So now we're gonna talk about the frontal sinus, extended frontal sinus procedures, and also a brief discussion on complications we need to think about when performing sinus surgery. Now the frontal sinus, they'll tell you, poses the greatest challenge when it comes to endoscopic sinus surgery. This is a type of surgery where we're working with 70 degree endoscopes, angled instruments, and trying to access structures well above what we can normally reach. So the ability to have manual dexterity, as well as a good review of the scan to understand the three dimensional aspects of that anatomy, is critical in order to perform a good dissection. And also you need adequate instrumentation. And sometimes certain surgery centers, hospitals, just don't have that instrumentation to allow you to do a good dissection. In general, though, we don't dissect a frontal if we see that there's minimal disease. And the reason why is if that sinus is finding a way to function on its own, best to leave it alone. However, in a patient who has moderate or severe frontal sinus disease, especially if it's symptomatic, that's where an endoscopic frontal sinus procedure is indicated. And we usually start off, if there's no prior frontal dissection done, performing a Draf IIa frontal sinusotomy. And we'll go over what the borders and aspects of that dissection are. If there's an incomplete dissection from prior surgery, you can still do that Draf IIa. In certain cases, there's scarring, neosteogenesis or complex anatomy, you may go immediately to an extended endoscopic frontal sinus procedure. Which we'll touch on as well and try to look at CAT scans and demonstrate which case that may be used for. So with respect to the frontal sinus, it's important to have a surgical game plan and perform the dissection in a stepwise fashion. And the way I used to do that, the way I was trained in fellowship, is just looking at the frontal recess as a box. It's a box with four borders. The anterior border is the agger nasi cell that you see here as well as the uncinate process that would be attaching to this agger in this location. The posterior border is the ethmoid bulla or a supraorbital ethmoid air cell, which is not seen on this imaging, as well as knowing where the anterior ethmoid artery is, right here. And as you can see, when you take out the anterior face of the bulla, you are anterior to that anterior ethmoid artery. So it's protected, it's not at risk. But when you start to go past that point, that's where that vessel is at potential risk. The lateral border of the dissection is the lamina papyracea or the medial orbital wall. And that's why it was critical when we were talking about taking down the uncinate and finding the medial orbital wall, because that is the lateral limit of your dissection. The medial border is the sagittal attachment of the middle turbinate. So essentially that box, or that Draf IIa frontal sinusotomy, means removing all the cells from the sagittal attachment of the middle turbinate all the way to the lamina papyracea. If you look at a side view, removing the agger nasi and this bulla, or any cells above it, in order to create the maximal anterior to posterior dimension to that frontal sinus opening. So that's essentially a frontal recess dissection in a nutshell. Now we talked about the importance of reviewing the CAT scan and knowing and understanding the anatomy that you'll need to dissect. I don't think there's any sinus where that's more important than with respect to the frontal sinus. And many times it's very difficult to conceptualize, cuz you really need three views, this coronal, sagittal, as well as the axial views, to try to recreate in your mind a three-dimensional view. So you'll know as you're performing that dissection where those cells are. So let's kind of go through this scan. We're gonna take you through a real case, going over the scan, and then we'll go stepwise through the actual surgery and how it's done. So you look at the coronal scan, here's your agger nasi. Here is the right frontal sinus that's obstructed. There's also an air cell here medially that also is obstructed. And that's one during the dissection where you think you're done and we'll show you in the video, we actually go back and open up that cell. But here you don't see exactly where that frontal is draining. When you look at the sagittal, you can see here the frontal sinus is in this location, then there's a narrow drainage pathway going down into the nasal cavity. This is bordered by the agger nasi and this cell here called the frontal bullar cell. It's the bulla that's extending up into the frontal sinus. So now we know where the drainage pathway is on a side view. But where is it? Is it medial or lateral? Cuz in the dissection, you're going to probe that frontal either medially or laterally, to try to find the natural pathway. And if if you don't know where it is, you're gonna keep probing and injuring mucosa, making that dissection more difficult. And the best way to find if that frontal sinus drainage pathway is medial or lateral is using your actual scan. So this is actually us reviewing a scan, scrolling through images in the axial view and you pay attention to the right frontal sinus. So in the video on the bottom, this is actually us looking at an axial scan and scrolling through the frontal sinus and finding is that drainage pathway medial or lateral. And the best way to do that is put your cross hatch in the frontal and keep following it down inferiorly. And as you follow that airspace, that will take you either medially or laterally. So that way you know, when you're in the OR, where that probe is gonna be. Cuz you really wanna find the natural drainage pathway and not create your own inadvertently. So that five step process, one, we're gonna find that skull base and medial orbital wall. Two, find