Surgeon: Olivier Traxer, M.D.
After a training in general urology in Paris (SORBONNE-University Paris-France ex- Pierre et Marie Curie Paris-6), Olivier TRAXER completed a clinical fellowship at Southwestern Medical School, University of Texas, Dallas-Texas under the supervision of Professors Charles Y.C PAK and Margaret Sue PEARLE and obtained a subspecialty in Endourology and stone disease which represents his main field of interest. At present time, Olivier TRAXER is Professor of Urology in Tenon Hospital Sorbonne University Paris-France and is responsible of the department of minimally invasive surgery. He is also the Director of the Clinical Research Center (GRC Lithiase #20 at Sorbonne University). Main fields of interest: Stone disease (surgical and medical management) and Conservative treatment of UTUC.

Moderator: Michael Grasso, M.D.
Michael Grasso III MD received his medical degree from Thomas Jefferson University School of Medicine, where he also completed his Surgery and Urology residency training. While in Philadelphia he developed broad academic interests in minimally invasive surgery and Urologic Oncology. He served as Assistant and Associate Professor of Urology at Loma Linda University, Professor of Urology at New York University, and since 2001 he has been Professor of Urology at the New York Medical College. He is currently Director/Chairman of Urology at Phelps Medical Center in New York, Director of an Endourology fellowship-training program since 1999, while also stewarding basic science research in renal physiology with Thambi Dorai Ph.D at New York Medical College. Summary of curriculum vitae: 117 peer review publications, 56 text book chapters, 193 academic presentations, 27 instructional videos of surgical technique, and 349 visiting professorships and invited academic lectures worldwide.

 

Webinar Transcript

Dr. Jared Winaker:

Good morning everyone. Thank you so much for joining us. I'm Dr. Jared Winaker. On behalf of the Endourologic Society I want to thank you all for joining us regardless of what time of day it is where you are, we do appreciate you joining us for the latest installment of our master class in endourology and robotics.

Dr. Jared Winaker:

Just as a reminder, today's webinar like all of our webinars is going to be recorded so any of the slides or any of these questions you want to be able to review later, you'll be able to visit our website in order to see them, as well as the dictation of today's webinar, as well as any of your unanswered questions. Our experts will be happy to answer those.

Dr. Jared Winaker:

Today we're in for a treat. We're joined by two experts really in the field. We're going to be discussing the use of Thulium for Retrograde Intrarenal Surgery. Our surgeon is Dr. Dr. Olivier Traxer from Paris and moderating Dr. Traxer's semi-live prerecorded surgeries, we're joined by Dr. Dr. Michael Grasso from New York.

Dr. Jared Winaker:

Again, a reminder. All of this will be recorded and you can go ahead and visit our website, endourology.org. It'll be both on the home screen as well as by clicking under the education tab and master call.

Dr. Jared Winaker:

Before we do get started today, just wanted to remind everyone, we're taking a brief hiatus next week but in two weeks we're going to be returning again with the webinar. We're going to be switching a little bit over to robotics where we're going to have a lively discussion from many experts on Robotic Single Port Surgery specifically as they pertain to the prostate and the bladder. Again, you can register for this all by visiting the endourology website.

Dr. Jared Winaker:

With regards to continuing medical education for today's webinar and all of our webinars in the series, you'll be receiving a survey from Michele Paoli at the end of each month. When you receive that just go ahead and indicate which seminars you've actually attended during that month and then you'll be emailed your certificate. Importantly, please do remember to fill out the questionnaire that you're going to receive at the end of this and all of our webinars as these are actually important for you securing your CME credits.

Dr. Jared Winaker:

I want to encourage everyone to make use of the Q&A function, not the chat function on the bottom of your screen but the Q&A function to go ahead and ask our experts questions throughout the discussion. They'll do their best to answer as many as possible and any that are not unanswered, we will post those answers at a later date on the website.

Dr. Jared Winaker:

For those who aren't members of the society, we certainly do encourage you to join. There are many member benefits including of course, full text online access to all of our journals.

Dr. Jared Winaker:

Finally, it's never too early to save the date. The world Congress of Endourology and Eurotechnology is going to be resuming still in Hamburg, Germany but now in September of 2021 so please be sure to mark your calendars.

Dr. Jared Winaker:

Without further adieu, I appreciate your patience. I'm going to turn it over to Dr. Traxer and Dr. Grasso.

Dr. Michael Grasso:

Welcome everyone. We have a treat. Dr. Olivier Traxer, I think one of the world's experts on minimally invasive surgery with a ureteroscope, is going to present a relatively new technology. He's going to historically talk about Holmium laser lithotripsy to start, talk about evolving ureteroscopic lithotripsy techniques and then jump into the Thulium fiber laser which is a new technology on the scene which is very exciting and he has one of the largest world experience with this laser.

Dr. Michael Grasso:

Ask questions through the Q&A portal and as I get a group of questions I'll jump in and have some spirited discussion with Olivier through this presentation.

Dr. Michael Grasso:

So Olivier, you have the floor.

Dr. Olivier Traxer:

Thank you Michael. It's really a pleasure for me to be with you today. Yes, good morning for some of you, maybe good afternoon and good evening for the others. Really thank you for the invitation. It's a real pleasure for me to be with you tonight and to discuss and to share my experience regarding this new technology.

