GARRET CHOBY: This is Garret Choby, and today we will be discussing a combined open and endoscopic craniofacial resection for an esthesioneuroblastoma. Here is the patient's imaging studies. You can see he has a fairly extensive esthesioneuroblastoma, primarily involving the left side of his nose, but also crossing midline. And what you'll see on this sagittal MRI scan is that there's quite a bit of dural nodular enhancement that crawls up the posterior table to his frontal sinus, nearly to his apex.

So in this particular case, we elected for a combined open and endoscopic approach in order to maximize our exposure to the posterior table of the frontal sinus where this involved dura was. And as you'll see later in the case, there's also extensive involvement of the mucosa of the frontal sinus the whole way up to the apex of the frontal sinus, which this combined open approach really allowed us to get excellent access to.

And here is my neurosurgery partner, Dr. Van Gompel, beginning with a bifrontal craniotomy. You can see a bicoronal incision being carried out there and the scalp flap being raised. In this case, we are leaving the pericranium down onto the cranium itself and we'll raise that as a separate flap just here in a moment. This allows for a very nice, robust reconstruction option when you're doing a combined open and endoscopic approach.

You can see here now after the skin has been raised, an incision is made out in the pericranium to allow us to raise that anteriorly. Again, pedicled on our supraorbital and supratrochlear vessels, as you can see here. And the next thing we're going to look to do is go ahead and access the craniotomy just above our frontal sinuses, you can see in this particular case. So here are some burr holes being carried out as we enter into this area.

After the osteotomies have been completed, we then go ahead and raising and removing that bone flap, as you can see in this image. Dura is then being exposed, as you can see here. And then we'll incise into the dura here momentarily. Again, because of all that nodular enhancity crawling up the posterior table of the frontal sinus to its apex, we're going to go ahead and start by removing some of that dura in this particular case, just above there, in order to access this area and remove that portion of the patient's disease.

In this particular case, we will end up cranializing the patient's frontal sinus. So as you work through this area and address and remove the posterior table of the frontal sinus, we're going to, of course, remove this area for disease control and tumor resection. It's also very important that the entirety of the mucosa of the frontal sinus is completely removed to reduce his risk of post-operative mucocele formation or leading to other infectious etiologies. We, of course, sampled that mucosa as well. And much of that frontal mucosa was involved with tumor up until, again, the apex of the frontal sinus, which again was nicely accessed through our open bifrontal craniotomy.

Here we are now turning our attention to the intranasal portion of the case. What we'll do first is track and map out the tumor. I think it's very important to debulk the tumor that is freely hanging in the nose without any mucosal attachments, especially the area towards the nasopharynx. What that is going to allow for is egress of blood into the nasopharynx, allowing that egress port, if you will, in order to improve your visualization throughout the case. A large portion of the tumor has been taken already for permanent section pathology. And we'll debulk this lower portion of the tumor with a microdebrider, as you can see here. This portion that is simply free floating in the nasal cavity without any mucosal attachments.

Here's that last bit of tumor in the nasal pharynx being removed, again, to allow more ready access for egress of blood flow throughout this case with his vascular tumor. We're now tracking up onto the nasal septum, as you can see here, in the area of the patient's middle turbinate. Because the bifrontal craniotomy has already been completed, we'll be able to access that area readily and see that in short order. You can see here tumor is free from the lateral nasal wall in the area of the inferior turbinate towards the area of the maxillary sinus.

We'll take out the rest of the left middle turbinate, as you can see here, as tumor is involving it. And when dealing with sinonasal malignancies from an endoscopic standpoint, again, the key parts with tumor dissection are to debulk those areas that are freely hanging and then closely assess the mucosal areas that they're attached to, and then take wide margins around this.

So as you can see here, I'm using a needle tip Bovie cautery in order to incise wide margins around the nasal septal involvement, as you can see here. And then we'll sample all these areas for margins as we resect this area. Here we are, posterior nasal septum, making our mucosal incisions, then coming the whole way through the septum on the contralateral side. There is some tumor involvement in the high superior septum on his right side as well. But here we are making those mucosal cuts on the left side and then performing our septectomy.

And what I typically like to do is then sample the margin on the side left in the nasal cavity. So we'll resect the area of the tumor itself, and then we'll sample the mucosa on the side that's left in the nasal cavity. So just for some examples, here's incising then checking our left inferior septal margin, as well as an anterior inferior septal margin. And I like to be very careful with these as I label them to ensure I know exactly where in the nasal cavity they came from. So in case anything comes back positive, we can easily go back and track that.

