Surgeons: Necole Streeper, Michael Lipkin and Noah Canvasser

Moderator: Eduardo Mazzucchi, M.D.


Necole Streeper MD

Necole Streeper MD, is an Assistant Professor of Surgery in the Division of Urology at the Penn State Milton S. Hershey Medical Center. She completed medical school at the University of Iowa Carver College of Medicine followed by a residency in Urology at University of Texas Health Science Center at San Antonio. She also completed a fellowship in Endourology and Minimally Invasive Surgery at the University of Wisconsin. Dr. Streeper specializes in surgically treating complex kidney stone disease. In addition, she is the director of a multidisciplinary kidney stone prevention clinic that focuses on the prevention of kidney stones through both medical and dietary therapy. Her clinical research is dedicated to improving the prevention, treatment and detection of kidney stones. Specifically, she has received grant support to develop a wrist worn inertial sensor to improve fluid consumption for the prevention of kidney stones. In addition she is also interested in identifying management strategies to improve the quality of life in patients with kidney stones. Dr. Streeper has authored several research publications and book chapters in the field of kidney stone disease.

Dr. Michael Lipkin

Dr. Michael Lipkin is currently Associate Professor or Urologic Surgery at Duke University. He completed his general surgery and urology training at New York University Medical Center in 2009, and went on to complete a two year fellowship in Endourology and Minimally Invasive Surgery at Duke University in 2011. He completed his MBA at the Duke Fuqua School of Business in 2016. He is currently the Vice Chair of Clinical Operations for the Department of Surgery and the Associate Chief Medical Officer overseeing clinical operations for the physician practice at Duke University. He has been on faculty at Duke University for over 8 years. His clinical and academic interests are focused on the medical and surgical management of kidney stones. He has authored over 60 articles and numerous chapters on stone disease. His main research focus is on medical devices used to treat kidney stones, including laser lithotripsy and ureteroscopes. He helped co-author the AUA Core Curriculum on the Medical Management of. He has directed a metabolic stone course at the AUA for since 2015.

Dr. Noah Canvasser

Dr. Noah Canvasser is a fellowship-trained endourologist and minimally invasive surgeon, who focuses his practice on medical and surgical management of kidney stone disease, benign prostatic hyperplasia, and urinary tract reconstruction.

Eduardo Mazzucchi, M.D.

Associate Professor of Urology and Head of Endourology Section at Clinicas Hospital- University of São Paulo Medical School. Assistant Editor of the Journal of Urology and Journal of Endourology. Member of the Board of Directors of the Endourological Society.

 

Webinar Transcript

Moderator:

Good morning, good afternoon, wherever you are, everyone. Thanks so much for joining us. Once again, we're going to be rolling on with the Master Class of Endourology. We're sponsored by the Endo Society. We, of course, want to thank our sponsors today, Karl Storz, for their grant in support of this activity.

Moderator:

Of course, we all know we're here today to discuss flexible ureteroscopy. We're going to be discussing what type and why. As you can see, we have an esteemed panel of faculty, along with our moderator, Dr. Eduardo Mazzuchi. Very briefly, Dr. Mazzuchi is an Associate Professor of Urology as well as the head of endourology at Clinicas Hospital, as part of the University of Sao Paulo Medical School. I'll leave it to him to introduce the rest of our faculty today.

Moderator:

Just as a reminder, like all of our Master Classes, today's session is being recorded. This here is just an overview of today's CME program, so feel free to go back and look at this for more clarification at another time. With regards to continuing medical education, you'll be receiving a survey from Michele Paoli at the end of each month, and when you do get that, just go ahead and indicate which seminars you've actually attended during that previous month and then you'll be getting your CME certificate in the email. It's very important, though, we do ask that you fill out the evaluation questionnaire at the end of this and each of our webinars, as these are important for securing your credits. Of course, these webinars, like all of ours, are best when they are more interactive, so we encourage everyone to ask questions throughout. You can do this by using the Q&A function at the bottom, not the chat function. Our moderator, as well as panelists, will do their best to try and answer all those questions.

Moderator:

Of course, you can register for upcoming webinars and view the recording of this one all by visiting our website at endourology.org. I believe that's it, so Dr. Mazzuchi, I'll turn it over to you.

Dr. Eduardo Mazzuchi:

Hi, everyone. My name is Eduardo Mazzuchi. I'm Associate Professor of Urology at Clinicas Hospital, University of Sao Paulo Medical School. Today we are going to talk about flexible ureteroscopy, what type and why. I thank the Endo Society for the opportunity of moderating this webinar [inaudible 00:02:10]. Flexible ureteroscopy is probably the most [inaudible 00:02:15] for treating renal stones less than 2 cm. This is due to its high stone free rate, low incidence of severe complications, short hospital stay and fast return of patients to daily activity.

Dr. Eduardo Mazzuchi:

We know that flexible ureteroscopy is [inaudible 00:02:34] a modality of treatment [inaudible 00:02:37]. We have seen big progress in flexible ureteroscopy in the last years. This is probably due to new techniques and approaches like dusting the stones with high power lasers, relocating the stones from the lower to the upper pole to improve results, sheathless procedures, no stenting or short stenting after procedures and so on. And also due to the great development of devices. We have seen new lasers and fibers, new baskets, new digital scopes and more recently the single use scopes.

Dr. Eduardo Mazzuchi:

As a modality in transition and evolution, we have many controversies arising. We still have technical difficulties in dealing with lower pole stones located in [inaudible 00:03:29]infundibulopelvic pains. We have difficulty with abnormal kidneys, like horseshoe kidneys or very dilated systems. We have difficulty also with hard stones and tight ureters. We have problems with residual fragments, how to deal with them, how to follow-up these patients. Access sheaths, do they really increase stone free rates? Do they reduce sepsis and hematuria? Do access sheaths cause ureteral lesions and are these lesions being [inaudible 00:04:00]? Access sheath with suction, do they improve results? And the endless discussion on stents and symptoms, like lumbar pain, urgency and hematuria.

