Kidney Stones—Treating an Ancient Malady
LIKELY you have heard of someone who has suffered with kidney stones. In the United States, some 300,000 kidney stone sufferers are admitted to hospitals each year. The pain can be excruciating, comparable to childbirth.
Some think of kidney stones as a relatively recent health problem, possibly having something to do with modern diet or life-style. Actually, though, stones in the urinary tract have plagued mankind for centuries. They have even been found in Egyptian mummies thousands of years old.
The stones develop when minerals in the urine clump together and grow, instead of being diluted and passed out of the body. They assume various shapes and are composed of many substances. Clinical Symposia says: “In the United States, approximately 75% of all [kidney] stones are composed primarily of calcium oxalate, and an additional 5% are composed of pure calcium phosphate.”
Prevalence and Causes
According to one report, about 10 percent of men and 5 percent of women in North America will develop a kidney stone in their lifetime. And the recurrence rate is high. One in 5 persons who have a kidney stone will develop another stone within five years.
Why some people get kidney stones and others do not has perplexed doctors for many years. The formation of stones may occur for many reasons. These include disorders of the body’s metabolism, infection, inherited disorders, chronic dehydration, and diet.
About 80 percent of kidney stones are eliminated spontaneously during urination. In order to help pass them, patients are encouraged to drink large volumes of water. Although such stones are relatively small, often barely visible, the pain may be great. If blockage of the urinary tract occurs or a stone is too large to pass (they may become as big as a golf ball), medical treatment is needed to preserve the health of the patient.
Until about 1980, major surgery was required to remove kidney stones that would not pass by themselves. In order to reach the stone stuck in the kidney or in the urinary tract, a painful incision, some 12 inches long [30 cm], was made in the flank. The operation was usually followed by a two-week recovery period in a hospital and approximately two months of recuperation at home. But “with recent technological advances,” the medical textbook Conn’s Current Therapy (1989) notes, “the need for open surgical removal is rare.”
Now, difficult stones may be removed by a technique that uses only minimal surgery. Another technique more commonly used today, called extracorporeal shock wave lithotripsy (ESWL), requires no surgery at all. Citing these new medical innovations, Conn’s Current Therapy says that major surgery “is probably responsible today for removal of only 1 per cent of all [kidney stones].”
A Minimal-Surgery Technique
A technique that employs only minimal surgery is sometimes called percutaneous ultrasonic lithotripsy. “Percutaneous” means “via the skin,” and “lithotripsy” literally means “crushing.” The only surgery required is a half-inch [1 cm] incision in the flank. Through this opening a cystoscopelike instrument called a nephroscope is inserted. The interior of the kidney and the offending stone may be seen through the scope.
If the stone is too large to extract through the nephroscope, an ultrasonic probe is passed through a channel in the scope and thus into the kidney. Then, to fragment the stone or stones, the hollow probe is connected to an ultrasound generator that causes the probe to vibrate at approximately 23,000 to 25,000 times a second. The ultrasonic waves make the probe act like a jackhammer, shattering all but the hardest stones it contacts.
Continuous suction through the probe literally vacuums the interior of the kidney, thus ridding it of small stone fragments. The fragmenting and suctioning process continues until careful inspection reveals that all stone debris has been removed through the probe.
At times, however, there are still stone fragments that refuse to budge. In that case, the doctor can insert through the nephroscope a thin tube that has a tiny forceps device attached to it. The doctor can then open the forceps, grab the stone, and pull it out.
As percutaneous surgery developed, many methods were tried. A few years ago, Urologic Clinics of North America said: “New methods of percutaneous stone removal seem to appear with each month’s new issues of the medical journals.” The probability of success of the procedure, the journal observed, “varies with the size and position of the stone.” But the most important factor, the journal explained, is “the skill and experience of the operator.”
Even though sufficient power is generated to smash the stones, the procedure is relatively safe. “Hemorrhage has not been a significant problem,” says Clinical Symposia. One report does say, however, that there has been major bleeding in about 4 percent of patients.
Advantages of this procedure include minimal discomfort and a shortened recovery period. In most cases only five or six days are spent in the hospital, with some patients going home after just three days. This advantage is especially significant to wage earners, who may be ready to return to work as soon as they leave the hospital.
Treatment Without Surgery
A remarkable new treatment introduced in Munich, Germany, in 1980, is called extracorporeal shock wave lithotripsy. It employs high-energy shock waves to fragment stones without making any incisions whatsoever.
The patient is lowered into a stainless-steel tank that is half filled with warm water. He is carefully positioned so that the kidney being treated is at the focal point of shock waves generated by an underwater spark discharge. The waves easily pass through the soft human tissue and reach the stone without losing any of their energy. They continue to bombard the stone until it disintegrates. Most patients then pass the stone debris with ease.
By 1990, ESWL was being used in about 80 percent of all stone removals. The Australian Family Physician reported last year that since the introduction of this technique, “over 3 million patients worldwide have been treated on more than 1100 machines, using a variety of shock-wave generators to disintegrate kidney stones.”
Although ESWL produces some trauma to the kidney area, the Australian Family Physician explains: “It rarely damages adjacent organs such as spleen, liver, pancreas and bowel. The short term trauma effect is easily tolerated with minimal harm to the patients and most patients complain only of mild [muscle and skeletal pain] in the abdominal wall and some slight [blood in the urine] for 24 to 48 hours after therapy.” Even children have been treated successfully. This Australian journal concluded: “After 10 years of evaluation ESWL seems to be an extremely safe treatment.”
Indeed, the treatment is so effective that last year’s Conn’s Current Therapy explained: “(ESWL) has allowed symptomatic stones to be removed so easily and with such minimal morbidity that patients and physicians have become less rigorous in the medical management of urinary stone disease.”
Yet, kidney stones are a painful malady that you surely do not want. What can you do to prevent them?
Since kidney stones often recur, if you have had one, you will wisely heed the admonition to drink plenty of water. A urinary output of more than two quarts [2 L] per day is recommended, and that means drinking a lot of water!
In addition, it is wise to adjust your diet. Doctors suggest limiting your consumption of red meat, salt, and foods high in oxalate, which are believed to help form stones. These foods include nuts, chocolate, black pepper, and leafy green vegetables, such as spinach. Doctors also once recommended reducing calcium intake, but recent research indicates instead that an increase of dietary calcium tends to decrease the tendency to form stones.
Yet, in spite of your taking all precautions, if you should have another kidney stone, it may be somewhat comforting to know that there are improved methods for treating them.
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Nonsurgical treatment of kidney stones using a machine called a lithotripter
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Leonardo On The Human Body/Dover Publications, Inc.