Optical bone density as a prognostic risk factor for the development of medication-related osteonecrosis of the jaw in patients with bone metastases

Introduction Medication-related osteonecrosis of the jaw (MRONJ) is a complication associated with the intake of osteomodifying agents (bisphosphonates, denosumab). At present, its frequency, according to various authors, may reach from one to 10 cases per 100 subjects. The literature describes the main factors in the pathogenesis of the disease. The prognostic signs of its development, which would allow timely diagnosis and prevention of the disease, remain not fully understood. Materials and methods The retrospective analysis was based on the results of a study of 52 patients with MRONJ who were treated at the Department for Maxillofacial Surgery at the Central City Hospital No. 23 in Yekaterinburg from January 2015 to December 2019 Multispiral computed tomography was used for visualization, quantitative and qualitative assessment of the jaw bone tissue. The optical density of the spongy substance was determined in Hounsfield units (HU) on the side opposite to the lesion. Results The analysis of the results of optical density showed that D1 bone type was not detected in any patient. We observed type D2 using CT in 5 cases in the central part of the lower jaw (9.61 %), in 9 cases in the central part of the upper jaw (17.3 %), as well as in the area of the angle of the lower jaw on 6 CT-scans (11.53 %). D3 and D4 bone types prevailed, D5 bone type was less common. The optical density of the structures under study was in the range from 229.8 ± 56.6 to 534.8 ± 155.4 HU. Thus, patients receiving osteomodifying therapy with bone types D3, D4, D5 are more at risk of developing MRONJ than patients with bone types D1 and D2. Conclusion It is advisable to include a mandatory MSCT with classification of bone types according to Misch and determine optical density of bone tissue in the examination protocols of such patients.