Dr. Olivier Traxer:

I'm a consultant actually for IPG and Olympus. They are two companies actually involved in this new technology.

Dr. Olivier Traxer:

If you're okay Michael, I would like just to remember with few slides for my introduction and to remember few things regarding Holmium-YAG technology.

Dr. Olivier Traxer:

To start, just to talk very quickly regarding the origins of these names, Holmium and Thulium. It comes from a mineralogist, a Swedish mineralogist. He discovered many years ago these two elements and he named the first one Holmium regarding a city, Copenhagen, because Holmium in Latin means Stockholm and the second name, Thulium comes from the Greek name of a Scandinavia. It means Thule. That's the reason for these two nice names.

Dr. Olivier Traxer:

Very quickly, we need to keep in mind that when we are using laser, we are using lights. I think it's essential to never forget that we are using light. It's a special one but it's still light.

Dr. Olivier Traxer:

I think it's also important to remember these Moses Effect. It's a very basic effect of laser technology because we will use this Moses effect also with Thulium. It's very well-known with Holmium-YAG technology but you will see that we will use exactly the same effect with Thulium fiber.

Dr. Olivier Traxer:

Okay, I think yeah, there's a video. Just to illustrate what is Moses Effect and this is a photo acoustic effect. We can see on this video it's a slow motion video and it explains also why we are talking about pulsed laser. We already know that Holmium-YAG is a pulsed laser but Thulium fiber is also a pulsed laser so it means that when we have a pulsed laser we will have to fix energy and frequency.

Dr. Olivier Traxer:

It's also just to remember you that we are using Holmium-YAG since a long time now because the first report was in 1992 by Johnson so it's more or less 30 years actually that we are using Holmium-YAG technology. Moses Effect, Moses Technology, don't be confused. Moses Effect is not exactly Moses Technology. Moses Technology was recently introduced. The Moses Technology is in fact Moses Effect but it's a special Moses Effect and when it was introduced the company in fact introduced the concept of pulse modulation. If you modulate the regular pulsed from Holmium-YAG technology you can create a different pulsed and actually it's called the Moses Technology.

Dr. Olivier Traxer:

Holmium-YAG as we said before is actually the gold standard and it's a fantastic technology because we can use it for any kind of stones to treat urothelial tumor, to treat stenosis, to coagulate and also to treat BPA. It looks like the ideal technology in endourology.

Dr. Olivier Traxer:

We have actually two kinds of Holmium-YAG technology. We have what we call the low power. It's smaller 30 watts and we have high power technology. One hundred, 120 watts. What is the main difference when we are using low and high power? The main difference is the possibility to have more frequency when we're using high power and as you know, frequency gives the possibility to go faster so if you are using high power technology you are supposed to be able to go faster.

Dr. Olivier Traxer:

This is just to remember you regarding Holmium-YAG and actually, we have no clear consensus but I must say that we know more or less how to set Holmium-YAG laser if we would like to dust, if we would like to fragment or if we would like to use the popcorn technique and so we have actually recommendation in terms of setting. That's what we are using actually. Michael, just to fix that actually, the technology we are using.

Dr. Olivier Traxer:

Now ... Sorry. Now the question is why do we need to change if Holmium-YAG technology is so fantastic, if we can do everything? Why do we need something different? In fact, if we talk about Holmium-YAG after this long time I think we all know the limitations actually of Holmium-YAG. One of the limitation is that it's time consuming. It takes a long time all the time when we have to treat especially big stones so it's the first problem. The second problem is that even we are thinking that we dust the stone, we need to admit that most of the time the fragments that we produce with Holmium is at the end they are still too big. Still too big to evacuate spontaneously but also still too big to be aspirate. We have no system actually available to aspirate the fragments but it's true that even we would like to aspirate it's a bit difficult so that's why actually when we're using Holmium-YAG sometimes we're a little bit disappointed because it's time consuming and the fragments are still too big.

Dr. Olivier Traxer:

If we think about new technologies and what do we need, I would say for the future? Today we need new system to produce smaller fragments, smaller dust. We need to go what we said finer. This is the first point that we would like actually to improve regarding Holmium-YAG technology. And of course the second point is to go faster. That's actually the situation. Do you agree with me Michael?

Dr. Michael Grasso:

Absolutely.

Dr. Olivier Traxer:

Okay. Do we have some questions for the audience or should I proceed regarding-

Dr. Michael Grasso:

One of the questions was can comment about the pulse width and the effect with Holmium?

Dr. Olivier Traxer:

Okay. It was also recently introduced on the pulse width meaning that it's possible to have short bursts or longer one and it's something that we know since the beginning but I must say that in neurology we didn't care about these long and short burst for a long time but in the last years people realized that it was possible to use this possibility to have shorter or longer pulses and when we did it we obtain different results.

Dr. Olivier Traxer:

Just an example, if we select very short bursts we know actually that we produce fragments. If we are using longer pulses we are producing more dust, smaller fragments or dust. It's also very well known that if we are using a long pulse it's also something really nice, very helpful to treat your [inaudible 00:12:44] so this is besides energy and frequency, this is another parameter that we need actually to consider.

