At the International Kidney Stone Institute, our goal is nothing less than the cure.
In an active urology department, 30 percent of the surgical workload is related to the treatment of urinary stones. This past April in Chicago at the American Urological Association (AUA), the various factors that influence the worldwide treatment of stone disease and management of renal calculi was a hot topic.
“In the so-called “stone belt” countries, including India, Turkey, and Brazil, the incidence of urinary stones is in the range of 10 to 15 percent compared to 5 percent in the rest of the world,” said Dr. de la Rosette, Professor and Chair of the Urology Department at Urology Academic Medical Centrum University, University of Amsterdam, the Netherlands. “Secondly the availability of treatment technologies may differ significantly between countries.”
For decades, treatment of renal stone disease was dominated by open surgical stone removal. This is still performed in countries where limited availability of endoscopic equipment is combined with an excellent experience in open surgery, or because of a high number of staghorn calculi. But new modalities and approaches have seen global development and utilization.
“Since its first presentation in West Germany in the early 1980s, extracorporeal shock wave lithotripsy (ESWL) has revolutioned the treatment of urinary lithiasis,” Dr. de la Rosette said. ESWL gained rapid acceptance worldwide because of its ease of use, noninvasive nature, and high efficacy in treating kidney and ureteral stones. The wide availability of lithotriptors also was a factor. However, the current lithotriptors have not reached the potential of the original electrohydraulic device and provide inferior fragmentation rates compared with the original generation.
“The industry, in an attempt to minimize morbidity, compressed energy and reduced the size of the lithotriptor focal zone,” Dr. de la Rosette said. This fact, combined with the advent of advanced endoscopic techniques, has resulted in a renaissance of the endourological treatments of percutaneous nephrolithotomy (PCNL) and ureterorenoscopy (URS).
Among all urinary stone treatments, PCNL is the most challenging. “Training in PCNL has a steep learning curve that is mainly related to obtaining renal access,” Dr. de la Rosette said. “The quality of training during residency is likely related to the recruitment of patients at the training center and availability of complete up-to-date equipment.” “With increased understanding of renal anatomy and related viscera, urologists have altered patient positioning,” Dr. de la Rosette explained. “These alterations include the reverse lithotomy, lateral decubitus, and supine positions.”
Advances in ureteroscope design and newer methods of intracorporeal stone fragmentation have also resulted in treatment changes for the management of renal stones. Glenn M. Preminger, M.D., from Duke University Medical Center in Durham, North Carolina, is a pioneer and expert in the field of flexible ureteroscopy.
Calcium oxalate stones, which are the most common type of stone, tend to run in families. While a family history does not guarantee stone formation, it does increase the likelihood of forming stones.
A study published in the Journal of the American Medical Association in 2005 found that obesity and weight gain are associated with higher risk of stone formation, even after correcting for dietary influence, age and fluid intake. In addition, several studies have shown that insulin resistant patients, who are typically obese, form very acidic urine. This puts them at increased risk of uric acid stone formation.
The common American diet contains excesses sodium/salt and protein which both increase risk of stones; the former is most relevant for calcium stone formers, while the latter is important for both calcium and uric acid stone formers. Restaurant and prepared foods such as frozen entrees tend to be very high in sodium. A diet high in fresh foods, with moderate protein and minimal added salt may be beneficial for stone prevention.
Anything that decreases the amount of urine production can increase the risk of stones. When less urine is produced, the same amount of waste products are concentrated in a smaller volume of urine. Evaporative loss of fluid through the skin should be made up for with extra beverage intake.
The goal for stone formers should be to urinate more than 2 quarts, or 64 ounces, per day. Highly concentrated urine, associated with low fluid intake, is a risk factor for stone formation.
If you have had a kidney stone in the past, you are at increased risk of forming more stones in the future.
Blood in the urine, or hematuria, can come from any part of the urinary tract: the kidneys, ureters, bladder or urethra. The most common causes of hematuria are infection, stones and tumors. It is important that the source of bleeding be determined to rule out cancers or stones that are causing blockage.
One type of stone, called struvite, forms in the presence of certain urinary bacteria. Because they have more infections, women and people with urinary drainage tubes or ostomies are at highest risk for this kind of stone.
When urine sits in part of the urinary tract longer than usual due to anatomic blockage, the risk of stones increases. Stones can form in the kidney if the ureter drainage tube is blocked. They can also form in the bladder if an enlarged prostate is preventing the bladder from emptying.
Alterations in bowel function or length of bowel from surgery affect how and what is absorbed by the intestine. As a consequence, urine is altered and these patients may form stones more readily.
INDIANAPOLIS – “I’m sweating like a pig!” We have all made that comment at some point in our lives and summer is the season of sweat. BUT, for folks with kidney stones, “sweat” spells “dehydration”. Dehydration affects urine output, which is a problem for kidney stone formers.
Now, urine isn’t usually a topic of proper social conversation, but for those who form urinary stones, it’s a critical concept. When the body is dehydrated, the kidneys conserve water by making urine that is concentrated, and concentrated urine sets up a cascade for stone crystal formation.
According to Dr. James Lingeman, co-director of the International Kidney Stone Institute, “The focus in stone prevention is not the amount of fluid consumed, but rather the amount of urine produced. In the summer months, extra intake is necessary to counteract the season’s dehydrating effects. I tell patients they should never pass up a drinking fountain!”
The essential concepts of stone formation are as follows: stone crystals form in the urine only in the presence of particular molecules in enough quantity and concentration to allow chemical union. As Dr. Lingeman quips, “Crystals love one another and they seek togetherness.” The essentials of stone prevention, therefore, are to reduce either the quantity or the concentration (through dilution) of those molecules.
For the ten percent of Americans who will have a kidney stone at least once in their lifetime, the pain of the stone is a poignant memory. In the acute or immediate sense, stones can cause severe pain, nausea and vomiting, blood in the urine and infection. If left untreated, kidney stones can result in failure of one or both kidneys.
There are several types of stones, and people form them for various reasons. Many patients understandably want to know why they form stones. The metabolic issues are quite complex, but there are a number of universal steps patients can take to prevent stone formation.
In the summer months, the most important of these recommendations is the first: increase urine output. By increasing fluid intake in the summer months, the effects of dehydration can be minimized. Drink more fluids? No sweat!