ESWL (Extra-corporeal Shock Wave Lithotripsy)
DEFINITION
ESWL or "extra corporeal shock wave lithotripsy" is a procedure where sound waves are used to break up kidney stones. The kidney stone is broken up into small fragments, which then pass in the urine. The ESWL machine sends the sound waves through the body, so no incision is needed.

The first ESWL treatment was performed in Germany in 1980, and was approved for use in the United States beginning in l984. Initially, patients had to be partially submersed in a bathtub of water, but the newer machines use a regular x-ray table.

THE PROCEDURE
The procedure is done in an operating room that has a built in ESWL machine. The patient is positioned on the x-ray table and a water-filled cushion is placed under their back. The patient is put under anesthesia and the stone is localized on the x-ray screen. The shock wave machine is started and the procedure usually takes 30-45 minutes. During the procedure the stone is continually monitored on the x-ray screen. The patient is awakened after the procedure and usually dismissed to home a short time later.

PREPARATION
The ESWL treatment is done under anesthesia, so the patient will have to fast for 8 hours prior to the treatment. Some physicians will ask their patients to take several laxatives the night before to help with visualization of the stone. The ESWL machine does not use an incision, but it is very important that the patient not be on any blood thinners for a week prior to the procedure. This would include aspirin, coumadin and most arthritis drugs (such as Motrin, Advil and Aleve). Herbal products that may thin the blood (such as vitamin E) should also be stopped. The patient may also be asked to bring their x-ray films to help in the ESWL planning.

AFTER THE PROCEDURE
The patient is transferred to the recovery room after the procedure, and can usually be discharged home within an hour. Patients may experience some soreness on the part of the back where the procedure was done. They will usually have blood in their urine for the first 24 hours. Patients should limit their activities for the first 48 hours and drink plenty of fluids. The stone fragments may pass within the first few days, but occasionally take several weeks to fully pass. If the stone is in the kidney, the patient may be asked to begin "stone exercises" after the procedure to help all the fragments pass.

RISKS AND COMPLICATIONS
Common side effects to ESWL include:

  • blood in the urine
  • soreness in the back
  • pain caused from passage of the stone fragments
  • local skin reaction to the treatment
Less common complications include

  • bleeding around the kidney
  • urinary tract infection
  • nausea and vomiting
FOLLOW UP
Patients are generally seen back in the office in one to two weeks. An x-ray will be done to evaluate how well the stone fragmented. The success rate for most stones is over 80%. If your doctor placed a stent during (or prior to) the procedure, this will have to be removed in the office. Patients are asked to strain their urine and save the stone fragments so they can be analyzed. Most patients can return to work within 2 or 3 days of the procedure.