We're just going to go come around a little bit further down the corner, from the front, just in the pre-temporal area. Mike talked a little bit about infertemporal fossa extensions, why you'd use the orbital cranial to look down into the infertemporal fossa. I'm just going to talk about the infertemporal fossa tumors and the use of what I guess has been termed in the past the sub-temporal, infertemporal fossa approach. And like any of these approaches, there are many variations of that approach that can be used. The pathologies that occur in the infertemporal fossa are myriad, benign ones, the most common are meningomas that extend transcranially, schwannomas, both of the trigeminal, and I've seen some videan schwannomas in that location, juvenile nasopharyngeal angiofibromas, or other benign tumors. Malignant ones we see a lot of, the primary infertemporal fossa malignancies, osteosarcoma, Ewing's, rhabdo, synovial cell sarcoma, or chondrosarcoma, and then we see a lot of extensions of anterior maxillary and facial carcinomas, squamous cell carcinoma, adenoid cystics, which travel typically through the trigeminal nervous system back towards the infertemporal fossa, and rarely other diseases. In the last, I looked in the last five years, and this is how it broke down in our place, you know, 10 benign tumors and that number of malignancies. So the majority of the work here is based on malignant disease. The infertemporal fossa, you know, has definable boundaries. The anterior boundary is the posterior wall of the maxillary, the maxilla. The medial boundary is the pharyngeal wall. Laterally, it's the ascending ramus of the mandible and the zygomatic arch. Posteriorly, the styloid diaphragm, which separates the infertemporal fossa from the carotid space. Superiorly, it's the floor of the middle cranial fossa, and inferiorly, it's a line drawn through the inferior border of the angle of the mandible. These are anatomic drawings that we did, and I think what's really important to notice here are the lines, the planes, the cleavage lines between the different structures. And specifically, this is an important one. It's a plane that's medial to the pterygoid musculature, medial to the mandibular nerve, and lateral to the pharyngeal wall. And I think if you're doing excisions of the entire infertemporal fossa, this is going to be your medial boundary, and you find that just medial to your pterygoids and to your mandibular division of the trigeminal nerve. So a real simple case, this is a young man with a lesion where he had some pain. It'll describe the lesion at the base of his pterygoid plate, and you can see the loss of marrow signal at the base of the pterygoid plate here. Here you see on the CAT scan, it has a fairly smooth border, so we believed up front that it was a benign process. The approach, this drawing shows the entire full-blown sub-temporal and infertemporal fossa incision. But with this gentleman, as Mike showed, we just need to look down below the zygomatic arch. So this is a zygomatic arch osteotomy. That allowed us to bring the temporalis muscle inferiorly and allow us this view. So we haven't done a craniotomy. The temporalis muscle is under this retractor. This is the back wall, the maxilla. This is the pterygoid plates right here, and this is the pterygoid maxillary fissure. So being entirely extracranial, you can get to this point, open that up, and remove that, and this is the exact direction of our approach. This was an eosinophilic granuloma pathology. As we get more complex, tumors, it doesn't really change what we need to see. The exposure really is the same. You can see where this meningioma is sitting, the zygomatic arch, it just needs to come down a little bit so we get the temporalis muscle out of the way and we have the direct lateral approach to this tumor. This is a trigeminal schwannoma from the mandibular division. Just moving the zygomatic arch gets you into the tumor. Once you're in the tumor, you don't need anything else. You don't have to turn a craniotomy here. You just need to move a little bit of bone here, maybe a centimeter and a half, and then you have the entire tumor in your surgical field. This tumor you see is a little different, a little more anterior. This is a V2 schwannoma extending both intracranially and into the infratemporal fossa. You want to be a little more forward, so I think in this situation we did add an orbital zygomatic osteotomy. Again, we did not do a formal craniotomy. We did a subtemporal craniectomy. So that goes in one piece, reflected inferiorly on the masseter. Here's the intraoperative view. This is the orbit here. This is just a little bit of dura exposed here. This is the tumor in the infratemporal fossa, temporalis muscle is rotated inferiorly along with the orbital zygomatic osteotomy. Once the tumor is out, here's the orbit, here's a little bit of the bone