Background:
19 yo Male. Mild open bite and resulting lip incompetence. Unusually high mandibular plane (slightly over 45 degrees), especially when considered in conjunction with my relatively mild open bite (occlusal plane).
I am in a very similar situation. Yesterday I had a consultation with my oral surgeon, before which I had--somewhat thoughtlessly-- assumed that I would have lower jaw advancement in addition to upper jaw impaction and advancement. Like you, I was moderately deflated when I was informed that, considering past condylar instability, the additional forces caused by mandibular rotation and advancement might be great enough to cause further and likely significant condylar resorption and resulting relapse. The surgeon still presented it as an option of sorts, but only if I was willing to risk eventually needing artificial replacement TMJs, the prospects of which, while extremely flexible, surgically and aesthetically speaking, are fairly grim in terms pain, cost and durability, especially at a younger age.
The surgeon went on to inform me and my parent that a much more stable option would be superior repositioning of the maxilla, an operation which would, in and of itself provide the maximum functional improvement with minimal aesthetic improvement, which could of course be improved mildly with a genioplasty. Naturally, the information was somewhat disconcerting, as I had assumed a large change in facial morphology was needed to correct by current malocclusion.
Now, IANAD, but based of off the couple hundred articles from my university's database, here are a couple points:
1. Mandible (lower jaw) advancement can do very impressive things, especially in conjunction with genioplasty, however:
2. While the maxilla (upper jaw) and sliding genioplasty operations are considered very stable, mandibular advancement is significantly more unstable. Now, there are a number of contraindications for the operation, but the most important seem to be: A. Previous resorption of the condyle, of any amount, B: TMJ problems (significant pain, clicking, ect) C: High mandibular plane (angle of lower jaw relative to horizontal), large amount of change necessary, in term of both degrees and distance.
Even without ^ these ^ contraindications, however, mandible advancement is still fairly (once again, relatively) risky, as soft tissue can apply significant force on the jaws after the surgery. And, of course, in open bite patients, such as you and me, the counterclockwise rotation only increases the soft tissue tension. If we could see an xray (preferably) or even a picture showing the amount of open bite in the current condition, it would be easier to make a better call.
3. Regardless of any potential instability, the healing/wiring time is roughly the same for maxilla/genioplasty and maxilla/mandible/genioplasty operations. Maxilla impactions/advancements can cause significantly more swelling/disruption than mandible advancements do, and since both sites are healing at the same time, any difference in the healing process is largely negligible.
Now, in response to your pictures:
The pictures you took are not the best for evaluation purposes, as it seems that your head is inclined forward slightly, and is not truly parallel to horizontal. This, of course, makes your lower jaw appear as if it is more retracted than it actually is.
"Could this be improved by just chin work?"
Yes, a genioplasty, in conjunction with the slight autorotation to close your bite, will improve your profile. What the you and your surgeon have to decide is whether or not this aesthetic improvement will be enough. If you are unhappy with your appearance from the front, it may not be, as neither the maxilla impaction or sliding genioplasty will necessarily significantly alter your face from that perspective. If it is, instead, your profile that you are dissatisfied with(I hate putting it in these terms, as it makes us seem frighteningly superficial, even though we're frequently referring to significant operations)then you are more likely to be satisfied with your post-op appearance.
This is, of course, a highly personal decision, but I feel that if you think that a mild to moderate improvement in your profile is all that is necessary, you'll probably be satisfied with the results. If, instead, you are expect more of a facial renovation/reconstruction you are less likely to be satisfied with your final appearance. Once again, it is a highly personal topic, but regardless of any potential operation you are already very attractive, and anything that you do from here on out should only compliment it.
Ahhh this post got a bit long, but I can't really think about much else right now, so might as well embrace it, eh?
