The role of lumbar lordosis, vertebral end-plate inclination, disc height, and facet orientation in degenerative spondylolisthesis.

Degenerative spondylolisthesis (DS) is a common condition of the aging spine, but the underlying pathomechanisms remain controversial. Most previous studies focused on the role of facet-joint alignment and reported a pronounced sagittal orientation. This, however, may also be a secondary feature to the slippage. This study analyzed several radiologic findings in the lower lumbar spine in 23 patients with DS (group A) and 40 age- and sex-matched controls (group B). Facet-joint angulation, intervertebral disc height, lordosis of the lumbar spine (L1-S1), and inclination of the L4, L5, and S1 end plates were assessed from neutral standing lateral radiographs and computed tomography (CT) or magnetic resonance imaging (MRI) investigations. Two findings were found to be significantly different between the groups. Facet joints were aligned more sagittal in group A, and the inclination of the vertebral end plates was more horizontal in group B. There was no statistical difference in lumbar lordosis or L4-5 disc height between the two groups, with disc height being decreased in both groups. In group A, more gliding was associated with a further decrease in disc space, pronounced sagittal alignment of the L4-5 facet joints, and a decrease in lumbar lordosis. We concluded that further studies should focus on the analysis of spinal alignment and lower lumbar end-plate orientation to identify patients at risk for development of DS.