Bisphosphonate-associated jawboneosteomyelitis: Clinical, radiological andhistological features

Introduction and Objectives: Patients taking amino-bisphosphonatesmay develop jawbone disease. We evaluated theclinical, radiological and histological features of bisphosphonateassociatedjawbone disease with the aim of defining the natureof bone lesions and the possible pathogenesis.Methods: Thirty-five consecutive patients with bisphosphonateassociatedjawbone disease were studied. Clinical and radiologicalassessment were performed; the number and featuresof each lesion and history of previous traumatic events wererecorded. Eleven patients underwent extensive jawbone resection.Resected jaws were subjected to histological analysis. Basedon CT and MRI findings, bone specimens were obtained fromexposed necrotic areas, unexposed areas and resection margins.Results: Sixteen patients had metastatic bone disease and 19 hadmultiple myeloma without jawbone involvement. Forty-one bonelesions were identified (mandible 29, maxilla 12), correspondingto 1.2 lesions on average per patient. The mean duration ofbisphosphonate treatment before diagnosis was 32.8 months.Histologically, the specimens obtained from the areas of exposedbone were typified by non-vital bone, with rough boundariesand empty lacunae, vessels were scanty, without signs of boneremodelling. In contrast, specimens from the areas of unexposedbone were characterized, by a highly vascularized fibrous tissueand inflammatory infiltrate within large intertrabecular spaces; apeculiar feature was the detachment of osteoclasts from bonesurfaces. The margins of resected bone showed normal bonestructure and vascular supply.Conclusions: Our study suggests that bisphosphonate-associatedjawbone disease may be a form of osteomyelitis with peculiarfeatures, possibly caused by interference of bisphosphonates withbone remodeling, rather than avascular osteonecrosis