Non-Invasive Treatment of Urinary Tract Stones — ESWL
What is ESWL?
ESWL or Extracorporeal Shock Wave Lithotripsy is a non-invasive technique for treating stones in the kidney or ureter using high-energy shock waves. Stones are broken into "stone dust" or fragments that are small enough to pass in urine.
When can ESWL be used?
ESWL works better with some stones than others. The size and shape of stone, the predicted hardness of the stone, the location of the stone in your urinary tract, your health, and your kidneys' health will be part of the decision to decide the best treatment for your stone.
Kidney stones that are smaller than 2 cm in diameter are the best size for ESWL. Larger stones can be treated by PCNL or RIRS. However, larger kidney stones can be treated in experienced hands with multiple sessions and a ureteric stent.
Ureteral stones that occur in the upper third of the ureter near the kidney can be treated by SWL. Ureteral stones that occur lower (near the bladder) are more difficult to treat with ESWL, but can be successfully treated by experienced operators.
ESWL is more appropriate for some people than others. Because x-rays and shock waves are needed in ESWL, pregnant women with stones are not treated this way. People with bleeding disorders, infections, severe skeletal abnormalities, or who are morbidly obese also not usually good candidates for ESWL. lf your kidneys have other abnormalities, your doctor may decide you should have a different treatment. lf you have a cardiac pacemaker, your cardiologist will be involved in the decision on whether you can have ESWL.
What does the treatment involve?
You will be positioned on an operating table. A soft, water-filled cushion may be placed on your abdomen or behind your kidney. The body is positioned so that the stone can be targeted precisely with the shock wave.
ESWL is delivered with sedation and pain relief medication to help the patient remain still, reduce any discomfort, and this improves the breaking of the stone.
About 3-4 thousand shock waves are needed to crush the stones. The complete treatment takes about 50 to 70 minutes.
Sometimes, a ureteral stent is inserted prior to ESWL. Ureteral stents are soft plastic tubes which are introduced into the bladder and threaded up to the kidney. They have ensure good drainage of urine from the kidney to the bladder. They are used when the ureter is blocked, when there is a risk of infection and in patients with intolerable pain or reduced kidney function.
After the procedure, you will usually stay for about an hour then be allowed to return home if all is well. You will be asked to drink plenty of fluids, strain your urine through a filter to capture the stone pieces for testing, and you will be given painkillers to bring home. Alpha blockers which are drugs that relax the ureter may be given to help passage of the stone fragments after ESWL.
Does the patient need to be hospitalized?
Not usually. In most cases, lithotripsy is done on an day surgery basis.
What are the advantages and disadvantages of this treatment?
The main advantage of this treatment is that it treats kidney stones without an incision. As a result, hospital stays and recovery time are reduced.
But, while SWL can work, it doesn't always work. After SWL, about 50% of people will be stone free within a month. In others, stone fragments of various sizes remain. Sometimes a repeat procedure (or a different procedure) is needed.
You should ask your doctor about risks and benefits of SWL in your situation.
What can the patient expect after treatment?
The recovery time is usually fairly brief. After treatment, the patient can get up to walk almost at once, Many people can fully resume daily activities within one to two days. Special diets are not required, but drinking plenty of water helps the stone fragments pass. For several weeks, you may pass stone fragments.
After treatment, you may have blood in your urine and possibly abdominal pain or aching for a few days as the stone fragments make their way out of the kidney/ureter. Oral pain medication and drinking lots of water will help relieve symptoms.
Sometimes, the stone is not completely broken up, or big pieces remain and additional treatments may be needed.
Rarely, more serious problems occur, such as bleeding near the kidney that might require a blood transfusion, damage to the area around the stone, or blockage of the flow of urine by stone fragments.
How successful is shock wave lithotripsy?
ln those patients who are thought to be good candidates for this treatment, some 50-90% are found to be free of stones within three months of ESWL treatment. The highest success rates seem to be in those patients with smaller stones (such as less than 1 cm).
After treatment, some patients may still have stone fragments that are too large to be passed. These can be treated again if necessary with shock waves or with another treatment.
A video explanation of the procedure can be found here
Dr Robert Tan is a local pioneer in the non-invasive treatment of urinary stones, and was amongst the first batch of local urologists trained by Germany urologists sent to Singapore, on the use of Extracorporal Shockwave Lithotripsy (ESWL). His extensive experience, commitment and personal touch have led to excellent stone free rates with this technique.