Oxygen-Ozone in orthopaedics: EPR detection of hydroxyl free radicals in ozone treated “nucleus pulposus” material

The direct and indirect application of oxygen-ozone in several orthopaedic affections was briefly reviewed, trying to understand possible mechanisms of action explaining the surprisingly good results and no toxicity. Moreover, by using EPR spin trapping technique with DEPMPO the generation of free radicals by treating human "nucleus pulposus" material with oxygen-ozone (O2-O3) was investigated. The DEPMPO spin adduct of hydroxyl radical (DEPMPO-OH) was detected. The presence of · OH even at a very low ozone concentration (5 μg/mL) may explain why this material undergoes to a progressive breakdown with re-absorption and consequent disappearance of a hernial disk. Thus the intradiscal insufflation of a minute volume of O2-O3 may represent a new efficient, inexpensive and atoxic chemionucleolytic approach.