In 1983, Robert E. Marx, a prominent oral and maxillofacial surgeon, refuted the notion that trauma and infection were requirements in the development of ORN. Marx proposed that ORN was the result of cumulative tissue damage caused by radiation, creating disturbances in cell metabolism and homeostasis that resulted in cell death and hypocellular tissues. In addition, radiation causes injury to the endothelial cells of local vasculature, creating a hypovascular environment which leads to decreased oxygen delivery resulting in hypoxic tissues. The decrease of vasculature helps explain why the mandible is more commonly affected than maxilla, as the mandible is served primarily by the inferior alveolar artery, whereas the maxilla is served by various arteries and has a more robust blood supply. In sum, Marx believed that ORN was essentially hypocellular-hypovascular-hypoxic tissues behaved much like chronic non-healing wounds. Initial reports by Marx and others showing that treatment with hyperbaric oxygen (HBO) prevented ORN helped support this theory. However, later studies began to raise doubts about the effectiveness of HBO therapy and question whether Marxs theory was comprehensive enough to guide treatment.Current understanding is guided primarily by the work of Delanian and Lefaix, who proposed the radiation-induced fibroatrophic (RIF) process. Advances in lab techniques allowed scientists to perform more detailed studies of ORN specimens. Analysis of samples showed that tissues undergoing ORN underwent three phases of disease: 1) prefibrotic, 2) constitutive organized and 3) late fibroatrophic phases.
Tendinopathy, a type of tendon disorder that results in pain, swelling, and impaired function. The pain is typically worse with movement. It most commonly occurs around the shoulder (rotator cuff tendinitis, biceps tendinitis), elbow (tennis elbow, golfers elbow), wrist, hip, knee (jumpers knee, popliteus tendinopathy), or ankle (Achilles tendinitis).Causes may include an injury or repetitive activities. Less common causes include infection, arthritis, gout, thyroid disease, diabetes and the use of Quinolone_antibiotic medicines. Groups at risk include people who do manual labor, musicians, and athletes. Diagnosis is typically based on symptoms, examination, and occasionally medical imaging. A few weeks following an injury little inflammation remains, with the underlying problem related to weak or disrupted tendon fibrils.Treatment may include rest, NSAIDs, splinting, and physiotherapy. Less commonly steroid injections or surgery may be done. About 80% of patients recover completely within six months. Tendinopathy is relatively common. Older people are more commonly affected. It results in a large amount of missed work. Signs and symptoms
Symptoms include tenderness on palpation, swelling, and pain, often when exercising or with a specific movement. Cause
Causes may include an injury or repetitive activities. Groups at risk include people who do manual labor, musicians, and athletes. Less common causes include infection, arthritis, gout, thyroid disease, and diabetes. Despite the injury of the tendon, there are roads to healing which includes rehabilitation therapy and/or surgery. Obesity, or more specifically, adiposity or fatness, has also been linked to an increasing incidence of tendinopathy.Quinolone antibiotics are associated with increased risk of tendinitis and tendon rupture.