Dr. Eduardo Mazzuchi:

So today we will approach topics on ureteroscopy and we have three great experts from the US. The first topic will be an overview and an update on new devices and what's on the market. Do they help? This topic will be approached by Dr. Michael Lipkin, who is Associate Professor of Urologic Surgery at Duke University in North Carolina.

Dr. Eduardo Mazzuchi:

The second topic will be approached by Dr. Necole Streeper, who is Assistant Professor of Urology at Pennsylvania State University. She will give us some tips and tricks on treating lower pole stones with flexible ureteroscopy.

Dr. Eduardo Mazzuchi:

And finally, Dr. Noah Canvasser, who is Assistant Professor of Urology at University of California at Davis, who will give us an update on dusting, fragmentation, access sheaths and so on, and many tips and tricks. After the presentations, we will have some discussions with the panelists and the audience is encouraged to send questions by [inaudible 00:05:23].

Dr. Eduardo Mazzuchi:

So let's move quickly to the first presentation by Dr. Michael Lipkin. `Mike, thanks for coming. Welcome. It's a very great pleasure to have you here with us. Thank you.

Dr. Michael Lipkin:

Thank you, Eduardo. And thank you for the Endo Society and Karl Storz for sponsoring this and for all the behind the scenes work with Michele and Mike and the team.

Dr. Michael Lipkin:

I'm going, in the next 10 to 12 minutes, try to provide an overview of the current flexible ureteroscopes on the market and really with a focus on how to choose which scope and the sort of pluses and minuses to each type of scope. Obviously, it's a fairly robust topic to discuss in such a short period of time, so I'm going to try to keep it relatively high level. These are my disclosures. So, very broadly, when you look at types of flexible ureteroscopes, we have reusable and single use scopes, and we'll touch upon the categories within that. And again, I'm going to focus on really how do you choose, like when do you use which. I think this is largely based on performance characteristics, which we'll really talk about. And then I will very briefly touch a piece on cost. Cost has obviously been discussed a lot as it pertains to single use scopes, but it also is very institution dependent on sort of the cost benefit for the scopes.

Dr. Michael Lipkin:

So these are current, sort of the new generation digital scopes. All the major manufacturers have these digital scopes. There's the Olympus URF-V3, the Storz-Flex-Xc. There's the Richard Wolf Boa. I also mentioned there's also the Richard Wolf Cobra, which also comes in as a fiberoptic scope. And all these scopes have pretty similar performance characteristics and have really outstanding visibility. There are obviously reasonable fiberoptic scopes and there are benefits still, I think, to this day, of using a fiberoptic scope in certain instances and we'll touch upon that. You have the Olympus URF-P7, Storz-Flex-X2 and again the Richard Wolf Cobra, which is a dual channel scope and, as I mentioned, also comes in a digital form.

Dr. Michael Lipkin:

And then there is a litany of single use scopes, too many for me to really mention all. I feel like almost every day there's a new single use scope that's introduced to some market. A lot of these are regional, but I would say the three main scopes out on the market are Boston Scientific's LithoVue, which was really the first mass marketed clinically used single use scope. There's the Dornier AXIS and the Pusen Uscope. All of these are digital scopes.

Dr. Michael Lipkin:

So, how do you choose? When I think about how I'm going to use ... or which scope I'm going to use, I think about these performance characteristics primarily. Optics is probably the most important part in many instances. The size of the scope, and what I mean by size is really the maximal shaft diameter. The deflection, how well the scopes deflect and how much they deflect. Their durability, which is both relevant to single use and reusable scopes. How big is the working channel? And then the cost.

Dr. Michael Lipkin:

The working channel and cost I'm going to very briefly touch upon as far as performance characteristics. Quite simply, for the working channel, all these scopes basically have a 3.6 French channel with the exception of the Cobra, which is a dual channel. And there are advantages to using the dual channel, particularly in cases where irrigation and visibility is critically important. Upper tract tumor cases I think really come to mind in terms of an advantage for the scope. You can run irrigation through one channel and an instrument through the other, or you can run two separate instruments through two separate channels. There's a trade off because it is a bigger scope. It's about 9.9 French. But working channels, for the most part are standardized.

Dr. Michael Lipkin:

And then cost, I said I'd be brief and I meant it. Suffice it to say that digital scopes are more expensive than fiberoptic scopes. Single use scopes are at a range of prices, depending on the company, depending on where you are regionally, depending on your contracts with some of those companies, and really the analysis needed to determine if it's economically beneficial or feasible to use these scopes is really based off your institution.

Dr. Michael Lipkin:

So really I want to focus on optics, size, deflection and durability. Again, this is really a broad overview of types of scopes and this is how I think about my scope selection and how I think about performance when I compare these different scopes. So, optics, really this is actually a study that was done by Dr. Mazzuchi's group some time ago comparing two of the single use scopes, the LithoVue and Pusen, the Flex-Xc, which is a digital reusable scope. You can see that at least on a bench top, the imaging is pretty comparable. So I think in very controlled circumstances, most of these single use scopes perform fairly close to our reusable digital scopes. However, I think in practice it's not necessarily the case and so these are examples of cases. Here starting with a digital reusable scope. This is the Olympus URF-V2. You can see the image is fairly large. The lighting is fairly uniform. You have a good, broad depth of field. And I think at as far as imaging goes, the reusable digital scopes are really the standard bearers. There are subtle differences between the different reusable scopes, but most of them are fairly similar in their optical performance.

Dr. Michael Lipkin:

You can see next to that you have a fiberoptic scope that's reusable. Again, this scope is going to be ... the image is going to be much smaller. The lighting and depth of field in particular is a little less uniform. That being said, I still think the optics are certainly more than adequate to accomplish the majority of stone cases. And I think the optics have really improved over the years.

