Pain characteristics in medication-related osteonecrosis of the jaws

Purpose: To characterise pain from medication-related osteonecrosis of the jaws (MRONJ) and the effects of antimicrobial treatment on it. Methods: Data from files of patients diagnosed with MRONJ according to the position paper of the American Association of Oral and Maxillofacial Surgeons (2014) and Multinational Association of Supportive Care in Cancer and American Society of Clinical Oncology (2019) were collected retrospectively, including gender, age, primary disease, bone-modifying agents (BMAs)/anti-angiogenics, administration route, involved jaw, location, and exposure size. The patients were treated according to the abovementioned position papers’ recommendations, i.e. all patients who suffered from pain were staged as 2 or 3 and treated with systemic amoxicillin, or doxycycline or clindamycin in case of sensitivity, and local antiseptic and hygiene instructions. Results: Data from 77 MRONJ patients (aged 65.09 ± 11.9 years old) were analysed. Most (90.1%) received bisphosphonates for cancer (79%) and osteoporosis (17%). A total of 67.5% experienced pain; 36.5% had moderate-to-severe pain. Female gender was significantly associated with the presence of pain (p = 0.002). Osteonecrosis lesions after dento-alveolar surgery had a higher risk of pain development than spontaneous lesions (p = 0.045). Medical and oncologic background, type of pharmacotherapy, lesion size, and location were not associated with pain levels. Worse initial pain was significantly associated with better relief following MRONJ treatment (p = 0.045). Meaningful pain reduction (≥ 50%) was significantly correlated with initial pain severity (p = 0.0128, OR = 4.75). Conclusions: Pain from infection and inflammation often accompanies MRONJ. The presence of pain is correlated with longer BMAs pre-therapy and if surgery preceded the MRONJ. Persistency of the mild pain together with a resistance to common antimicrobial treatment, although not complete, is a feature that MRONJ pain shares with neuropathic-“like” pain, and requires further study and consideration during treatment.