A new MRI grading system to evaluate epidural fibrosis after microendoscopic discectomy

English Keywords:Epidural fibrosis  Microendoscopic discectomy  Lumbar disc herniation  Coefficiency

English Abstract:

  【Abstract】 Objective：To present a new grading system for evaluating the Magnetic Resonance Image （MRI）appearance of epidural fibrosis 3 months after microendoscopic discectomy （MED），and to evaluate its reliability as well as clinical practice.Method：Between March 2010 and August 2010，32 patients undergoing MED　were enrolled for the research.MRI of the lumber spine were obtained following a standard protocol at three months postoperatively，without and with gadolinum intensifying.Three individuals evaluated the MRI independently.Epidural scar area and epidural fibrosis index were obtained.Intraclass correlation coefficient （ICC） statistic was used to estimate the reliability of the new grading system.Result：The epidural scar area in three groups showed no difference（P>0.05）.The estimated ICC value was 0.771 with 95% confidence interval of [0.715，0.819].There was no statistical significance with respect to epidural fibrosis index among three groups（P>0.05）.The ICC of epidural fibrosis index for the three groups was 0.788 with 95% confidence interval of [0.659，0.881] which showed excellent agreement.Conclusion：The new grading system is of high efficiency and excellent agreement to evalutate the degree of epidural fibrosis appeared in MRI after discectomy.