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ObjectivesIn order to assess clinical behavior, response to treatment, and factors influencing prognosis of Korean patients with osteosarcoma of the jaws (OSJ).Materials and MethodsA retrospective study of clinical, and pathological records of 26 patients with OSJ treated at the Department of Oral and Maxillofacial Surgery in Yonsei University Dental Hospital from 1990 to March 2017.ResultsOf 26 patients, there were 9 men (34.6%) and 17 women (65.4%). Twenty-one of 26 patients had osteosarcoma of the mandible, and 5 of 26 patients had osteosarcoma of the maxilla. The histopathology of OSJ is highly variable, ranging from chondroblastic type (6 out of 26), osteoblastic type (10 out of 26), fibroblastic type (2 out of 26), to the rare variants like mixed type, small cell osteosarcoma types and more. All patients underwent gross total excision and only a few patients underwent neoadjuvant chemotherapy. Postoperative chemotherapy was given to most of the patients as adjuvant treatment or in combination with radiotherapy. The overall survival rate was 73.1% with an overall 2-year survival rate of 83.3%. The overall 5-,10-,15-year survival rates in this study were 73.5%, 73.5%, 49%, respectively. Using Kaplan-Meier analysis with log rank tests, the size of tumor (T-stage), and resection margins were found to affect the survival rate significantly. The chemotherapy was not significantly associated with improved survival rate.ConclusionSurgical resection with a clear margin is the most important factor in disease survival. The role of chemotherapy and radiotherapy in OSJ remains controversial, and deserves further studies.

Reports suggest a high incidence of nerve injuries, and diverse methods, such as two-point discrimination and the pin prick test, have been attempted to evaluate the severity of nerve damage. However, these tests rely on subjective sensations and may not accurately represent the damaged area. A previous experiment revealed that 18F‑FDG positron emission tomography/magnetic resonance imaging (PET/MRI) detect peripheral nerve damage. This study aimed to assess peripheral nerve damage according to severities of damage using 18F-FDG PET/MRI in a rat sciatic nerve. Eighteen rats were divided into three groups: 30-second (G1), 2-minute (G2), and 5-minute (G3) crushing injury groups. The severity of nerve damage was measured in the third week after the crushing injury using three methods: revised withdrawal threshold (RevWT)), standardized uptake values ratio on PET/MRI (SUVR), and immunohistochemistry (intensity ratio (IntR)). There were significant differences between G1 and G3 in both SUVR and IntR. There were no significant differences in both SUVR and IntR between G2 and G3 and no significant differences in RevWT among the three groups. There was a significant difference in SUVR but no significant difference in IntR between G1 and G2. Although PET/MRI did not show results consistent with the immunohistochemistry in all respects, this study demonstrated that the severity of nerve damage as assessed by PET/MRI increased with a longer crushing time. PET/MRI showed potential as an objective diagnostic tool in this peripheral nerve injury model. If research is supplemented through further experiments, PET/MRI can be used as an effective diagnostic modality.