False aneurysms and arteriovenous fistulas are rare complications of orthognathic surgery. The vessel most commonly involved with false aneurysms following mandibular surgery is the internal maxillary artery, and this vessel, especially the sphenopalatine branch, may also be involved following maxillary surgery. An unusual factor in the presentation of false aneurysms following Le Fort I osteotomies is an initial episode of epistaxis occurring greater than 2 weeks postoperatively. Arteriovenous fistulas following orthognathic surgery are more apt to involve large vessels, especially the internal carotid artery. Embolization procedures are the treatment of choice for false aneurysms and arteriovenous fistulas in the maxillofacial region following orthognathic surgery
