This was a very sobering post, Kavan, and your explanations of CCWr via demonstration with the triangle were very informative -- thank you.
Enclosed is a diagram of a rotated triangle.
So:
. CCWr rotates the triangle on a fixed point. It still ultimately results in forward advancements, but the terminology 'linear advancement' refers to:
. The entire triangle (all points) moving forward as a unit
What I'm still uncertain about is whether or not in a plan like mine,
both of these different movement patterns are taking place -- that
first the triangle is rotated as much as is favorable,
then it is linearly advanced to bring the maxilla to the final planned 11mm (where the rest of the mandibular advancement takes place via genioplasty).
The reason I ask is that I take it only
so much advancement can be brought about by the CCWr because eventually, you'll end up at a 0-degree occlusal plane.
Regarding the theoretical problem of chimp lip, if the entire amount of advancement of the upper and lower jaws could be accomplished with CCWr
alone (with the rest of the pogonion taken care of by genioplasty), the risk of chimp lip would surely be very small, as the ANS area associated with the upperlip/under nose fullness would rotating
downwards. Hopefully I have this understood correctly.
There is no ABSOLUTE CERTAINTY to be guaranteed here and NO BETTER predictions to be made here than the one you got already. It's inherently a decision made under uncertainty.
What you have expressed regarding the inherent uncertainty involved aligns with what I have been going through in my own head; whatever decision, it ultimately devolves to something of a leap of faith. I cannot verify that the changes I might wish to make to the plan -- being a non-expert -- would translate to a more favorable result, nor can I guarantee that the soft tissue predictions I've been provided are wholly accurate either.
That said, I have been attempting to resolve some of this anxiety by learning about the well-established attractive norms. For example, it is well-established that for the incisors to line up with the soft tissue nasion is considered attractive, so even if I did opt to dial the advancement of the maxilla down to meet this metric, I would hope I would be in a relatively 'safe' position as to have a favorable outcome (i.e to not be under advanced). The same goes for tried and tested criteria like the True Vertical Line. I appreciate your earlier comments that the
individual nature of my own situation must take precedence over cookie-cutter values, however.
Having spoken to my surgeon, they are very willing to make changes based the concerns I have about being advanced beyond what I consider aesthetically pleasing, but you're right -- I have to have something of a solid basis for doing so, and it's difficult to know how much is based on fear and objective reality.
For example, I have attached a publicly available before and after from another patient my surgeon operated on. When this was posted on another public forum, many people said the result was excellent, and many also said they thought the person's jaws were now too big and that their upper lip area had become too protrusive (these were large movements of 18mm at the mandible and 8mm at the maxilla, with CCWr, If I recall -- she is around 5 weeks post op in those images).
As I puzzled the images myself, I went back and forth. It is no doubt there is a great improvement overall, but is there also credence to the notion that she may have been more balanced with slightly less advancement? Perhaps. And there in lies the subjective element of all this that I'm never really going to get a definitive answer to.
As you say, I'm not going to get any better prediction than with the displacement models the surgeon can provide, so it may make sense for them to design a 'dialed back' alternative and then compare them to reach the ultimate conclusion. They said we could design two separate plans.
You have expressed this is likely an optimal plan/likely outcome and made well-founded points as to why. I just now have to make a decision on which direction this 'leap of faith' is going to go.