Decade-Wise Computed Tomography-Based Morphometric Measurements of a Single Lumbar Spinal Motion Segment L4-5

A spinal motion segment comprises facet joints and intervertebral disc. A complex interplay of biomechanical factors occurs between them with degeneration giving rise to numerous pathological conditions. We conducted a study to find a correlation between facet joint orientation and intervertebral discs with age.

A cross-sectional study of 203 consecutive subjects undergoing a computed tomography scan of abdomen and pelvis were included. Subjects were divided into 5 groups based on age (group I: 18-30 years; group II: 31-40 years; group III: 41-50 years; group IV: 51-60 years; group V: 61-70 years). Using 3-dimensional reconstruction images, orientation of lumbar facet joints at the L4-5 level was measured. Similarly, adjacent disc heights at L3-4 and L4-5 were measured and their ratio was documented.

The study included 106 males and 97 females. A positive correlation was noted between age and sagittal facet orientation until age 60 years. However, after age 60 years, a negative correlation with age was seen, which was statistically significant. Similarly, the disc height ratios show a progressive decline in their values with age. However, this decline was statistically significant only after age 60 years.

The gradual change of facet joint orientation from sagittal to coronal as the age crosses from 30 to 60, to beyond 60, with a simultaneous and parallel diminishing in the disc height probably is one of the attributes of the phenomenon of autostabilization of a motion segment.