ESWL to Treat Kidney Stone Disease
Extracorporeal shock wave lithotripsy (ESWL) introduced in the early 1980s transformed the treatment of patients with kidney stone disease. Patients who once required major surgery to remove their stones could be treated with ESWL, and no incision was necessary. As such, ESWL is the only non-invasive treatment of kidney stones, requiring no incision or internal telescopic device.
ESWL involves a series of shock waves to the targeted stone. The shock waves, which are generated by a machine called a lithotripter, are focused by x-ray onto the kidney stone. The shock waves travel into the body, through skin and tissue, reaching the stone where they break it into small fragments. For several weeks after treatment, those small stone fragments are passed out of the body in the urine.
In the two-plus decades since ESWL was first put into practice in the United States, we have learned a great deal about how different patients respond to this treatment. We can now recognize patients who will be less likely to experience a successful outcome with ESWL, and we can foresee other patients who will be more likely to clear their stones. We have researched techniques to make lithotripsy safer and more effective, along with the newest state of the art technology to make this an effective treatment choice for kidney stones.
Advantages of ESWL
The primary advantage of ESWL is that it is completely non-invasive.
Who should be treated with ESWL?
ESWL is well suited to patients with small kidney stones that can be easily seen by x-ray.
ESWL is NOT a particularly good treatment for:
- Pregnant patients
- Patients on blood thinners or patients with bleeding disorders. Aspirin or other blood thinners must be discontinued for at least 1 week prior to ESWL
- Patients with chronic kidney infection, as some fragments may not pass, so the bacteria will not be completely eliminated from the kidney
- Patients with obstruction or scar tissue in the ureter, which may prevent stone fragments from passing
- Patients with abdominal aortic aneurysm (AAA)
- Patients who require immediate and/or complete clearance of stone material
- Patients with stones composed of cystine and certain types of calcium, as these stones do not fragment well with ESWL
Because ESWL is a completely non-invasive therapy, most ESWL treatments are performed on an out-patient basis.
Although the use of anesthesia does depend on patient and physician preference, recent data suggest that the results of ESWL may be improved with the administration of an anesthetic, which usually consists of sedation or "twilight".
When the patient has been adequately anesthetized, a computerized x-ray machine is used to pinpoint the location of the stone within the kidney. A series of shock waves (several hundred to twenty-five hundred) is administered to the stone. Our treatment protocols incorporate the latest research findings which suggest that adjustments of both the shock wave power and the rate at which the shock waves are delivered can affect treatment outcome. Our goal when performing ESWL is to maximize the breakage of a patient's kidney stone while minimizing injury that the shock waves can cause to the kidney and surrounding organs. Typically, an ESWL procedure last for approximately 30 minutes.
Most patients experience some degree of discomfort for a day or two after ESWL. The pain is usually described as a dull ache over the kidney, and is typically at its worst the evening following surgery. The pain lessens over the following days. It is normal to see blood in the urine for several weeks after surgery.
New onset pain or pain that is getting worse instead of better may indicate that either there is bleeding around the kidney as a result of ESWL or that the kidney stone fragments have all fallen into the ureter and are blocking the drainage of urine from the kidney.
Large amounts of blood or blood clots in the urine, which may indicate that the kidney was injured by ESWL treatment.
Fever, which may indicate that there is a serious kidney infection.
How do I know if ESWL was successful?
Several weeks following ESWL treatment, we will perform a follow-up x-ray, to determine of the stone broke up into small pieces, and if those small fragments passed out of the kidney. If the stone has broken up into small fragments, but the fragments have not cleared, the x-ray may be repeated in a few weeks. If the stone has not broken up into small fragments, we will likely recommend further treatment. I most cases, if the stone does not break up following one ESWL treatment more ESWL treatments are unlikely to be successful. In this situation, other treatments, such as ureteroscopy or percutaneous nephrolithiasis may be recommended.