Extracorporeal shockwave lithotripsy

Published by Bupa's Health Information Team, January 2011.

This factsheet is for people who are having extracorporeal shockwave lithotripsy (ESWL) to treat kidney stones, or who would like information about it.

ESWL is a procedure that uses high-energy shockwaves to break down kidney stones into crystals small enough to be passed out in your urine.

You will meet the doctor carrying out your procedure to discuss your care. It may differ from what is described here as it will be designed to meet your individual needs.

About extracorporeal shockwave lithotripsy

Extracorporeal shockwave lithotripsy (ESWL) is a procedure used to break down kidney stones.

Kidney stones are small, solid masses that form when salts or minerals normally found in urine become solid crystals inside the kidney. Usually, the crystals are very small and pass harmlessly out of your body. But if they build up inside your kidney, they can cause pain, infection and damage your kidney function.

Sometimes, smaller kidney stones move out of the kidneys into the tubes that carry urine from your kidneys to the bladder (ureters). These small stones can cause severe pain if they rub against or get stuck in your ureters.

What are the alternatives?

Depending on the size, density and position of your kidney stone, your doctor may recommend alternative treatment options.

• Medical expulsive therapy (MET) – if the stone is less than 10mm (1cm), your doctor may give you medicines to help the stone pass out in your urine (this isn’t commonly done in the UK).
• Ureteroscopy – if the stone is lodged in your ureter, your surgeon will use a long fine, flexible instrument called ureteroscope to remove it. This procedure is usually done under general anaesthesia and a laser may be used to break up the stone before flushing it out. Often a stent is left in the ureter to stop further blockage.
• Percutaneous nephrolithotomy (PCNL) – if the stone is large or in an awkward place, your surgeon will pass a fine instrument through your back into the kidney to remove the stone. This procedure is usually done under general anaesthesia.

Preparing for extracorporeal shockwave lithotripsy

Your doctor will explain how to prepare for your procedure.

Lithotripsy is routinely done as an out-patient or day-case procedure, without the need for anaesthesia. This means you will be awake during the procedure and can go home the same day. You will usually be offered a sedative to relieve anxiety and help you relax, and an injection of painkiller.

You can drink fluids as normal on the day of your procedure. But you will need to go without food for four hours before your treatment.

If you normally take any medication (eg tablets for blood pressure), continue to take this as usual unless your doctor specifically tells you not to. If you’re unsure about taking your medication, contact the hospital.

At the hospital, your nurse will check your heart rate and blood pressure, and test your urine.

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 what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will help you to be informed, so you can give your consent for the procedure to go ahead, which you may be asked to do by signing a consent form.

What happens during extracorporeal shockwave lithotripsy

Lithotripsy takes about 30 to 60 minutes. Usually only one kidney is treated per session.

You will be asked to lie down on a couch. Ultrasound is used to pinpoint the exact position of the kidney stone(s). Your doctor will spread gel onto your skin to allow good contact with the lithotripter sensor. The sensor focuses the shockwaves precisely onto each stone. The intensity of the shockwaves is increased gradually. Try not to make any movements during the treatment, otherwise the kidney stone may move out of focus.

The shockwaves can cause pain in your kidneys and a stinging pain in the skin on your back.

What to expect afterwards

You will need pain relief to help with any discomfort. Your doctor will usually prescribe strong painkillers for the first 48 hours, and he or she may also give you antibiotics to reduce the risk of infection.

Your nurse will give you a date for a follow-up appointment and ask you to pass urine before you go home. Sedation temporarily affects your co-ordination and reasoning skills, so you must not drive, drink alcohol, operate machinery or sign legal documents for 24 hours afterwards. If you’re in any doubt about driving, contact your motor insurer so that you’re aware of their recommendations, and always follow your doctor’s advice.

Recovering from extracorporeal shockwave lithotripsy

Continue to take your painkillers as directed by your doctor. Always read the patient information that comes with your medicine and if you have any questions, ask your doctor or pharmacist for advice.

It's sensible to take it easy for the rest of the day. Most people feel able to resume normal activities within a couple of days.

Drink plenty of clear fluids when you get home, to help flush the kidney stone fragments out of your urinary system.

Contact your GP if you develop any of the following symptoms as you may have developed a urinary tract infection (UTI):

• severe pain or pain that lasts for more than 48 hours
• high temperature
• burning sensation on passing urine or smelly urine
• inability to pass urine
• worsening blood-staining in your urine

What are the risks?

Lithotripsy is commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications of this procedure.

Side-effects

These are the unwanted but mostly temporary effects of a successful treatment.

Side-effects of lithotripsy include:

• pain and discomfort
• some blood and fragments of stone in urine for two or three days
• bruising or blistering of the skin of your tummy or groin

Complications

This is when problems occur during or after the treatment. Most people are not affected. Your doctor will be experienced at performing lithotripsy but, even so, there is a chance it may not be successfully completed and may need to be repeated.

Specific complications of lithotripsy are uncommon, but include:

• infection – you may need antibiotics to treat this
• blockage of ureters – you may need surgery to unblock the tubes
• kidney damage – this can be permanent and affect your kidney function and blood pressure (this is very rare)

The exact risks are specific to you and differ for every person, so we have not included statistics here. Ask your doctor to explain how these risks apply to you.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.