Dr. Michael Lipkin:

And then here's an example of a LithoVue. This is a single use scope that I have access to. Again, you can see the image is large. The lighting is a little less uniform. You do get these hot spots. And again, some of the other scopes have ... As these scopes evolve, this has improved. The image is not quite up to what I would say the reusable digital scope. One of the other issues, as I'm going to move forward a little bit in this video, you'll see with the LithoVue you do get some interference from the laser. Again, there have been some software upgrades to try to mitigate this, but it is a factor that is particularly pronounced in these single use scopes. So I would give the digital scope sort of the highest rating for optics, followed by single use scopes and then fiberoptic scopes, again all three being adequate for the majority of stone cases.

Dr. Michael Lipkin:

The next thing I consider, size again, broadly the digital scopes tend to be about 8.5 French to 9.9 French, and again this is measured as the maximal shaft diameter, not necessarily the tip diameter that sometimes the companies will quote you. These scopes tend to taper up to size fairly quickly, so the tip diameter is in some ways irrelevant. The fiberoptic scopes range from 7.5 to 7.9 French and then the single use scopes, again, there's a broad range, but they range from on the small end, the new Pusen scope which is 7.5 French to about 9.6 French for the LithoVue. Is this important? Well, I think it matters. Sometimes smaller is better and this is particularly relevant for cases where you don't want to use an access sheath and maybe don't want to leave a stent. Those are cases I'll pass a fiberoptic scope up over a wire. If you're inclined to use a smaller access sheath, maybe a 10/12 access sheath, or if you have an anatomically tight ureter, where you just are struggling to get a scope up, more often than not the fiberoptic scopes will help you achieve access to the kidney where a reusable digital scope or a single use scope may not. So I for one prefer, as far as size, smaller scopes more often than not. And in those cases, fiberoptic scopes seem to be the best.

Dr. Michael Lipkin:

Next is deflection and Dr. Streeper will talk a lot more about lower pole stones, but suffice it to say we are attacking more and more larger and larger lower pole stones with ureteroscopy and I think it's a good option for our patients in my many instances. Quite frankly, we have a lot of patients on anticoagulation, where percutaneous procedures are quite difficult to perform and where shock wave lithotripsy is contraindicated. So deflection is really important in choosing a flexible ureteroscope, particularly for these types of cases.

Dr. Michael Lipkin:

Again, looking at some data from the group in Brazil, you can see that the single use scopes have very comparable deflection in an empty working channel compared to our reusable scopes. One thing I do want to highlight and one advantage a single use scope has is it has that deflection every time you use it, because it is new every time you use it. Whereas our reusable scopes over time, the deflection mechanisms fatigue and they don't quite have the same deflection. This is some work that we've done at Duke and what I would point out again is that in an empty channel, both the LithoVue and the Dornier AXIS have superior comparable deflection to reasonable scopes and they're very good at maintaining their deflection, even with instruments in the working channel. Here with a 200 micron fiber and a 1.9 basket. Again, this is very helpful when you're accessing the lower pole, because you're able to deflect down.

Dr. Michael Lipkin:

And also, to be blunt, if you deflect into the lower pole and pass your instrument in a deflected scope in a reusable scope, that's a big no-no because you'll injure the working channel, but in a single use scope it's kind of like "who cares" because if I injure my working channel, I'm going to throw it out. So I think this is important and I think for deflection, a single use scope really has an advantage and that digital and fiberoptic are pretty much equivalent. There may be some subtle differences between different scopes, but more or less equivalent.

Dr. Michael Lipkin:

And then finally, durability. Truthfully, the reporting on this is all over the place. I think digital scopes, there have been groups that have gotten about 100 cases per use. Most, on average, are looking at 10 to 20, 10 to 30 cases, but suffice it to say our reusable scopes break at a fixed rate. This is a really great study that Tom Chi did out in California, real life cases comparing LithoVue and their fiberoptic scopes and they found an in case scope failure rate of about 4% for LithoVue and about 8% for their reusable scope. So I think durability is a real issue.

Dr. Michael Lipkin:

Again, most of the companies that sell single use scopes have a sort of one scope per case guarantee in the sense that if the scope fails and you open a second scope because of the failure that you're not charged, but that is variable depending on your relationships. But suffice it to say that all these scopes can break. Within a single use scope, again, this is a study we had done at Duke to look at how durable the single use scopes are. You can see that after 200 deflections, there is some fatigue, but they still deflect over 250 degrees, which is often more than adequate to get the case done. And I would say that it's very rare anybody is deflecting more than 200 times in a surgery unless perhaps you're trying to pull out every crumb like Dr. Canvasser in some of his previous studies. So here I would give durability probably an edge to digital over fiberoptic. I put not applicable necessarily for our single use scopes, because often if they break, you can pull out another one.

Dr. Michael Lipkin:

And then finally, looking at a recent real life comparison. This is a prospective clinical comparison of cases with LithoVue, Pusen and URF-V2, a group from Australia. Here again, I will preface this by saying none of these differences were statistically significant. There was a relatively small study, about 40 to 50 patients in each group. But you can see scope failure was similar. Loss of deflection was similar though, again, in the URV-V2. That loss of deflection is your new baseline for your next case. So it's cumulative. Complications and OR time are similar. And then need for second procedure, which was their sort of surrogate for stone free, was similar across the board. So I think all these scopes are clinically pretty comparable.

Dr. Michael Lipkin:

So, what do I do? If visibility is important, I choose a digital scope if I can get access sheath and I can get the scope up into the kidney, particularly for upper tract tumors and anticoagulated patients. Tight ureters or stentless procedures, these are cases where I'm not going to use an access sheath. My preference is a fiberoptic scope, because it's the smallest scope I have. And then for lower pole stones or complex anatomy, I will use a single use scope because of the superior deflection and the fact that at the end, no matter what happens, I'm going to throw the scope out.

Dr. Michael Lipkin:

That's all I have.