Dr. Michael Grasso:

So there's a whole series of questions now that you made that comment. One of the questions is, does Moses Technology produce fine dust? I think you're going to answer that coming up with a few slides but you can touch on it now if you want.

Dr. Olivier Traxer:

Yeah, but I think if we proceed because since we're talking about these smaller fragments I will give [inaudible 00:13:21]. Let's talk about finer. How is it possible actually to produce smaller dust? We need to talk in general regarding laser physics. First, it's true that we would like to have really small, small fragments, what we call the dust, because we all know that when we produce these very thin particles we observe that the particles evacuate immediately during the treatment and at the end of the treatment we have all seen a lot of dust into the ureter and the patient will also evacuate in the next following days this super thin dust. We know that so we can dream that if we can produce exclusively this dust the patient will probably evacuate so that's the reason we would like to have this very small dust actually. That's the reason.

Dr. Olivier Traxer:

But one question is, okay but is exactly dust? Who knows the exact definition of dust and as you know, if you ask experts some people said it's less than one millimeter or less than [inaudible 00:14:37] millimeter, no millimeters exactly, the exact definition and this is really I think something we need actually to fix a definition and to accept this definition to evaluate technologies and of course to evaluate results of [inaudible 00:14:57].

Dr. Olivier Traxer:

Since we have no definition in my lab in Paris we decided to find a definition of the dust so we did a lot of experiment and at the end we consider that to talk about dust we need to have some kind of floating effect and also the possibility to be aspirate through the working channel of flexible [inaudible 00:15:29] 3.6 French.

Dr. Olivier Traxer:

If we consider these two parameters in the lab of course we fix a limit and this limit was 250 microns and this is actually the definition of the dust that we expect when we are doing comparison between Holmium and Thulium fiber. If we consider this definition less than 250 microns how is it possible to produce 250 microns? First we need to remember size of laser fiber. It's easy to understand that if we are using small fiber the contact with the surface of the stone will be relatively small and then we will produce a small piece.

Dr. Olivier Traxer:

Talking about the size of the fiber it seems logical actually to lose smaller fiber. Considering Holmium it's possible to use 270, 200 microns fiber but if we were using something smaller then we will be able to produce smaller pieces.

Dr. Olivier Traxer:

Let's consider an example and I put on my slides two different fibers. 270 and 150 micron. If we consider these two fibers regarding the diameter when we are going from 270 to 150 we divide the diameter by 1.8 but if you look at the cross section you divide the cross section by 3.3. It means that if you are using some energy and I put an example, 0.3 joule, with a fiber of 270 micron. If you would like to keep exactly the same energy density using a 150 micron fiber you need to divide the energy by 3.3. This is the difference in terms of cross section. It's due to the energy density so with the 150 we will be obliged to use much lower energy compared to what we do actually with 270 micron fiber.

Dr. Olivier Traxer:

This clearly demonstrates just to give you some results again from the lab. If we move from 150 to 270 the pulse energy if we decrease the energy by three, the energy density is exactly the same and at the end the ablation volume is also divided by 3.4. So it means that if we keep the same energy [inaudible 00:18:31] but if we decrease the size of the fiber we produce smaller pieces. This is something we need to remember. We need a new technology able to use smaller fiber and able to produce much lower energy to keep the same energy density. This is the first point.

Dr. Olivier Traxer:

Now if we do this how is it possible at the same time to go faster? To go faster as we said in introduction, we need to play with the frequency. If you're using plenty of pulses per second, what we call high frequency, you are supposed to go faster. Coming back to my example with the three, the 270, 150 micron we divide the cross section by three. So if I would like to go faster I will have to use a frequency at least three times more.

Dr. Olivier Traxer:

This is just an example. You see what happened if we compare two laser technology. One is using high frequency. Another one is using very high frequency. You see that it has the same effect but we have much more bubbles with the very high frequency. This is the way actually to go faster.

Dr. Olivier Traxer:

If we summarize, this is something very basic. If we would like to go at the same time finer and faster we need a new technology as we said able to use smaller fiber, for example 150 micron or maybe less, able to produce very low energy and able at the same time to produce very high frequency and if it's possible to mix these three points then it's possible to imagine that we will produce smaller pieces and relatively fast. The question is, okay but maybe we can use Holmium but if we consider Holmium technology unfortunately not. It's impossible actually to use smaller fiber than 200, 200, 270. This is the minimum we can use. Impossible to go lower. It's also impossible with Holmium-YAG to produce very low energy, to keep the same energy density and we also know the limitation in terms of frequency. Actually the max we can use is 80 hertz. If we consider these three points Holmium-YAG is not actually the laser that we would like for the future.

Dr. Michael Grasso:

Olivier, stop here for a second.

Dr. Olivier Traxer:

Sure.

Dr. Michael Grasso:

Jared, let's ask a couple questions just to emphasize what was presented already. Can you put up those questions Jared?

Dr. Michael Grasso:

Okay, for the audience, there's three questions here for you all. I'll read them to you. We can go through them. All are true with regard to Holmium-YAG laser lithotripsy except based on the photo acoustic principle of stone fragmentation. The vaporization bubble forms on the cores fiber tip in an acquiesce medium. Laser settings vary depending on stone composition and density. Power density is inversely proportional to fiber diameter. That is a 200 micron fiber has higher power density than a larger fiber. The last is frequency of pulsation and pulse width do not affect stone migration.

