The sliding genioplasty is a well known and effective chin reshaping procedure. Besides being an autologous chin augmentation method its value lies in its ability to make multi-dimensional changes particularly in the horizontal and vertical projections. But in so doing it does create an abnormal shape to the normal lazy S-shaped bony profile of the chin often referred to as a ‘bony stepoff’. This appears exactly like a stair step in the particularly when pure horizontal forward movements are done.
This change in the natural bony chin shape on the surface appears to be an interesting but irrelevant detail of the sliding genioplasty procedure. For some patients that can be true but for those affected by postoperative lip and chin tightness, which may also some lip position and speech issues, the change in bone shape has great relevance.
The anatomic significance for those affected by these postoperative symptoms is the bony step off represents a change in the soft tissue to bone relationship. There is now more bone surface to cover than the overlying soft tissue was made to do. During intraoral closure the mentalis muscle is pulled over the bony stepoff but as healing occurs the soft tissues are pulled down into the bony step defect. This is seen externally as a deepening of the labiomental fold which is an aesthetic tradeoff but when it is symptomatic it is now a scar contracture which represents a tissue deficiency.
The definitive treatment of persistent lower lip tightness after a sliding genioplasty is a release and placement of a soft tissue graft. Some surgeons remove the fixation hardware in the belief that will provide improvement in the lip tightness. But it usually doesn’t since adhesions to the plate are not then cause. The real benefit of removing the hardware is that forces one to do a through soft tissue release.
With a good release there is adequate room to place an adequately sized fat graft. Enough of a dermal-ft graft should be placed that completely fills the release and spills out of the open incision.
Closure is done in in two layers, superficial muscle and mucosa with resorbable sutures. It does not need to be tight.
The concept of a release and fat graft is to add supple soft tissue to the scar contracture into the bony step off created by the bony genioplasty. A scar contracture no matter where it occurs represents a soft tissue deficiency in both quantity and quality. Adequately treating it can not be done by a release alone.
Dr. Barry Eppley
World-Renowned Plastic Surgeon