Tissue-engineered vascularized patient-specific temporomandibular joint reconstruction in a Yucatan pig model

Current pediatric temporomandibular joint (TMJ) reconstruction options are limited. The aim of this project was to develop a proof-of-principle porcine model for a load-bearing, customized, 3D-printed and bone morphogenic protein 2 (BMP-2)-coated scaffold implanted in a pedicled (temporal) flap as a regenerative approach to pediatric TMJ mandibular condyle reconstruction.

Scaffolds were customized, 3D-printed based on porcine computed tomography, and coated with BMP-2. Two operations occurred: (1) implantation of the scaffold in temporalis muscle to establish vascularity and, (2) 6 weeks later, unilateral condylectomy and rotation of the vascularized scaffold (with preservation of superficial temporal artery) onto the defect. Six months later, pigs were sacrified. The experimental side (muscle-scaffold) and control side (unoperated condyle) were individually evaluated by clinical, mechanical, radiographic, and histologic methods.

Scaffolds maintained physical properties similar in appearance to unoperated condyles. Vascularized scaffolds had new bone formation. 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.

In our porcine model, customized 3D-printed TMJ scaffolds coated with BMP-2 and implanted in vascularized temporalis muscle have the ability to (1) reconstruct a TMJ, (2) maintain appropriate condylar height, and (3) generate new bone, without impacting functional outcomes.