Shock wave lithotripsy (ESWL – extracorporeal shock wave lithotripsy) is a way of treating kidney stones without an incision and without inserting an instrument into the body. Shock waves produced by a machine outside the body are focused on the stone and break it into fragments, which come out with the urine.
The method is suitable for some patients with kidney stones – above all for smaller stones in a suitable position. Dr Penev decides whether it is the right choice for you after a kidney stone consultation with an ultrasound and a CT scan.
When it is recommended
The method is usually considered for:
- kidney stones up to roughly 1.5–2 cm in the renal pelvis or in the upper and middle calyces;
- stones in the upper part of the ureter that do not come out on their own;
- stones of low or moderate density on the CT scan.
The method is not suitable during pregnancy, with an active urinary infection, impaired blood clotting or anticoagulants that cannot be stopped, a blockage of the ureter below the stone, an aneurysm near the kidney, very dense stones or stones larger than 2 cm. In these cases Dr Penev usually recommends endoscopic and laser stone treatment, in which the stone is usually removed in a single procedure.
How it works
- Positioning. You lie on a special table, and the shock wave source is aimed at the kidney through a layer of gel.
- Targeting. The stone is located with ultrasound or X-ray guidance and placed at the focus of the machine.
- Fragmentation. The machine sends shock waves at a steady rhythm, with the power increased gradually. A session lasts roughly 30–60 minutes.
- Pain relief. Painkilling medicines are given and, if needed, light sedation; general anaesthesia is rarely necessary.
- Finish. After a short period of observation you usually go home the same day with someone accompanying you.
Preparation
- Tests. A urine test for infection, a full blood count, blood clotting and kidney function, as well as an up-to-date CT or ultrasound scan on which the procedure is planned.
- Medicines. Blood-thinning medicines are stopped or replaced only on the instructions of the doctor who prescribed them; your blood pressure must be under control.
- Food. If sedation is planned, do not eat for about 6 hours before the procedure; the day before, avoid foods that cause wind – gas in the bowel makes targeting more difficult.
- Tell the doctor if you have a pacemaker, are or might be pregnant, or have had previous kidney operations.
After the procedure and results
For the first few days your urine may be pink and you may feel a dull ache in your lower back. While the fragments pass down the ureter, colicky pain is possible, so Dr Penev prescribes painkillers and a medicine that relaxes the ureter. Drink enough fluid, keep moving and pass your urine through a fine strainer to catch a fragment for chemical analysis – it guides your diet and the prevention of new stones.
Go to an emergency department immediately or call 112 (the European emergency number) if you have a temperature and shivering, pain that is not controlled by the prescribed medicines, persistent vomiting or if you stop passing urine: a blockage by fragments combined with infection requires urgent drainage of the kidney.
A follow-up ultrasound is usually done after 2–4 weeks; if fragments remain, a second session or endoscopic removal is planned. For a larger stone, a temporary JJ (double-J) stent is sometimes inserted before the fragmentation to make drainage easier. The result depends on the size, density and position of the stone, so Dr Penev discusses realistic expectations with you in advance.
Where it is done
The consultation, ultrasound and follow-up take place at Dr Penev’s practice in Plovdiv (5 Anri Barbyus St) and at Vita Med Medical Centre, Karlovo, by appointment. The fragmentation itself is planned at the Department of Urology at Kaspela University Hospital (UMBAL Kaspela), Plovdiv (64 Sofia St), depending on the equipment available.
Price
Initial consultation – €50, follow-up consultation – €30. The price of the procedure is confirmed at the consultation.
To find out whether your stone can be broken up without surgery, book an appointment with Dr Penev for a consultation and a discussion of the most suitable method.
Frequently asked questions
Does shock wave lithotripsy hurt?
The shock waves feel like a rhythmic tapping in the lower back, which can become unpleasant as the session goes on. That is why a painkiller is given before the start and, if needed, light sedation. Most patients tolerate the procedure without difficulty.
How many sessions are needed?
For a small stone one session is often enough, while a larger or denser stone may need two or three, usually one to two weeks apart. The decision is made after a follow-up ultrasound scan.
How long does it take for the fragments to come out?
Usually within days to a few weeks, depending on their size and the position of the stone. Drinking enough fluid and staying active help, and the follow-up consultation shows whether the kidney is clear.
Why do some stones not respond to shock waves?
Very dense stones – for example cystine stones and some calcium oxalate stones – are difficult to break up. A large distance between the skin and the stone is also an obstacle, as is a position in the lower pole of the kidney, from where fragments come out slowly. In these cases endoscopic treatment gives a more reliable result.
Can the procedure damage the kidney?
When the indications are followed, the risk is small. Slight blood in the urine and bruising of the skin pass within days. Rarely, a bleed can form around the kidney, which is why blood clotting and blood pressure are checked before the procedure.
The information on this website is for general education and does not replace an examination and consultation with a doctor. If you have urgent symptoms, seek medical help immediately or call 112.