Is primary chronic osteomyelitis a uniform disease?: Proposal of a classification based on a retrospective analysis of patients treated in the past 30 years

Introduction: Primary chronic osteomyelitis of the jaw is a rare, non-suppurative, chronic inflammatory disease of unknown aetiology. To date, classification is confusing due to a non-uniform terminology. The aim of this study was to establish a simple (clinical) classification based on patient data from our clinic. Methods: Retrospective analysis revealed 30 cases of which clinical course, radiology, pathology, therapy and outcome were analysed. Results: Both sexes were equally represented. The mean age at onset of disease was 35 years (range 5-76 years). Onset of disease revealed two peaks of incidence, one in adolescence and one after age 50 years. While clinical symptoms were similar in all cases, an increased intensity of these symptoms was noted in younger individuals as well as in the early stages of the disease. Five adults and one adolescent presented with additional non facial bone, joint and skin manifestations consistent with the diagnosis of SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome, or chronic recurrent multifocal osteomyelitis. Radiology demonstrated sclerosis, osteolysis and periosteal reaction in variable stages in all cases. However, findings were more extensive in younger patients. Histology revealed different stages of chronic inflammation in all cases. Microabscess formation was noted in 11 cases, six of which were children/adolescents. Therapy consisted mainly of surgery, antibiotics and hyperbaric oxygen therapy. At the end of the follow up period, 11 patients demonstrated complete remission, while in 14 cases amelioration and in 5 no significant improvement was noted. Conclusion: Based on differences in age at presentation, clinical appearance and course, radiology and histology, a subclassification into early and adult onset primary chronic osteomyelitis has been established. Cases with purely mandibular involvement should further be distinguished from cases associated with other syndromes. (C) 2003 European Association for Cranio-Maxillofacial Surgery.