Rigid fixation of intraoral vertico-sagittal ramus osteotomy for mandibular prognathism.

The standard surgical treatment for mandibular prognathism is sagittal split ramus osteotomy (SSRO) if the proximal and distal segments of the ramus require fixing with screws or metal plates. In this procedure, however, it is frequently difficult to avoid neurosensory disturbance (NSD) of the inferior alveolar nerve (IAN) when the posterior margin of the ramus curves inward or when the ramus is thin (Fig 1A,B).