DCR and Nasolacrimal System (Cadaver)
- Anatomic Landmarking
- Create Mucosal Flap
- Expose Nasolacrimal Sac
- Drill Area of Nasolacrimal Sac
- Release Flap
- Drill Area of Nasolacrimal Sac
- Lacrimal Duct Probe
- Lacrimal Sac Incision
- Cover Exposed Bone with Mucosal Flap
TranscriptionsPlease note that, unless otherwise stated, these transcriptions have been auto generated and therefore we can not guarantee their complete accuracy.
Alright so I’m just going to show some of the anatomy of the nasolacrimal system. And do a dacryocystorhinostomy to demonstrate that. The first step I guess is to evaluate your anatomy and the middle turbinate here. I’m holding a sickle knife and I’m operating on the right side of the patient using a thirty degree camera. So, key landmarks are the axilla of the middle turbinate, the vertical attachment, the inferior turbinate, superior edge, here, the uncinate is also going to be used as a landmark for this. Sometimes it’s kind of flexible in this case it’s kind of rigid. You get the sense that it ends right around there. The virtual landmarks are where you imagine the lacrimal sac to be. It actually begins about a centimeter above the axilla. It can be quite high. And then of course, from there it comes down, siphon to his lacrimal duct and it will exit the inferior medialis. Look how high it goes and oftentimes you have to remove the anterior wall of the agger nasi to get to the lacrimal sac. The other thing is when you do a real one, you evaluate your septum too. This one is really nice. The septum is over and can see I can technically get in here. Don’t hesitate to take your time to do a little septoplasty, get it out of the way.
So I make my incision and what I’m going to do, for this next step, is create a mucosal flap. So I’m going to start roughly a centimeter above, axilla, and come forward. And this can bleed in real life so you want to inject ahead of time, best you can. We’re going to use a needle tip bovie to do this. Then you’re going to make a vertical incision. You can use a scalpel for this, or a beaver blade or again the cautery. In this case we’re just going to drag the sickle knife so it might not be the nicest incision here. And then lower horizontal incision is going to be somewhere on top of the inferior turbinate and it’s going to bleed a little bit too. And i want to attach those. All right. And I’m just trying to stay right on bone.
Now I’ll take my freer. You always do the mucosal flap? Pretty much. Because then I’ll try to use PJ Wormald’s technique. And try to preserve that because you can use that it later to cover some of the exposed bone that you create. I find that it creates a lot of, I mean we didn’t preserve the mucosal flaps, because it would just get destroyed. But I think it is a good idea because it does scar a lot. Even if I do end up removing some of it, I like to preserve it initially, because i can use it to protect the middle turbinate, even if I do end up taking a few quarters of it later. See a lot of really good exposure of the nasolacrimal of the bone. Less kind of exposure You can even make that incision more anterior. Right. I always take it back to where I sort of part of the uncinate. Here I think I’m right at the uncinate there. I need to release that down here. And this actually is an avascular plane if you get down into it right. All right. Now unfortunately, the thickest bone around the nasolacrimal duct is right where you’re trying to get to it. The thinnest part is in the posterior part where you can’t access, surgically.
Now I’m digging a Kerrison. For my next step I’m going to expose the nasolacrimal duct, nasolacrimal sac. So I’m taking my Kerrison and I’m just insinuating back there, trying to get behind the uncinate. Where, actually the bone is in front of the uncinate really. And I’m taking this off. And I’m kind of cracking it and letting it go, pulling it. Do you drill or-? I’ll drill later, yea. What drill do you use? I just use a DCR drill, 20 degree, guarded DCR drill. What I used in fellowship was the Sonopet, fancy, expensive. I mean it was because Alex was using it. He was doing the DCR.
So again, anyways. I’m crunching it, letting it go a little bit. The reason I let go is because there’s a chance I can nag the nasolacrimal duct. I don’t want to tear that. I just want to get the bone. As you get higher, you kind of lose the advantage of your Kerrison. You can’t, at this angle you can’t really get much more. Now in theory, we’re probably looking at the sac of the duct there. The lower part of it. Now I can push from the outside and there we go. You see it kind of moves there. Now you might ask yourself, “Could that be the orbit? The periorbita?” Well not really, look how far interior you are, and I’m not pressing that deep, so.
So my next step is to take my drill and drill away the part that I could not get away with the Kerrison. Twenty degree angle on there, it’s got a guard on it. He’s drilling the area of the nasolacrimal sac. You see it’s pretty high up there. You guys see how the DCR has a guarded tip. That’s the DCR right? Right, except I go hard on the back here, to guard my mucosal flap and middle turbinate. Again this is the thickest part of your dissection, of bone dissection. The frontal process of the maxillary bone.
I’m releasing my flap, just a little bit more, to get it out of the way. This is very dense hard bone. Sort of skeletonizing the bone here, thin it out. Minimize my drill on the sac mucosa or the mucosa itself. I’m just exposing more and more of the sac. Alright so a little bit more drilling and I’ll just puncture through here. Alright. So you can see we went a little bit too far. So this is, that’s not lacrimal sac, that’s actually skin, the periosteum. So I actually went too deep there. No harm done but that you can just come back and check the lacrimal sac moving right up there or not.
Alright. Now from the outside, I try to put a probe into the lacrimal duct, the lower canaliculus. I’ll try to advance that here. I can see it moving. Again, nice confirmation that we’re in the right spot. And lower canaliculus joins with the upper one to form a common canaliculus and that’s what enters the sac. And I’m really not trying to torque this probe at all. It’s just sitting right there naturally. I’m getting confidence that I’m in a good location and I can also put my flap back. There’s a middle turbinate. I can see where my middle turbinate axilla is. Which is right there. So I can probably actually go higher. I think for the purposes here, I’ll just stop, but you can go higher. So I’m going to make a little incision in the sac. The anatomy is kind of set. From here on out, it’s sort of just technical things to get the right instruments to make these incisions.
The lacrimal sac is here. This is going to be more tough than it should be. Because often, been infected. So that’s kind of a...there’s nice movement. You can tell that I had to go through several layers to get to that. You can be mislead and think you’re in the sac but you’re really not. Just extending this down. So this flap, you can just lay back and you can imagine that’s going to heal, really well. That’s one of the advantages to endonasal approach over the external approach. The external approach they don’t preserve this flap. Plus they’ve made a hole on the other side of the sac. They have very good results too. But that’s just one of the theoretical advantages of our technique. So you kind of see how it does go higher. I probably would take a little bit more time and drill this away. Even before I made an incision I could because I already knew from where the axilla of the middle turbinate is right here, so I’m still a little bit low. This is probably good enough for most cases.
There we go. So you might have seen I had a little difficulty getting through there and it actually a little valve right here and some of that valve cannot be cooperative to you. But this is really nice so I didn't have to tear, of course it’s not going to bleed here, but I didn’t really push through or tear, it fell in by itself. Now in a case like this you might argue not even have to put in, you just over canalicular, tubing, guibor, something like that, usually I will for revision cases, at least. All right and now your flap, still here and it’s not so important for the anatomy here, but I would just trim this flap so that it would cover this bone, cover this bone up here. That’s a nice dissection up here. Yep, real nice. Now I probably didn’t cut that the best you can get the sense that it’s mucosa you can lay back down here. It looks like it went too high but I didn't, it turns out I didn't really have to go higher but I could go higher. All right. If you guys look at the monitor there’s a probe going through the canaliculus. You gotta identify that. That’s how you know how high you are. If you don’t see that then you have to go higher. Right. That looks great. All right.
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