The treatment of macrogenia (large chin) is much different than that of microgenia (small chin) and is also more challenging. Expanding the chin (chin augmentation) can done very reliably and in a straightforward manner through an implant or sliding genioplasty as it pushes out the overlying skin and soft tissue. While a prominent chin bone can be reduced, the success of any chin reduction procedure usually depends on what happens to the resultant excess soft tissue that will result from loss of bone support.
While a few limited chin reductions can be done from an intraoral approach, significant chin reductions require a different approach for two reasons. First, significant chin reduction requires a multi-dimensional approach to the bone reduction. This often includes horizontal, vertical and width bone removals. If the surgeon is skilled in bony genioplasty techniques and the patient is young, an intraoral vertical and midline wedge bone removals can reshape a large chin. But the best access to doing every dimension of bony chin change is from a submental approach from below. Secondly, any successful management of excess chin soft tissue involves excision which can only be done from below. Resuspension or ‘tightening’ of chin tissues done intraorally is not really an effective method making the chin soft tissues less in volume.
A submental chin reduction has several key technical steps to be successful. These include the location and extent of the incision, the method of bone removal and tye closure method which includes a submental tuck-up procedure,
The submental incision needs to precisely placed and put back a few millimeters further that the standard submental skin crease (many young people do not have such a crease) The curve of the inferior border of the jawline is marked out and the submental incision placed 5 to 10mms behind it. Its length is no greater than 3.5 cms and is curved to follow the curve of the jawline.
The submental skin incision allows direct access to the entire bottom of the chin which is done through wide subperiosteal undermining. A reciprocating saw is the most reliable way to make horizontal, vertical and width bone reduction with little risk of damaging the skin edges of the relatively small access incision. Burring can be done to smooth out all reduced bone edges. The bone should only be reduced until the marrow spaces are encountered where some bleeding will occur. That can easily be controlled by bone wax.
After chin reduction and reshaping the soft tissue chin pad is pulled over the reduced bone and its mentalis muscle edges sewn to either the bone edges (through drilled bone holes or to the muscle and periosteam on the underside of the bone edge. This fixes the anterior edge of the submental incision. The excess submental tissues behind the incision are advanced forward and the ‘excess tissues’ are trimmed and the incision closed. Rather than removing the redundant chin soft tissue pad, they are redraped over the reduced chin bone. This ensures that the submental incision is moved behind the new inferior border of the chin and the now ‘fuller’ neck tissues are removed and brought forward.
The technique for submental chin reduction is not well described or frequently performed. But careful attention to detail can create a submental scar that is both very aesthetically acceptable and not overly long.
Dr. Barry Eppley