Denosumab and bisphosphonate associated bilateral osteonecrosis of the external auditory canal

Denosumab-related osteonecrosis of the external auditory canal-benefit of the early surgical management

Background: Antiresorptive drugs are widely used to reduce bone mineral loss in patients with osteoporosis and to prevent skeletal-related events in patients with metastatic cancers and multiple myeloma (MM). Both the bisphosphonates (BP) and denosumab typically used in this indication were shown to be effective and relatively safe. Obviously, this medication could have some adverse effects; one of them is osteonecrosis of the external auditory canal. Only sporadic cases of external auditory canal osteonecrosis have been published yet. Here, we provide a case of denosumab-related osteonecrosis of the external auditory canal successfully treated surgically in the early stage of the disease. Case report: A 68-year-old patient with breast cancer underwent comprehensive oncological treatment, including denosumab administration. She was diagnosed with osteonecroses in the jaw and ear canal. The necrotic bones in both regions were resected with primary wound closure. Both affected sites healed well with no signs of necrosis recurrence. Conclusions: Osteonecrosis of the external auditory canal is a rare but probably underdiagnosed complication of antiresorptive medication. It has a negative impact on patient quality of life if left untreated. Early surgical treatment appears to be effective. The authors highlight several similarities with medication-related osteonecrosis of the jaw. Therefore, an analogous disease staging and treatment rationale is suggested.

Medication-related osteonecrosis of the external auditory canal - A rapid review of the literature and relevance to special care dentists

AIMS

There is growing evidence that anti-resorptive and anti-angiogenic medications can cause medication-related osteonecrosis of the external auditory canal (MROEAC). It is possible that patients taking risk medications may also suffer from concomitant medication -related osteonecrosis of the jaw (MRONJ) or temporomandibular joint (TMJ) involvement. The aim of this paper is to conduct a rapid review of the literature on MROEAC, and, its relevance to special care dentists.

METHODS AND RESULTS

A rapid review of the literature was carried out using PubMed, Science Direct and Google Scholar to identify papers relating to MROEAC. The grey literature and non-English papers were also consulted. Overall, 19 papers were identified from 2005 until December 2022.

CONCLUSIONS

Patients at risk of MRONJ may also be at risk of MROEAC and present to special care dentists. Dental/orofacial disease may cause signs and symptoms suggestive of MROEAC. It should be considered as a potential cause of orofacial pain in special care patients. MROEAC can have a significant impact on a patient's dental treatment, including access, the provision of sedation, communication difficulties, and consent issues.

Rat Calvaria Model Mimicking the Intraoral Lesion of Medication-Related Osteonecrosis in the Jaw: A Preliminary Test

Numerous preclinical intraoral models have been proposed to study medication-related osteonecrosis of the jaws (MRONJ). However, an extraoral animal model is necessary to investigate the effects of interventions such as grafts or direct therapeutics. This study aimed to establish a MRONJ rat model on the calvaria. Seven rats were allocated to either the control or MRONJ group. The MRONJ group received injections of zoledronic acid and dexamethasone to induce osteonecrosis over 4 weeks. Two weeks after these injections, the maxillary first molar was extracted, and two calvaria defects were created using a 4 mm trephine burr. One defect was left untreated, while the other was filled with harvested calvaria bone. A histological examination of all calvaria in the MRONJ group revealed avascular necrosis and the destruction of cortical bone. An independent t-test and Pearson's correlation coefficient were used for statistical analysis and the evaluation of alveolar and calvaria defects. The total alveolar and calvaria defect volume in the control group was significantly smaller than that in the MRONJ group. A statistically significant correlation was observed between alveolar and calvaria defects (Pearson correlation = 0.6, p = 0.023). The autogenous grafts showed poor results in the MRONJ group since they failed to revascularize and exhibited necrosis. The calvaria in this study successfully mimicked MRONJ lesions with avascular necrosis. This preclinical model could be used to develop treatments that are applicable to MRONJ.

Medication-Related Osteonecrosis: Why the Jawbone?

Medication-related osteonecrosis of the jaw (MRONJ) has emerged as a complication of anti-resorptive medications. Despite its low incidence rate, this problem has gained attention in recent years due to its devastating consequences and lack of preventive strategy. The fact that MRONJ incidence has been exclusive to the jawbones, despite the systemic effect of anti-resorptive medications, could be a starting point to unravel the multifactorial pathogenesis of this condition. This review aims to negotiate the question of why the jawbone is more susceptible to MRONJ than other skeletal sites. Approaching the problem from this perspective could provide new directions for the prevention of MRONJ and expand our understanding of the unique oral microenvironment.

Two Cases of External Auditory Canal Osteonecrosis in Patients on Antiresorptive Therapy for Osteoporosis

Bisphosphonates and denosumab have demonstrated overwhelmingly favorable skeletal benefit/risk profile in managing postmenopausal osteoporosis. External auditory canal osteonecrosis is a rare skeletal complication of antiresorptives previously described in 11 patients with bisphosphonate exposure and 1 bisphosphonate-naïve patient on denosumab. We present 2 patients who developed external auditory canal osteonecrosis while taking antiresorptives for postmenopausal osteoporosis; a 79-year-old asymptomatic bisphosphonate-naïve woman with 2-year exposure to denosumab, and a 64-year-old woman with otalgia after 5 years of risedronate and 5 years of denosumab treatment. Neither patient had previous exposure to glucocorticoids or local radiotherapy. Otoscopy performed by an ear/nose/throat (ENT) surgeon revealed exposed areas of bone in external auditory canal in both patients. Computed tomography of temporal bones found no evidence of bone erosion. Bone turnover markers were suppressed. Both patients ceased denosumab and were managed conservatively, with stable external auditory canal findings after 12 months. Although external auditory canal osteonecrosis is a rare skeletal complication of antiresorptive use, development of localizing symptoms in the ear should alert physicians to this rare clinical entity and prompt ENT surgical referral for early diagnosis and initiation of management.