Management of Osteoradionecrosis of the Mandible in Patients with Oral and Oropharyngeal Cancers / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Osteoradionecrosis (ORN) of the mandible is one of the most serious complications following radiotherapy for oral and oropharyngeal cancer. However, the predisposing factors and clinical course of ORN are variable and its proper management is currently undetermined. The objective of this study is to review our ORN cases and evaluate the treatment methods. PATIENTS AND METHODS: We retrospectively reviewed 57 cases of oral and oropharyngeal cancers, where patients received combined surgery and radiotherapy from 1990 to 1998. Osteoradionecrosis occurred in 5 cases, and we evaluated the predisposing factors, clinical course and results of treatments. Four patients were treated with radical sequestrectomy and open reduction of mandible. Of these four patients, three received the combined treatment with hyperbaric oxygen (HBO) therapy, and one received the conservative treatment. RESULTS: Four ORN cases occurred at the lateral mandibulotomy site and one case arose at the opposite mandibular body unrelated to osteotomy. The interval between ORN and radiotherapy was so variable as 3 to 140 months. Four patients were successfully treated with the combined surgical and HBO therapies (3 cases) or with the conservative treatment (1 case). The remaining case could not be controlled by surgical treatment without HBO. CONCLUSION: Osteoradionecrosis usually occurred at lateral mandibulotomy sites, especially combined with sagittal partial mandibulectomies. We recommend that lateral mandibulotomies should, whenever possible, be avoided if the radiotherapy is planned postoperatively. And the patients who received radiotherapy at the mandible should be observed for osteoradionecrosis for long time. Our treatment results suggest that a combined surgery with HBO therapy can be a primary treatment modality for ORN.

A Study on the Relation between Delaire's Ideal Occlusal Plane and Masticatory Muscle Activity in Korean Normal Angle Class I Occlusion Individuals

According to the functional matrix theory, Delaire proposes that individual occlusal plane was determined by variable effects of teeth, maxilla, mandible, cranium, cranial base and soft tissue matrix including the orofacial musculature. and that there is the ideal occlusal plane determined by the most proper spatial position of maxilla and mandible, functionally and esthetically. This study was designed to find out the relation between Delaire's ideal occlusal plane and muscle activity of masticatory muscles in individuals who have normal maxillo-mandibular relationships. Lateral cephalometric radiographs were taken and his/her individual occlusal plane and ideal occlusal plane were analyzed with Delaire's architectural and structural craniofacial analytic method. For evaluation of muscle activities of masticatory muscles, electromyography of anterior temporal muscle, superficial masseter muscle, and anterior belly of digastric muscle was recorded in fifty Korean normal Angle class I occlusion individuals. According to the average value of ideal occlusal plane, fifty normal Angle class I occlusion individuals were classified into three groups: Ideal occlusal plane group(I group), hyperrotation group(I+ group) and hyporotation group(I-group). The result of this study was as follows: 1. The results of Delaire's architectural and structural craniofacial analysis of lateral cephalography of the fifty Korean normal Angle class I occlusion individuals are that twelve persons(24%) have consistent or parallel with ideal occlusal plane and the average of angular difference was 1.22 degrees +/-3.69 degrees. 2. There is no significant difference in muscle activities of masticatory muscles during resting(p0.05) 4. Although there is no significant differences of masticatory muscle activities among the three groups, the fact that increasing tendency of masseter muscle activity of ideal occlusal plane group(I+) than those of any other groups(I+ and I-) during bilateral clenching was noted. There is only the implication that occlusal plane makes some effects on masticatory muscle activities, espacially that of masseter muscle during bilateral clenching. In conclusion, the hypothesis that occlusal plane is one of the factors which affect the muscle activities of masticatory muscles and that anyone whose occlusal plane consistent with Delaire's ideal occlusal plane has an extraordinary functional advantage in masticatory muscle function cannot be proven with electromyography methods.

Mandibulotomy, A Surgical approach for Oral cancer: Its Complications and contributing factors

We reviewed 56 patients who received mandibulotomy at Yonsei medical center between 1989 and 1999. We also analysed the complications associated with mandibulotomy and its contributing factors. The complications occur in 16 patients(28.6%) and are classified into two categories; intraoperative and postperative complications. Nonunion was observed in 5 patients and osteoradionecrosis in 5. The patients who received preoperative radiation therapy were more tend to develop nonunion and osteoradionecrosis. This study suggests the benefits of mandibulotomy as a surgical approach to oral cancer: 1. Paramedian osteotomy was recommended for preservation of neurovascular bundle and ease of surgical access. 2. By using thin saw blade, reapproximation was improved with minimal bone loss. 3. osteotomy on anterior mandible which lies outside the usual portals of radiation therapy decreases the incidence of osteoradionecrosis.