Age-related changes in the orientation of lumbar facet joints.

STUDY

DESIGN

A measurement and analysis of the orientation of the lumbar facet joints at the L4-L5 level of different age groups.

OBJECTIVE

To explore the correlation between age and orientation of the lumbar facet joints.

SUMMARY OF BACKGROUND DATA: Previous studies have shown an association between sagittal orientation of the lumbar facet joints and degenerative spondylolisthesis, however, there is no information available on the association between orientation of the lumbar facet joints and age. This article studied the association between orientation of the lumbar facet joints and age.

METHODS

Three hundred spinal disease-free people coming for periodic physical examination during May 2007 and 2008 in our hospital accepted lumbar computed tomography (CT) scanning and were randomly selected. All the subjects were divided into 6 groups based on age (group I: <30 years of age, group II: 31-40 years, group III: 41-50 years, group IV: 51-60 years, group V: 61-70 years, and group VI: >70 years of age). CT scans of the lumbar spine were stored in digitized form for measurement and analysis. The orientation of the lumbar facet joints at the L4-L5 was measured on axial CT scans, and the intersection angle of the midsagittal line of vertebra to the facet line represent the orientation of the facet joint.

RESULTS

The angles of the L4-L5 facet joints to the vertebral sagittal plane of group I to VI are 50.61 degrees +/- 6.55 degrees, 47.05 degrees +/- 7.53 degrees, 46.56 degrees +/- 7.38 degrees, 43.39 degrees +/- 6.19 degrees, 40.95 degrees +/- 7.27 degrees, and 39.89 degrees +/- 9.05 degrees, respectively (P = 0.000).

CONCLUSION

The coronal orientation of the L4-L5 facet joints was negatively correlated to age (r = -0.456, P = 0.000), which could be one of the explanations that the aging people are prone to degenerative spondylolisthesis.