Dr. Michael Grasso:

Why don't you all take a minute with that question. See what you think. Olivier talked a little bit about frequency of pulsation and the effect of varying frequency of pulsation and efficiency and pulse width which is a relatively new parameter that we can play with. Most people felt that the last answer is the incorrect parameter. Frequency of pulsation and pulse width need to be varied to increase efficiency when you're using the Holmium. Almost everyone is there with that.

Dr. Michael Grasso:

Can we go to the next question?

Dr. Michael Grasso:

Let's see. How do I bring up the next question?

Dr. Michael Grasso:

Variables which effect the efficiency of Holmium-YAG laser lithotripsy include low water density courts fiber diameter. Fiber tip shape and profile. Delivered power and frequency of pulsation. Varying the pulse width of the deliverable light energy. That's all of those is the correct answer and everyone jumped on that.

Dr. Michael Grasso:

Let's see if I can go to the third question here. Share those results.

Dr. Michael Grasso:

The last question is techniques to improve the efficiency of Holmium-YAG laser lithotripsy include relocating lower pulse stone fragments through an upper pulse location for easier access and Olivier's going to touch on that a little bit later with talking about angulation of a flexible scope and laser fibers but that's a pretty standard technique. Employing a large 550 micron laser fiber through an actively deflectable, flexible ureteroscope. Dusting large dense calculi with high frequency settings. The only one of those three that doesn't fit is putting a large fiber through a flexible ureteroscope. Not only is the power density drop and the efficiency drop but it's going to prohibit deflectability in the instrument so we don't use 550 fibers to flexible ureteroscopes. I think everyone, the majority of everyone looking at the polling came up with those answers.

Dr. Michael Grasso:

Olivier, I'm going to ask one question now before you get into the Thulium fiber laser and that is, this is a flexible or rigid ureteroscopy program, most flexible working in the kidney a lot. Is there any place at the attendant hospital for percutaneous nephrostomy lithotomy or shock wave lithotripsy that you'd use those technologies and when do you use them?

Dr. Olivier Traxer:

Yes, of course. We still use not exclusively flexi but of course shock wave lithotripsy and PCNL. Definitely for big stones supposed to be more than two centimeters. PCNL should be discussed first with patients. I think there's no discussion on that. It's through that in my department we don't exactly respect that. We are thinking that we can do flexi for bigger stone and that's what we do but if we look into the guidelines we of course, we are supposed to discuss with the patient PCNL.

Dr. Olivier Traxer:

Shock wave lithotripsy, I like to, I still use it of course and especially for kidney stone. I like to use it for stone up to 12 millimeter. When it's more than 12 I prefer to use flexi first actually.

Dr. Michael Grasso:

Great. Floor is yours.

Dr. Olivier Traxer:

Sorry?

Dr. Michael Grasso:

The floor is yours. Go right ahead. Let's talk about Thulium fiber laser.

Dr. Olivier Traxer:

Okay, so we proceed. Now we need to discuss this new technology regarding Thulium fiber and to understand what is actually Thulium fiber. You maybe remember Holmium-YAG is using a crystal, a very pure crystal. Crystal-YAG [inaudible 00:26:57] with Holmium element so you need to forget that.

Dr. Olivier Traxer:

A Thulium fiber, it's a solid state laser but it's not using a crystal, it's using a fiber. It's a very long fiber. It's a thin one but very long. 10 to 30 meters fibers and the internal part completely conspirant is 10 micron core so really, really thin. Inside we put Thulium element and that's what we call actually a Thulium fiber. It's a long fiber and inside we have Thulium element. Don't be confused. This is not the surgical fiber. This system, this fiber with Thulium is into the backs, into the laser backs.

Dr. Olivier Traxer:

To activate the system you know with Holmium we are using a flash lens so the Thulium fiber, we are not using a flash lens, we are using Diode laser and we can use multiple one and they are directly connect to these system, to these long fiber and when you activate the system at the end of the fiber you connect a surgical fiber and as we said before it could be a very small one like 150 micron.

Dr. Olivier Traxer:

We have two systems available actually in the world, commercially available. The one is from IPG, the name is Urolase and the second one from Olympus, the Soltive system.

Dr. Olivier Traxer:

Now do we have to compare these two technologies? I think there's no discussion that we have to compare the outcomes. What can we get with each system because if we are comparing the specifications, since the two technology are completely different nothing is comparable. If we look at the wavelength for example, you know that Holmium-YAG, it's 2,100 nanometers. It's into the infrared spectrum and it's completely absorbed in water, in saline.

Dr. Olivier Traxer:

The Thulium fiber is 1,950 nanometers. Still in the infrared spectrum. Very close to Holmium but as you can see it's also completely absorbed in water but it's also at the maximum peak of absorption. 4.5 times more absorbed that Holmium-YAG. Even is very close.

