Degenerative spondylolisthesis is associated with low spinal bone density: a comparative study between spinal stenosis and degenerative spondylolisthesis

Abstract

Spinal stenosis and degenerative spondylolisthesis share many symptoms and the same treatment, but their causes remain unclear. Bone mineral density has been suggested to play a role. The aim of this study was to investigate differences in spinal bone density between spinal stenosis and degenerative spondylolisthesis patients. 81 patients older than 60 years, who underwent DXA-scanning of their lumbar spine one year after a lumbar spinal fusion procedure, were included. Radiographs were assessed for disc height, vertebral wedging, and osteophytosis. Pain was assessed using the Low Back Pain Rating Scale pain index. T-score of the lumbar spine was significantly lower among degenerative spondylolisthesis patients compared with spinal stenosis patients (-1.52 versus -0.52, P = 0.04). Thirty-nine percent of degenerative spondylolisthesis patients were classified as osteoporotic and further 30% osteopenic compared to only 9% of spinal stenosis patients being osteoporotic and 30% osteopenic (P = 0.01). Pain levels tended to increase with poorer bone status (P = 0.06). Patients treated surgically for symptomatic degenerative spondylolisthesis have much lower bone mass than patients of similar age treated surgically for spinal stenosis. Low BMD might play a role in the development of the degenerative spondylolisthesis, further studies are needed to clarify this.

Figure 1

Main results from the lumbar AP scanning. The figure illustrates the inclusion of only those vertebrae not part of the fusion in the calculation of the overall bone mass.

Figure 2

Boxplot of the Low Back Pain Rating Scale pain index at follow-up closest to DXA-scanning. P values are nonparametric test for trend across group. Two-way Anova results in no effect of diagnosis (P = 0.42), but significant effect of bone status (P = 0.02). DDD: Degenerative disc disease. DS: Degenerative spondylolisthesis.

Figure 3

The two activity- and function-related scores from the DPQ according to diagnosis and bone status. There is no significant trend across the groups in any of the groups (P  values > 0.10) DDD: Degenerative disc disease. DS: Degenerative spondylolisthesis.