Dusting Away Kidney Stones
Julio Davalos, MD, Medical Director of the Kidney Stone Program at Chesapeake Urology, talks about a new method for treating kidney stones.
Can you talk about kidney stones and how they’re formed?
Dr. Davalos: Kidney stones occur in about one in ten Americans over a lifetime. There’s about a million patients that will experience a kidney stone attack this year. Kidney stones form for a variety of reasons. One of the things that we do at Chesapeake Urology is that we not only do the surgical aspects of treating patients, but also preventative aspects in terms of trying to figure out their stone type and what metabolic disorder may have led to their stone disease. There are about a dozen different reasons that stones can form and most patients, including physicians out there as well, will sort of have a few ideas as to what causes a stone, but there’s really more complexity to it than just being able to say one or two things cause stones. There are obvious things that can cause stones such as dehydration; certain dietary changes, and then certainly there are some things in terms of just how you are born.
What would be some of the treatments that are available right now?
Dr. Davalos: In terms of looking at stones; the majority of stones are not surgical stones. Most stones you can pass on your own—with just some supportive care. Looking at options to actually treat a stone would include things like shockwave lithotripsy, in which a machine is used to locate the stone with x-ray and shock waves are used to break up the stone. Other options would include a scope surgery; where a scope is placed internally to locate the stone and a laser is used to break up the stone. A more invasive procedure would be a small incision surgery going in to the kidney directly or laparoscopic or even open surgery in extreme cases.
When is it necessary to have surgery to remove a stone?
Dr. Davalos: Size matters when it comes to stones. Size is really the big determiner as well as your own anatomy. For the most part a stone that is four millimeters or smaller we say is virtually universally passable. There’s a very small chance that a four millimeter stone or smaller will not pass. But five millimeters you get to the fifty, fifty point where you sort of flip a coin, half of them will pass, half of them won’t. Then every millimeter above five millimeters you start to really get diminishing returns in terms of being able to pass a stone. So stones that are six, seven millimeters and bigger you can certainly consider treatment. Anything that’s above ten millimeters, I always tell my patients, well you may be able to pass a ten millimeter stone and set a record. For the most part we consider anything above ten to be not passable. So it’s really all determined by size.
What’s the largest you’ve ever seen?
Dr. Davalos: I’ve seen stones that are over one hundred millimeters in size that are filling the entire kidney.
I know that these are supposed to be excruciating painful.
Dr. Davalos: They can be quite painful. The interesting thing is that the smaller stones that try to pass may actually be more painful than a stone that gets really big. The reason being that it’s all about where the stone is as well in terms of pain. Most of my patients who have very large kidney stones that are twenty, thirty, forty millimeters in size will describe more of just an achiness in their back and they may not have that typical stone pain. Once a stone moves out of the kidney and travels through the tube, that connects the kidney to the bladder called the ureter, that’s when you can really experience some significant pain. It has been described as more intense than labor in women who have delivered within a short time of having a kidney stone. When you see patients that are trying to pass a stone you really do see the intensity of the pain in their face.
Once it gets large enough is when you would consider using this new laser treatment?
Dr. Davalos: We certainly offer patients the options to try to pass their stone, but if they’re in too much pain or we really think that it’s not going to happen then absolutely using the laser is a great choice for them.
Obviously it’s not for someone that really needs an invasive surgery, like if their entire kidney was filled up; you probably wouldn’t use it?
Dr. Davalos: Well not necessarily. You can use a laser in multiple scenarios. That’s one of things that I like about the laser is that it’s a very versatile instrument. I use the laser in stones that are trying to pass through the ureter, but I also use the laser in large kidney stones cases. For example, if you have a patient whose got that thirty, forty millimeter stone you may have a collection of stone in the part of the kidney you can only get to with a flexible scope. While we are doing more invasive surgery, to get a bulk of a stone out, some of the smaller areas of stone, I would use the scope and the laser even in that scenario. So it has a lot of applications.
What would be some of the other advantages of using this over other types of treatment?