Dr. Eduardo Mazzuchi:

Thank you, Mike. There's one comment and one question for you. Generally, people don't pay much attention on breakage of scopes outside of the OR, and we know that about 20, 25% of breakage occurs outside the operating room. What's your advice for more young people that are starting their practice about how important it is to have a good nurse, a very well-trained nurse on preserving scopes?

Dr. Michael Lipkin:

Eduardo, I think it's critically important. I'll use an example from when I was a fellow with Glenn Preminger. This was 12 years ago. We were using an Olympus URF-V, their first digital scope, and about six months into ... At that time, our scope never left our OR. The nurses took it, cleaned it and processed it literally in a sink outside the room. Six months into my fellowship, it finally broke during a case and I asked the nurse to get the other URF-V and she said, "Well, we've only had one." And I was like well, we just used it probably for over 100 or 150 cases because it never left our hands. So I think it is really important if you can convince the hospital to have a nurse who's dedicated to your scopes. It also is important to discuss with your sterile processing people the importance of proper maintenance and handling. As a young endourologist or urologist, you really should take ownership of that process, because you know these scopes best.

Dr. Eduardo Mazzuchi:

Okay, thank you.

Dr. Eduardo Mazzuchi:

So, let's move to our second talk. Dr. Necole Streeper will talk about how to deal with lower pole stone, tips and tricks. Once again, Dr. Streeper, welcome and thanks for participating in this seminar.

Dr. Necole Streeper:

Thank you for the introduction. And thank you for the Endo Society for allowing me to present today. I have no disclosures.

Dr. Necole Streeper:

First of all, when do I choose ureteroscopy for lower pole renal stones. I consider it when the stone burden is less than 1.5 cm. If the density is higher or if the lower pole angle is more acute, then I would have a lower size threshold for doing percutaneous nephrolithotomy. I would also consider doing ureteroscopy in cases where shockwave lithotripsy or percutaneous nephrolithotomy are contraindicated, so in cases where anticoagulation cannot be stoned or in certain cases, patients with obesity. But ultimately using shared decision making, taking your patient preferences into consideration, is important.

Dr. Necole Streeper:

So when to choose a single use ureteroscope. We have a nice overview by Dr. Lipkin. I would consider using a single use scope if you had a high suspicion in a case that you may have scope damage to your reusable scope. So in a case where you have a difficult lower pole angle, you have your scope at maximum deflection or torquing the scope, or a case that's going to be a long duration with the scope deflected like this, I would consider using it. Another point would be that the LithoVue single use ureteroscope does have the working channel at the three o'clock position. So in certain cases, especially within the left kidney, that can be a more favorable angle for getting into the lower pole of the left kidney.

Dr. Necole Streeper:

Prior studies have shown that single use scopes are comparable to reusable ureteroscopes. The treatment outcomes are similar. Deflection is maintained throughout the case. There are a couple studies that have shown that there is a lower cost associated with preferentially using single use ureteroscopes for difficult lower pole stones, or in cases where you suspect there's a high risk of scope breakage.

Dr. Necole Streeper:

Tip number one is use a small laser fiber and basket. I use a 200 micron laser fiber. I use a basket that's 2.2 French or less. And then it's important to advance your laser prior to deflection of your scope. A larger laser fiber basket will impair your scope deflection, so I've got some pictures here that show that. The top pictures show a fiberoptic scope. This is a P7 Olympus scope. Without a fiber, you have good deflection in both directions. You maintain pretty good deflection with your 200 micron laser, but you see with a larger laser fiber, this is the 365 micron at the bottom, you do start to lose some deflection.

Dr. Necole Streeper:

Tip number two. In cases where you choose to use a ureteral access sheath, you may end up needing to pull back your sheath, because the sheath can prohibit your maximum deflection. So in the top photo you see just that. The sheath is well advanced into the collecting system. The bottom image, the initial upper arrow here, shows here the sheath initially was. This bottom arrow shows where the sheath needed to be pulled back so that the scope could now deflect into the lower pole in order to treat the stone. So often times you need to position your sheath well below the UPJ in order to achieve this. Sometimes it can be helpful to simultaneously adjust the sheath as you advance your scope so that you don't pull your sheath back too far.

Dr. Necole Streeper:

And then we have a video showing just that. We had just finished clearing our upper pole stones. This shows where our sheath is located. We're attempting to get our scope to deflect into the lower pole and running into some difficulty with doing that. So now we're going to be pulling back our sheath here. As we're pulling back the sheath, we're coming down below the UPJ and we start to see the ureter here. So now we know we've got our sheath pulled back far enough. We're re-advancing our scope and now we're able to get into the inner polar calyces here and then eventually we'll be able to get down to the lower pole here.

Dr. Necole Streeper:

So, when can you treat a lower pole stone in situ? I would say that it's a safe treatment for most cases. I would say that you don't automatically have to translocate the stone to an upper pole. It's particularly necessary if the stone is attached. Sometimes you’re not able to make contact with the stone with the laser, so in those cases I would choose to increase the power of my laser settings and use a popcorn technique, with the goal being to try to fragment or detach the stones so that you can flush or basket out the stone if it's somewhere difficult, and put it somewhere that's easier to treat. This is an example of treating the stone in situ. This is the case of a patient that's got a partial staghorn calculus within the lower pole. She unfortunately was not a candidate for having percutaneous nephrolithotomy, because she couldn't stop her anticoagulation. And I want to point out that this is a fiberoptic scope, so the working channel is at the nine o'clock position. So this is a right-sided kidney.

Dr. Necole Streeper:

As you can see, it's favorable to have the laser in that location for this right-sided kidney. You're able to get to the stone a lot easier than if it had been coming out at the three o'clock position. So, as we're treating the stone, it is completely filling that calyx and was obstructing it. So once we're treating the stone and getting it unobstructed, unfortunately in this case we did start having a lot of efflux of purulent material, so out of concern for infection, this case actually was terminated pretty shortly after we released some of this infection. In some cases where your lower pole angle is not very acute, I think you can safely treat the stone in situ. So in this case, you can see that the ureteroscope is just minimally deflected.