the drainage pathway or the natural drainage pathway. Step three is taking down the agger nasi cell, that anterior border of the frontal recess. Step four is completing the posterior frontal recess dissection. And step five, those finishing touches. Number one, find the skull base and medial orbital wall. And you see here in this drawing the pointer is right up on the medial orbital wall. And if you look, we're in a mid-ethmoid height. The reason why is we're in that initial lamellar part of the dissection moving anterior to posterior, inferiorly. And we're gonna get back to the sphenoid, find the skull base like we did in this slide. And now we're coming anteriorly, along the skull base, approaching that frontal recess area. So we found the orbit, we found the skull base, and now we've made our way to the frontal recess. Now we can actually begin that dissection and try to find the drainage pathway. See, here we're looking, here's the agger nasi. Here's that frontal bullar cell where I'm putting the probe. And the frontal, a true frontal, has to be in this zone right here. So you have a lot of polypoid tissue. So we're looking for this pathway right here. Probe was in the agger nasi and the frontal bullar cell. Now we're gonna use some hand instruments to take down some of those partitions. And you start to see, if we slow things down, a little air space right here, and that's our natural frontal sinus drainage pathway. So even though we're removing tissue and it looks quick in the OR, you almost have to slow things down and try to find these little avenues of egress. Any little bit of daylight that you can tell you, wow, that's the natural drainage pathway. Once you've found that, then the rest is easy as far as taking down those partitions and trying to do a complete dissection. And once we've found that pathway, step three was taking down the agger nasi cell, which we're doing here. This is a Cobra forceps, which is an anterior biting curved kerrison, you might call it, which is taking down that agger nassi. There's also a medial aspect to this agger as well. So we use a side-to-side through-cutting instrument in order to remove the medial wall of that agger nassi to try to gain as maximal dimension as possible to that frontal sinus drainage pathway. And now we took down that agger nasi. We identified the skull base posteriorly. Now we have to address the posterior frontal recess. And the reason why we're a little bit more careful there? In that posterior frontal recess was where the anterior ethmoid artery lived. So that's why being a little bit cautious there is prudent. And as we come into the frontal here, where that agger nasi is, now we have to address this partition here, the frontal bullar cell. And that's what we're using, a through-cutting instrument to take that cell upwards, and then a side-to-side to take down that portion of the cell that's extending up into that frontal sinus. And as we do that, that gives us a nice adequate frontal sinus opening. So step five is the finishing touches. Remember that review of the scan I showed you in the first slide where there was that high cell that I thought was obstructed that needed to be open. This is where when we look in this patient, we have a good opening. But going after that cell, as you see here, is important in order to perform a complete dissection. Here we're using a front-to-back instrument to remove that cell. And although it looks done, there's still more of that cell located superiorly. And using angled probes angled at 70 to 90 degrees, we can actually dissect out those individual partitions or walls of the cells, in order just to remove the bone, but to preserve the underlying mucosa, and leave a well mucosalized frontal sinus drainage pathway like we're seeing here. And this is at the conclusion of the procedure. You see a patent frontal sinus, a well cleaned out skull base, and a patient hopefully will have a long-term good result with respect to this frontal recess dissection. That is essentially the Draf IIa frontal sinusotomy in a nutshell. Now what about the patient we talked about where a Draf IIa may not be the best procedure to perform up front? When do we go right to a Draf IIb? And this is just one example. This is an elderly patient who has a mucus seal potentially of the agger nasi that expanded to this size and grew up into the frontal sinus, caused obstruction of the right frontal. And you see here the left frontal has been elevated to this area, so a very thin rim around that frontal. So how do we attack this particular case? And the way we do that is, we essentially drain this first mucus seal, this is the mucus from here, we're draining that. Once we do that and clean that air cell out, then it becomes a little tricky. We took down the residual agger and turbinate, so now we're flush with the septum. So we have a wider working window to introduce instruments. And now we use a probe to try to come through the cap of this cell into the true frontal sinus. And now you see the purulent drainage that's hiding there. So you feel good when you took that first mucous seal down, but if you don't take care of this, that person's headaches and acute frontal sinus disease will persist. And here we have an instrument working above our 70 degree endoscope, in order to reach the cap of that cell and remove it. So only with the Draf IIb would we have the room to maneuver in this fashion, as well as to reach to the top of that cell, as well as to create a large opening that hopefully will not try to stenose down in the future. And taking down each part of that cell, those little bony partitions, is critical in order to get that frontal sinus drainage pathway to heal appropriately. And there you see, there's that first mucus seal, and here's the true frontal sinus in this location here. This is where a Draf IIb upfront was