Ross Simon, MD, MS, Urologist at Tampa General Hospital, talks about Kidney Stones and how MOSES creates a new way to treat stones.
Talk to me about kidney stones. How common are they?
SIMON: Kidney stones are very common. About one in 11 people across the United States will develop a kidney stone in their life. Particularly during the summer months, we see an increased incidence of this because of the weather, predominantly. A lot of us do not take in enough fluid and that can lead to increased stone formation in most people. Each kidney filter is about 13% of your body’s blood flow with every beat of your heart. And that kidney then takes that blood flow, filters it out, and a lot of compounds, such as calcium, for instance, can accumulate and crystallize in the kidney, and that can form kidney stones. If we don’t drink enough water to dilute that calcium and other deposits that can form the kidney, that can lead to kidney stones in most people.
And talk to me about this new technology, the MOSES laser technology. How does it work?
SIMON: The MOSES laser technology has really revolutionized what we can do with stones. The main reason why is that it allows us to treat bigger stones than we were previously due to the fact it’s more efficient. It’s able to fragment or dust a stone, as we say in urology, more effectively and quickly and the reason why it’s able to do this is the technology allows, one, faster firing. It fires two pulses of a laser, which adds to increased penetration of the stone and it also allows the stone to be kept in place for longer. This is important when you’re treating stones, as you begin to break off and fragment into smaller pieces, those little pieces can be kept in place and lasered down even smaller if that’s what you wish to do at the time, versus them being knocked around in different parts of the kidney when you’re working. That could be take time, it can allow you to be less effective, and ultimately allow you to not be able to treat stones as effectively.
If those pieces break off, is there a possibility that they could be missed?
SIMON: Certainly. Yeah, visualization is another aspect of this. If stones go in a place you can’t see easily, then you could miss them. You want them to keep in the same place so that you’re able to treat the stone you’re intending to effectively in one place. You’re not chasing stones around, you’re not missing stones. The MOSES technology also allows you to have a more flexible fiber which can get around corners in the kidney and access different stones that we weren’t able to do so as easily before. Another advantage is that we’re able to treat larger stones up in the kidney because the technology allows to treat the stones more effectively and quickly, so we’re not keeping the patient under anesthesia for prolonged periods of time that would’ve required, previously, with these larger stones.
Before the MOSES, what other treatment options were there for larger stones?
SIMON: Well, lasers have been around for a long time. I would say that, at a certain point, you would have to access the kidney through the back with a procedure called percutaneous nephrolithotomy. We still do those today and it’s very appropriate for large stones. However, it allows us to offer both options to patients. Additionally, if a patient’s been on blood thinners and can’t come off them, you can still perform a laser procedure on a stone as where you could not perform a procedure that accesses the kidney through the back because they would have to come off blood thinners for that.
Are there any other people that this would, I guess, benefit more? Like already people than are taking blood thinners who else would this benefit more?
SIMON: I’d say in any person the technology allows the stone to be treated quicker and more effectively. So that’s less time under anesthesia. That’s even another patient that could be treated that same day as well with the stone because we’re able to do these more effectively. I think those are two major advantages. I don’t really see a patient that wouldn’t be a candidate for this laser that would have to have some other type of laser. I think this laser can treat pretty much all stones that we encounter.
So there’s no restrictions on the people. So for the procedure what’s the time difference versus the other laser?
SIMON: That’s a good question. I think the difference is more noticeable in the larger stones. Let’s say, for instance, a two-centimetre stone in the kidney, which is probably the upper limits to something you can trigger the laser you could probably do that, within an hour or so as where that might extend past an hour, maybe even two hours, maybe even take multiple procedures with the prior laser.
OK. And these are only for larger stones. The smaller stones would a doctor typically say, let it pass on its own?
SIMON: You can do kind of watchful waiting with stones and just see if they pass, you’re right. Sometimes don’t pass even if they are small and they still need to be treated even if they are small. If they don’t pass on their own, you can’t leave a kidney stone blocking the kidney for longer than four to six weeks without having long-term kidney damage, and so we still want to treat those stones either way. The MOSES is able to treat the big stones as well as small. You are able to adjust your power and settings to whatever you wish. It is very versatile in that sense that you can treat a multitude of sizes.
Are there any side effects for this procedure?
SIMON: No more increased side effects with the MOSES laser compared to other procedures. Any time you access a kidney stone, you’re going through the ureter, which is the tube that drains the kidney to the bladder. There can be scar tissue formation because you are introducing instruments in there as soon as you have to dilate the ureter. Any time you’re destroying a stone, there can be bacteria trapped in the stone, and that bacteria can escape, go to the bloodstream. So urosepsis, as we call it, which is a blood-born infection from the urinary tract can occur. We try to minimize that with preoperative antibiotics or ensuring that there’s no positive urine culture prior to surgery as well. So those are the two most common risks, I would say. The other additional risk is that we typically leave stents in the kidney after we remove a stone to prevent swelling of the ureter. We also leave stents if the stone is not able to be accessed effectively and we have to go back and treat the stone at another date. The stent allows the ureter to dilate and be larger so that we can get our instruments and lasers up and treat the stone effectively. If a stent’s left in for too long, it can become encrusted or calcified, and that can be very difficult to remove down the road. It could cause potential kidney damage.