Dr. Davalos: The thing I like about using the laser and the dusting settings in particular is that you’re able to actually break the stone into fine pieces almost like sand that can pass. I won’t say painlessly, but certainly more easily than the other larger fragments may pass. It’s only with this laser technology that I’m able to actually use the settings on the laser to allow it to fragment in to such small pieces.
What would be the complications for this?
Dr. Davalos: Any time you do surgery there’s always the potential for complications and I tell all my patients you can’t do a surgery without there being some risk, but you can’t get in the car and drive to work without there being some risks. Certainly there are risks of injury to the ureter; there are risks of stones that can get lodged. Even the smaller pieces can sort of make a plug and cause a blockage, but really there’s minimal risk compared to the benefit and certainly the pain and discomfort and the risk to the kidney that exists if you don’t treat the stone.
What are the risks if the stones are not treated and what that can mean for your overall health?
Dr. Davalos: If any of my stone patients lived a hundred years ago or a hundred and fifty years ago some of these stones, which we can treat very easily could actually lead to their death. If a stone blocks the ureter and blocks the kidney you can get an infection; you can form an abscess in the kidney and then that could lead to infection in the blood stream which is called sepsis and can lead in extreme cases to death. In some cases if you don’t treat these stones it could lead to kidney damage, infection and some very serious complications.
So it could be life threatening?
Dr. Davalos: It could be life threatening yes. Thankfully with the technology we have today that’s pretty rare and uncommon. However, even today, I do some cases where patients have, particularly with the large stones in the kidneys, they may have ignored the pain, because it wasn’t really an intense pain and they can sometimes show up with a life threatening infection as presenting symptom for their stone.
For the average person millimeter they don’t understand so how big would that be?
Dr. Davalos: Your kidney is about maybe the size of your hand; that would be around ten to twelve centimeters or that would be a hundred and twenty millimeters; so we’re talking about a stone that maybe is about the size of the palm of my hand in terms of length. These stones kind of branch, because the inside of the kidney is like a hollow center almost like a cave and the outside of the kidney is sort of the part that everybody knows in terms of a kidney bean or the kidney shape, that’s where the blood is filtered. However, the stone is formed inside that hollow center and they sort of have all these branches. We call the big stone stag horn stones because of all the little sort of horns that they form.
Kidney stones are just like a stone you pick up out on the ground right?
Dr. Davalos: Yes, very much so.
They actually are very hard?
Dr. Davalos: Some of them are. We look at the hardness of stones and we say that the soft stones are actually about as hard as bone. Then once you get to the harder stones they’re going to be three, four, five times more dense than bone. Most of us think of our bones as being pretty hard structures; so you can imagine these kidney stones.
I talked to one guy who was putting lemonade in the water because of the citrate.
Dr. Davalos: One of the things that I like to do with all my patients is once we get to a point where we’ve treated their stones I think it’s very important to move on to the preventative measures, the medical management of stone disease. There are a lot of things out there that people have heard; you need to cut back on cheese or milk, because calcium can cause stones and that’s probably not entirely accurate. When you look at the science there are four things I tell all my patients that make kidney stones, which there’s a lot of good evidence. One is quite obvious, which is hydration; you want to make sure you drink plenty of fluids. People ask me does coffee cause stones, does soda cause stones and I say well really it’s just about hydration. There are many reasons why you may not want to drink a lot of caffeine or coffee, but really as far as making stones you just want to drink plenty of fluids. You want to get a target of about a half-gallon of urine output in a twenty four hour period. That’s something that you can maybe try to gauge. You’re going to have to drink at least that much or maybe a little bit more than that in order to be able to you know keep your kidneys flushed. The second thing is that salt is really a big culprit for stones. The average American diet has about five thousand milligrams of salt in it. We’re supposed to really only be consuming around twenty five hundred maybe three thousand at most. A lot of my patients, who go through the medical testing, we end up seeing that they have pretty high salt levels. It’s quite easy to get a lot of salt in your food even if you don’t actually grab the salt shaker, because many processed foods will have quite a bit of salt. The reason that salt is a problem with stones is that salt and calcium have a love affair with one another and calcium will follow the salt out of your kidneys and when you consume too much salt your body just dumps it in the urine. The calcium chases the salt out and then you end up getting elevated calcium levels nothing really to do with how much milk or cheese that you’re having in your diet but really having to do with the salt. The other thing is protein. There are a lot of diets out there that throw the focus on high protein and unfortunately a high protein diet can also leads to stones. It has to do with the way your body handles the proteins and it sort of puts an acid load in to your kidneys and that sort of thing can also lead to stones.
