Clinico-statistical Observations on Orthognathic Surgery at the Department of Oral and Maxillofacial Surgery, Nara Medical University

Abstract

Forty-five patients underwent orthognathic surgery from 1981 to 1993 at the Department of Oral and Maxillofacial Surgery, Nara Medical University during the past 11 years and 7 months. There were 17 male and 28 female patients whose ages ranged from16to30years with an average of 21 years and 3 months.Thirty-three patients (73.4%) had mandibular prognathism including asymmetry, open bite and/or maxillary retrognathism. The other diagnoses were facial asymmetry in 4, skeletal open bite in 3, mandibular micrognathia in 2, maxillary prognathism in 2, and skeletal open bite with asymmetry in one.Thirty-nine patients (86.7%) were operated on with ramus sagittal splitting osteotomy (Obwegeser-Dal Pont's method). Four patients in the early stage underwent wire osteosynthesis, considering the influence of rigid fixation on the condylar position. Because wire osteosynthesis resulted in dislocation of bone fragments, long-term intermaxillay fixation and relapse, miniplate osteosynthesis has been employed since then. Miniplate osteosynthesis had simplicity and minimal complications as compared with wire osteosynthesis, and produced better results when combined with tongue reduction and/or suprahyoid myotomy.Four patients underwent two-jaw surgery (three had mandibular prognathism with maxillary microgn-athia, and one had skeletal open bite). Fixation of bone fragments was accomplished by a double -splint technique. After the maxilla was secured to the cranium, the mandible was sectioned and fixed to the maxilla. In these cases, it was very useful to employ autopreserved blood reinfusion and hypoten-sion anesthesia for preventing complications of transfusion.