Investigation of the computed tomography grading of lumbar facet joint osteoarthritis and its clinical significance

English Keywords:Lumbar vertebrae  Facet joint  Osteoarthritis  Computed tomography grading  Low back pain

English Abstract:

  【Abstract】 Objective：To investigate the computed tomography grading system of lumbar facet joint osteoarthritis and its clinical significance.Method：From January 2008 to December 2010，a retrospective study was carried out in 100 consecutive patients with low back pain and/or leg symptoms，who were referred to our hospital and underwent CT examination of the lumbar spine.There were 43 male patients and 57 female patients with average age of 52.5 years（range，23-81 years）.The facet joint spaces width，osteophyte formation and subchondral sclerosis or cysts in the CT axial bone views were regarded as grading signs.Every sign was divided into four types on the basis of severity degrees，and corresponding scores were 0 to 3.The grades of osteoarthritis on CT were scored on the same four-point scale according to total scores：grade 0，normal；grade Ⅰ，1-3 scores；grade Ⅱ，4-6 scores；grade Ⅲ，7-9 scores.Three independent spine surgeons（ranking as senior，middle，and primary） respectively evaluated CT images of facet joints from the L1/2 through L5/S1 levels of 100 consecutive patients two times on the PACS system.Kappa analysis was used to evaluate the consistency of the results of grading.To investigate the Spearman correlation of the visual analog scale（VAS） scores and Oswestry disability indexs（ODI） and age with the CT grading of lumbar facet joint osteoarthritis.Result：A total of 1000 facet joints from 100 consecutive patients were evaluated by three independent spine surgeons two times respectively.200-211 joints（20.0%-21.1%） were considered to be grade 0，384-403（38.4%-40.3%） grade 1，301-310（30.1%-31.0%） grade 2，85-106（8.5%-10.6%） grade 3.The Kappa values of intraobserver were ranged from 0.773 to 0.833，representing substantial or excellent agreement in 84.1%-88.4% of 1000 joints.The Kappa values of interobserver were ranged from 0.756 to 0.827，representing substantial or excellent agreement in 82.9%-87.9% of 1000 joints.The VAS scores and ODI had no significant correlations with the average CT grading of lumbar facet joint osteoarthritis（r=0.186，0.192，P>0.05）.The average CT grading of lumbar facet joint osteoarthritis existed a positive correlation with age（r=0.558，P<0.05）.Conclusion：The CT grading system to assess the severity of lumbar facet joint osteoarthritis is presented good reliability，which can be helpful in research.Lumbar facet joint osteoarthritis exists a positive correlation with age，but has no significant correlations with low back pain VAS and ODI.