Osteoradionecrosis (ORN) of the mandible is a significant complication of radiation therapy for head and neck cancer. In this condition, bone within the radiation field becomes devitalized and exposed through the overlying skin or mucosa, persisting as a non-healing wound for three months or more. In 1926, Ewing first recognized the bone changes associated with radiation therapy and described them as "radiation osteitis". In 1983, Marx proposed the first staging system for ORN that also served as a treatment protocol. This protocol advocated that patients whose disease progressed following conservative therapy (hyperbaric oxygen (HBO), local wound care, debridement) were advanced to a radical resection with a staged reconstruction utilizing a non-vascularized bone graft. Since the introduction of Marx’s protocol, there have been advances in surgical techniques (i.e. microvascular surgery), as well as in imaging techniques, which have significantly impacted on the diagnosis and management of ORN. High resolution CT scans and orthopantamograms have become a key component in evaluating and staging ORN, prior to formulating a treatment plan. Patients can now be stratified based on imaging and clinical findings, and treatment can be determined based on the stage of disease, rather than determining the stage of disease based on a patient’s response to a standardized treatment protocol. Reconstructions are now routinely performed immediately after resection of the diseased tissue rather than in a staged fashion. Furthermore, the transfer of well-vascularized hard and soft tissue using microvascular surgery have brought the utility of HBO treatment in advanced ORN into question.

Jacobson, Buchbinder, Hu, Urken, , , , , (2010). Paradigm shifts in the management of osteoradionecrosis of the mandible. Oral oncology, 2010 Nov;46(11):795-801. https://www.ncbi.nlm.nih.gov/pubmed/20843728