GARRET CHOBY: This is Garret Choby. Today we'll be showing you a few videos looking at raising nasoseptal flaps for skull base reconstruction.

This case is a right-sided nasoseptal flap for a planum meningioma. So here we are in the right nasal cavity, you can see, making the inferior incision for this flap along the choana, then bring that down along the posterior aspect of the nasal septum towards the nasal floor, as you can see here. In this case, we expect a big defect, so we elected to raise this in a slightly extended fashion onto the nasal floor, as you can see here, towards the inferior meatus, then bringing that up anteriorly towards the nasal cavity.

The second incision is more superiorly based, coming about the level of the natural os of the sphenoid sinus that allows for a nice wide pedicle. I'm going to keep this about a centimeter or two below the skull base to preserve olfaction. Then once you reach the head of the middle turbinate, as you can see here, you can bring that more securely towards the vault of the nose and then connect things anteriorly near the mucocutaneous junction of the front of the nose. So here's a nice view looking at the incisions. There's our pedicle back there, with the superior limit being our sphenoidotomy and the inferior limit being the choana.

And onto the next case is a little bit more involved. This is an esthesioneuroblastoma. We're going to raise a left-sided flap in this case. One of the tricky parts here is that the tumor actually involves part of the nasal septum, which will alter a bit the way we make our incisions. In addition, the patient has a septal fracture posteriorly with some imbricated mucosa in a deep cleft in the posterior aspect of the nasal septum.

So here we are outfracturing the middle and superior turbinates. We're going to make the inferior incision here, once again along the choana and bring this down towards the floor of the nose in order to preserve a nice wide pedicle here. Bring this on to the nasal floor here, once again, we're expecting quite a large cribriform defect here. So I'm going to go ahead and incorporate the majority of the mucosa before the nose, bring this high into the inferior medius, as you can see here, towards the front of the nose.

And as we go towards the back, the next incision we're going to see here is coming below the mucosa, below the tumor, as you can see here. Then what I like to do is go ahead and biopsy the superior aspect of the flap later on to confirm that it is tumor free in order to preserve the pedicle here. But of course, this is an oncologic surgery, so one must make sure that the flap itself reconstruction is completely free of tumor.

Here we are bringing this nice and high to nasal vault to create a nice, wide distal flap, then connect this anteriorly with the mucocutaneous junction back towards the floor of the nose. Then we typically raise-- this with a caudal elevator and then followed with a suction elevator as well. You raise this in a submucoperichondrial plane, very similar to performing a septoplasty from anterior to posterior, as you can see here. There's typically some tenacious fibers in the area of the septal body, which, you may need to come through with some scissors. And once that's all raised, we're tucking that back into the nasopharynx for safekeeping.

Now, after our tumor has been removed in its entirety, you can see a nice cranial base defect there in that image. We typically would do an inlay with fascia lata. So you can see here, my neurosurgery partner, Dr. Link, placing this fascia lata inlay, as you can see here, and then a little bit of abdominal fat over the top of it as well.

And once these are in place and we're happy with this, we're going to grab that nasoseptal flap that's been stored in the left nasopharynx, stretch that out along the septum, as you can see here, and we'll rotate this into place, covering the entirety of the defect over top of that fascia lata in that small abdominal fat graft. We usually like to sort of stick it more anteriorly, as you can see here, and then rotate it into place to get nice and flush along the cranial base from orbit to orbit, as we rotate that into place.

And here we are placing this and flattening it with some gel foam followed by NasoPore, as you can see here, and just sort showing the outline of the incisions here, where the mucosa was harvested along the nasal floor and the anterior nasal septum, as you can see. The nasoseptal flap is the workhorse for skull-based reconstruction, however, it's also a versatile flap. It's been described for use CSF rhinorrhea through the Eustachian tube from a lateral skull-based defect, as well as for lining the orbit for orbital defects or even for lining the tonsillar fossa after a radical tonsillectomy.