The chin occupies the most prominent part of the lower third of the face. This is why it is the subject of many different chin reshaping options. The most common dimensional chin change is one of an increased horizontal projection. This can be done using either an implant or an advancement bony genioplasty, each with their own advantages and disadvantages.
The chin can also be vertically lengthened which is indicated when the lower third of he face is disproportionally deficient. Just like cutting the chin bone and moving it forward, it can also be cut and vertically lengthened. Known as a lengthening bony genioplasty, it is held in its lowered position by a small spanning titanium plate with screws. While it can be vertically lengthened by any amount, it usually takes up to 8 to 10mms to see a significant external chin lengthening change.
Since this type of facial osteotomy exposes the marrow space of the chin bone on both side of the bone cut and the down fractured chin segment is well vascularized through the maintenance of his inferior soft tissue attachments, it is likely some bone healing would naturally occur in the gap space. But with a bony gap that may be up to 10mms, I prefer to graft that gap to allow for maximal bone healing between the superior and inferior bony chin segments. This is most needed in the central area where the gap distance is the greatest. The size of the gap becomes less at the sides of the chin where it tapers down to actual contact between the upper and lower segments. Graft options include cadaveric bone and synthetic hydroxyapatite blocks.
A pure vertical lengthening genioplasty is very effective at chin lengthening and is the ‘least’ traumatic of all bony chin movements since the bone segment is merely opened to create the dimensional change.
Dr. Barry Eppley
Indianapolis, Indiana