Dr. Necole Streeper:

And then tip number three. In some cases, it can be helpful to translocate your stone. So I would use a basket to remove the stone from the lower pole and choose a more favorable calyx in the upper pole or if in cases you're using a guidewire as a safety, it can be helpful to place your stone in that location so you can easier find your stone. These are examples of two more common baskets that are used, the N-Circle and the N-Gage. The N-Gage is a front grasping basket and so the one benefit of that, it does release the stone a little bit easier. This allows for you to treat the stone without deflection of the ureteroscope. One key is to just make sure that before you go to translocate the stone, you do want to make sure that the stone is not too big. This works for stones that are not attached to the calyx. So here's a video of that. We were having trouble getting the stone treated in the lower pole and it kind of wrapped into a calyx that was around the corner, so we worked on N-Circle basket in there so we could grab it.

Dr. Necole Streeper:

And then the angle was a bit acute here, so we did have some difficulty getting that to come out. Then we used both our irrigation and the basket to eventually get the stone to come out of the lower pole so that we could get it into a more favorable location to treat the stone.

Dr. Necole Streeper:

One trick is you do happen to get your stone stuck within the basket, you can actually advance a laser fiber alongside the basket to treat the stone until you're able to release the stone or extract the stone. This is another reason why it's important to use a smaller laser fiber and basket, so that they can both be within the working channel at the same time in case you need it.

Dr. Necole Streeper:

Tip number four, use both hands. I know this sounds really simple and intuitive, but sometimes just minor adjustments can help you be successful at getting into the lower pole. So the one hand in the picture, on the control, should do the majority of the work to twist the scope and then also deflect downward into the lower pole. But you do want your second hand, as you see in the picture, to be on the distal ureteroscope shaft. Sometimes you can gently twist the scope with that hand. It can give you a little bit better of an angle. Or you can re-approach the stone. What I mean by that is if you're in the lower pole and you can't get to the stone, sometimes if you just back the scope back up to the renal pelvis and then re-advance it into the lower pole, sometimes you can get a little bit better angle to get to where the stone is located.

Dr. Necole Streeper:

One trick if you're still not able to get to the stone is you can actually, with the scope deflected, continue to advance the scope and that will cause a secondary deflection where the bend point becomes a bit more proximal in the scope, so seen here in the x-ray. It will give you a little bit more of a bird's eye view of that calyx. When you do this maneuver, you'll notice that at some point as you push the scope further in, it'll actually back up the scope from where the stone is located. So in order to get closer to the stone, sometimes you do have to pull back the scope just a little bit. And then if that still fails, there is some technology that uses flexible probes, so EHL or NPL could be potential options.

Dr. Necole Streeper:

The last time is using irrigation to basket the stone. Sometimes if your stone fragments are in a difficult to reach location, you can use your hand pump irrigation and you can use short quick pumps to move the stone. You do have to be cautious though, because this can increase the intrarenal pressure. Then you flush the stone and use the basket to quickly close it. It does require good hand-eye coordination to this. This shows an example of that in a calyx where we can't quite get the stone, so we've got our basket. Initially we're a little slow on getting our basket to close as we're flushing the stones around, but eventually we're able to grasp on here.

Dr. Necole Streeper:

And that concludes my talk. Thank you for your attention.

Dr. Eduardo Mazzuchi:

Thank you, Dr. Streeper. There is a question from Dr. [inaudible 00:32:29] about using a safety guidewire when using the access sheath. What's your opinion on that?

Dr. Necole Streeper:

I don't think that you necessarily need to use a safety guidewire. It sometimes can make it difficult to get your sheath up. I typically have one in unless I'm not able to get the sheath to go up. Then in those cases, I wouldn't use one. But I think that it's not completely necessary. I just find it's easy when I'm finished to just pop my stent up with having it already in there. So I think it's something that's surgeon dependent, not completely necessary.

Dr. Eduardo Mazzuchi:

Okay. [inaudible 00:33:17]. So, let's move to our third talk with Dr. Noah Canvasser. He will talk about dusting and access sheaths and so on. Noah, welcome and thanks for participating in this webinar.

Dr. Noah Canvasser:

Thanks, Eduardo. I'd also again like to thank the Endo Society and Michele and Mike for coordinating and organizing all of this.

Dr. Noah Canvasser:

So, for those who I have not met who are listening in, my name is Noah Canvasser. I'm currently the endourologist at UC Davis in Sacramento. So, good morning to everybody, from out in California.

Dr. Noah Canvasser:

My focus of this Master Class is going to be on basket extraction, fragmentation extraction and dusting. I am a consultant for both Cook and Boston Scientific. When we often discuss fragmentation and dusting, we often try to figure out which one is better. With fragmentation extraction, we know that CT stone free rates are not as great as we would like to believe. Most of our CT data shows only approximately 50% of cases are truly stone free. When it comes to dusting, we don't really have good consistent CT data. So I consider CT stone free dates to be unknown with that technique. There is one good prospective trial from The Edge Group comparing fragmentation extraction and dusting, which showed that fragmentation extraction had a higher stone free rate, but longer operative times. On a multivariate model comparing or adjusting for stone size, it showed there was really no significant difference. What I'd like to emphasize to everybody is that you really should be competent in both. One technique is not better than the other. Cases are variable, patients are variable, stone density, composition and location is all variable. So you really should know how to do both techniques well. The goal of any procedure, regardless of the technique you use, is to try to leave no stone greater than 2 mm. We know that larger residual fragments have a higher risk of repeat surgery down the road. This is good data from Dr. Portis' group.

