Patients with obstructive sleep apnea (OSA) commonly have associated mandibular deformities, particularly mandibular hypoplasia (retrusion) that can create a decreased oropharyngeal airway contributing to OSA. The OSA patient may present with a retruded mandible (often associated with a retruded maxilla and a high occlusal plane angle) that can displace the tongue posteriorly into the oropharyngeal space, severely com­promising the functional airway. OSA patients may ben­et from orthognathic surgery to advance the maxillomandibular complex forward, usually in a coun­terclockwise rotation direction that predictably increases the oropharyngeal airway. Although combined maxil­lary and mandibular osteotomies for advancement are usually required for correction of OSA involving a decreased oropharyngeal airway, this chapter focuses only on various mandibular osteotomies that may be incorporated in the management of the adolescent and adult OSA patient. Maxillary osteotomies are presented in another chapter. Also, mandibular distraction proce­dures are not addressed in this chapter. Particular atten­tion is directed to the mandibular ramus sagittal split osteotomy, as this is the primary osteotomy technique for advancing the mandible, so essential to predictable outcomes in the OSA patient.

preformed implant with a selection of sizes and designs (. Fig. 26.4a, b). It is recommended that alloplastic augmentation genioplasty be performed after eruption of the mandibular anterior teeth.

tion. Loss of the segment may require further alloplastic or bone graft reconstruction. A large amount of bone resorption can be expected if a free bone graft is used to augment the chin or if the soft tissue pedicle to the mobilized chin segment is lost. Pedicled osseous genio­plasties usually undergo anterior bone resorption of about 10–20%. Infection most commonly is caused by avascular necrosis, contamination, and wound break­down. Displacement of the alloplast may occur follow­ing trauma or inadequate stabilization. This may require additional surgery to restabilize the implant. Lower lip ptosis may be caused by inadequate positioning, resus­pension, and stabilization of the mentalis muscle and associated soft tissues. Normally, when relaxed, the lower lip should be in level with the lower incisor edges. Correction of lower lip ptosis requires repositioning and resuspension of the mentalis muscles. Anesthesia or par­esthesia of the lower lip and chin may result from trauma to the inferior alveolar and/or mental nerve branches from incision design, dissection, retraction, or direct injury when performing osteotomies. Nerve injury may be avoided by careful incision placement, careful dissec­tion, minimal nerve retraction, and carefully planned bone cuts. If nerve transection is directly visualized, immediate repair is indicated.

malunion may necessitate additional surgery to reposi­tion and stabilize the segments and rigid xation, with or without bone grafting.

Periodontal defects may occur as a result of vascular compromise, inadvertent removal of the cervical inter­dental bone, or major damage to the periodontal tissues. Defects also may occur by creating tears or vertical incisions in the osteotomy area.