This procedure targets deformities of the chin that affect facial aesthetics. It is most commonly a cosmetic procedure as opposed to being medically necessitated.
With regards to the relevant anatomy, the main muscle involved is the mentalis which elevates and protrudes the lower lip. The motor nerve supply comes from the marginal mandibular nerve of the facial nerve. The mental nerve supplies sensation to the overlying skin of the chin and lower lip, labial gingivae of the anterior teeth. With regards to the blood supply, the region is served by the mental and inferior alveolar arteries as well as the labial branches of the facial artery.
In terms of the procedure a transoral approach is taken to the chin. There are a number of incisions that can be made such as a vestibular approach or a sulcular incision. Care must be taken to avoid the mental nerve.
A mucosal flap is raised to expose the mentalis muscle which is then dissected and a mucoperiosteal flap is raised to expose the chin.
Osteotomy lines are then marked and subsequently the bony cuts are made. Internal fixation is performed ordinarily using miniplates.
Note a number of cuts can be made depending on how you wish to change the shape of the chin and a range of movements can be performed. For example, with this procedure it is possible to reduce/increase the height of chin and retrude/protrude the chin.