Dr. Olivier Traxer:

If we compare the pulse width we said before in terms of long pulse if we look about that Thulium fiber, it's possible to produce pulses 18 times more longer than Holmium-YAG. Pulse energy for the maximum is the same, six joules, but we never use. We never need six joules but if we look at the minimum you see that for the minimum the Thulium fiber is able to produce 10 times less energy per pulse compared to Holmium and you'll remember that we need a laser able to produce very low energy so interesting. The peak power, this is something that many people don't really consider but actually we realize that this is really, really important and this is something very important in terms of retropulsion. If the maximum peak power is too high you really produce retropulsion and this is one of the problem with Holmium. The peak power is a little bit too high but if you look the peak power of Thulium fiber, it's four times less so also interesting to reduce, for example retropulsion. The maximum average power is in favor of Holmium but again do we need to use 120 watts? Absolutely not. Repetition rate frequency, as you can see 25 times more when we are using Thulium fiber and you'll remember that we said we needed new system able to produce very high frequency. Again, interesting.

Dr. Olivier Traxer:

And for the fibers, again, it's possible this is the maximum repetition rate. Now you have already seen these two videos. The left is Holmium, the maximum 80 hertz. On the right you see 2,000 hertz with the Thulium and you see the difference of course.

Dr. Michael Grasso:

Olivier, there's a question. I want to jump in for a second. I need you to carefully define the difference between Thulium fiber laser and a Thulium laser. There's some-

Dr. Olivier Traxer:

You're right. We need not to be confused. Thulium-YAG already exists and many people are using Thulium-YAG actually to treat prostate, BPH. This is not a technology actually that we can use for stones. It's exclusively for BPH. It already exists since a long time now but it's, even it's using the same name Thulium. It's just completely different technology. Thulium-YAG for the BPH okay. This new laser is Thulium fiber. Again, we are not using a crystal YAG. We are using a fiber. Don't be confused. Two different technologies.

Dr. Michael Grasso:

The next question is the Thulium fiber laser, the fiber in the solid state box, the fiber that attaches onto that is a standard silica quartz fiber?

Dr. Olivier Traxer:

Absolutely. The surgical fiber that we connect at the end of the backs, you see the picture on this slide, the small backs. You connect surgical fiber exactly like we do actually with Holmium and this is still quartz fiber. Exactly the same [crosstalk 00:32:59]-

Dr. Michael Grasso:

[crosstalk 00:32:59] whatever you normally do with Holmium you can do with this fiber as far as shortening it, adjusting it and what have you.

Dr. Olivier Traxer:

Exact. Absolutely.

Dr. Michael Grasso:

Thank you.

Dr. Olivier Traxer:

The last comparison regarding the size of the fiber as we said with Holmium-YAG we can use for the smallest one something in the range of 200 micron, not below but with the Thulium fiber this is also another advantage. In theory it's possible to use very small fiber up to 50 microns. Actually, commercially available exclusively 150 micron but probably we will have in the near future we'll have probably less than 150.

Dr. Olivier Traxer:

Why can we use this very small fiber? It's due to the laser beam profiles. With Holmium-YAG we know it's small as 300 micron and we have to focus this laser beam profile into the surgical fiber and that's the reason why we cannot use less than 270, 200 microns with Holmium. But the laser bream profiles produced by Thulium fiber is really small, really focused, 70 microns. The reason why actually it's possible to use much smaller fiber. There's a good connection between the laser box and the surgical fiber.

Dr. Olivier Traxer:

Holmium-YAG we are a little bit limited to 200. With Thulium fiber in theory we can use up to 50 microns so if you make the comparison in terms of diameter, in terms of cross section as you can see in terms of diameter it's four times less but in terms of cross section it's 16 times less. Remember what we said, if we are using smaller fibers we are able to produce smaller pieces. This is actually this benefit.

Dr. Olivier Traxer:

We compare recently and we very recently published what we can produce is 150 and 270 micron into the lab and of course we completely confirm that using smaller fiber we produce smaller pieces. It's also demonstrated by many, many publications actually so we just confirm what the people said before.

Dr. Olivier Traxer:

If we look about this definition of dust, less than 250 microns and we compare Holmium and Thulium. In the same period of time Thulium fiber produced at least two times more dust compared to Holmium even using this new Moses Technology. Again, it's into the lab.

Dr. Olivier Traxer:

We need to confirm this in the real life. Another paper that we recently published we also evaluate if it was possible to produce this dust less than 250 micron with any kind of stones and the answer is yes. Even you are using Thulium fiber with very hard stone like monohydrate for example, you are still able to produce very small pieces. As you know-

Dr. Michael Grasso:

[crosstalk 00:36:24] the parameters at all for it? Are the parameters different?

Dr. Olivier Traxer:

You're right Michael. You have to adjust a little bit the parameters, increase a little bit the energy level because the stone is much harder but if you adjust the good energy level regarding the stone composition you can produce these tiny, tiny pieces.

Dr. Michael Grasso:

Even sifting, are you at smooth sifting [crosstalk 00:36:47]-

Dr. Olivier Traxer:

Even sifting. Absolutely. Exactly. We will have of course to practice much more clinically to confirm but again coming from the lab it works absolutely perfectly actually.

Dr. Olivier Traxer:

Just an example, this is a video I like to show. This is coming from the lab again. We are using a single use ureteroscope on the left just to see the vision and you see that even we are using very high frequency, 1,000 hertz per second which is very low energy, 50 millijoules. The vision is still okay, still acceptable and the reason why we're able to go much faster because we keep a good endoscopic vision.

