Shock Wave Technique Used to Smash Inoperable Gallstones

Doctors in Canada and Europe have used electrically generated shock waves to smash painful and often dangerous inoperable gallstones wedged in the bile duct, a researcher reported.

“We are very encouraged by the initial success. We know the technique works and has no immediate side effects. But we don’t know what will happen 10 years hence,” said Dr. Laszlo Fried, associate professor of radiology at Dalhousie University Medical School in Halifax, Nova Scotia, Canada.

Some 4% to 15% of the 500,000 Americans who undergo gallbladder operations each year also have stones lodged in the narrow duct that connects the gallbladder to the liver and the small intestine.

Left undetected, the stones produce such symptoms as pain, jaundice or even life-threatening infections in the majority of patients within five years.

Using a method called extracorporeal shock wave lithotripsy, or ESWL, European and Canadian doctors have crushed bile duct stones in 60 patients. The Food and Drug Administration has approved U.S. testing of the technique for such cases.

Fried and his team used the focused shock waves generated by high-voltage sparks to blast away bile duct stones in 15 of 16 inoperable patients.

Stones Clogging Duct

The stones were clogging the duct that carries bile--a substance produced from cholesterol by the liver and stored in the gallbladder for use in digesting fat--from the gallbladder and liver to the intestines.

ESWL, one of a variety of methods aimed at eliminating the stones, works at times when others do not and may cause less stress to the patient, Fried reported at the 88th annual meeting of the American Roentgen Ray Society.

Doctors have used the procedure since the early 1980s to treat kidney stones and since 1986 to smash stones in the gallbladder. In the United States, the technique has been approved for general use only for kidney stones.

The patients in Fried’s study could neither undergo surgery nor have the bile duct stones removed through a tube implanted in the abdomen or threaded through the throat. These methods were ruled out for reasons ranging from the stones being too large to being lodged in inaccessible sites.

The patients were immersed in a tank of water. An electrode fixed at the top of the tank generated shock wave energy, and a mirror focused the waves on the affected area. The stones were smashed and either passed by themselves or were removed through an abdominal tube. ESWL, lasting from 30 minutes to an hour, was performed under spinal or general anesthesia.

The only side effects noted were changes in liver enzymes--but with no signs of any liver damage--and some temporary bruising in the treatment area.

Usually, bile duct stones are removed surgically or are allowed to pass out or be fished out with a tiny wire basket through a tube implanted in the abdomen or threaded through the throat. The tube has to be left in place for up to seven weeks, a drawback eliminated in lithotripsy.

“Lithotripsy will probably take its place among the major techniques for removing bile duct stones,” Fried said, “but it will not be our salvation.”