever, pain and problems passing urine, contact your doctor.
• Heavy bleeding. A small amount of blood in your urine is expected but if there’s lots of blood or blood clots, speak to the hospital unit where you were treated.
• A blockage in your ureter (the tube leading from your kidney to your bladder). Sometimes the pieces of broken stone pile up here and get stuck. You may need surgery to remove them.
• Sometimes the procedure might not work straight away and you may need to have more treatment. See our FAQs for more information.