Lithotripsy Treatment for Kidney Stones
A non-invasive way to remove kidney stones
Extracorporeal shock wave lithotripsy (ESWL) is a technique for treating stones in the kidney
and ureter that does not require invasive surgery. Instead, high energy shock waves are passed through the body and used to break stones into pieces as small as grains of sand. Because of their small size, these pieces can pass from the body along with the urine.
The lithotriptor attempts to break up the stone with minimal collateral damage by using an externally-applied, focused, high-intensity acoustic pulse. The patient lies down in the apparatus bed, with the back supported by a water-filled coupling device placed at the level of kidneys.
A fluoroscopic x-ray imaging system or an ultrasound imaging system is used to locate the stone and aim the treatment head so that the focal point of the parabola of the shock wave is focused on the stone. The sensation of the treatment is likened to an elastic band twanging off the skin.
The successive shock wave pressure pulses result in direct shearing forces, as well as cavitation bubbles surrounding the stone, which fragment the stones into smaller pieces that then can easily pass through the ureters.
Frequently asked questions about lithotripsy
What does the treatment involve?
The patient lies on a soft cushion or membrane through which the waves pass. About 3,000 shock waves are needed to crush the stones over a period of 30 minutes.
What are the advantages and disadvantages of this treatment?
The main advantage of this treatment is that many patients may be treated for kidney stones without invasive surgery. This disadvantage is that the patient has to pass the small fragments of the original stone. It is common to pass blood in the urine after the procedure and to have pain in the kidney and ureter as the small stone fragments pass.
Unfortunately, not all types of kidney stones
can be treated this way. Uric acid and cysteine kidney stones are not visible on plain X-ray and cannot be easily treated using lithotripsy. In addition, stone fragments are occasionally left in the body and additional treatments are needed.
Does the patient need anesthesia?
In general, some type of anesthesia – either sedation, regional or general – helps the patient remain still and to reduce any discomfort.
Are there any restrictions after treatment?
After treatment is complete, the patient can move about 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 lower pole kidney stones, use of an inversion board may help with stone passage. Some pain may occur when the fragments pass, which begins soon after treatment and may last for up to four to eight weeks. Oral pain medication and drinking lots of water will help relieve symptoms.
Usually a lithotripsy patient is asked to strain his or her urine afterward to collect pieces for analysis and to determine what the stones are made of.
Are there complications or side effects?
Most patients have some blood in the urine for a few days. The shattered stone fragments may cause discomfort as they pass through the urinary tract. Sometimes, the stone is not completely shattered, and additional treatments may be needed. Patients may develop a urinary tract infection or bleeding around the kidney.
ESWL usually is not used if you:
- Are pregnant. The sound waves and X-rays may be harmful to the fetus.
- Have a bleeding disorder.
- Have a kidney infection, urinary tract infection, or kidney cancer.
- Have kidneys with abnormal structure or function.
The passage of stone fragments may take a few days or a week and may cause mild pain. Patients may be instructed to drink as much water as practical during this time. Patients are also advised to void through a stonescreen in order to capture stone fragments for analysis.
A patient of the procedure has equated the after effects to "a punch to the kidney" (pain while urinating, sometimes with blood).
Can all kidney stone patients have this kind of treatment?
No. The size, number, location and composition of the stones are factors that must be taken into account when exploring treatment options. Also the stones must be clearly viewed by the x-ray monitor so the shock waves can be targeted accurately. If anatomical abnormalities prevent this, other methods of stone removal may have to be considered.
Through examination, x-ray and other tests, the doctor can decide whether this is the best treatment for the patient. In some cases, extracorporeal shock wave lithotripsy may be combined with other forms of treatment.
How successful is extracorporeal shock wave lithotripsy?
In those patients who are thought to be good candidates for this treatment, about 70 to 90 percent are found to be free of stones within three months of treatment. The highest success rates seem to be in those patients with mobile stones that are located in the upper portions of the urinary tract (kidney and upper ureter). After treatment, some patients may still have stone fragments that are too large to be passed. These can be treated again if symptoms persist.