Relation of Cortical Versus Cancellous Bone – The Crucial Ratio

The sagittal ramus osteotomy has become the standard procedure due to the large contact area of the split bone segments and the associated optimal conditions for bone healing with sufficient bone overlap. However, due to the intrabony course of the inferior alveolar nerve (IAN) throughout the whole length of the osteotomy this surgical technique is closely associated with a potential injury of the IAN. Thus, temporary postoperative lesions occur up to 87% and permanent lesions between 3% and 39%. In order to reduce the risk of injury, the most precise knowledge of the anatomical course of the IAN within the osseous-mandibular structures is absolutely essential. The neurovascular bundle of the IAN enters lingually through the mandibular foramen into the mandibular canal. Depending on the split on the lingual side, the IAN will be more or less exposed to a risk of trauma.