BACKGROUND: Treatment of large bone defects is an important problem faced by orthopedic physicians. Allogeneic bone transplantation is a classic method, but it has many restrictions. The membrane guided bone regeneration technique has become an important method for the research nowadays.OBJECTIVE:To compare the effects of self-made high strength biodegradable nano-hydroxyapatite/multi(amino acid) copolymer (n-HA/MACP) guided bone regeneration membrane tube and allograft bone graft segment in the repair of large segmental bone defect in goats. METHODS: The model of 30 mm large segment bone defect in the middle section of the femur in 32 adult goats was established. Experimental group used self-made n-HA/MACP tube to bridge defects following bone plate fixation. The control group was treated with allograft bone graft bone segments combined with plate fixation. The animals were sacrificed at 4, 8, 12 and 16 weeks after operation, and the bone callus growth was observed in the specimens. The X-ray and histological observations were performed at the same time. Biomechanical measurement of plate fixation of allograft cortical bone segment was done at 12 and 16 weeks after operation. RESULTS AND CONCLUSION: (1) After 4 to 16 weeks, gross and pathological results showed fibrous callus growth inside and outside of the membrane tube, and the fibrous callus gradually hardened into a bony callus. Additionally, the callus was larger in the experimental group than in the control group. X-ray films showed significantly increased lateral callus density in the experimental group as compared with the control group. (2) Maximum bending strength was significantly higher in the experimental group than in the control group at 16 weeks (P < 0.05). Overall, the n-HA/MACP membrane tube used for bridging large segment bone defects in goats can obtain similar repair effects to the allograft cortical bone, and further achieve the better mechanical strength of the new bone segment than the allograft bone.

Three-dimensional (3D) printing technology is characterized by "inside-out" stack manufacturing. Compared with conventional technologies, 3D printing has the advantage of personalization and precision. Therefore, the shape and internal structure of the scaffolds made by 3D printing technology are highly biomimetic. Besides, 3D bioprinting can precisely deposit the biomaterials, seeding cells and cytokines at the same time, which is a breakthrough in printing technique and material science. With the development of 3D printing, it will make great contributions to the reconstruction of vertebrae and intervertebral disc in the future.
Biocompatible Materials ; Bioprinting ; Humans ; Intervertebral Disc ; growth & development ; Printing, Three-Dimensional ; Tissue Engineering ; methods ; Tissue Scaffolds