The mandibular symphysis as a donor site in maxillofacial bone grafting: a quantitative anatomic study

The goal of this study was to quantify the amount of bone graft material present in the mandibular symphysis as well as to determine the maximal size of the corticocancellous bone block that can be harvested while avoiding mental nerve injury, tooth injury, and simultaneously preserving the preoperative facial contour.

Sixteen fixed dentate cadaver mandibles were studied. Osteotomies were performed in a monocortical fashion, 5 mm anterior to the mental foramen, cephalad to the inferior border of the mandible, caudal to the expected position of the apices of the anterior teeth, and at the midline. The size of the corticocancellous block was then measured. Bone volume, using 2 techniques, was measured by displacement volumetry.

The average volumes obtained were 4.84 mL and 4.71 mL (range, 3.25 to 6.50 mL), respectively, for the 2 techniques of volumetry. The average block size was 20.9 x 9.9 x 6.9 mm; the smallest block was 21.0 x 6.5 x 6.0 mm, and the largest was 25.0 x 13.0 x 9.0 mm.

Based on the results of this study, it is apparent that the mandibular symphysis can be reliably selected as the harvest site in a variety of oral and maxillofacial reconstructive procedures.