Etiological Relationship Between The Facet Joint Angle And Degenerative Lumbar Spondylolisthesis

Objective To investigate the etiological relationship between the angle of facet joint and degenerative lumbar spondylolisthesis(DLS).Method From January 2010 to July 2013,100 patients with DLS at L4/5 were enrolled as the research group.100 patients without back pain or spondylolisthesis as the control group.The patients in two groups were matched in gender and age.Both two groups recieved CT Scan and X-examination.The degree of spondylolisthesis(Boxall index) was measured on X-ray image.The cranial CT image of facet joint was selected through the inferior endplate of upper vertebrae,and caudal image was selected on the level of superior endplate of the lower vertebrae.The angle formed with facet joints and coronal of the vertebral bodies was measured.The degree of degeneration of facet joints were classified under CT window of bone.Result DLS group L4/5 cephalic facet joints (58.8 ± 6.3) and caudal facet joints (56.2 ±6.1°) were higher than the control group (50.6 ± 7.9°), (47.1 ± 7.8±), respectively, and the differences was statistically significant (P<0.01). DLS patients L4/5 head to tail side angle difference (2.4 ± 0.6±) was less than the control group (4.9 ± 1.7°), (P<0.01). DLS group L4/5 right and left facet joints asymmetry (7.8 ± 2.0±) was higher than the control group (5.1 ± 1.6±), (P<0.01). Stratified by the facet joint degeneration rating, DLS patients were divided into three groups, the difference of slipping Boxall index between the groups was significant (P< 0.05), while the difference of degenerative hierarchy head, caudal facet joint angle were not statistically significant (r=0.061, P> 0.05).Conclusion The change of direction of facet joint is the result of a secondary remodeling under stress in the development of the degenerative lumbar spondylolisthesis.