Etiology and Pathogenesis

Osteomyelitis of jaws is a multifactorial disease. It has various etiological factors which lead to the inflammation of the medullary portion of the bone. The various predisposing factors for osteomyelitis include immunosuppressive conditions, malnutrition, metabolic bone disease, tobacco, alcohol, odontogenic infections, etc. Sometimes haematogenous dissemination of infection to healthy bones and infection associated with peripheral vascular disease may also lead to maxillofacial osteomyelitis. The process leading to osteomyelitis is initiated by acute inflammation which leads to hyperaemia, increased capillary permeability and infiltration of leukocytes which further results in destruction of bacteria and vascular thrombosis. The process also leads to release of proteolytic enzymes which causes tissue necrosis and accumulation of pus. This results in the rise of intramedullary pressure resulting in vascular collapse, venous stasis and ischemia of the concerned area. The pus then travels through the haversian and nutrient canals and accumulates beneath the periosteum of the bone leading to its elevation from the underlying cortex which further reduces the vascular supply to the bone. This is vascular impairment in the jaw which is a contributory factor in the development of osteomyelitis.

Keywords: Haversian and nutrient canals, Hyperaemia, Intramedullary pressure, Odontogenic infections, Osteomyelitis of jaws, Periosteum, Vascular thrombosis.