OK. And then how’s the recovery like?
SIMON: Recovery, I would say, is pretty quick. The stent, like I mentioned, if we leave it in for a few days – most people feel much better after the stent comes out. It does prevent some complications, but also can irritate the bladder. But once the stent is out, I would say you’re back up, feeling like yourself in a few days after a kidney stone surgery once all the stones have been removed.
Is there any restrictions afterwards?
SIMON: I always tell people, if it feels fine, it’s fine. If it doesn’t feel fine, you probably shouldn’t do it. No real hard and fast restrictions that we say you cannot do. If it feels uncomfortable, then we recommend you don’t do that activity.
OK. With this laser is it covered by insurance?
SIMON: Yes. It’s covered by insurance and it’s at Tampa General Hospital that we operate at.
OK. And is there compared to this one the MOSES laser versus the still standard one, is there any, I guess, questions that patients should ask to decide which one they should use?
SIMON: That’s a good question. I typically wouldn’t recommend the older technology now that we have this one available. Because they’re both holmium lasers, so it’s the same technology, just improved upon. It’s the reason why I should buy an old car versus a new one. The new car is always going to have more features and be better without with less side effects and risks. So, I would say that the new one is inherently better and there’s no real added risks associated with it.
With this latest technology, could it be used for any other conditions?
SIMON: So the nice thing about MOSES laser, especially the 2.0 that has come out now, you can use it effectively for BPH, you can do procedures called a HoLEPS, which is holmium laser enucleation of prostate or a HoLAP, which is holmium laser ablation of prostate. So you are able to effectively treat prostate conditions for BPH, which can lead to urinary retention and things of this nature as well. And I gradually think the technology is improving with that so that we can further treat these more efficiently and quickly too.
And going back to kidney stones, are there any, I know you mentioned during the summer, people need to drink more, but are there any other surprising risks for kidney stones?
SIMON: I would say increased sodium intake can cause increase secretion of calcium in the urine, so that’s another risk factor. Eating animal protein can lead to acidic urine, which is a risk factor for stone formation as well. It also can lead to increased uric acid production, which can cause uric acid stones. Additionally, family history can be a risk factor as well. So many things to prevent them are increased fruits and vegetables, this can lead to more basic urine and increased fluid intake.
And talk a little bit about Jack’s case.
SIMON: So Jack came in initially with a lot of pain and initially attempted to pass the stone on his own, which I do recommend for a lot of people. Surgery is great, but doing things on your own naturally is always the preferred method if you can but at a certain point, as I mentioned, you can’t leave a stone blocking your kidney forever, and that was Jack’s case predominantly. Luckily we were able to get him in fairly quickly, address the stone, remove all the stone debris. I did leave a stent temporarily on Jack, but that was removed in a few days. Jack seemed to do really well and recovered very quickly after his procedure.
And I was reading for the procedure, it also helps with helping to reduce the risk of recurrence?
SIMON: Any time you completely eliminate the stone burden in someone, which is definitely a factor of the efficiency of the technology, ability to get the stones out quickly, and ability to see in various places of the kidney, you’re decreasing your risk of stone formation. Stone debris and other things like this can be a nidus for future stone formation. So as long as we get you stone-free, we can then work on preventative measures to prevent future recurrence as well.
What are some of those preventative measures?
SIMON: Well, in addition to increasing your fluid intake, reducing animal protein, we can get things called a 24-hour urine collection, which tells us if there’s any risk factors in a patient, particularly, that can lead to further stone formation. Conditions such as hypoparathyroidism as well can be a risk factor. Obviously, that would be treated with surgery to remove the parathyroid gland and that and just, again, increasing fluids is the main factor in most people.
And when someone has a kidney stone and they’re taking the let it pass on its own approach, besides taking fluids, is there anything else that they could do to help the stone pass?
SIMON: We do offer medication called Flomax, which has some mixed results but has been shown, in some cases, to help the passage of stone. We typically give pain medications as well but a lot of your body does the work for the most part during that period and it’s one of the things, if you’re able to tolerate it and pass it on your own, again, that’s the preferred method if the stone’s a reasonable size and it’s possible.
Is there any way to measure what would be, I guess, a large kidney stone size versus a small one that can pass on its own?
SIMON: So typically say about five-millimeter stone has a 50% chance of passing and it goes down after that. After a centimeter, we don’t recommend trial of passage at all. So that would be definitely a surgical stone. From five to one centimeter, we kind of base it on the patient’s pain as well as where in the ureter how far down it has gone on its own as well. We just give patients the percentages and we let them decide on their own and give them all the risk and benefit.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
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