Disc Height Narrowing Could Not Stabilize the Mobility at the Level of Cervical Spondylolisthesis: A Retrospective Study of 83 Patients with Cervical Single-Level Spondylolisthesis

Methods@#The images of 83 patients with cervical single-level spondylolisthesis were studied. We looked at 52 slipped levels for anterior slippage and 31 for posterior slippage. The imaging parameters included slippage in the neutral, flexed, and extended positions, axial facet joint orientation, sagittal facet slope, global cervical alignment, C2–C7 angle, C2–C7 sagittal vertical axis, range of motion (ROM), and slipped disc angle ROM. @*Results@#With the narrowing of the intervertebral disc height, slippage in the flexed position of both anterior and posterior spondylolisthesis increased. However, in both anterior and posterior spondylolisthesis, disc height narrowing did not show stability. The narrowing of the intervertebral disc height was found to be a risk factor for a translation of slippage of 1.8 mm or more in flexionextension motion in anterior spondylolisthesis in multivariate regression analysis. @*Conclusions@#Narrowing the intervertebral disc height did not stabilize the translation of slippage in flexion-extension motion in cervical spondylolisthesis. Instead, narrowing of the disc height was associated with a translation of slippage of 1.8 mm or more in flexion-extension motion in cases of anterior slippage. Therefore, we discovered that degenerative cascade stabilization for cervical spondylolisthesis was difficult to achieve.

Association of Continuous Vertebral Bone Bridges and Bone Mineral Density with the Fracture Risk in Patients with Diffuse Idiopathic Skeletal Hyperostosis

Methods@#We examined the computed tomography scans from the thoracic vertebra to the sacrum used to diagnose DISH in 140 patients (98 men and 42 women; average age, 78.6 years). We compared patients who did (n=52) and did not have (n=88) fractures at the continuous vertebral bodies fused by bone bridges. The relationship between the vertebral fractures and the maximum number of vertebrae that are bony cross-linked with contiguous adjacent vertebrae (max VB) from the thoracic vertebra to the sacrum or from the lumbar vertebra to the sacrum and proximal femur BMD were analyzed using a logistic regression model. @*Results@#We found that after adjusting for the confounding factors, higher max VB, both from the thoracic vertebrae to the sacrum and the lumbar vertebrae to the sacrum, was associated with a higher risk of vertebral fractures. This difference was statistically significant. The risk was higher when only the lumbar vertebrae to the sacrum was considered (thoracic vertebrae to the sacrum: odds ratio, 1.21; p<0.05; lumbar vertebrae to the sacrum: odds ratio, 2.78; p<0.01). Moreover, low proximal femur BMD in DISH patients raises the fracture risk (odds ratio, 0.47; p<0.01). @*Conclusions@#Many continuous vertebral bone bridges, especially those that extend to the lumbar spine and low proximal femur BMD, are risk factors for fracture in DISH patients.