Osteomyelitis is an infection of the bone. Refractory osteomyelitis is a bone infection which has not responded to appropriate treatment. Hyperbaric oxygen increases the oxygen concentration in infected tissues, including bone. Hyperbaric oxygen directly kills or inhibits the growth of organisms which prefer low oxygen concentrations (strict anaerobes). These effects occur through the oxygen-induced production of toxic radicals or through an indirect effect medicated through the white blood cells (polymorphonuclear leukocytes). Conversely, hyperbaric oxygen has no direct effect on organisms which prefer high oxygen concentrations (aerobes). In fact, hyperoxic conditions may induce aerobic organisms to produce increased concentrations enzymes protective against oxygen radicals (e.g. superoxide dismutase). When hyperbaric oxygen increases the oxygen tension in infected tissue, however, the oxygen-dependent killing mechanisms of the polymorphonuclear leukocyte are provided sufficient oxygen to function. Thus, hyperbaric oxygen treatment provides the necessary substrate (oxygen) for the killing of aerobic organisms by the polymorphonuclear leukocyte.
Hyperbaric oxygen also augments the efficacy of bacterial killing by certain antibiotics (aminoglycosides, vancomycin, quinolones and certain sulfonamides). Hyperbaric oxygen provides adequate oxygen for fibroblast activity, cells which promote healing in hypoxic tissues. Finally hyperbaric oxygen prevents polymorphonuclear leukocytes from adhering to damaged blood vessel linings. This decreases the degree of inflammation which may accompany the surgical treatment of refractory osteomyelitis. Hyperbaric oxygen is used clinically for the treatment of refractory osteomyelitis as noted above. Hyperbaric oxygen is adjunctive therapy and is used with appropriate antibiotics, surgery and nutrition. There are open, patients used as there own controls and randomized clinical studies supporting the use of HBO for the treatment of refractory osteomyelitis.