removal. That's all we really see of the temporal dura, and this is the sphenoid sinus. So coming through the medial and anterolateral triangles, you get into the sphenoid sinus, temporalis muscle is inferior. We just reconstruct, and you know, you can take that up higher too. So if the tumor goes up into the cavernous sinus, especially these trajectinal schwannomas, you can just add this exposure through the same thing, just a little small craniotomy here to get subtemporal. This gets you your V1 carotid, V2, V3 carotid, GSPN. The apex is out here too. Sinus is open here. There's vidion. So I think just that, without having to turn a formal frontal craniotomy, move the zygomatic, orbital zygomatic arch out of the way, do a subtemporal craniotomy, remove your greater wing sometimes, and you can have an ample view. And here's the reconstruction again. Plate on the orbit, plate on the body, important, and a plate at the back of the arch. Now we're starting to some malignancies. It's a little bit different, you know, because I think, you know, we want to ideally stay extratumoral if possible, and in order to achieve a margins negative type of resection. This is one of the lower grade of malignancy. But I think with the higher grade malignancies, you know, you want to take out all the structures touching cancer, including the back wall, the maxilla, the mandible, the infratemporal fossa. So this is what we're going to try to do here. And again, remembering we talked about those planes. This is a divided mandibular nerve, which again, this was a malignancy, a primary sarcoma, which spared the maxillary division of the trigeminal nerve, but was right here with the mandibular division going into it. But when you divide the mandibular division, just medial to it, you get into that plane we saw, just medial to the pterygoids, and that just takes the entire infratemporal fossa off of the pharynx. So this is the pharyngeal wall here. In the sphenoid sinus, you open it here, vidion is there, and here you can get, when you look anteriorly, you can actually go into the maxillary sinus this way, and if you work anteriorly, you're into the nasal pharynx, you can actually see the opposite eustachian tube right there. That is, you're able to do that because of the planes in the infratemporal fossa that are medial to the pterygoid musculature. And that's that plane there. That really facilitates the en bloc removal of that area. And that's what you can kind of get. Now, there's really not much important in the infratemporal fossa functionally. You have the V2 and V3, but not much else. But it's what's really next to the infratemporal fossa that's real important. So you've got your parapharyngeal space there, your carotid space. This is a multiply recurrent embryonal rhabdo in a heavily treated young lady. No idea whether we're going to find a plane on that carotid artery or not. So I think you have to plan for that ahead of time. And for this young lady, here's her old incision. We did the full corpus. We brought that incision down into her neck, did a formal neck dissection, got the vessels up front so that we could have this view. Here are the great vessels. We did not take out her parotid. We worked under her mandible, dissected out the facial nerve. Here's the upper branch of the facial nerve at the top of that soft tissue here. And then took down her previous work and left us with this. Working from above, down, from submandibularly up, we're able to take that out on block. The carotid artery is here, 12. This is the maxillary division and trageminal. Mandibular is gone. And the infratemporal fossa is empty. Orbit is here. And this is a free flap replacing the infratemporal fossa. And these are type of examples where that kind of operation is necessary, osteosarcoma, Ewing's. This is an adenocarcinoma, believe it or not, a hemangiosarcoma right here, recurrent synovial cell sarcoma, and a rhabdomyosarcoma. So people always ask what malignancies in the infratemporal fossa. They traditionally have done poorly. I think that that tends to exist in the pre-aggressive skull-based multimodal therapy. This is a modern series of 39 patients had infratemporal fossa extension. All had multimodal management. And the median progression for free survival in all comers was two and a half years. Median overall survival, 4.7 years, with an overall survival of 53%. That's in the literature if you want to see that. That's all comers, all in the infratemporal fossa malignancies. So just a little bit further back from what we talked about, but still not in the temporal bone, is the infratemporal fossa. We'll talk about the temporal bone tomorrow. But in case there are some easy ways to get there with just some movement of the zygomatic arch or orbital zygomatic process. Thanks.

infertemporal fossa

tumors

surgical approaches

zygomatic arch osteotomy

survival rates