Examination of the Safe Zone in Mandibular Ramus Osteotomies.

Abstract

In the surgical procedures such as osteotomy to be applied to ramus of the mandible, care should be taken not to damage the inferior alveolar nerve (IAN). The safe zone, which is the area above and behind the mandibular foramen (MF), is the ramus of mandible area, where these surgeries can be performed without damaging the inferior alveolar neurovascular bundle. It was aimed to determine the safe zone in the ramus of mandible in the cone-beam computed tomography (CBCT) images of individuals. The CBCT images of 300 Turkish individuals between the ages of 18 to 65 were bilaterally and retrospectively evaluated. Three parameters on the sagittal and two parameters on the axial plane were measured. Additionally, two ratios were calculated which determined the superior and posterior part of the safe zone through the measured parameters. In this study, the safe zone was determined as the area where 55% of the upper part and 49% of the posterior part of the mandibular ramus. Determining the safe zone in surgical procedures to be applied to the ramus of mandible will help protect the neurovascular structures passing through the MF, reduce complications and increase the success rate of the surgical procedure. However, it is seen that there are few studies on this subject in the literature and there are some differences between these studies. The authors think that preoperative CBCT screening will be safer for each patient in the mandibular ramus osteotomies and more studies should be done on different populations to determine standard values.