Dr. Noah Canvasser:

So, when do I choose fragment extraction? Certainly when I can place a sheath. That's going to make going up and down the ureter a lot easier. With smaller stone burdens, I tend to do more fragment extraction. I find that I'm fairly efficient with this modality. Certainly with infectious stones, when we're trying to pull out every last little bit to reduce the risk of recurrent infection, we use an extraction technique. And when I'm doing a second stage procedure. Certainly in my hands with fragment extraction, the risk of requiring a third stage procedure after this would be quite low, so if they've already had a failed shock wave lithotripsy or they're doing a second look after PCNL, I really do try to do a fragment extraction technique. For dusting, I use it when I cannot place a sheath. Certainly that's going to be the more optimal way to treat the stone. With larger stone burdens, certainly it's more efficient to, I think, dust that stone first. At least down to the more manageable size. And if the patient wants to avoid a stent, obviously. If you're trying to do a stentless procedure, not putting a sheath in there is going to allow you to do that a little bit or with a higher probability.

Dr. Noah Canvasser:

So, going over some tools for fragment extraction. First, access sheaths. A lot of people are a bit hesitant to use access sheaths and certainly it is perhaps arguably the most dangerous portion of a ureteroscopic case. I recommend trying either an 8/10 coaxial dilator or a dual lumen catheter before you attempt a sheath. Not only is this good to get a safety wire in if you're going to use, but also allows some calibration of the ureter, lets you know how big that ureter is, perhaps more so than a retrograde pyelogram. If the 10-French portion goes fairly easily, I'm pretty confident I'm going to be able to get an 11/13 or a 12/14 French sheath in. Conversely, if the 10-French portion is quite tight, I know I'm probably not going to be able to get a good sheath and I'm going to think more of a dusting technique without a sheath in place.

Dr. Noah Canvasser:

A lot of baskets on the market. Dr. Streeper highlighted the N-Gage basket. So these are the grasping style baskets compared to the tipless baskets. These, I think, are really helpful when you're doing fragment extraction. It becomes a bit more efficient for grabbing the stone and we'll go over some details of that a little later.

Dr. Noah Canvasser:

Lastly, laser. One nice thing about fragment extraction is any laser really will do. You can use lower power settings with 0.8 joules and 0.8 Hz with most laser systems. We use a fairly simple 20 watt laser that's probably been around for 15 or 20 years, that's very consistent and gets the job done.

Dr. Noah Canvasser:

So the goal of the fragmentation technique is to control the fragment size. You don't want to make hundreds of little pieces that you have to go up and down and get. You want to try to make them just small enough to fit in the sheath. So when we use this technique, we first try to make precise contact with the stone with the end of the laser. We drive into the stone in order to pin it against the calyx. And I use what's called a single shock technique. So this is a single press of the pedal system. So one single press, hopefully one shot of energy into the stone can control our fragment size a little bit better. It also reduced the amount of retropulsion with the stone. So this is really just a pop, pop, pop, pop of the laser system. I'm not prolonging my foot on that pedal.

Dr. Noah Canvasser:

You'll also notice that we're using a hand irrigation system, so I'm squeezing the irrigator here very gently to help reduce the amount of retropulsion. Again, the less that stone moves, the easier it is to control those fragment sizes. Sometimes we deal with kidneys that are hypermobile, especially with respiration. So in those scenarios, using an endotracheal tube and asking the anesthesia to hold the respirations can be helpful in those difficult cases.

Dr. Noah Canvasser:

One trick I like to use and actually Dr. Streeper pointed this out for her lower pole stone, is that if the laser fiber is on the opposite side of where you want it, you can flip the scope around. We can use this for both digital and fiberoptic scopes. So this is the case of a left approximate 6 mm mid pole stone. As we rotate to get into this end, you can see it's just not an optimal viewing angle in order to fragment the stone. So in this case, we flip our scope upside down. We leave the camera in place with the scope upside down and that puts the laser on the opposite side of the screen. Again, I do this with both my fiberoptic and my digital scopes actually fairly frequently. When you do this, it's important to note that your location during the procedure has not changed. So your rotation does the exact same motion, but what changes is your deflector. So if you were down is down, now it's going to be down is up. So that is the only adjustment you have to make in your mind. But if you start doing this and practicing it, you can be flexible in your mind and with your hand in adjusting your technique.

Dr. Noah Canvasser:

Extraction I think is fairly straightforward, especially when you're using a grasping style basket. The nice thing when you do this, is the surgeon is in control. You are grabbing exactly what's in front of you. It does not take any special manipulation of the basket in order to work. I always tell the residents when they're doing this, you want to go slow to the sheath. So after you grab that stone, go slow to the sheath to prevent an inadvertent urothelial injury. But once you're in the sheath, you can actually pull pretty quickly in order to get it out. This is a patient process. It is not typically a super fast process. But put on some good music and take your time to try and pull every single stone out.

Dr. Noah Canvasser:

Ideally we want to try to make it as efficient as possible and really my technique for doing this is related to muscle memory. So when you go in there trying to laser the stone and basket the stone, think about how much rotation you're putting into the scope in order to get into that calyx. You're going to use that same motion every single time going up and down in order to get into the proper calyx. So we've actually calculated this a few times. You can be fairly efficient in getting a stone extracted every 12 to 20 seconds. So if you're going to go 30 to 40 times, you're only adding about eight to 10 minutes to the case.

Dr. Noah Canvasser:

One trick that we use if we grab too big of a stone that we need to reorient, is a reorientation move. This is most helpful or actually can be done in stones that are what I consider long. So they're narrow enough for the sheath, but perhaps the length is a little bit too long. It's very difficult to do with a perfectly round stone, because typically no dimension of that stone is going to fit into the sheath. So in this example, you'll see this stone is just a little bit too big. So what I'm doing, I'm going to slow the video down in a second, is we are using obviously a grasping basket. We are opening the basket and doing a very gentle in and out motion with that basket until it frees the stone. So, again, opening the basket and slowly going in and out. You probably can't appreciate how gentle I am going in and out here, but we are not pulling hard on that stone. I think that risks urothelial injury. But it's a very gentle maneuver and we do this fairly frequently because again we're trying to grab the stones that are just small enough to fit into the sheath.