the ideal procedure and a Draf III was not necessary. Now when is the Draf III frontal sinusotomy necessary? The Draf III takes down this intersinus septum between the frontal sinuses and creates one common frontal sinus. If you look here, this was an elderly lady who had a right frontal sinusitis that extended to the orbit, was admitted for IV antibiotics, has a history of polyps. And on the left side you see a opacified sinus with an air cell right here. This was a large type-three frontal cell, so an air cell located within the sinus itself. So here is where a Draf III opening was considered. And the reason why is we get into this right frontal here and drain it. We try to achieve and drain that mucus. See on here, see the purulent drainage coming from that sinus. So we've entered the sinus, we've opened it. We also have opened the other side, which you'll see in a short view which is here. And this is what we call a snake eye site. If you just see these two tight openings, these are not openings that are going to stay patent long term. This is where we decided to take down this intervening segment and perform a Draf III frontal sinusotomy. Here are hand instruments that we are using. In order to get this cell here you'll see the cap or the anterior border of this cell come into view as we drill down the bone over it. And now once we access it, now we can reflect that cell using this instrument. And as we do that, look at the purulent drainage you'll see shortly that's hiding above that cell. So without removing that cell, you see it right here. So without removing that cell completely, we could be leaving potential infection behind. And this was a patient who had already had IV antibiotics at admission for an infection on the contralateral side. So although this patient did not have a prior frontal sinus dissection, going right to a Draf III was felt to be necessary due to the complex anatomy and clinical picture in this patient. So balloon sinuplasty is essentially a new armamentarium in the world of frontal sinus surgery. It's indicated in patients who may have mild to moderate frontal sinusitis. And it's indicated in cases where you don't feel you need tissue biopsy. Cuz the one thing the balloon does is dilate and drain the sinus, but it does not give you tissue sampling. It does allow you to irrigate into the sinus. But in certain cases, it may be useful in a patient who has a good frontal sinus dissection and starts to re-stenose. And in the office setting we can place that balloon to redilate that opening and prevent taking that patient back for another surgery. This video shows just that, a patient who had a left frontal sinusotomy. But due to neosteogenesis, there was some contraction of that ostium. And by using the balloon, we were able to actually cannulate the natural ostium, dilate it in an atraumatic fashion, and then retract the balloon and see a much wider opening. And this opening is still patent after three years. And this was a patient who was on aspirin and Plavix, where taking that patient back to surgery for revision procedure would have been challenging from a medical standpoint. So this allowed us in the office setting to do something under the local anesthesia and not put them at risk from the medical side. And what about complications of sinus surgery? The one I wanted to focus on is whether CSF rhinorrhea is present. And the reason why is because many times it can be mistaken for nasal mucus after a sinus surgery, and patients may have delayed onset or recognition of this going on. So in any patient who has clear watery rhinnorrhea, especially from one side, and has had prior surgery, and that drainage increases with Valsalva or increase in pressure, a CSF leak is something to consider. And you always wanna try and collect that fluid and send it off for something called beta-2 transferrin. That's essentially diagnostic of cerebrospinal fluid, and that patient has a leak somewhere that needs to be patched up. Now this was a patient who had an encephalocele here on the right side, had prior sinus surgery, and on imaging you see a CAT scan defect right here. When we took that patient to surgery, we did a patch over that area. We used mucosa from the septum and placed a patch over that defect. The reason why we color it blue is that the mucosal side has to be facing into the nose. You don't wanna put that mucosal surface internally and deliver mucus inside. So that's the reason why we label it so that way it's more noticeable for us as far as which side should be facing out. It sounds like it'd be obvious, but when you take that mucosa down it can be very tough to see. So in summary, with respect to sinus surgery, maximal medical management is needed before moving on to any surgical intervention. In those patients who fail in maximal medical therapy, getting that CAT scan and looking to see is sinus surgery indicated is imperative. And surgical intervention should be performed with mucosal preservation, open and natural openings in order to avoid iatrogenic sinusitis like we saw some of the mucus seals, etc., in some of those slides. And lastly, treatment failures are still a challenge. We have patients who have excellent surgery, we manage their allergies, we treat their infections, but they still suffer from chronic sinusitis. And those are the patients where we can't give up on trying to find those zebras, or those underlying medical issues that they may have that we may not have thought of. So this will hopefully give you an idea of seeing a patient with both acute and chronic rhinosinusitis and developing an understanding of not only how to diagnose them, how to treat them, and when to get them in the care of a sinus specialist. Thank you all for your time and I hope you enjoyed module four. The role of sinus surgery in the treatment of chronic rhinosinusitis.
