Panicking when my surgeon showed me my simulation (pic attached)

[kavan]

Disclosure: I'm having insurmountable problems with my old computer which is low on memory. So, I won't be referring to any images on IMGUR.

We are spinning our gears here on what the surgeon could have meant by excess gonial flaring because he didn't explain the 'why' of that to you. All we know here is that he has determined that you are not a good candidate for what you are asking for.

To spin more:

It could be a consequence of having to perform a CCW rotation in order to bring the maxilla forward. What is true is that a CCW-r (when posterior drop is needed) drops posterior aspect of lower jaw down and allows for more BSSO advancement. So, that can give a more 'square' looking gonial angle. That type of thing usually works well for people who want to MINIMIZE maxillary advancement and MAXIMIZE lower jaw advancement. Also helps decrease the mandibular plane angle for those who have a high slope to it. Patients with MPAs on the low side (those with jaw angles that are low set already and those with chin points that would not benefit by some of the uptilt that could be yielded via the advancement don't benefit that much from it.).

It could have to do with something that COULD make the jaw angles flare out more. When they cut the lower jaw, the cut (to split) goes through the back of the jaw angle in order to slide the rest of the mandible forward. So, the splitting process is a separation process where an opening is made between the gonial area to release the rest of the mandible forward. MAYBE the little bone particles from the cut get in between that area and the healing process jump starts more bulk (bone generation) between the cut. I've seen cases relayed on here (this board) where the person conveyed the angles showed wider in frontal. However, I'm not conversant in the medical mechanism of this, nor the extent of the widening as a function of the advancement.

In closing, I don't know your surgeon's explanation for this consequence. However, what I do know about what is TRUE about displacements in maxfax surgery is that it's not a thing where the exact amounts of maxillary and mandibular advancements can be chosen by the patient based on a morph.

[kavan]

The doctor/s are saying that the width of the split made through the gonial angle area to release and move forward the rest of the mandible will get wider for advancements in excess of the doctor's proposal.

Mandibular advancement is increase of go-pog distance (point on the gonial angle to point on the chin); PROFILE perspective. This distance is length (of the mandibular border). So, the 'go' point (for the most part) stays where it is when viewed in profile perspective. Width increase relationships are not viewed from profile perspective.

Inter-Gonial distance is go-go; FRONTAL perspective. This distance is width. So, if the extent of the split between the gonial angle needs to be increased to increase the distance between go-pog in the profile perspective, the go-go intergonial width in frontal perspective would increase.

Length increase (go-pog) is a function of width of the separation of the split to the gonial angle. It sounds like  Length and width distance relationships become interdependent with your particular request. There very well could be an unwanted increase in go-go with a wanted increase in go-pog to accommodate an increase in maxillary advancement. That is what can be concluded from what BOTH surgeons are saying is so. That type of concept is called a 'TRADE-OFF'.

Let's say your gonial angle area is THICK in its own right. When the angle area is SPLIT sagittally in to parts (before any mandibular movement), when mandibular advancement proceeds, the part of the split close to the CHEEK does not move but the part of the spit close to the TONGUE moves. So, it is not a thing where you can assume the 'whole' gonial angle stays the same the part of it closer to the tongue is moving forward with what ever thickness it might have and to move forward its extent of thickness to accommodate an extra mandibular advancement could yield extra thickness and/or unwanted flare out to the angle itself.

This is very hard to articulate. It's one of those things where you have to stare at a BSSO diagram and accept as 'true' what the doctors are saying and try to 'see' what could be going on. I think Thomasjohn hit on the general concept in his reply #14. It gets hard to visualize when you take the implicit assumption that the 'WHOLE' jaw angle area stays where it is. The part of the jaw angle area that stays where it is is the part next to the cheek that you see in profile, the other side that is being moved forward is the part next to the tongue due to the split.

On the doctor's proposal diagram, the dark gonial angle area is the part of the sagittal split close to the cheek. The other part; the light light brown area that is moving forward is the part closer to the tongue. What ever thickness it might have is moving closer and closer to an area right at the jaw angle that might be thick enough as to add unwanted extra thickness and flair to the angle itself with the extra mandible advancement.