Coronal-splitting Reduction Genioplasty Combined with Bilateral Osteotomies of the Mandibular Inferior Border for Macrogenia.

There are various types of chin deformities, and the least established surgical method for deformity correction may be reduction for anteroposterior macrogenia. Anteroposterior macrogenia is commonly corrected by either setback genioplasty or burring reduction, but these approaches are less likely to produce aesthetically pleasing results. Both procedures have poor reduction effects because of the low response rate of soft tissues to skeletal alterations. There is a high likelihood of chin ptosis and flattening. Setback genioplasty can also yield step deformities at the inferior mandibular border. To overcome these drawbacks of conventional methods, I developed a novel technique of coronal-splitting reduction genioplasty. I have performed more than 83 procedures with a high success rate over the past 10 years. Alloplastic chin implant-shaped bone fragments were resected from the prominent bony chin, in which the average thickness of resected bone was 8.2 mm. Sufficient sagittal reduction effects were then achieved in most cases, although the soft tissue response rate remains 25%-50%, as reported in the literature. The no-degloving technique with cephalic suspension of the mentalis muscle prevents chin ptosis. Combined bilateral oblique osteotomies of the inferior mandibular border contribute to minimizing obvious postoperative chin flattening. Moreover, macrogenia can be large in multiple planes, including anteroposterior, vertical, transverse, or their combinations. This new technique can handle all three planes by combining both bilateral oblique osteotomies of the inferior mandibular border and burr ostectomy. Overall, these findings suggest that the coronal-splitting genioplasty method may replace conventional methods for correcting macrogenia.