Chin surgery V: treatment of the long, nonprojecting chin.

Abstract

Correction of the long, nonprojecting chin requires both vertical reduction and sagittal augmentation. Wedge excision-based therapy reduces chin height and allows for advancement of the distal segment, but it is associated with at least a 10 percent incidence of mental nerve injury. The authors propose two innovative ways to correct the long, nonprojecting chin. There are two approaches, intraoral and extraoral. With the intraoral approach, following a gingivobuccal incision, a single horizontally oblique osteotomy is made at least 6 mm beneath the mental nerve foramina. The vertically long genial segment is freed and the posterior edge is contoured with a side-cutting burr. The contoured jumping genial segment is secured to the mandible with countersunk screws and contoured in situ to preserve the lower 8 to 10 mm. With the extraoral approach, following a submental incision, the anterior and posterior surfaces of the symphysis are cleared (a double-armed suture is placed through the posterior musculature). A reciprocating saw is used to remove the lower border of the symphysis to reduce the vertical excess. The tagged musculature is resuspended, and a tapered, textured implant is secured to the new symphysis. Aesthetic outcomes using these two techniques were good and there were no complications. Representative patients, operated on by the senior author, illustrate these techniques. Both the intraoral one-cut in situ contoured jumping genioplasty and the extraoral vertical reduction/sagittal augmentation genioplasty reduce excess chin height, control sagittal advancement, provide pogonion projection, and avoid the risks of a standard wedge. Both techniques provide custom projection at the lower pole of the new symphysis.