Help for kidney stone sufferers
A new laser that attacks a kidney stone the same way a jackhammer breaks up a boulder could mean less time under anesthesia and less post-procedure pain for many patients.
While laser technology has been available for 20 years as a treatment for painful stones in the urinary tract, Cape Cod Hospital’s newest version, made by Lumenis, is "state of the art” and has more force than the hospital’s previous model, said Hyannis Urologist Evangelos G. Geraniotis, MD, FACS. It also has an innovation called MOSES technology that prevents the target stone from recoiling from the laser’s blast and moving further into the urinary tract, he said.
“The beauty of the new laser is that it’s a much higher-powered laser than the previous generation, so when you have a large stone, or basically any size stone, the procedure time is reduced dramatically because the laser just breaks it up faster,” he said.
The machine is likely to get a lot of use. Researchers say the incidence of kidney stones is on the rise. In 1994, one in 20 people in the United States were likely to be affected. Now, thanks to obesity, diabetes and changes in our diet and lifestyles, it’s one in 11. Doctors at Cape Cod Hospital have kidney stone surgical cases almost every day, Dr. Geraniotis said.
He recently answered some questions about urinary tract stones and why the new laser is such an effective treatment tool. (Some of his answers have been edited for length.)
Let’s start with the basics. What’s a kidney stone?
Kidney stones form because of an imbalance in the urinary system of different minerals, predominantly calcium, oxalate and uric acid. When the concentrations of these are higher than they should be, crystals form, and eventually the crystals get big enough that they'll form a stone. The ones that obstruct the ureter are anywhere from 4 to 8 millimeters. An 8-millimeter stone is about the size of a raisin.
Do stones always present a problem?
Stones that reside in the kidney, itself, will often sit quietly without causing any problems. But when one of these stones drops into the ureter and tries to pass, it will get stuck and then that's when the pain issues and other symptoms begin.
Are some people more susceptible to kidney stones?
People who produce too much calcium, which goes into the urine, form stones. People who are chronically dehydrated form stones. People with a history of gout, who have high levels of uric acid, form stones. People with bowel problems and people who had bowel surgery are at a higher risk of stones as well. People who have had bariatric surgery are also at an increased risk of stones. We know that the incidence of kidney stones is increasing, and many researchers feel that this is due to dietary changes that are happening on a national level.
What kind of dietary changes?
Excessive salt, excessive protein, or, more specifically, excessive animal protein contributes to the stone formation. Also, there are a lot of people using protein supplements that have ingredients that can contribute to stones.
How does a laser help with treating kidney stones?
The laser uses advanced technology where we pass a very thin, flexible fiber through a miniaturized camera system that goes into the urinary tract. This is done under anesthesia. We’re able to get into the bladder through the urethra and then into the ureter, which is the tube that runs up to the kidney. We can, with that camera, go up to the stone and then we pass the laser through the camera system and the laser is actually like a miniaturized jackhammer. The energy that comes out of the fiber physically breaks up the stone into little pieces by chipping away at it. The diameter of the smallest fiber we use is 200 microns. [Note: A human hair is about 75 microns.] If you looked at it, it would seem amazing that so much energy could go through such a small fiber.
What happens after you blast the stone?
The little pieces break off and we can then pass another flexible fiber – called a basket –- that has wires at the end that can grab the stone pieces and pull them out. Usually we leave a stent in the kidney for anywhere from one to two weeks. The purpose of the stent is to allow the ureter to heal without blocking up and causing more pain and other issues. The stent is typically removed in the office under a local anesthetic.
What’s the experience like for the patient?
I would say that 90 percent go home the same day. Patients who were in pain prior to their surgery feel much better and go home feeling pain-free. Most patients report mild to moderate discomfort after a procedure like this. A lot of it depends on where the stone is and how big the stone is. One of the advantages of the newer laser is that because the surgery time is reduced, the overall pain is reduced. We do give medication to reduce any discomfort and stent irritation.
You seem to be a fan of this new technology?
The other bonus of the laser technology is that it can be used to treat bladder cancer. The laser beam is so precise, it can deliver energy to a very small area without harming the surrounding tissue. I think that having this technology here is just a big plus for the whole community. It’s one of these things that, as physicians, we almost take for granted, but as I use this laser, I remain impressed with it and am grateful that we have it available to our patients.