Vertical lengthening of the chin is an interesting procedure that entails different considerations than traditional horizontal chin augmentation. It differs because the techniques to elongate the chin are not well known or used as the diagnosis of vertical chin deficiency is frequently overlooked. From a traditional standpoint vertical chin lengthening was perceived as only being able to be done by an opening wedge bony genioplasty. There has not been a chin implant that was able to do so until recently with the vertical lengthening chin implant. (VLC)
Each of these two vertical lengthening chin procedures have their advantages and disadvantages. An opening wedge genioplasty is an autologous procedure that avoids an implant and has few restrictions on how much vertical lengthening can be done. It is however more invasive and it involves a horizontal osteotomy. A vertical lengthening chin implant is less invasive and can better other dimensions with the lengthening if desired. (chin width and projection) Its main drawback is that it is more limited in the amount of vertical lengthening given the tightness of the overlying soft tissue chin pad.
But there is a marriage between an opening wedge genioplasty and an implant in the total jawline augmentation method known as an opening wedge genioplasy combined with a custom jawline implant. Such a concept is indicated when a total jawline augmentation is desired but significant vertical chin and jawline lengthening is also needed which exceeds the safe ability of an implant to do so at the chin. This approach uses two implants, a plate to stabilize the vertically lengthened chin and a custom designed wrap around jawline implant to create the rest of the augmentation effects desired.
This concept hinges on the custom design process where the genioplasty portion can be digitally created onto which a custom jawline implant is design to wrap around the front of the lengthened chin. Such bony geniopasties are typically in the lengths that exceed 10mms where such a large volume of implant material is ill advised in the tight overlying soft tissue chin pad.
The overlay across the chin of the custom jawline implant provides a dimensional change that the genioplasty can not do…making a wider more square shaped chin.
The entire procedure is done intraorally with the opening wedge genioplasty done first. A fixation plate is used to establish the vertical length and bent to accommodate for any horizontal projection needed. Once the chin bone is stabilized at the length, the opened wedge in the chin bone is filled with tissue bank block bone. The custom jawline implant is placed by splitting the implant initially into two pieces. Through bilateral posterior vestibular incisions the split jawline implant is introduced and passed forward to the chin. Once over the chin bone it is reunited in the midline and stabilized.
This joint autologous and alloplastic jawline augmentation method has arisen from the need to safely vertically lengthen the chin when a significant amount is needed. My learned rule for the chin is that it can not be safely loaded with an implant when the combined vertical and horizontal lengthening needed exceeds the number of 12mms in a primary augmentation method. This places too much stress in the tight chin pad with an avascular material beneath it. In the opening wedge genioplasty the soft tissue chin pad remains attached to the bottom side of the bone which then safely gets carried down with the bone as the chin is lengthened.
Dr. Barry Eppley
Indianapolis, Indiana