Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
Introduction: Osteonecrosis of the jaw (ONJ) is a rare yet detrimental iatrogenic complication of oncological treatment. Patients can develop ONJ from medication-related osteonecrosis (MRONJ) or radiotherapy-related osteonecrosis (ORN). ORN usually develops when a bone segment is subjected to a radiation dose of >60 Gy. MRONJ, however, typically occurs following exposure to chemotherapeutics with bone-modifying properties. There is no standard of care for the treatment of ONJ; however, depending on the severity, debridement to eventual surgical reconstruction of the jaw is agreed on. It is generally accepted that a fibular free flap is the first choice for mandibular reconstruction, given its abundant bone stock and blood supply. In this study, we aim to review patients who have been diagnosed with ORN and MRONJ, comparing the clinical and functional outcomes after fibular flap reconstruction.
Methods: We retrospectively reviewed the demographic, imaging, and treatment data of 40 ONJ patients (23 ORN and 17 MRONJ) from 2006 through 2024. We performed Chi-Square tests for patient characteristics and outcome variables. Descriptive analysis was performed using R, with a p-value of < 0.05 corresponding to statistical significance.
Results: The average age at surgery was 68.2 years, with no difference between ORN and MRONJ groups (65.5 vs. 71.9 years, p=0.1123). A significantly higher percentage of males was observed in the ORN cohort compared to the MRONJ cohort (87.50% vs 52.94%, p=0.0292). All other demographic profiles, such as BMI, race, and ethnicity were similar between the two groups.
Most of the comorbidity profiles, including diabetes, hypertension, and cardiovascular disease did not significantly differ between the two cohorts. However, the ORN group suffered from thyroid disorders more than the MRONJ group (25% vs 0%, p= 0.0327). The overall incidence of previous dental extractions was high in both cohorts (75.00%), with no difference between the cohorts (p=0.4709). Most presenting symptoms showed no differences in the two groups, but the patients with MRONJ presented with more oral fistulas (23.53% vs 0%, p=0.0235).
Regarding post-discharge complications, a high incidence of minor complications was observed among ONJ patients (72.50%). The ORN cohort experienced a significantly higher proportion of these complications (p=0.0061). The overall reoperation rate was 42.50%, with 56.52% of ORN patients and 23.53% of MRONJ undergoing subsequent surgeries (p=0.078). Notably, the ORN group had higher rates of exposed bone (30.43% vs 0%, p=0.014) and dysphagia (30.43% vs 0%, p=0.014) on postoperative evaluation. Other complications, including infections, pathological fractures, and purulent discharge, showed no differences between the two cohorts (p>0.05).
Conclusion: Our findings, particularly the high reoperation rates, underscore the complex clinical trajectory of ONJ patients. Consistent with existing literature, our study observes a male predominance and higher complication rates in the ORN group. Some findings, such as the higher incidence of fistulas in the MRONJ cohort, are inconsistent with other studies, emphasizing the need for further research in this area. Recognizing the clinical and etiological distinctions between ORN and MRONJ might guide more targeted and effective treatment strategies.