Silvia Chiandussi

Bone Scintigraphy and SPECT/CT of Bisphosphonate-Induced Osteonecrosis of the Jaw

Endovenous bisphosphonate therapy seems associated with osteonecrosis of the jaw. The aim of this study was to evaluate the additional diagnostic value of hybrid SPECT/CT in 99mTc-methylene diphosphonate 3-phase bone scintigraphy of osteonecrosis of the jaw in bisphosphonate-treated patients. Methods: We studied 15 patients (12 women and 3 men) with extraoral tumors affected by lytic bone metastases and multiple myeloma. All patients were previously treated with intravenous bisphosphonates (zoledronic acid) for 1–3 y, were negative for dental disease at clinical examination, and had suspected osteonecrosis of the jaw. All 15 patients underwent panoramic x-ray orthopantomography, CT or MRI (or both), microbiologic examination, 3-phase bone scintigraphy, and SPECT/CT of the maxillary region. Results: Three-phase bone-scintigraphy showed increased perfusion and an increased blood pool in 9 of 12 and 10 of 12 patients, respectively; at the metabolic phase, SPECT was positive in all patients and showed abnormal hyperactivity in the maxilla of 2 patients, in the mandible of 9 patients, and in both the mandible and the maxilla of 4 patients. Hybrid SPECT/CT was of particular value in 8 of 15 patients, allowing discrimination of the osteonecrotic core from nearby hyperactivity due to viable bone. Whole-body scintigraphy showed remote and multiple metastases in all patients. Orthopantomography showed nonspecific bone rarefaction in all patients but was not able to aid diagnosis of osteonecrosis of the jaw. CT and MRI showed anomalies in all symptomatic patients: CT was helpful in evaluating both cortical and trabecular bone aspects, and MRI was able to detect soft-tissue involvement but not cortical bone destruction. Conclusion: In appropriately selected oncology patients treated with bisphosphonates, an increased uptake of 99mTc-methylene diphosphonate in maxillary bones may suggest probable osteonecrosis of the jaw. In such cases, SPECT/CT may be of value in increasing the diagnostic accuracy of bone scanning, providing a precise functional anatomic correlation for the definition of the extent of disease.

A novel animal model to study non‐spontaneous bisphosphonates osteonecrosis of jaw

The aim of this study was to evaluate a novel animal model of bisphosphonates-associated osteonecrosis, which realistically recapitulates the same pathological human condition. Five Wistar rats were given intravenous zoledronic acid 0.04 mg once a week for 5 weeks. After 2 weeks, the animals underwent the extraction of an upper molar, producing a 4 mm-diameter bone defect on the same site. After 7 weeks from the extraction, the animals were clinically examined and a bone scintigraphy was carried out. After an additional week, the rats were killed and both Computerized Tomography and histological analysis were performed. Five rats, not treated with zoledronic acid and exposed to the same surgical treatment, were used as controls. At 7 weeks after the extraction, all the rats treated with zoledronic acid showed expansion of the defect and bone exposure. These features were confirmed by bone scintigraphy. The rats of the control group demonstrated epithelialization of the bone defect and a normal uptake of the contrast medium during the scan. The Computerized Tomography scan disclosed irregularity of the cortical margin and bone destruction, which were not evident in the control group. On microscopy, the samples showed necrotic bone, loss of osteocytes and peripheral resorption without inflammatory infiltrate, while the controls showed normal bone healing. The rat treated with zoledronic acid can be considered a novel, reliable and reproducible animal model to understand better the pathophysiology of osteonecrosis of the jaw and to develop a therapeutic approach.

Clinical aspects and management of bisphosphonates-associated osteonecrosis of the jaws

Objective. An increasing incidence of osteonecrosis of the jaws (ONJ) in patients treated with intravenous bisphosphonates has been reported in the literature. The aim of this study was to evaluate the clinical aspects, diagnostic investigations, and management of ONJ associated with bisphosphonates in a series of 12 patients. Method. Our patients included 1 asymptomatic and 11 symptomatic subjects. For the symptomatic patients, the osteonecrosis was diagnosed through histological investigations of exposed bone that showed avascular and necrotic tissue with inflammatory infiltrate. The patients were complaining of swelling, fever, and bone exposure involving the jaws. The asymptomatic patient presented as an occasional finding during a routine dental examination and the necrosis was confirmed on the basis of imaging investigations. Radiographic, scintigraphic, and microbiological examinations were carried out for all patients. Treatment included antibiotics, minor surgical interventions, and hyperbaric oxygen therapy. Results. The radiological investigations revealed osteolytic areas and the scintigraphy demonstrated increased bone metabolism. The microbiological analysis showed pathogenic micro-organisms in the majority of patients. Therapy was useful in obtaining short-term symptomatic relief. Conclusions. Histological, radiological, nuclear medicine, and microbiological investigations are important diagnostic tools for patients with bisphosphonates-associated osteonecrosis of the jaws. However, a long-term follow-up is necessary if we are to better understand the treatment outcome.

Cancrum oris in developed countries

Cancrum oris (or noma) is a rapidly progressive disease characterized by destructive necrosis of oral tissues and underlying bone. It is part of a multistage condition and may represent the outcome of untreated necrotizing stomatitis. Necrotising stomatitis and cancrum oris predominantly affect children in developing countries, especially in Africa. Only few cases have been reported in developed countries, and were associated with debilitating diseases and disorders of the immune system. We report a case of noma in an elderly immunosuppressed Italian patient in whom necrosis caused an external buccal communication. This case stresses the importance of an early identification and prompt management of the necrotic condition, in order to avoid diffusion of the destructive process within the oro-facial tissues.

Descending Necrotizing Mediastinitis of Odontogenic Origin

Descending Necrotizing Mediastinitis is a rare complication that can be secondary to dental infections or surgical procedures involving the oral region. Despite a prompt pharmacological therapy and surgical intervention, a delayed diagnosis is still responsible for a too high mortality rate (about 40%). We present a review of the current literature on Descending Necrotizing Mediastinitis, focusing on the evolution of its management from Pearse to today. In particular, recent patents focused on novel compositions and methods to prevent and treat oral infections.