Calcium sulfate cement augments transient stability of pedicle screw in osteoporotic vertebral body / 中国组织工程研究

ABSTRACT

BACKGROUND:Poor implant anchorage in osteoporotic bone impacts its stability and requires the new solutions for the treatment. The augmentation technique with bone cements or bone substitutes is one strategy for the solutions. OBJECTIVE:To evaluate the transient stability of pedicle screw augmented using calcium sulfate cement in osteoporotic vertebral body. METHODS:Fresh calf lumbar vertebrae were selected to measure bone density, and then classified into four groupsthe group by pedicle screw in normal vertebral body;the group by pedicle screw augmented using calcium sulfate cement in normal vertebral body;the group by pedicle screw in osteoporotic vertebral body;the group by pedicle screw augmented using calcium sulfate cement in osteoporotic vertebral body. Pedicle screw of equal specification was twisted into the tested pedicle of vertebral arch. The maximum axial screw pul-out strength and the maximum energy required to failure were recorded so as to assess the transient stability of pedicle screw augmented using calcium sulfate cement. RESULTS AND CONCLUSION:The maximum screw pul-out strength and the maximum energy required to failure were significantly less in osteoporotic vertebral body compared with normal vertebral body (P<0.05). The maximum screw pul-out strength and the maximum energy required to failure after augmentation using calcium sulfate cement were significantly increased (P<0.05). The maximum screw pul-out strength and the maximum energy required to failure after augmentation using calcium sulfate cement were identical between normal group and osteoporosis group. These results suggested that calcium sulfate cement could effectively increase the transient stability of pedicle screw. Calcium sulfate cement is effective in augmenting fixation in osteoporotic bone, and has potential in clinical application.