Here we are making our incisions on the lateral nasal wall. Again, fairly sense of involvement here in the lateral nasal wall. So we'll make our incisions and then take our margins adjacent to it. I prefer a needle tip Bovie cautery, although other things can be utilized here, including a Cottle elevator or other cold steel instruments. Obtaining and tracking the margins on the intranasal side is a very important part of this surgery.

Here we are coming through and marking the contralateral side and then making corresponding incisions in the patient's right side of his nasal cavity. Again, we'll make our incisions here and take out that septum, but then we'll mark out and take our right-sided margins as well, in short order. As I mentioned earlier, a large nasoseptal flap is not possible in a case like this due to tumor involvement of it.

So in these cases, even if we would choose a purely endoscopic craniofacial resection, a pericranial flap would likely be needed for our reconstruction. However, in a case like this, where we're doing a combined open and endoscopic approach, the pericranial flap is already raised and accessed. And we'll drop that in from above for our reconstruction later on.

Here we are outlining the mucosal incisions again for our right-sided mucosal incisions of the nasal septum. And then we're going to go ahead and take out all that bone and cartilage and complete our septectomy. The most important thing in these cases is to completely remove the tumor and obtain negative margins. So if we think about these tumors from a philosophical perspective, certainly there are different tools to do that. There's purely endoscopic approaches. There's combined approaches. And there are purely open approaches.

But the bottom line is, the approach you select should really be dictated by the tumor and what you're most comfortable with obtaining complete tumor resection. Here we are on the right side. I complete an uncinectomy, and we'll open up the maxillary sinus for long-term surveillance, although the tumor is not directly involved in that area. We are also anticipating that he will receive adjuvant radiotherapy which can cause scarring and chronic sinus problems in many patients. So this is also helpful to prevent that long-term.

Here we are now opening up the sphenoid sinus, as you can see here. I like [INAUDIBLE] for a lot of the work back here towards the sphenoid. What you can see here is that sphenoid mucosa looks very normal. Now we will also sample the areas around here to ensure it's negative as well before chalking it up to being normal, but it certainly has a normal clinical appearance in this sphenoid sinus.

Now here we are back on the left side. You're seeing the left nasopharynx there with our lower septectomy defect, which will all come out here in a few moments, and looking to the contralateral side as well. And again, we'll make some incisions here in order to fully remove all of the mucosa in this area. We'll again sample margins as we work through this area as well, of course.

Here we are completing our septectomy, bringing that bony posterior septum off the rostrum of the sphenoid and removing that in its entirety. And then bringing our Kerrison up again in the area where we've made our mucosal cuts and incisions in the more anterior septum to resect that in its entirety as well. There you can see the rest of the septum coming out of the nose and just completing that inferior portion as well.

Now here we are working on the lateral nasal wall. We're over the top of the nasolacrimal duct in this particular shot, as you can see here. We have already taken margins anteriorly. And here we are peeling all the soft tissue off of that area. As I mentioned earlier, I'll go ahead and complete a maxillary antrostomy and open the ethmoids on this side as well.

You can see that area of the maxillary sinus is secondarily obstructed, and there's mucoperial in that particular area. The mucosa there is inflamed, although not directly involved with the tumor. And we, of course, took samples of it to ensure that as well during the surgery.

And I'll keep working here in the lateral nasal wall, taking this mucosa as it transitions from the lateral wall over to the nasolacrimal duct and towards the orbit. What you can see here is us carefully peeling all this mucosa out over this area and beginning to expose the bone of the lamina papyracea and the nasolacrimal duct.

And here we are opening up the left sphenoid sinus. Again, you can see there's a lot of post-obstructive secretions within the sinus, although the sinus itself was not directly involved. We, of course, sampled that mucosa as well, but it was negative.

You just caught a glimpse of the craniotomy from above and a [INAUDIBLE] coming through in that particular area. I will note that the anterior and posterior ethmoid arteries have already been cauterized from above, and bilateral olfactory bulbs have already been resected.

Because a large portion of this bone was exposed, although not directly involved with the tumor, I thought it would be prudent to go ahead and drill down the entire [INAUDIBLE] rostrum to remove that. I find, in many patients that have exposed bone following this surgery and undergo adjuvant radiotherapy, that area has a tendency to crust long-term and can cause problems with osteoradionecrosis. So I do like to remove the bulk of that bone whenever possible in order to help to prevent some of those side effects of radiotherapy.