Dr. Olivier Traxer:

All these results again are confirmed by many people actually especially the colleagues from Russia since you know that this technology is coming from Russia initially and they totally confirm actually that the superiority of Thulium fiber compared to Holmium in terms of stone ablation, more dust and much faster.

Dr. Olivier Traxer:

We have several publications actually to confirm that and it's all the time more efficient. This is something interesting that even we are moving a little bit from the stone so what we call the stone distance. With the tip of the fiber we are all the time superior regarding using Thulium compared to Holmium-YAG so this is also something really interesting actually.

Dr. Olivier Traxer:

The team from the US, from Dr. Molina also confirmed this recently, also published these results to say that it was producing more dust and much faster when he was using this Thulium fiber system.

Dr. Olivier Traxer:

If we come from the lab actually definitely we can say that the superpulsed Thulium fiber laser is able to go finer and is able to go faster but again, all these results actually are coming from the lab.

Dr. Olivier Traxer:

Regarding retropulsion, we talked before about retropulsion. It was also evaluate actually and again recently published, we published our results from the lab regarding retropulsion. Thulium fiber was all the time superior to Holmium technology even we were using Moses Technology was a good model actually to reduce retropulsion but Thulium fiber is superior to this.

Dr. Olivier Traxer:

Again, it was confirmed by other publications that Thulium fiber is a good technology to reduce retropulsion. This is again another publication, again coming from the [inaudible 00:39:57] collects [crosstalk 00:39:58]-

Dr. Michael Grasso:

Okay [crosstalk 00:39:59]. There's a number of questions now coming in about dusting stones with Thulium laser fiber. Okay. Questions all kind of surround tissue effects next to the dusting. You see more hematuria. With Holmium if you increase the frequency and energy often when the stones are banging around the kidney it'll irritate a papilla or an infundibulum and you'll see some hematuria. You see it as much with Thulium laser fiber?

Dr. Olivier Traxer:

I think it's a very important question Michael, because we have seen recently some tweets. Some tweets coming from Indian colleagues and they're sad that they were a little bit afraid to use the Thulium fiber into the ureter because they have seen after that some ureterostenosis. My explanation about that is Thulium fiber is not dangerous into the ureter. What is dangerous if you are using too much frequency. People would like to take the advantage to a very high frequency to go fast but we all know that when we are using high frequency into the ureter we are not able to control all the pulses because the space is really limited and of course, some pulses are touching [inaudible 00:41:18] and if you repeat this many, many times then you will produce a sliver of injury of the ureter and potentially stenosis. So, since Thulium fiber is able to produce very high frequency I would say it's safe into the kidney because you have space and you are less risk to touch the [inaudible 00:41:40] and since you have less retropulsion the risk for the [inaudible 00:41:45] is really limited.

Dr. Olivier Traxer:

My feeling is that it's even safer compared to Holmium but into the ureter, if you don't reduce the frequency at lower level there is a risk that at the end you will damage the ureter so for me I have set things for the kidney and I have set things for the ureter and the main difference in terms of setting is frequency.

Dr. Michael Grasso:

What's the limit of frequency in the ureter because Indian colleagues now are jumping on this. I'm getting questions about this so can you give some ... You opened the door with that. Now I'm getting questions from India. What's the parameters that you would employ in the ureter versus the kidney?

Dr. Olivier Traxer:

Okay, so into the kidney if I'm using a smaller fiber, 150, the 150 fiber is limited to 25 watts. If you are using smaller fiber together with lower energy as we said and let's take an example, 50 millijoules. With the 50 millijoules the maximum you can use is actually ... Sorry for the calculation. One thousand, okay. But since you are using smaller fiber, 150, you are limited to 25 watts so the maximum is 500. I test it. 50 millijoule together with 500 frequency works perfect and the vision is still good but when I'm moving into the ureter, what I'm doing actually, my clinical experience is limited but I start with 20 hertz. I look at the effect. If I can control all the pulses, if I see that I'm in good condition accept to increase a little bit frequency. Maybe to 80 or 100 but I'm much more limited because if I try to keep 500 then I will have problems because 500 pulses per second I'm not able to control by myself. I'm sure we lose some of them against the [inaudible 00:43:55].

Dr. Olivier Traxer:

I start with 20, I test it. If the conditions are okay I accept to accelerate a little bit with more frequency. Otherwise I keep 20 and you know Michael, into the ureter usually the stone they are not too big. It's not too sentimental stone. It's smaller stone so even you are using less frequency. It takes a little bit more time but the stone for you is not so big.

Dr. Michael Grasso:

So if you had an impacted, middle third, one centimeter, calcium oxalate monohydrate stone?

Dr. Olivier Traxer:

Monohydrate I will use more energy. I will start with 100. 100 millijoules and maybe I will increase to 150 or 200 according to the effect if it's really hard or not. According to this energy level then my frequency of course will be limited. Especially if you are using smaller fiber.

Dr. Michael Grasso:

Holmium can do the same thing. If you have an impacted stone in the ureter and you use high energy you're going to stick to the ureter too with Holmium. You want to move those stones and those fragments out of the impacted segment, out of the edema where you have some room to work.

Dr. Olivier Traxer:

You're right. [crosstalk 00:45:07]-

Dr. Michael Grasso:

With either laser.

