Abstract
Introduction
Vertebral osteoporotic fracture increases both elastic and time-dependent (‘creep’) deformations of the fractured vertebral body during subsequent loading. This is especially marked in central and anterior regions of the vertebral body, and could explain the development of kyphotic deformity in life. We hypothesise that vertebroplasty can reduce these creep deformations.
Methods
Twelve pairs of spine specimens, each comprising three vertebrae and the intervening soft tissue, were obtained from cadavers aged 67-92 yr. They were compressed to failure, after which one of each pair underwent vertebroplasty with polymethylmethacrylate cement, the other with a resin (Cortoss). A 1kN compressive force was applied for 1 hour before fracture, after fracture, and after vertebroplasty, while creep deformation was measured in the anterior, middle, and posterior region of each vertebral body using a MacReflex optical tracking system.
Results
Cement type had little influence on creep deformation, so data from all 24 specimens were pooled. After fracture, creep in the anterior vertebral body increased from 4,863 (STD 5060) to 57,674 (STD 57,663) microstrains (P<0.001), and creep in the central vertebral body increased from 738 (STD 5,643) to 37,025 (STD 43,519) microstrain (P<0.001). Vertebroplasty reduced creep deformations by 67% (P=0.002) and 66% (P=0.011) in the anterior and central regions respectively.
Conclusion
Vertebroplasty reduces progressive creep deformations of a fractured vertebral body. These findings suggest that vertebroplasty may slow or prevent the development of kyphotic deformity following vertebral osteoporotic fracture.
Conflicts of interest: None
Source of Funding: This work was funded by Action Medical Research. Vertebroplasty materials were provided by Stryker and by Orthovita.
We can confirm that this abstract has not been published previously in whole or substantial part and that they have not been presented previously at a national meeting.