Now as we're looking at the nasal cavity you'll see, obviously, a much wider view there with the septum gone and the cranial base gone. I'm now taking down the lamina papyracea in order to expose the periorbita. On the patient's preoperative scans, the tumor certainly abutted the orbit in this area. There is no clear intraorbital extension. So in these cases, what I typically do will be remove the entirety of the lamina papyracea and then remove and sample the periorbita itself to see if it's involved with the tumor.

If it is involved, we may go ahead and resect the entirety of it. If it's clean, however, we'll typically leave the remaining portion of the periorbita in place. I like to maintain that plane right along the periorbita to make sure this fat stays intact to make sure your biopsy does not inadvertently get the medial rectus. The periorbital was free of tumor in this case as well.

And then, again, I think it's prudent in these particular cases where the tumor abuts the nasolacrimal duct system to go ahead and drill down the entirety of that lacrimal system and then sample the lacrimal sac and the other soft tissue contents in the lacrimal system to ensure it's not involved with the tumor. So here we are drilling down the lacrimal system and using a 2 millimeter Kerrison to take the rest of that bone down.

There we are entering that mucosa over the top of the lacrimal sac, as you can see there. And we'll go ahead and sample that mucosa for frozen section pathology. As I mentioned earlier, in this particular case, this came back negative for tumor involvement. However, I do think it's really important to be extensive in these cases. I'd much rather open up someone's lacrimal system and deal with a [INAUDIBLE] later on than to leave tumor there during their resection. In my experience with radiotherapy, many of these patients will end up scarring down their lacrimal system and may require DCRs down the road.

I have, in the past, stented this system prophylactically. But typically what I'll do nowadays is I'll let them get the radiation and heal from that, and then we'll consider doing a DCR down the road.

Here I am just drilling down the frontal beak, as you can see here, ensuring that there's no further mucosa in that particular area and just visualizing this area better for our reconstruction and for long-term surveillance. Now we'll go ahead and get a combined look both through the nose and from above.

After the tumor has been resected and we've achieved our negative margins, we are beginning to think about our reconstruction. Here we are just drilling down smooth. Again, the anterior-- [AUDIO OUT] the frontal sinus in making sure that our flap is going to lay down there very nicely on top of smooth bone.

Here is one of the final views endoscopically prior to reconstruction. You can see both spheroids there and the planum resectioned with [INAUDIBLE] from above through a craniotomy defect. And then what will become our new neofrontal sinus after cranialization. For our typical reconstruction [INAUDIBLE] such as this, what we like to do is to use our fascia lata as a primary closure as a patch in the dura, which is sutured to the dural defect. We then will lay in our pericranial flap covering the entirety of the cranial base from planum to the remnant inner table of the frontal sinus, and orbit to orbit, and then reinforce some of those edges with additional fascia lata as needed.

After we're satisfied with our reconstruction, I'll typically put some absorbable packing material in the nose. In cases like this where there's very little support in the nose, and the majority of intranasal contents have been resected, I will typically place some mirror cells as well. In this case, we placed [INAUDIBLE] mirror cells underneath our packing to have nice support in that area. And here is the patient's post-operative MRI scan, as you can see here. He's undergone an extensive resection, cranialization of the frontal sinus, and then reconstruction with a pericranial flap, as well as fascia lata graft, as you can see here. With the [INAUDIBLE] up there.

And here is him postoperatively, about a month or so after surgery. Things have been opened. He's been debrided. And you can see some crusting there along that pericranial graft, which happens in most of these cases.

When considering sinus malignancy resection, such as esthesioneuroblastoma, in many cases, we are able to complete this with a purely endoscopic anterior cranial base resection. However, the extent of tumor will dictate the approach that's needed. In a case such as this with extensive dural involvement along the posterior table of the frontal sinus, and frontal sinus mucosa itself, we elected for a combined open and endoscopic approach. This allows a bit better access for tumor removal, as well as nice reconstruction with a pericranial flap when things like a septal flap are not available for reconstruction.

The most important part of considerations for these cases is a complete resection of tumor with negative margins, and selection of the approach is dictated by what will give you the greatest chance of achieving that. Long-term surveillance is needed. And many patients will also go on to receive adjuvant therapy such as radiation or, in select cases, chemotherapy.