AIM:To evaluate the effects of percutaneous ozone injection via the posterior-lateral route and inner margin of the facet joint in the treatment of large lumbar disc herniation.METHODS:Fifty-eight patients with large lumbar disc herniation were treated with percutaneous injection of ozone via the posterior-lateral route and inner margin of the facet joint under digital subtraction angiography.Second injections were performed 5 d after the initial injection.All patients were followed up for 6-18 mo.A modified Macnab method was used for assessing clinical outcomes after oxygen-ozone therapy.RESULTS:Successful puncture was obtained in all patients.The overall efficacy was 91.4;the outcome was the excellent in 37 cases(63.8),good in 16 cases(27.6) and fair/poor in 5 cases(8.6) according to the Macnab criteria.No severe complications were found throughout this study.CONCLUSION:Percutaneous intradiscal ozone injection via the posterior-lateral route and inner margin of the facet joint is effective and safe for treatment of large lumbar disc herniation.