Abstract:

Objective To determine the appropriate puncture method for pigs and the evaluation methods of the safety and effectiveness of bone cement in preclinical animal experiments. Methods Twenty-four Yorkshire pigs with a body mass of 60 to 80 kg were randomly divided into two groups, group A and group B. Group A was the Tecres bone cement group, and group B was the Spine-Fix Radiopaque Bone Cement group, with 12 pigs in each group. Under the surveillance of a C-arm X-ray machine, the materials were percutaneously implanted into the vertebral bodies of lumbar vertebrae L1 and L4 of the pigs through the unilateral pedicle approach. At 4 weeks and 26 weeks after the operation, the animals were euthanized by the euthanasia method. The vertebral body of lumbar vertebra L4 of the animals was taken for compressive strength testing, and the vertebral body of lumbar vertebra L1 was taken for hard tissue pathological examination to observe the local inflammatory reaction, bone necrosis, and bone integration degree at the implantation site. Results There was no statistical difference in the compressive strength test results between group A and group B at 4 weeks and 26 weeks (P>0.05). At 4 weeks after surgery, the test samples could be seen under the microscope in both group A and group B. The test samples were wrapped by proliferative fibrous tissue, and inflammatory reactions mainly characterized by lymphocyte infiltration could be seen around them. The combination of the test samples and bone tissue could be seen, and the trabecular bone was disordered. Osteoblasts and a small amount of osteoid formation could be seen in both groups. At 26 weeks after surgery, the test samples could be seen under the microscope in both group A and group B. The newly formed bone tissue was gradually mineralized, the trabecular bone was gradually fused, the trabecular bone structure became regular and dense, and the continuity became better. No obvious inflammatory reaction was seen. Conclusion There were no significant differences in compressive strength, local inflammatory reaction at the implantation site, osteonecrosis condition, and degree of osseointegration between Group A and Group B.

Key words: Vertebroplasty, PMMA, Osteoplastic material, Compressive strength, Hard tissue pathology, Osseointegration, Pig