Dr. Noah Canvasser:

What happens if the stone gets stuck? Dr. Streeper showed this with her talk as well. You can use a laser and basket technique. I use what's called an applied Sureseal as my sealing device for both my basket and my laser, but you can put actually both together. There's my video. So we'll feed our laser alongside the basket. It tends to show up right in the middle of the basket, which is nice. When you're often in the ureter or just inside the sheath, it is a bit challenging to deflect. So, it's rotation that determines where you're going to fragment that stone. So you rotate your scope into position in the center of the stone, break up the stone and then you can continue on your way.

Dr. Noah Canvasser:

Moving on to dusting. The tools required to dust, I put access sheaths here. Obviously it's optional. You don't need to use it. I do like to use an access sheath, at least a small one, when I'm dusting because I think it helps with outflow, and I'll show you some video of that in a second. Obviously the basket is going to be a little less critical because you're not going to be going up and down as much, so choose the basket that you like, if a basket at all. Laser is really the important tool when we're dealing with dusting. Obviously, a higher powered laser is going to have higher frequency options. Ideally, you want to have something that at least goes to 40 Hz to get a good dusting effect. If you have a lower power laser, a variable pulse laser, where you can do a wide pulse mode, will give you a similar dusting type technique.

Dr. Noah Canvasser:

This is my algorithm for dusting. I think people have published a lot of things that are similar. I more or less mimic them. I typically start it between 0.2 and 0.5 joules and I really just maximize the hertz. My machine goes to 80 hertz, so we start at 80 hertz pretty much on everybody. Certainly 0.2 joules is going to be a softer stone and then the 0.4 to 0.5 joules is going to be for a harder stone.

Dr. Noah Canvasser:

We start dusting until we notice increased retropulsion. At that point, that's when you have to start decreasing the water to the machine. So either decreasing the joules or the hertz. For harder stones, we typically need to maintain a higher joules setting, so we start to decrease the hertz first. For softer stones, we'll decrease the joule energy. We continue to decrease that energy until essentially the dusting becomes inefficient and you've got too much retropulsion. At that point, we tend to switch to a fragmentation technique.

Dr. Noah Canvasser:

So here's a case. This was a 11 or 12 mm upper pole infundibular stone that after we put our sheath in, and actually we were planning to do a fragmentation technique, after we put our sheath we noted that the proximal ureter UPJ was actually fairly narrow. I had to switch from a digital scope to a fiberoptic scope and it just barely went through that sheath. But inside we started to do a dusting technique instead. You can see we worked circumferentially, try not to dig any holes. Once you start digging holes, you tend to start getting larger pieces to come off. The one thing I know with dusting is that oftentimes the vision gets a little less clear. My tip for this is you have a sheath in place to back up into your sheath. After you wait a few seconds, all that cloudy stone debris will start to flush out. When you go back into the kidney, it tends to look a bit clear again. We do this multiple times throughout the case. Every time it gets a little bit cloudy, we will go back into the sheath and give it time to clear.

Dr. Noah Canvasser:

At the very end of the case, I always still look around just to make sure there's no large or significant fragments. Given the size of his ureter, I want to break these stones up a little bit smaller, so we did another single shot fragmentation into smaller pieces. Then clearly at the end we're going to basket out a few of these pieces. But really, dusting in this case was quite nice, although it was a harder stone. We had a lot of real true dust, so we only had to pull out a couple fragments, and that was it.

Dr. Noah Canvasser:

So, in summary, I think you should optimize your tools and equipment to be able to do both techniques, having multiple baskets available. Hopefully a grasping type basket will improve your extraction efficiency. If you can have a high powered laser to be able to do dusting, that's obviously optimal as well. I think you really should learn to utilize both techniques. If you are strictly a fragmenter or strictly a duster, try the other approach. The more you do it, the better you'll get at it. Because with most of our cases, we need to be flexible in our approach and we can't often apply a one size fits all model.

Dr. Noah Canvasser:

Thank you.

Dr. Eduardo Mazzuchi:

Thank you, Noah. Excellent presentation. We have some points and some questions from the audience. You told us that using the access sheath is absolutely optional. Are there any cases that using an access sheath is mandatory? For instance, if the patient had a big infection just before the procedure is one situation. Or any other [crosstalk 00:47:46].

Dr. Noah Canvasser:

Yeah. Certainly, if you're going to do a true fragment extraction, I think you need an access sheath, so that is mandatory. I think it's optional if you're going to be doing a dusting approach. But for me, an access sheath is pressure control. And pressure equals infection. If you are concerned about infection, somebody who's got a history of struvite stones, recurrent infections, having that sheath in there will really help to reduce that pressure. I think we can actually take visual cues during the case to see how well our access sheath is working. One thing is we'll actually look and see, is there effluent coming out where the scope inserts on the sheath? Do you see a nice consistent drip coming out of the kidney? If you don't, it probably means you're building up some pressure. Similarly, if you look inside the kidney, if you have really good vision and the pelvis is really distended, it probably means your pressure is building up. So infection is the one scenario where I think it is mandatory to have a sheath.

Dr. Eduardo Mazzuchi:

Any special type of access sheath you like? Like 11/13 or 12/14 or depends on the case?

Dr. Noah Canvasser:

Yeah, that's a good question. My go-to is the 11/13. I tend to use a digital scope and ours is 8.5 French for the length of the shaft. I believe there have been a couple investigators who have shown that a 2 French difference between the inner diameter and your sheath allows you to control that pressure and minimize that intrarenal pressure more. So for me having an 8.5 French scope means I need a sheath greater than 10.5 French. So 11/13 is the next size up where I'm fairly consistent about getting it in. Pre-stented ureter, I will often try to get a 13/15 sheath in if the patient has a stone size that warrants it, a large stone. But typically it's an 11/13.

