Background:The chin is the dominant feature of the lower third of the face. When in good balance with the rest of the face it is an asset and a pleasing feature. When it is short or weak, it makes the face profile too convex and suggests a weak nature to the person. When it is too prominent, the facial profile becomes concave and makes the midface look retruded. Eitherway the chin plays a major role in facial appearance
Macrogenia, or overgrowth of the chin, creates a lower face that is out of balance with the upper and middle facial thirds. Most cases of macrogenia are a combination of excessive horizontal and vertical bone development. While macrogenia can be a reflection of an overall lower jaw overgrowth as evidenced by a Class III malocclusion, most larger chins occur in isolation. In women, the position of the chin should be slightly convex in profile and not too vertically long. Too much chin projection creates too strong of a lower face and a more masculine look.
Correction of a large chin is more complex and difficult than correction of an underdeveloped or small chin. While the bone reduction is fairly straightforward, whether by osteotomy or burring reduction, management of the excess soft tissues is another matter.In small chin reductions, the soft tissue will shrink and adapt to the new bone shape. But in large chin reductions, the soft tissues will not shrink enough and will sag if not removed or tightened. This can create the classic ‘witch’s chin deformity’.
Case Study: This 33 year-old female felt her chin was too big and wanted it reduced. She had a slightly concave facial profile, a vertically long chin, and a normal occlusion. In doing an imaging analysis based on photographs, the amount of chin reduction needed was a minimum of 8mm horizontal reduction and a 6mm vertical reduction. This amount of bony movement was felt to be too much for an intraoral osteotomy in which the soft tissues would only bunch up with the backward or reverse sliding genioplasty.
Under general anesthesia, a submental approach to her chin reduction was done. Through a curved 4 cm skin incision, the chin bone was widely exposed. A fine burr was initially used to make a deep vertical bone cut in the midline down through the outer cortex of 8mms in depth. A burr was then used to remove the side portions of the remaining chin bone down to the same level and tapering it into the prejowl area. From the inferior edge, the chin bone was burred down 6mms. A wedge of skin, muscle and fat was removed from the front edge of the incision and the muscle layer was then put back together and tightened over the lower edge of the reshaped chin bone. The skin was then closed and a tape dressing and ice pack applied.
She had a fair amount of chin swelling after surgery that took three weeks before any amount of chin reduction could be appreciated. After three months, a very evident reduction in the size of the chin would be appreciated.
Of the two methods for chin reduction, the submental approach is the most versatile. It allows not only for better bony chin reshaping but permits soft tissue reduction and tightening as well. Failure of the soft tissues to adhere tightly to the new reduced bony chin shape will result in an unsightly soft tissue sag.
1) A large and prominent chin consist of both excess bone and soft tissue. Both must be managed for a successful chin reduction procedure.
2) Most chin reductions are best done from a submental approach where the bone can be reduced in all dimensions and the soft tissues tightened.
3) Chin reduction surgery involves a temporary period of swelling and several months to see the final result.
Dr. Barry Eppley