Today I had a meeting at UTHSCSA.
We talked for a bit about general health questions. The surgeon was able to review my records before hand.
He enumerated the various treatments for ameloblastoma. He said there was
- enucleation alone
- enucleation followed by application of Carnoy’s solution
- enucleation followed by cryology, freezing the surrounding tissue
- radiation and chemotherapy – not very effective and don’t work on all tumors
- block resection (I don’t remember if he said this? but I did remember from my reading seeing this and asking him what the difference was)
- segmental resection
As he was telling me this, I was thinking about the list in the Wikipedia article. He gave a pretty good summary of what people actually did to treat this and I didn’t write this down since I already knew this.
He said that with segmental resection, you had recurrance rates of 10-15% or less. The other treatment methods had much higher recurrance rates.
I asked him what the difference between segmental and block resection was and he told me and I drew a picture and asked him if it was correct (to check my understanding):
I guess at this point I asked him about perforation or layering of the soft tissue again, because in my notes I have this:
He had a 3D CAD/CAM model showing a patient with a mandibular tumor. It appeared to be made out of a clear plastic, perhaps acrylic material. He should be what would be removed and I wondered if the edge that sticks up on the mandible would be removed. This is called the coronoid process. So I would loose this as well.
I asked him what happens with you remove the coronoid process. It’s just not there for no reason at all. He said that the tempromandibular muscle comes down from the right side of the head and attaches here. When you bite down, this is one of the muscles which contracts. After it’s cut, it snaps right back up. The muscle doesn’t atrophy or dimish, it just won’t be used any more. They don’t remove it because you would have a
So I naturally asked if this affected your ability to chew or bite down. He said it didn’t.
He said that some surgeons did the surgery at the same time and some did a deferred reconstruction. So, they perform a segmental mandibularectomy, then close everything up for 6 months to give it all a chance to heal. After 6 months, they perform a bone graft into the mandible. This is the safest approach with the least chance of infection, but the scar tissue from the first surgery would make it more difficult to preserve the facial or marginal mandibular neve. Wikipedia says this is actually called the “marginal mandibular branch of the facial nerve”. Thus, when they go back in, there’s a slightly higher chance of nerve damage to this nerve. The scar tissue causes abnormal anatomic boundaries. If this nerve is damaged, the left side of my lip will droop. This nerve actually controls the musculature of my lips.
Incidentally, I did not actually write the above image down (obviously). I have instead adapted my crude drawing to be on top of a real mandible (courtesy of user Dake on Wikipedia).
The other thing he told me was that the lingual nerve is on the inside of my jaw beyond the periosteum, like such:
He said that I could have possible tongue anesthesia for 2-3 months following the surgery. Now when he removes periosteum which is in contact with where the ameloblastoma has perforated through, he could damage the lingual nerve. There is a risk of this. We talked about damage scenarios and how they’d be repaired. If the nerve had very minor damage and was intact or maybe nicked, there would be no issue. If the nerve was just cut, they can do microsurgery to repair it. However, if a segment of the nerve is missing or is cut out, then they’d have to borrow some nerve tissue from my neck or the surral(?) nerve to repair it. The chance of success from microsurgery if it had to be performed is about 60%.
They always need to take the next soft tissue layer. I asked him what happens if the tumor has perforated the periosteum. He said that it was very rare for an ameloblastoma to perforate the periosteum.
Now here is one difference, at least if I understood both oral surgeons. Oral surgeon #1 punches out (unless I misunderstood), while oral surgeon #2 takes a larger portion. So for example, if the tumor is 4cm with a 2cm hole, oral surgeon #2 would take 3cm. I mentioned this example and he said that was correct.
I read in the Trokel(?) article that frozen sections should be used to confirm wide tissue margins during the surgery. He said that frozen sections are usually used for cancer, but not in a situation like this. The “frozen” isn’t cryo-frozen, but frozen in the sense that the sample is fixated, so that all cellular activity is frozen in time. Frozen samples also aren’t used for bone, because bone samples must be demineralized and that can take weeks. Even for cancers, the margin around the tumor is usually not more than 1-1.5 cm. You can do a frozen section with the periosteum, but the “yield” is limited. This is not routinely done. If there is a breach in the periosteum, then they’d do a frozen section. They have a pathologist on standby and it takes about 20 minutes.
I also asked if they did intraoperative specimen radiographs. He said that he doesn’t do them and that they’re rarely done. He instead makes a 3D CAD/CAM model based on my anatomy. He would take a real CT scan with resolution of around 1mm (not just a CB CT). This is sent out to a place in Colorado which makes the model. It takes about 1 week or so for the model to come back. The 3D model is an almost exact replica of my skull and he uses that to prefit the bone strap, which saves about 45 minutes of time in the operating room. The bone strap is a titanium-vanadium-aluminium alloy.
He said that he recommended extracting my backmost molars, then waiting for it to heal, which would take about 2 weeks. He didn’t recommend the one step solution where you remove the bone and teeth at once, because he said there was a much greater risk of bacterial contamination from the mouth. To elaborate, in the one step surgery, when the jaw bone + teeth are removed, there will be 2 holes where the back teeth previously were. This will be stitched up, but stitching is never tight enough to keep everything out, thus the fisk of infection. He said that 80% of the wounds strength is achieved in 2-3 weeks.
He also said, relative risk of infection:
2 step (with removal, 2 tooth extraction, 1 step tooth & jaw 6 month wait before < then removal and < removal and reconstruction) reconstruction reconstruction
But he also cautioned me again that the the 2 step with 6 month wait had risk of nerve damage.
I asked him if they could use platelet rich plasma (PRP). He said that he was not convinced from the scientific literature that it had any benefit and that some surgeons preferred to use PRP, but he didn’t. He also said that it would just displace the marrow he was going to pack around the graft, so that instead of having bone producing cells, you’d have plasma.
I then asked him if they used rhBMP2. He said that insurance often treats it as experimental and sometimes limits approval to sinus lifts. It is fairly expensive. But he would use it if approved.
Then we talked about donor bone graft sites. He said that there was a greater amount of bone in the posterior iliac crest (PIC) than in the anterior. Grafts from the anterior iliac crest (AIC) have higher risk of complications. There is a 40% chance of numbness at the donor site with AIC vs. a 10% chance with PIC. Gait complications risk post-surgical with AIC vs PIC are more significant.
He said he’d take a chunk of cortical bone, scoop marrow out. And marrow would be packed into the space between the graft and the remaining jaw bone. [I think at this point, I misunderstood and my pictures were wrong – he did not understand this]
He would use a dissolvable crib, made out of polylactic/polyglycolic acid to hold the bone graft together. The crib dissolves to H20, CO2. The periosteum is layered on top of this. Strap, then crib, bone packed.
He said that if my tumor was only 4cm he’d need about 50cc of bone material, which would be fine for an AIC. But in my case, he’d need 55-60cc of bone material.
Various graft and cross section pictures:
[TODO: put image here]
They do this once per week to every few weeks according to him.
There was more to this, but it was such a long meeting that I got tired of writing it up and ran out of time. So I’m publishing it as-is. If you want the rest, please ask and I’ll go back in my notes and fill it out.