ABSTRACT
BACKGROUND:In senile osteoporosis patients, capacity of pedicle screw fixation is relatively poor due to fragile bone substance. Currently, augmentation of pedicle screw fixation with bone cement can improve the ability of screw fixation, but bone cement leakage and difficulties in screw removal become the problem to be solved. OBJECTIVE:To develop a novel pourable pedicle bone cement and to investigate its biomechanical properties, safety and practicality, thus providing the basis for clinical treatment of osteoporosis and spinal diseases. METHODS:Six cases of complete wetting spines were colected at the Affiliated Hospital of Nanjing University of Traditional Chinese Medicine from December 2013 to January 2015, including 42 vertebrae. Pedicle screw fixation with X-ray assisted bone cement injection (2 mL) was performed unilateraly as experimental group, and conventional pedicle screw fixation was done contralateraly as control group. Bone cement dispersion was observed in the two groups. RESULTS AND CONCLUSION:It was 3-4 minutes for bone cement to agglomerate. Injection of bone cement paste into the infusion cylinder using a syringe was more convenient. The cylinder was connected tightly with the tail-end of the screw with no leakage. The push bar could provide sufficient perfusion force. Bone cement dispersion was found in the holow part and side holes of the screw. Side holes arranged regularly, and the hole pitch was equal. Compared with the control group, the yield load and yield displacement were significantly higher in the experimental group (P < 0.05), but the ultimate strength and ultimate displacement were significantly lower in the experimental group (P < 0.05). Bone cement around the pourable cement screw dispersed regularly, which was diffused into the surround cancelous bone and integrated with adjacent bone cement mass. The axial withdrawal force was increased by 114% in the experimental group compared with the control group (P < 0.05). The maximum rotary torque was significantly higher in the experimental group than the control group (P< 0.05). These finding suggest that the new pourable cement screw combined with bone cement putter and infusion cylinder is applied more convenient, can effectively control the leakage of bone cement, and can improve the stability of the pedicle in osteoporosis patients, which has been widely used.
ABSTRACT
Comparison of the institutional setup, policies and adverse event report mechanism for medical risk control in the countries of UK, USA, Canada, and Australia by means of browsing information on their official websites. It is found that these countries maintain a national patient safety authority, coupled with a tiered management at national, local, medical institutions and NGOs level; the USA pattern features laws and regulations, that of UK and Australia features guidelines as policy guarantee for medical safety; these countries regulate adverse event reporting by either government leadership or cooperation with trade associations. Inspirations from this study suggest China to enhance institutional construction, complete regulations, and advocate the culture for medical safety, and to build the national-level reporting and study system for medical safety events, and improve medical risk management.
