| 1 IntroductionIntervertebral fusion is a common technique in treating spinal disorders. Autograft achieves highly successful rate, but limited autograft and chronic pain in donor area are not solved. Good clinical outcomes was achieved with solid n-HA/Col in interbody fusion. With the development of minimally invasive spinal surgery, injectable bone substitute is necessary as filler. n-HA/Col integrated specific cage is a new method,which is fitting for manipulating demand of minimally invasive spinal surgery. N-HA/Col developed by the material department of Tsinghua university has similar structure to natural bone, with good biological compatability,good biodegradability and absorbility, and good bioactivity. In our study,we applied injectable n-HA/Col as filling material to intervertebral space, to investigate its osteogenesis ability between bodies in order to provide the evidence of animal experiment for the following clinical appliance.2 ObjectiveTo observe the fusion effect of injectable n-HA/Col between vertebral bodies.3 MethodsThere were 16 New Zealand white rabbits, we excised anterior discs and built defect areas between L5/6, L6/7 and L7/S1 through anterior lumbar approach operation in each animal. Of these, no material was implanted in defect area between L5/6; injectable n-HA/Col was implanted in defect area between L6/7; and solid type n-HA/Col was implanted in defect area between L7/S1. One animal was randomly selected to receive radiological examination at different time point postoperatively, and the radiological data of interbody fusion was analysed. We killed 4 animals at 4w,8w,12w,16w postoperatively respectively, and harvested lumbosacral vertebrae specimens. We made organization slices of L5/6, L6/7,L7/S1 segment in every specimen, and HE and masson dyeing were performed to compare osteogenesis difference of the 3 groups. The masson-dyeing organization slices of L6/7 and L7/S1 segment were analysed with Image-pro plus 6.0 software to compare the difference of osteogenesis ability between the two groups.4 ResultsThe postoperative day CT image displayed that experimental models was achieved successfully. With time prolonged, L6/7 and L7/S1 segment displayed more and more osteogenesis radiologically. Both compared, L6/7 segment has stronger osteogenesis than L7/S1 segment. However, L5/6 segment had no osteogenesis performance eventually. Histologically, gradually strengthened osteogenesis was observed in the slices of L6/7 and L7/S1 segment. However, the slices of L5/6 segment had no osteogenesis performance eventually. The image analysis of the masson-dyeing organization slices of L6/7 and L7/S1 segment showed that the osteogenesis ability is no difference between the two groups.5 ConclusionInjectable n-HA/Col can achieve exact interbody fusion. |