Dr. Olivier Traxer:

Yeah. It's a general recommendation using laser of course because again, as we said at the beginning we are using light. It's not a shock wave, it's light and light is able to burn the tissue so even we are using Holmium or Thulium. Absolutely.

Dr. Olivier Traxer:

That's the slide Michael, that you described before regarding the-

Dr. Michael Grasso:

[crosstalk 00:45:32]-

Dr. Olivier Traxer:

The fiber when it's fully deflect into the lower port. This picture is coming from Holmium. This is a Holmium-YAG technology and you see that it was really flexed and we used too much energy so at the end we broke the laser fiber. We did exactly the same experimentation using a Thulium YAG and it was really amazing to see that when we're using 200 micron fiber even when we were using six joules. So the maximum in terms of energy than Thulium fiber was able to produce, we didn't break the fiber and we bent, we flex the fiber up to nine millimeter so it was really amazing to see that it was completely resisting. So for me it means that it's supposed to be much safer into the lower port compared to Holmium.

Dr. Olivier Traxer:

In terms of burnback, you know that burnback is also in relation with the peak power. If you have a very high peak power you also generate more burnback. The reason why with Holmium this is a problem when we are using very short bursts with high peak power we have burnback. Since the peak power of Thulium fiber is lower when we compare again less burnback with Thulium fiber. It's another benefit.

Dr. Olivier Traxer:

Regarding the safety for endless lapse, it's very comparable to Holmium. It means that if you see the tip of the fiber on the screen you are safe. Even you activate the laser you don't generate damage to the endoscope. If you see the fiber you are safe so very comparable to Holmium for that.

Dr. Olivier Traxer:

Temperature change. You know it's an issue. People are very concerned actually about the temperature into the kidney. Again, if you compare to Holmium-YAG high power system, Thulium fiber is completely comparable. It's no more, no less and again, the team from the states, from Dr. Molina, he also confirmed that. That the temperature change were exactly the same when he compared Thulium fiber and Holmium-YAG so it's good to know.

Dr. Michael Grasso:

Olivier, stop there.

Dr. Olivier Traxer:

Yeah, sure.

Dr. Michael Grasso:

That slide. Can you go back one slide?

Dr. Olivier Traxer:

Sure.

Dr. Michael Grasso:

If you look at those parameters that he was using in comparison there, that's a little different than what we're talking about dusting. This is questions that are coming up. You're in the kidney and you're dusting a uric acid stone with Holmium. Let's say you're using .8 joules and frequency of 40 hertz. That creates a certain amount of temperature. With the Thulium laser fiber if you're using say max 2,000 hertz with a sizeable fiber, which do you think is hotter? Which causes higher temperature when you have these both maximized? Which is hotter or is it the same?

Dr. Olivier Traxer:

It will be ... At the end that's the total energy that you produce by a unit of time. We increase the temperature and there's also something important. What about the energy that you're able to bring to the surface of the stone because if the energy's going to the stone it's not going into the water so it's not boiling the water and for me that's a problem actually when we recommend our very high frequency with Holmium. It works, no discussion, but you are also losing a lot of pulses. They are not efficient. They are not going to the surface of the stone. Many pulses in fact are waste into the fluid and warm the fluid.

Dr. Olivier Traxer:

When I dust with Holmium I'm using the same energy level, .2, .3 but I'm using very low frequency. Not very low. I'm using 20 hertz. Doing that, my quality of vision is good and I can decrease size and to bring most of my pulses at the surface of the stone and I do it continuously. I don't have to stop. Probably using low power Holmium-YAG, I think that you produce much less temperature into the kidney. This is one of the difference.

Dr. Olivier Traxer:

But now with Thulium fiber, since we are able to use more frequency because the vision is still okay we are much closer to Holmium in terms of total energy and the risk for the temperature is probably the same.

Dr. Michael Grasso:

Great, thank you.

Dr. Olivier Traxer:

Additional benefits are, I'm not sure that this is actually the decision to change from Holmium to Thulium but we need to mention that the Thulium fiber is much, much lighter, up to six times lighter but again, if the system is not efficient I will not move for a smaller box because it's smaller but actually we must say that it's smaller and lighter.

Dr. Olivier Traxer:

This is also a benefit that the system to plug that Thulium fiber is a regular one. It means that you don't need additional equipment to connect the laser so it's also a good point compared to a very high powered system.

Dr. Olivier Traxer:

The wall-plug efficiency, much more efficient and this is the reason why actually. For the cooling system Thulium fiber, we don't need a very big system to refresh the technology. A very small fan and it explain why at the end the Thulium fiber is so compact. It's a very small box because the wall-plug efficiency is so good that there's no need to refresh too much the system.

Dr. Olivier Traxer:

The maintenance, it's a very solid system, very [inaudible 00:51:49]. If you shock the system it's still okay, you don't damage the system. It's another benefit regarding Holmium. That's actually the comparison with the two technologies.

Dr. Olivier Traxer:

Now, if we are talking Michael, about initial clinical experience we need to recognize that actually it's very limited. We have a few evaluations coming mainly from Russia and from India. As you know they are using these systems in more than two years now so there are some clinical experience and one is coming from Moscow and Moscow actually the colleagues said that when they are using Thulium fiber they are able to go two to five times faster according to the patients but two to five times faster when they compare with previous experience with Holmium-YAG.

