By Jane Ehrhardt
Kidney stones impact one in ten people in this country, and about 10 to 30 percent of those cases require some sort of intervention, such as shock waves or invasive surgery. Though the three main treatment approaches have not changed in the last five years, advances in the tools and technology utilized in those treatments have expanded the options for patients.
The most pronounced advancement arrived four years ago with the FDA approval of the thulium fiber laser (TFL). “The energy it creates allows for a higher frequency of delivery, making it more efficient in breaking them,” says Kyle Wood, MD, associate professor and vice chair of research in the UAB Department of Urology.
Prior to thulium, holmium lasers were used and are still in play. “But at UAB, because we’re a tertiary referral center, we see more complex cases requiring longer operating time, and the thulium technology has become a game changer for us,” Wood says, whose training included a two-year fellowship in the advanced surgical techniques and dietary treatment of kidney stones.
To reach larger kidney stones, surgeons make an incision through the back to access the kidneys and then break up and remove the stone. That procedure generally takes one to over two hours of surgical time. The thulium laser’s higher frequency, however, breaks up stones more quickly which shortens the time needed in the operating room. “In larger cases, this laser typically saves 15 to 20 minutes,” Wood says. “Those become meaningful differences to a patient under anesthesia.”
With the power of the thulium and the advancement in smaller instrumentation, some of these more severe cases are now handled noninvasively. “There’s no cutting. We enter through the normal anatomy channels and up through the ureters to reach the kidney, then use the laser to break up the stone,” Wood says.
Smaller instruments have also enabled more less-invasive approaches to kidney stones, including navigating through the ureter. “We use a lot of accessories, like mini baskets and wires. And it’s a bunch of small advancements in all those things that have led to better surgery,” Wood says.
Even more drastic has been the developments in optics, which have empowered urologists to reach more stones through the body’s natural channels. “When TVs and cameras get better, it trickles down into surgery rooms,” Wood says. “We usually follow a few years behind what we get in our living rooms. Fiber-optic cameras have been replaced with digital ones, which has led to them becoming smaller. We’re working in millimeters here, so a tiny difference makes a big difference to us.”
Positioned at the end of the ureteroscope—the thin tube used to reach the kidneys through the bladder and ureters—the cameras now measure just a few millimeters in diameter.
The reduction in size now allows urologists to access more deviations and sizes of ureters, which vary among individuals irrelevant of the person’s size or age. “Before the new optics, the ureter was too tiny to fit the camera. It’s very rare now where we can’t get up to the kidney through the ureter,” Wood says.
The ultra-high definition also offers a new level of detail of the lining of the ureters and kidneys. “Not only can we navigate the anatomy in order to put the technology where we need it, but we can see so much better,” Wood says. “It’s not pixelated. We can tell the difference between tissue and stone.”
Not surprisingly, the new tech is pricey. A flexible catheter runs $20,000 to $30,000 for just one camera per operating room. But fragile tech is known to break every eight to 10 cases, which can cost into the thousands to repair.
With 30 to 50 percent of patients getting another stone within 10 years and 10 percent tending to have more than three stones in their lifetime, Wood says finding the cause should become a priority for physicians. Knowing the makeup of a stone is a vital step, since the cause can vary from low urine pH to genetics. “Physicians should get a metabolic and genetic work up of the stones,” he says. “We need a more personalized medicine approach to kidney stone diseases. Getting at the heart of the cause will lead to better treatment options.”
The South rates high on prevalence of kidney stones. At 12 percent, it’s nearly double that of the Northeast. And it’s no longer a predominantly male affliction. “In the last decade, women have almost caught up,” Wood says, though no one knows why. “It used to be a Caucasian dominate disease, too, but now African-Americans have caught up. It’s probably dietary and trends in comorbidities.”