|SPECIAL FEATURE||Vol.6 No.9 (November 2001)|
Reshaping the Face with Orthognathic Surgery: An Overview
Dr. Edward W. H. TO, Dr. Walter W. K. KING2,
Dr. Otto AU2
1Department of Surgery, The Chinese University of Hong Kong,
2Plastic & Reconstructive Surgery Centre, Hong Kong Sanatorium & Hospital
Orthognathic surgery, literally meaning straightening of the jaws, is referring to a group of corrective bone operations that involve movements of the jaw bone in toto as well as of their parts.
Correction of severe jaw deformities dated back from the 19th century when it was first applied to the closure of an anterior open bits. The deformity resulted from the effects of sear contracture secondary to a burn inhibiting anterior mandibular growth. Initially, only mandibular osteotomies were performed. During the last century, precise and standardized procedure for correction of the mandible was established. In 1955 Obwegeser and Trauner introduced the sagittal split osteotomy by an intraoral approach. It was a breakthrough for orthognathic surgery as a standard treatment for corrections of the mandible.1 Multiple modifications allowed control movements of small fragments, rigid fixation with malleable monocortical miniplates osteosynthesis, and finally the awareness of the importance of a precise positioning of the condyle. Surgery of the maxilla also dated back to the middle of 19th century. Le Fort (1901) described the classic lines of maxillary fracture. Le Fort I type osteotomies to gain access for resection of tumors in the nasomaxillary area were first described by von Langenbeck in 1859 and Cheever in 1867. The first surgeon to use an osteotomy on Le Fort I level to correct a malocclusion was Wassmund (1927). But it was Axhausen who risked the mobilization of the whole maxilla in 1934. With further refinements and additional modifications, Le Fort I osteotomy was popularized by Obwegeser as a standard procedure in maxillofacial surgery to correct dentofacial deformities (1965, 1966).2 Tessier mobilized the whole midface by a Le Fort III osteotomy and showed new perspective in the correction of severe malformations of the facial bones, creating the basis of modern craniofacial surgery.
A review of the literature clearly shows that dental and facial disfigurements have significant effects and can be an important social disadvantage. The motivational pattern of patients requesting orthognathic surgery are many and varied, but a desire for improvement in esthetics and alleviation of functional impairments are the two commonly cited reasons. Patient satisfaction following orthognathic surgery has been reported as high overall. Many of the studies found that patients had improved self-confidence and social skills after treatment.3
Patients with jaw deformity have to be carefully assessed with a detailed analysis of the soft tissues, the underlying maxillofacial skeleton and dentoalveolar relationship. This should be carried out by both the orthodontists and surgeons while the different treatment options are thoroughly discussed. In most cases, the treatment would consist of pre-operative orthodontics, surgery and post-operative orthodontics. In principle, the pre-operative orthodontics should aim at proper alignment of teeth in the jaw by alignment and decompensation of the dentoalveolar adaptation of the underlying skeletal deformity. Surgery aims at correcting the skeletal discrepancy. Post-operative orthodontics should be incorporated to finalize the occlusion. The effect that changes of the jaw bones will have on the covering soft tissues, including the nose-lip-chin profiles has been discussed in detail in the literature.4,5
Surgery of the face may include the mandible, maxilla or both. Patients can present with a class III facial type, facial asymmetry, long face, bimaxillary protrusion, class II facial type and with short face.6 Overall, there could be a high incidence of two-jaw deformity, necessitating surgery of both jaws.
1. Developmental jaw deformity or disproportion
2. Cranial facial syndromes
3. Acquired traumatic or iatrogenic cases
4. Sleep apnoeas
Commonly performed aesthetic orthognathic surgery includes sagittal osteotomy to correct mandibular hypoplasia or hyperplasia, anterior maxillary or mandibular segmental osteotomy to improve maxillary or mandibular protrusion, Le Fort I osteotomy to reposition the maxillary, genioplasty to reshape the chin and surgical reshaping the prominent angles of the mandible to reduce the appearance of a "square jaw".
Most developmental jaw deformities are amenable to improvement with modern surgery and orthodontics in appropriately motivated patients.