| Objective The design of the device of the curved injection needle. To investigate the fesibility and safety of using unipedicular puncture to achieve bipedicular augumention in vitro vertebroplasty experiment and quick restore biomechanical strength.Methods In the fisrt part, the design of the device of curved injection needle, which be made of nicke titanium alloy can directional corner piece. The diameter and longitudinal diameter of pig vertebral was measured for calculating corner angle. Thermal treatment was used to curved injection needle and then doing mechanical experiment to test the maintain of corner piece. In the second part, the development of pig model of osteoporotic vertebral fracture,50T12-L2vertebrals of pig were dipped into0.4916mmol/L EDTA-Na2for14days to incur osteoporosis. Dual energy X-ray absorptiometry bone mineral density instrument was used to monitoring bone mineral density. All vertebrals of pig were compressed to cause vertebral fracture using biomechanical testing machine. In the third part, the study of in vitro vertebroplasty application study,36specimens were randomly divided into3groups (12specimens per group), unipedicular vertebralplasty, bipedicular vertebralplasty, and unipedicular curved needle vertebralpalsty. The vertebral heights of all specimens were recorded at the anterior and posterior of vertebral bodies preoperation and postoperation. Cement injection and vertebralplasty were performed under C-arm fluoroscopy monitoring with the same experimental conditions. Biomechanics experiment was implement to measure the strength and stiffness after vertebralplasty.Results Using the ultra flexibility of nickel titanium alloy successful design the device of the curved injection needle for treatment osteoporotic vertebral compression fractures. Each group treatment resulted in statistical significance to the vertebral body height of pre-compression, post-compression and post-treatment(P<0.01). The quantity of injected bone cement in unipedicular vertebralplasty was3.28+0.16ml, bipedicular vertebralplasty was5.96±0.19, and unipedicular curved needle vertebralpalsty was6.06±0.25ml. There were significant difference between initial and augmented strength, no significant difference between bipedicular vertebralplasty and unipedicular curved needle vertebralpalsty. There were significant difference between initial and augumented stiffness, no significant difference between bipedicular vertebralplasty and unipedicular curved needle vertebralpalsty. and the augmented stiffness was less than the initial stiffness in all groups.Conclusion According to the vertebral body shape successful design the device of the curved injection needle. In vitro models test, unipedicular curved needle vertebralpalsty comply with the requirements for vertebralplasty, which can transport bone cement targeted into area that traditional methods can not reach. To achieve the bilateral pedicle puncture for the purpose of strengthening the double side. |
