Calcium sulfate bone cement with or without injectable polyamino acid for goat vertebral defects:a comparative experiment

doi:10.3969/j.issn.2095-4344.2017.06.002

Abstract：BACKGROUND:Our previous study has proved that the novel injectable polyamino acid/calcium sulfate (PAA/CS) bone cement possesses a good safety and biocompatibility. But its repair effect on spinal defects is never reported. OBJECTIVE:To evaluate the degradability and osteogenesis of the PAA/CS bone cement in vertebral repair. METHODS:Twelve healthy adult female goats were selected. The vertebral defects ofφ4 mm×15 mm were prepared through the right lumbar pedicle, and the vertebrae of each goat were then randomly divided into two groups (groups A and B), followed by filled with the injectable CS or PAA/CS, respectively. The goats were sacrificed at 4, 8, 12 and 16 weeks after surgery, and micro-CT scan, quantitative analysis and histological observation were conducted. RESULTS AND CONCLUSION:New trabeculae grew in the defect area from the edging to the center in the two groups. At the end of 4 weeks, no filling material was found in the two groups, and the defect region was clear. At the end of 6 weeks, there was still an irregular cavity in the bone defect of the group A and the newly-formed trabeculae were dense and arranged disorderly. In the group B, the defect region was almost filled with trabeculae that were clear and connected well. With time, the bone volume fraction, thickness and number of trabeculae were on a rise, while the trabecular separation was in decline in both two groups. Histological observation showed that there were a large number of new trabeculae in both two groups, a part of which were connected, but most of which had the similar structures to normal trabeculae at the 16th week. These results suggest that the PAA/CS bone cement can be degraded thoroughly in vivo and has better osteogenesis than the CS. Addition of 10%PAA does not significantly delay the degradation of PAA/CS bone cement.