Dr. Seth Bechis of UC San Diego introduces the reusable instrument set needed to perform minimally invasive PCNL on an outpatient basis and demonstrates procedural steps, including the vacuum effect.
So I'm gonna talk a little bit about mhm the equipment itself and what's involved in doing Ah, MEP, I think once you're armed with with the tools for access which Doctor, sir gave a really nice talk on the shifting towards ultrasound, I'm going to just touch on the tools and how you can take advantage of them. And what would the potential benefits be over another system? So the MIPS set, which is a minimally invasive PCL, um, this is a picture of the entire set. It's nice because it's a modular, reusable system. Eso everything that you need, you know, for the actual procedure is here now. Obviously, there are some additional equipment items you need for getting access for performing with a trip. See, but in general, the equipment for dilation navigating the kidney. There's even a grasshopper that comes with the set for stone removal. Um, pretty much the majority. The equipment that you need isn't contained in this set, and it's reusable. That potentially translates into cost effectiveness. A Z you are cutting down on your needs for disposable items on a canvas illit ated a to Bliss PCL or even an outpatient PCL. because of the size of the track in the United States, there's three main size sets designated small, medium and large or a myth s myth em up myth l that really refers to the size of the Nef ra scope. Uh, the camera. So we primarily is the myth M set, which is a 12 French scope, and it comes with three different chief sizes that range from a 15 or 16 French, 17.5 French in a 22 French. You can see those laid out here. Each sheath comes into lengths. There's a regular length on, then a length designated with an S for supine, which is to facilitate. If you're doing the case in a prone versus a supine position, it's slightly longer to account for the increase skin to stone distance for lower poll in the supine position. So once you've picked a size, the the equipment that you need is shown here. All you really need is a single step violator you can see in the video that's me putting the dilation operator through the operating chief. Eso you need your sheath, you need your dilator. You need the net for a scope and then possibly a sealant applicator to close the tract. When you're all done and again, it's a single step dilation, which will come back to so simplifies the process. So some key features of the MIPS set obviously it's size is very advantageous. Um, compared to Standard PCL, which often are either 24 or 30 French dilation tracks, you could make a much smaller tracked here. The single step dilation we talked about. One advantage of this set is that it's an open system design. What I mean by that is the sheath itself and the telescope are not locked together, so you can see in this picture Bye bye. Maintaining freedom of movement of the camera, um, independent from the outer sheath, it maintains an open channel for outflow around the Net. Frisco. By doing that, you could really maintain a lower pressure state in the kidney because you're not at risk for blocking the outflow, which could lead to increased pressures inside the kidney. It also facilitates stone extraction, um, using the vacuum effect which will touch on in a minute. Obviously, this system allows you to close the track after with sealant. If you want. And then there's a large angle of view relative to the scope, and that's because the NYT FRA scope itself. It is very small compared to the diameter of your access chief and the regulation on the camera. So it translates into a very good visibility inside. So the vacuum effect, I think this is one of the main advantages of the MEP is it facilitates fast removal of stones of both dust and also small particles. The idea is the in flow through the Net Frisco has shown by this red current creates an eddy current approximately 1 to 2 centimeters in front of the tip of the camera, and then the draining fluid, which comes outside the sheath because of the physics of that interaction, creates an eddy current right in front of the camera, which you can use to trap stones. And by withdrawing the Net, Frisco pure actually withdrawing larger stone fragments in this eddy current, and then the continuous flow promotes smaller dust and fragments toe also drain on their own at the same time. An advantage of this is it could potentially is faster, and you don't need to use disposable retrieval devices such as baskets and grass spurs. The video from Dr Sir that highlights this effect. You can see here there's a never a scope is inserted. You can see the continuous drainage of fluid around the sheath. And then, as you bring the scope back, you can see the stone pieces air coming out, landing on that gauze pad beneath the camera. There, you can see on the right. Uh, there's a stone that's being trapped right there, and it's held about one centimeter in front of the scope all the way as it's being withdrawn. And some of the subtle tips are as you're withdrawing the stone, you want to tip your risk so that you can maintain that that vacuum effect all the way to the end of the sheath and you can see in a pretty short time he's already pulled out. There's at least eight large stone fragments visible on that cause, so if done right, it's a very fast and efficient step. So I'm going to just go through quickly the steps of the procedure overall and and, uh, and then show you sort of one option for technique and how to use the system So the first step, obviously, is Thio, get your literal access on this Could be done depending on how your set up is. I personally do assist Oscar P, um, place. So you read your catheter, but you can also do a retrograde eureka. Rosco p, this is a picture showing the table set up so you can see, in my case, I've selected the MIT M set. So, really, all I have is my sheath, my introduction, my dilating operator on my net for a scope. And then I have a few other things that come with your and my access needles over here. That's the methylene blue. Have a one suitor for the end of the case, So I I do prone positioning. So after we've placed a urethral catheter, we then, uh, with the patient and prone position and you can see have a set up similar to Dr Sirs illustration. We have the C arm up here, the compliment access, and then the visualization monitors. And at the foot of the bed is the ultrasound monitor. Here. This is just shown with the lights off. You can see there's a nice view, so step two, obviously obtaining access, and this could be through a variety of technique on. And once you, the key is obviously getting access with. Here's a flash of urine. In this case, we've used methylene blue, Um, and then you want to pass your wire either into the kidney or ideally down the ureter into the bladder. Thing is the single step dilation, which is, um, one of the hallmarks is, once you have your wire, you twist your operator over the wire in a slow fashion. You can use Flora's to be to guide it, and when you're in, you can see there's a second port that were alluding to here and that will drain urine so you know the operators in the right place. When you see your coming out, you then pass the second wire through this channel. Once you've done that, you actually withdraw the dilator off of the two wires and reinsert it just over one of the wires. That so that you can maintain a safety wire outside of the tracked. And here you can see we're advancing the sheath over the violating operator. You can see the sheath there once it's confirmed inside the kidney Then you can remove the the working wire and the Interop traitor, and you have just a working sheath with a wire safety wire outside of that system. If you're having difficulty, there's other maneuvers you can use. You can possibly use a A 10 French or 8 10 French dilator to pre dilate the tract prior to passing the dilator, Um, or even a balloon. Um, the next step is treating the stone, so this is using either laser or a with a trip to of your choice. Commonly, I think people use some form of laser. Uh, nowadays, I do think that the Moses or a dusting laser, or even a few Liam any of these higher energy laser systems that enable dusting of the stones, um, potentially will lead to faster drainage. Due to the vacuum effect of the myth, you can both extract the stones as we've seen, and also drain all the dusting in the small stone fragments and then at the end, um, either leaving a frost me tube. Although this system, to be honest, really is, is geared for leaving an internalized, you literal stent, potentially even going totally to bliss in our practice, we leave a stent with an external, uh, tether. So we place the stent and then leave the string externalized thru are tracked. This facilitates easier removal. 3 to 5 days later, the patient comes into the office. One of the nurses just removes the stent by pulling the string. It also saves the patient having under grossest Oscar P, which many men are particularly excited about on you can see here that there's just a Band Aid left behind.