The effect on anterior column loading due to different vertebral augmentation techniques

Background. Vertebral compression fractures are a significant cause of morbidity amongst the elderly, resulting in pain, kyphosis, decreased mobility, and often depression. The two most popular operative treatments of compression wedge fractures are vertebroplasty and kyphoplasty, however, which method leads to restoration of normal spinal loading is unknown. Methods. A cadaveric thoracolumbar spine model was fractured and then treated using one of two techniques: vertebroplasty or kyphoplasty. Three non-destructive loading regimes were applied to the intact, fractured and treated cases. Sub-adjacent nuclear pressure, used as a measure of anterior column loading, was determined for each experimental variant and loading case. Findings. The data indicate that nuclear pressure was substantially reduced after the spine was fractured. These pressures were minimally increased after treatment, however, not to the level of the pre-fractured condition. In all loading cases, there were no significant differences between the two treatment types. Interpretation. While our data show that both vertebroplasty and kyphoplasty allow the disc to generate higher nuclear pressures, neither treatment increased nucleus pulposus pressure above the level of the intact state. This directly relates to the clinical condition in that adjacent segment fractures sustained subsequent to either treatment is likely the result of overall disease progression, and not a direct result of the intervention.