What is shock wave lithotripsy (SWL)?
Shockwave Lithotripsy (SWL) has emerged as the most popular treatment for removing kidney stones. It is a non-invasive procedure in which ultrasonic waves, also known as shock waves, are generated outside the human body and then a machine called lithotripter is used to penetrate through skin and tissues to target the unwanted kidney stones. This fragments the stone into small pieces or dust which is passed in the urine. It is also known as Extracorporeal Shock Waves Lithotripsy.
- Extracorporeal = outside the body
- Shock waves = high-pressure waves
- Lithotripsy = litho means stones and tripsy means crushing
Factors considered when using SWL:
- Size and shape of stone
- Location in the urinary tract
- Overall health of the patient
- Kidney health
When is SWL useful?
Shockwave lithotripsy is most useful when the stones are less than 3cm in diameter. It is best suited for a stone between 2.5 to 3.0cm stones in kidney or ureters.
For whom SWL is not recommended?
Shockwave Lithotripsy is not recommended for the following set of patients:
- Urinary Tract Infections
- Patients using Blood Thinners & aspirin-like drugs – These drugs must be stopped before the procedure
- Uncontrolled hypertension/diabetes
Preparing for the SWL procedure:
The SWL procedure is performed on an empty stomach. So, the patient will be advised to avoid eating any food (solid or semi-solid) at least five hours before the scheduled appointment. If you take any regular medication such as for hypertension, diabetes, and arthritis, then check with your doctor. Your blood pressure and heart rate will be checked as well as urine testing will be done before performing SWL procedure.
During the procedure:
- The procedure is performed on an out-patient basis.
- The patient will be placed on the operating table.
- A water-filled cushion will be placed behind the lower abdomen.
- Though there is no incision done, still the patient is operated under the effect of mild sedation to avoid any discomfort and ensure a still posture.
- Lithotripter is the machine which generates shock waves that pass through your body and precisely target at the kidney where stone is lodged.
- The whole procedure takes about 45 minutes to 1 hour.
- If everything goes well, patient will be asked to rest for an hour, after which you can go home.
- In case of larger stones, a repeat procedure may be required.
After the procedure, doctor will ask you do drink lot of liquids. A filter will be provided to strain your urine and collect pieces of stone which will be tested later.
Recovery and care
- After SWL, the recovery is very fast. Patients can walk up almost immediately after the procedure and most can even resume their daily activities within 48 hours.
- Patient will have to drink lots of water to help broken stone pieces to pass out in the urine which may happen over a course of maybe 3-4 weeks
Possible complications after the procedure
- Blood in the urine
- Abdominal pain and cramps
- Chronic backache
- Ulcers in stomach and small intestine
- Kidney infection
A doctor may prescribe oral painkillers and antibiotics to help alleviate the symptoms. Serious complications include blockage of the urine, bleeding near the kidney or any damage to the kidney and surrounding areas. If the patient experiences extreme pain or is unable to pass urine, consult your doctor immediately.
Advantages and disadvantages of SWL:
- The main advantage of shock wave lithotripsy is that it does not require any incision and is completely non-invasive treatment. This ensures shorter hospital stay and faster recovery time.
- It does not work for all types of kidney stones. Sometimes, a repeat procedure may be required to remove the remaining stone pieces. There is evidence of injury to the kidneys and development of high BP and diabetes in some patients.
How successful is shock wave lithotripsy?
- Most patients who undergo SWL become free of kidney stones within three months of the treatment. The success rate is higher for patients with smaller stones, less than 1 cm.
- However, in case stone pieces are left behind which fail to pass through urine, then another round of shock wave can be performed or doctor may put a stent to remove the fragmented pieces.
How much does shockwave lithotripsy (SWL) cost?
- The cost of lithotripsy varies in various hospitals. It can range from anywhere between Rs. 10,000 to 30,000 or more in India.