ABSTRACT
This modification of the original GA differs in that the initial osteotomy is an inferior horizontal osteotomy approximately 8-10mm from the inferior border of the mandible (Fig. 11A). This fragment is down-fractured with a periosteal elevator and the exact location of the GGM insertion can be observed after this segment is down-fractured. A superior horizontal osteotomy is performed to the width of the central incisor dentition. A beveled osteotomy connecting the superior osteotomy to the inferior osteotomy creates a trapezoid shaped fragment, where the lingual cortex containing the GGM insertion is wider than the outer or buccal cortex (Fig. 11B). This outer cortex of the geniotubercle fragment is removed and contoured for cosmetic concerns (Fig. 11C). The lower border fragment containing the geniohyoid, mylohyoid, and digastric muscles is advanced and immobilized (Fig. 12). There is an increased risk of mandible fracture with this technique, but also a greater success rate and reduced relapse rate.
