Postoperative fractures of the lingual plate after bilateral sagittal split osteotomies.

We encountered the unusual complication of postoperative fracture of the lingual plate in four patients after bilateral sagittal split osteotomy. We then did a retrospective review to identify possible risk factors. Over a 1-year period we did 52 bilateral split osteotomies. The patients' casenotes were examined and a number of variables were recorded, including surgical technique, and the patient's sex, age, presence or absence of third molars, and the height of the mandible in the region of the osteotomy. Significant risk factors were a vertical mandibular height of 2 cm or less distal to the last molar tooth (p=0.02), and a depth of 0.6 cm or less from the apex of last molar root or impacted third molar to the lower border (p=0.005).