摘要
BACKGROUND:Silk fibroin has excel ent biocompatibility, biodegradability and unique mechanical properties. Its composite, silk fibroin/nano-hydroxyapatite, can simulate the composition and structure of nature bone tissue, contributing to remedying the insufficient mechanical properties of nano-hydroxyapatites. OBJECTIVE:To observe the biological safety of silk fibroin/nano-hydroxyapatite composites. METHODS:Silk fibroin/nano-hydroxyapetite composite biomaterial was synthesized by the coprecipitation method using silk fibroin, calcium chloride and diammonium phosphate as raw materials. According to the demands of International Standard Organization (ISO10993) and Technical Evaluation Standards of Biomedical Materials and Medical Instruments promulgated by Chinese Board of Health (GB/T 16886), experiments of cel toxicity in vitro, acute toxicity and hemolysis were investigated to evaluate the biocompatibility of silk fibroin/nano-hydroxyapetite composite. RESULTS AND CONCLUSION:L929 cel s co-cultured with silk fibroin/nano-hydroxyapatite composite leaching liquor had good cel morphology, metabolism and proliferation. The leaching extract of silk fibroin/nano-hydroxyapatite composite injected into mice intraperitoneal y had no significant adverse reactions. And silk fibroin/nano-hydroxyapatite composite extracts caused 2.39%blood hemolysis, less than the international standards 5%. These experimental results on cel toxicity test in vitro, acute toxicity and hemolysis met the demands of ISO10993 and GB/T, which show the biological safety of the silk fibroin/nano-hydroxyapatite composite for clinical application.
摘要
Objective To discuss indications,operation method and clinical outcome of posterior short-segment pedicle fixation at the injured level for treatment of thoracolumbar spine fractures.Methods A total of 38 patients with thoracolumbar spine fractures were equally randomized to Group A(treated with classic short-segment pedicle screw fixation)and Group B(treated with short-segment pedicle screw fixation at the injured level)based on fixation methods(19 patients per group).Preoperative and postoperative JOA score,segmental lordosis(Cobb' s angle),R value(anterior fractured vertebral body height/mean normal vertebral body height×100%),VSA score and internal fixation condition were assessed and compared clinically.Results All patients were followed up for 6-37 months(mean 20.5 months),which showed no statistical difference upon Frankel scores of two operation modes,while the segmental lordosis,VAS score and R value in Group B were than those in Group A.There occurred nuts loosening in one patient and screw bending in one in Group A.There was no implant breakage,loosening or emersion in Group B.Conclusion Posterior short-segmental fixation at the injured level is an adequate and effective procedure for compression fractures and mild to moderate burst fractures of the thoracolumbar spine.