Infection of the bone, osteomyelitis, may occur after injury, surgery or if infection has spread from another part of the body
Chronic Osteomyelitis (persistent bone infection)
Osteomyelitis can be caused by bacterial or fungal infection and people with problems such as diabetes or after an organ transplant are at higher risk of developing infection.
Different bones around the body may be affected, including the vertebra, bones in the legs and the base of the skull. Complications of osteomyelitis can include pain, deformity and bone death. Chronic osteomyelitis, infection that is persisting over the longer term, can also make a person feel generally unwell.
Malignant otitis externa / base of skull infection
This occurs most often in older people with diabetes and may start as an infection of the ear canal. The infection can spread through the skin, into the bone of the skull. The infection can spread and effect the nerves which come from the base of the brain and cause weakness of facial muscles as well as problems with speech and swallowing.
The mainstay of treatment of osteomyelitis initially is antibiotics. Sometimes surgery is needed, for instance to remove metalwork present which may be harbouring the infection. If the infection continues to persist after these measures, HBO may be helpful, in conjunction with ongoing antibiotics and review by the surgical team.
HBO is helpful for osteomyelitis for different reasons. Some bacteria cannot live in high oxygen conditions. Some drugs which fight infection are only effective if there is enough oxygen for the drug to be absorbed into the right place.
Osteomyelitis (Refractory and including malignant otitis externa)
This is defined by the UHMS as osteomyelitis that persists or recurs after appropriate interventions have been performed or where acute osteomyelitis has not responded to accepted management techniqures. It also includes individuals who have failed to respond to definitive surgical debridement (if possible) and four to six weeks of appropriate antibiotic therapy. Those with malignant otitis externa fall within this category.
The rationale for using HBO starts on the basis that the oxygen tension within osteomyelitic bone often drops as shown by Mader and Ninikoski. Esterhai confirmed that HBO will increase the PO2 within rabbit tibia to above that required for leukocyte oxidative killing. Further to this Mader’s study showed directly increased phagocytic activity at higher oxygen concentrations.
HBO has also been shown to improve penetration of certain anti-biotics into tissues due to oxygen dependent mechanisms. In particular, it is helpful for aminoglycosides and cephalosporoins (Mendel (1999).
There is evidence that HBO enhances osteogenesis by improving osteoclast function. Ueng showed bone healing to be superior with the use of HBO in animal studies.
Finally, the same principles of wound healing and evidence (as discussed on our Problem Wound healing page) does have some relevance in this cohort. Many individuals will have an overlying wound and are often diabetic.
Of note, Tisch showed a significant improvement in patients with Malignant Otitis Externa where 21 out of 22 patient with anti-biotic referactory MOE were cured after HBOT.
Individuals felt to be most suitable are those who have failed with conventional treatment and /or have a Cierny-Madar stage 3B or 4B. Those with high risk, such as spinal, skull or sternal osteomyelitis, are likely to be considered at a lower stage.
Treatment entails 20-40 HBOT daily session over 4-8 weeks. Response is considered and this is as an adjunct to gold standard treatment.
Further information regarding the Referral and Funding process can be found here.
Hyperbaric Oxygen Therapy Indications (2014)
Lindell K, Weaver MD Editors. Undersea and Hyperbaric Medical Society 13th Edition 2014 :P113-138
Esterhai JL Jr et al. Effect of hyperbaric oxygen exposure on oxygen tension within the medullary canal in the rabbit tibial osteomyelitis model. J Orthop Res 1986; 4(3):330-336
Ninnikoski J, Hunt TK Oxygen Tensions in healing bone. Surg Gynaecol Obstet 1972; 134(5): 746-750
Mader JT, Brown GL, Guckian JC et al. Amechanism for the amelioration by hyperbaric oxygen of experimental staphylococcal osteomyelitis in rabbits. J Infect Dis 1980; 142:915-922
Mendel V et al. Therapy with hyperbaric oxygen and cefazolin for experimental osteomyelitis due to Staphlococcus aureus in rats. Undersea Hyperbar Med 1999; 26(3)169-174
Straus MB “Refractory Osteomyelitis” J Hyperbaric Med 1987; 2:147-159
Tisch M, Maier H Malignant external otitis. 2006; 85(10):763-769; quiz 770-773
Ueng SW et al. Bone healing of tibial lengthening is enhanced by hyperbaric oxygen therapy: a study of bone mineral and torsional strength on rabbits. J Trauma 1998; 44(4):676-681