Dr. Eduardo Mazzuchi:

Okay. Necole, do you agree with that access sheath? Do you think they improve stone free rates?

Dr. Necole Streeper:

I think that what Noah was saying about having sort of a combination of what you do. I think there's certain situations where dusting the stone is appropriate and some situations where you need to fragment. So I kind of use a combination, depending on how the stone is dusting and the size of the stone and if there's infection risk. So, I agree. I think you don't need to use it for every case, but there are some instances where it definitely can be helpful.

Dr. Eduardo Mazzuchi:

Noah gave us a tip on how he sets his laser at the beginning of the procedure. Do you do more or less the same? You start with the low power and high frequency, or you do something different at the beginning of the surgery?

Dr. Necole Streeper:

It depends what I'm doing, if I'm going to be dusting or fragmenting. My go-to starting dusting settings are 0.2 and 80. And then if I had a hard stone, I typically just go up with the joules to 0.3 and keep with the same frequency. And then if I'm fragmenting, I typically use 0.8 and 8 and if it's a harder stone then I'll go up on both the energy and the frequency.

Dr. Eduardo Mazzuchi:

Yeah. Mike, there is one difficult question for you and also comments from the audience. What about the environment impact of using single use stones. I think this is an unanswered point, but I'd like to hear your opinion on that. The second point is, do you think that every hospital would have, if possible, at least two options of scope, one single use and one reusable scope? For instance, for different situations we face every day.

Dr. Michael Lipkin:

Thanks, Eduardo. For the first question, the environmental impact, I think that's a very relevant question if you think about the amount of things we throw out in the OR. There has been, that I'm aware of, one study ... I think it was Damion Bolton's group in Australia ... actually looked at this. They compared the carbon footprint for a single use scope and reusable scopes and they did it sort of all inconclusive. So for the single use scope, it was manufacturing, it was what you threw out, it was the packaging. With the reusable scope, it was similarly the case you keep it in, the sterilization, etc., and they actually reported that the carbon footprint is actually fairly similar per use. A lot of that potentially has to do with how you process the scopes. Admittedly, and they acknowledged this in the paper, the methodology they used was never designed to look at scopes. It was, I think it's called the big mac technique, it was meant to look at it from fast food companies. So I think it's an open-ended question and it's something that we probably need to look at and it's probably even a broader question for medicine in general.

Dr. Michael Lipkin:

As to your second question, I think having a single use scope on the shelf is nice because in a lot of institutions they only have two or three reusable scopes and if they break or if there's a problem with processing and you have a patient asleep, then your only option now is to put a stent in or abort the procedure. At least if you have a single use scope, you could care of that patient. For the time being, single use scopes every case is probably not feasible or the right thing at every institution. But I think having some on hand just to ensure that you could take care of your patients, I think makes a lot of sense, even if it's just in case of emergency.

Dr. Eduardo Mazzuchi:

Okay. Noah, do you agree with Mike? What type of scopes do you have in your service? At least two or three?

Dr. Noah Canvasser:

We're very fortunate. We have a number of both fiberoptic and digital scopes available, but I would concur with him that having a single use scope available for those cases where you risk scope breakage. As Dr. Streeper was saying, those larger lower pole stone burdens, sometimes you can't really appreciate the angle of the infundibulopelvic angle until you actually get in there and see how it works with your sheath. Once you've started the case, you might be concerned that you're going to deal with scope breakage and giving the opportunity to switch to a single use scope intraoperatively is a nice option. So I think that you should, if you can, have all scopes available and, again, be flexible in your approach. Once you've started the case, you can change to try to minimize that risk of damage.

Dr. Eduardo Mazzuchi:

I think the message here is that use of a single use scope is absolutely [inaudible 00:54:40]. You don't have a rule for every case.

Dr. Eduardo Mazzuchi:

Necole, another question for you. When treating a lower pole stone in a solitary kidney in patients on anticoagulation, do you change any of your access or approach?

Dr. Necole Streeper:

For a solitary kidney, I don't really change my approach. I do the same that I do for a regular case.

Dr. Eduardo Mazzuchi:

And for anticoagulated patients? Any tips for not having bleeding in the beginning of the surgery [inaudible 00:55:19]?

Dr. Necole Streeper:

Yeah. I think I typically try to be careful on all cases, so to be honest I don't think I really have a difference in technique when they are anticoagulated. My goal is always to try to keep them from bleeding as much as possible. Because I think even in a patient that's not anticoagulated, you could definitely get into trouble with bleeding and you have to stop the case before you're finished. So I do the same approach.

Dr. Eduardo Mazzuchi:

You don't change your laser settings in patients on anticoagulation?

Dr. Necole Streeper:

I don't. I use the same.

Dr. Eduardo Mazzuchi:

Okay. Mike [crosstalk 00:55:56].

Dr. Michael Lipkin:

Eduardo, can I make one quick comment. I agree with Necole. The one thing I do differently, and I don't know how you guys counsel your patients preop, in older men who I operate on anticoagulation, I actually mention the fact they may wake up with a Foley catheter. I do not routinely leave catheters after ureteroscopy and even on anticoagulation patients, I admit it's rare, but there are these large prostates where during the case you come out at the end and you're like, oh, this patient is not going to urinate. And I just place a catheter in at the end of the case. I don't normally counsel that for ureteroscopy.

Dr. Eduardo Mazzuchi:

I think that in older men it's a wise decision, because they frequently get retention after the surgery.

Dr. Eduardo Mazzuchi:

So, we are right on time. I would like to thank all the panelists. It's been a great pleasure to have you here. Unfortunately, the subject is very broad and we could stay here for hours talking about flexible ureteroscopy and [inaudible 00:56:57], but I think we were able to help the people in the audience.

Dr. Eduardo Mazzuchi:

I thank you so much for your participation and I thank the Endo Society for this great opportunity. Have a nice day, everyone. Bye-bye.