Tissue Engineered Vascularized Patient-Specific Temporomandibular Joint Reconstruction in a Yucatan Pig Model

Purpose: Pediatric temporomandibular joint (TMJ) reconstruction occurs as a result of acquired, developmental, and/or congenital conditions. Current pediatric reconstruction options are limited. The aim of this project was to develop a proof of principle porcine model for a load bearing, customized 3-dimensional (3D) printed and BMP2-coated scaffold implanted in a pedicled (temporal) flap as a regenerative approach to pediatric TMJ mandibular condyle reconstruction. Materials and Methods: Scaffolds were custom designed and 3D printed based on porcine computed tomography and absorbed with BMP2. Two operations occured: (1) implantation of scaffold in temporalis muscle to establish vascularity, and six weeks later, (2) unilateral condylectomy and rotation of the vascularized scaffold (with preservation of superficial temporal artery) onto mandibular ramus defect and secured with titanium screws. At 6 months post-implantation, the pigs were sacrified. The experimental side (muscle-scaffold) and the control side (unoperated condyle) were individually harvested at 6 months and evaluated by clinical, mechanical, radiographic, and qualitative/histologic methods. Results: Scaffolds maintained physical properties similar in appearance to unoperated condyles. The vascularized scaffolds had bone formation at edges and adjacent to scaffold-bone interface. New bone was visible in scaffold. Condyle height on the reconstructed side was 68% and 78% of the control side. Reconstructed condyle stiffness was between 20% and 45% of the control side. Conclusion: In our porcine model, customized 3D printed TMJ scaffolds impregnanted with BMP2 and implanted in and pedicled on temporalis muscle has the ability to (1) reconstruct a TMJ defect model, (2) maintain appropriate condylar height and upper airway diameter, and (3) generate new bone, without impacting functional outcomes.