Background: The chin-jawline is the border that separates the face from the neck. The more pronounced the skeletal lower third of the face is the less the neck is seen. While the entire jawline contributes to the projection of the lower face, the chin makes the greatest contribution since it is a single point projection of it.
The short chin, and the short horizontal jaw length that accompanies it, affects the neck which has numerous muscle and ligaments attached to it. While many short chins have more modest projection deficiencies (less than 7mms) greater chin deficiencies are associated with a more obtuse cervicomental angle with shorter attached muscle lengths. While a chin implant may have its merits in terms of being able to provide a widening effect a sliding genioplasty provides an improved effect on the neck as it drags certain muscle attachments forward with it.
The most common neck contouring procedure is liposuction. Removing a thicker subcutaneous fat layer does help in the shorter neck but a greater uplift can occur from muscle tightening as well. Combining midline platysma plication with the liposuction creates this enchanted effect. (submentoplasty) The platysma muscle is plicated inferiorly until it no longer easily comes together. Thereafter the muscle is back cut to allow it to be released and retract posteriorly.
Case Study: This male had always been bothered by his short chin/jaw and lack of much neck definition. He sought a combination of moving the chin bone forward and tightening up the neck.
Under general anesthesia an intraoral 10mm sliding genioplasty was performed. This brought the back end of the downfractured chin segment just past the front edge of the superior chin segment. The wings of the sliding genioplasty had better bone contact. The bony step off from one wing to the other across the midline plate fixation was grafted with 5cc of hydrated allogeneic corticocancellous bone chips.
Through a 2.5cm curved submental incision the entire submental region and lateral neck was treated by small cannula liposuction. The central neck than had a wedge of fat removed followed by midline platysmal muscle plication. The lower end of the platysma muscle just above the thyroid cartilage was released on both sides by cuts through the muscle. (submentoplasty)
His intraoperatve result showed the dramatic change in his facial-cervico-mental angle relationship.
The diametric movement of the chin projection coming forward and the cervicomental angle moving up and back makes for a substantial profile improvement. The neck change makes the chin projection look better and the chin change makes the neck look better. One of the advantages of the sliding genioplasty as it relates to the neck is the ability to pull/lengthen the geniohyoid muscle. When this muscle is pulled forward and the platysmal muscle is pulled back the profile change that occurs is more significant than if one does a more commonly used approach of a chin implant with submental liposuction.
- A short lower chin/jaw is often associated with a very obtuse cervicomental angle due to loss of adequate projection points for the neck muscles.
- For short chins that need 10mms or greater horizontal projection a sliding genioplasty is preferred over a chin implant because it pulls some neck muscles with it as it is moved forward.
- In obtuse cervicomental angles a submentoplasty provides a better result than neck liposuction alone.
Dr. Barry Eppley