Figure 6
From: Bone Regeneration Based on Tissue Engineering Conceptions — A 21st Century Perspective
Load-bearing critical-sized ovine tibial defect model using mPCL-TCP scaffolds manufactured by FDM. Scaffolds (A=clinical image, holes are oriented towards neurovascular bundle to further promote ingrowth of vasculature) exhibit mechanical and structural properties comparable to cancellous bone and can be produced with distinct control over scaffold properties (porosity, pore size, interconnections etc.) by AM. B= Side and top view of a mPCL-TCP scaffold visualised by microcomputed tomography. The fabrication via FDM enables well-controlled architecture as evidenced by the narrow filament thickness distribution, leading to a porosity (volume fraction available for tissue ingrowth) of 60%, with interconnected pores. Scale bars are 5 mm. [Image B reproduced with permission from (246), © The Authors.] C-H = Surgical procedure: A 6cm tibial defects is created in the tibial diaphysis (C-D) and the periosteum is removed from the defect site and additionally also from 1cm of the adjacent bone proximally and distally. Special care is taken not to damage the adjacent neurovascular bundle (E, bundle indicated by Asterisk). The defect site is then stabilised using a 12 hole DCP (Synthes) (F). Afterwards 6cm mPCL-TCP scaffold loaded with PRP and rhBMP-7 is press fitted into the defect site to bridge the defect (G-H) and the plate is fixed in its final position. Xray analysis at 3 months after implantation (I) shows complete bridging of the defect site with newly formed radio-opaque mineralised tissue (in order to provide sufficient mechanical support, the scaffold is not fully degraded yet and scaffold struts appear as void inside the newly formed bone tissue).
