Can sliding genioplasty be done through submental incision rather than intraorally?

Sliding genioplasty (either for advancement or for reduction of the chin) can be performed via both intraoral or extraoral (submental) approaches. The choice of approach depends on the desired changes to the chin, the physical characteristics of the patient, and the personal preferences of the patient and surgeon. This decision would be made after a thorough consultation. The submental incision for sliding genioplasty is slightly longer than what might be employed with a silastic chin implant placed via the same route, but the resulting scar still hides nicely under the chin. I find the submental approach useful in sliding genioplasty if more dedicated contouring of the mandibular border is necessary or in cases of preexisting asymmetry of the jaw.
Sliding genioplasty versus silastic chin implant for augmentation of the chin each have their pros and cons. In both cases, implants of some sort are required (typically silastic for the chin implant, and titanium plate/screws for the sliding genioplasty). A full consultation in our office would be necessary to determine which option and approach would be best for your case.

Are you referring to an advancement genioplasty or reduction genioplasty? A reduction genioplasty can be performed through an extraoral incision but an advancement genioplasty needs to be performed through an intraoral incision. With an advancement a plate and screws are placed and this would require a long submental incision. The intraoral incision allows for limited muscle dissection and no extraoral scar. My patients who undergo genioplasty procedures are advised to eat a normal diet that evening and experience little to no pain. There is no change to the bite. As far as your exisiting submental scar, this can be improved with one or two passes of a CO2 laser.... which can be performed at the same time as the genioplasty.

It is important to remember that the incision to get to do the sliding geniopalsty surgery is merely a point of access. What has to be done once inside is the same whether it be cutting the bone or cutting through the mentalis muscle. The downfractured chin bone survives because of the blood flow through the muscle and the attached soft tissue chin pad. With the submental approach the entire soft tissue chin pad its stripped off so the blood supply to the bone is a little more compromised. But of equal importance is the need to apply fixation devices to fix the bone in its new position. Coming from below this makes plate and screw fixation much more difficult although not impossible. Whether coming from the submental approach can be successfully done depends on the type of bony dimensional movements that you need. It has more limited options for bone movement so this must be carefully considered before choosing that incisional approach