Dr. Davalos: Not altogether. However, some people are born with low levels of citrate in their urine. Citrate is just citric acid, so it’s found in things like lemons and oranges. It’s found in the highest concentration in lemons by several factors higher than anything else. If you happen to like lemonade then you know lemonade is a great option to help prevent stones. If you’re going to pick a fluid to drink, something that you really want to try to consume a lot of then lemonade made from real lemon juice is really what you need to go for. And so people ask me what’s that mean. Well I’ve been to many you know fast food places or you go to a convenience store and you pick up a container of quote unquote lemonade and you see it has sometimes three percent lemon juice sometimes it says zero percent lemon juice. So that’s not really lemonade. The lemonade that’s going to help you prevent stones has to be at least ten percent real lemon juice. That’s what I tell my patients, you’ve got to go out and find the stuff that has at least ten percent or you can make your own and I have a way for them to have you know a homemade lemon juice using concentrated lemon juice. It doesn’t cost much for them and it’s a way to get a lot of lemonade made with the right concentration of lemon.
I heard before that people mostly thought it was red meat, but now it’s come out that too much fish, red meat or chicken actually can all form stones. What about eggs?
Dr. Davalos: I don’t think there’s any compelling evidence that eggs will cause stones. Most of the evidence has to do with land animals. We used to focus on the red meat. I used to tell my patients who are big red meat eaters, to cut back. I still think that that’s going to give you the highest potential for kidney stones. However, really all land animals are sort of now the target in terms of protein. I don’t know that there’s any specific research on eggs, but there is some new evidence that says all proteins can be a factor.
How does the dusting procedure work?
Dr. Davalos: Let’s look at dusting stones versus a standard laser lithotripsy. Lithotripsy means to break stone. Dusting the stone requires a special laser machine that allows you to put settings that can fragment a stone in to very minute pieces. When the patient is asleep, we run a scope in to the bladder, then in to the ureter, which is the tube that connects the kidney to the bladder or all the way up to the kidney depending on where the stone is. Once we visualize the stone with the scope we then pass a laser fiber through the scope and then we use special settings on the laser in order to fragment the stone in to minute pieces that really resemble just little tiny grains of sand. Our goal is to get your stone to be less than one millimeter in size, the fragments. It’s felt that any stones that are less than a millimeter in size will flush out of the body much more easily than leaving behind fragments that are maybe two, three, four millimeters in size.
So before they would still break them down but how would they remove them?
Dr. Davalos: There’s some debate out there in terms of do you remove stones. Patients may think to themselves why can’t you just go in there and just grab it and pull it out? What I tell them is if your body couldn’t pass it then for me to grab your stone and pull it out is dangerous. I could cause an injury to the ureter. Once we laser it in to smaller pieces we can certainly try to basket out some of these smaller pieces. Every time we run a scope in and out of the ureter, every time we go to basket there’s always a small chance that we may cause an injury. I think it’s much safer to take the laser, put it on certain settings, where it allows you to dust the stone in to these minute fragments, and then the patient can safely pass that, rather than try to basket and cause an injury. Or even just an irritation to the ureter. Overall I think it’s a better approach and a safer approach. I always tell my patients that’s really my goal for you it’s not just to get rid of your stones, because I know that’s what you want, but I have to do it in a safe way and I think this is a much safer approach.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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