Dr. Olivier Traxer:

We evaluate also our experience. Very few cases actually. I must say very few cases but again when I compare my experience with Thulium and the Holmium I completely confirm according to the stone I'm able to go two to five times faster actually so very comparable to the Russian colleague experience.

Dr. Olivier Traxer:

This is the case, this one, just an example. This is the case I presented at the last awards congress. It was really impressive for me. It was a huge stone. 6,900 cubic millimeter and we were able to dust the stone completely in one hour 40 minutes [crosstalk 00:53:25]-

Dr. Michael Grasso:

What's the composition?

Dr. Olivier Traxer:

Sorry?

Dr. Michael Grasso:

What was the composition?

Dr. Olivier Traxer:

It was probably ... It was a soft stone. Mainly with probably some [inaudible 00:53:35], a little bit infected stone. Not very hard. It was not ... And you see it was 1,000 [inaudible 00:53:42] more or less so not very hard. It was not the right rate of course but if I compare to my experience I know what I'm able to do with my Holmium technology. I'm absolutely not able to do it in the same period of time and that's what we published recently.

Dr. Olivier Traxer:

We need all the time to consider what we produce in the lab and what we're able to produce in the real life. There's a big difference. That's why actually I can tell you that the technologies from testing regarding the lab, it seems to be super promising for the real life but we will have to confirm that. I think it's absolutely essential to make these evaluation.

Dr. Olivier Traxer:

For me a good point to make this comparison is to calculate the joule per cubic millimeter and the cubic millimeter per second regarding what you do with Holmium and you can calculate exactly the same with the Thulium fiber. It's a very objective parameters actually to compare yourself with the two technologists.

Dr. Olivier Traxer:

We recently, last Monday I did my first cases in France and again, I can tell you that what I did on Monday and Tuesday was much faster than what I'm doing usually with my Holmium and my good friend, our good friend, Michael [inaudible 00:55:11], he also receive his laser and he also tweets doing exactly the same. He said much faster compared to what I'm doing usually with Holmium so it seems to come from everywhere that people are telling much faster, much finer and much faster. We still don't know if the [inaudible 00:55:33] will be better. It's another discussion but in terms of speed I think there's a big, big, big advantage.

Dr. Olivier Traxer:

Finally, it's also a nicer system because it works also for BPH and it works also for urothelial tumor and you know Michael, that you are the top leader for that. I did my first case on Tuesday. I'm sure you will love it, the technology. It works very perfect. Super precise, really minimum bleeding. I'm very excited to be more cases of course but I was really happy because it was my first case last Tuesday and I'm sure you will love it.

Dr. Michael Grasso:

Excellent, looking forward to it.

Dr. Michael Grasso:

There's a couple questions Olivier, in the last minute or two that I can ... One of the questions is can you reuse the Thulium fibers? The plug in fibers, do you reuse those fibers or it's one time use?

Dr. Olivier Traxer:

I think, I don't know exactly regarding the IPG system. It's maybe reusable. I'm not sure but for sure for the Soltive for the Olympus system actually it's single use.

Dr. Michael Grasso:

I see.

Dr. Olivier Traxer:

Exclusively single use I think.

Dr. Michael Grasso:

Next question is with that solid state laser, does the box get hot? Is there a temperature issue? I think you answered it. I don't think it gets particularly hot.

Dr. Olivier Traxer:

That's what we call the wall-plug efficiency. 10 to 20 percent so no. It's really cool, really fresh.

Dr. Michael Grasso:

Let's see. I had one slide to throw up about tissue effects. This is just an interesting slide showing tissue effects of the various lasers and I just wanted to emphasize the fact that ND:YAG which we use for prostates and bladder tumors historically and occasionally an intrarenal tumor gets up to a centimeter of depth, of penetration of thermal effect which can be too much actually. Holmium is less but the Thulium laser fiber, to your point, is very precise and very, very superficial which protects tissue. That's why this concept of using it in a ureter for impacted stones seems a little odd. The effects should be very localized. I think as you said, if you increase the frequency really high it's going to get really hot and you shouldn't do that in the ureter, that's your point.

Dr. Olivier Traxer:

Exactly. I think it's a very important point to remember. Low frequency, low frequency into the ureter. Start with low frequency.

Dr. Michael Grasso:

Excellent.

Dr. Michael Grasso:

Jared, you have a comment there?

Dr. Jared Winaker:

No, that was wonderful. That was a nice ending. We want to of course thank the two of you, Dr. Traxer and Grasso for a wonderful discussion. I'm sure this could've gone multiple hours and it looks like there are still questions rolling in so we'll ... For all our viewers we'll be sure to have our experts answer those and those will all be available on the endourology website along with a dictation as well as a recording of today's webinar. Of course we want to thank Dr. Adrian Joyce, Dr. Ben Shu, Michelle Paoli and everyone from the education committee of the endourology society for all their work for this webinar.

Dr. Jared Winaker:

For those who are listening, just a reminder that we're taking a break next week and the master class will roll on in two weeks from today at the same time where we're going to be shifting gears over to robotics specifically for single port pertaining to surgeries for the prostate and the bladder. With all that, I thank you all for joining and we'll see you in two weeks.