Blasting to Smithereens

Using sound waves to disintegrate painful kidney stones

Kidney stones are one of man's most common afflictions, and among the most agonizing. As many as one in ten American males and one in 40 women will eventually suffer excruciating pain caused by the accumulation of crystalline material in the kidneys. The incidence of the disease is two to three times higher in the Southeast U.S., which, for reasons unknown--perhaps diet, water supply or climate--has one of the highest rates of kidney stones in the world. Usually a stone will be spontaneously excreted by the sufferer. But each year about 200,000 Americans are hospitalized for the ailment, and 10% to 25% require major surgery that is both costly and painful.

A new instrument, developed in West Germany and Austria, is now making this surgery obsolete in many cases. The percutaneous nephroscope allows doctors to remove stones through a tiny opening in the patient's back or to shatter them into harmless fragments with bombardments of sound waves. Introduced in the U.S. in the fall of 1981, the technique is being used by more than a dozen major medical centers around the country.

Doctors begin the new procedure by administering a local anesthetic and making an incision no larger than 1/4in. Conventional surgery would have required an 8-in. to 10-in. cut. A catheter is inserted near the stone, and, depending on the circumstances, the patient will either be sent home for a week, while his urine drains into a bag, or remain overnight in the hospital. The advantage of waiting a week is that it allows time for tissues around the opening to harden, thus enabling doctors to complete the job using only local anesthesia.

When the patient returns to the operating room, the surgeon removes the catheter and inserts the nephroscope. Optic fibers in the device provide a clear view of the quarry. The doctor then eases a tiny, basket-like grabbing device through the nephroscope and manipulates it to grasp and remove the stone.

If the stone is too big to be "basketed," doctors insert a metal rod that conducts high-frequency sound waves into the stone. "The surfaces tend to be pretty hard," says Urologist Robert Kahn of the University of California at San Francisco, "but once the thing is cracked, it falls apart." The fragments are removed by suction or the grabbing tool. Total time from start to finish: between half an hour and two hours, depending on the size, number and chemical composition of the stones.

"After this procedure, patients are up and around pain-free the next morning," reports Urologist Culley Carson of Duke University Medical Center. "It would be difficult for them to walk around for three or four days after conventional surgery." Another advantage: nephroscopy patients can return to their jobs in about a week; surgical patients require ten days of costly hospitalization and up to eight weeks of convalescence. "There really is no trauma to the system with this method," says Dr. Joseph Segura of the Mayo Clinic, which pioneered the technique in the U.S.

Ultrasonic therapy should be an especially valuable technique for patients who require treatment for recurrent stones. Repeated operations can eventually destroy the kidneys. Says Carson: "With the new technique, there is less risk."

A more esoteric stone-blasting method is now being tested at Munich University's Urological Clinic. No surgery at all is required. Dr. Christian Chaussy places patients in a tub of water and, using special equipment, directs shock waves at the kidney stone, which is located by X ray. The patients, who are partially anesthetized, can relax in comfort while listening to piped-in music. Afterward, however, cramps may occur while the stone fragments are being excreted. The pain occasionally persists for up to three months, but only two of 351 patients have required surgery to remove seemingly shatterproof stones. There is a hitch: to date, Munich has the only such apparatus in the world. Consequently, Chaussy says, "we are overrun by prospective patients." This file is automatically generated by a robot program, so viewer discretion is required.