Dear Doctor Column, September 30, 2002
Question:
My son thinks he has a kidney stone — again! His last stone was about the diameter of a pencil. He is interested in having lithotripsy, if he's a candidate. What do we need to know?
Answer:
Kidney stones are one of the most common disorders of the urinary tract, striking more men than women, usually between the ages of 20 to 40. The National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health estimates that 10% of all Americans will have a kidney stone at some point in time. Fortunately, about 90% of stones pass through the urinary system without treatment. In cases where this does not occur, treatment to remove stones may be needed.
Lithotripsy, also known as extracorporeal shock wave lithotripsy (ESWL), is a technique for treating kidney stones that does not require surgery. Instead, high-energy shock waves are passed through the body and used to break stones into pieces as small as grains of sand, which can then pass from the body along with the urine.
According to the National Kidney Foundation, there are two ways to remove stones using shock wave treatment. In one method, the patient is placed in a tub of lukewarm water. Using x-rays or ultrasound to pinpoint the location of the stones, the body is positioned so that the stones are targeted precisely. In the second, more common method, the patient lies on top of a soft cushion through which the waves pass.
For most types of ESWL procedures, some type of anesthesia is needed. The complete treatment takes about an hour. ESWL may be performed on an outpatient basis. Recovery time is short, and most people can resume normal activities in a few days.
Some pain may occur when the fragments pass through the urinary tract, which begins soon after treatment and may last for up to 4 to 8 weeks. Most patients have blood in the urine for a few days following treatment, and bruising and minor discomfort on the back or abdomen due to the shock waves also are common. Oral pain medication and drinking lots of water helps relieve symptoms. Sometimes, the stone is not completely shattered, and additional treatments may be needed. In those patients who are thought to be good candidates for this treatment, about 70% to 90% are found to be free of stones within 3 months of treatment, according to the National Kidney Foundation.
Unfortunately, not all types of kidney stones can be treated this way. The size, number, location, and composition of the stones are factors that must be taken into account when exploring treatment options. Through examination, x-ray, and other tests, the doctor can decide whether this is the best treatment for the patient. Some stones may be dissolved by medications. In other cases, one of the following methods of stone removal may be needed:
- Percutaneous stone removal may be performed when stones are large or in a location that does not allow effective use of ESWL. In this method, the surgeon makes a small incision in the back and creates a tunnel directly into the kidney. A tube is inserted and the stone is removed through this tube.
- Ureteroscopic stone removal. For stones found in the lower part of the urinary tract, the doctor may pass a ureteroscope (a hollow tube-like device) up into the bladder and ureter. A basket-like device is passed through the tube to grasp and withdraw the stone.
For more information, visit the following Web sites: