Houston, TX 77005
10:00 a.m. Tuesday, Dec. 4, 2012
On Campus | Alumni
Craniofacial defects resulting from trauma and resection present many challenges to reconstruction due to the complex structure, combinations of tissues, and environment, with exposure to the oral, skin and nasal mucosal pathogens. Tissue engineering seeks to regenerate the tissues lost in these defects; however, the composite nature and proximity to colonizing bacteria remain difficult to overcome. Additionally, many tissue engineering approaches have further hurdles to overcome in the regulatory process to clinical translation. As such these studies investigated a two stage strategy employing an antibiotic-releasing porous polymethylmethacrylate space maintainer fabricated with materials currently part of products approved or cleared by the United States Food and Drug Administration, expediting the translation to the clinic. This porous space maintainer holds the bone defect open allowing soft tissue to heal around the defect. As part of the same stage, a vascularized bone flap is generated in a chamber placed against the periosteum of a rib. In the second stage, the bone flap can be removed from the chamber and transferred into the bone defect after removal of the space maintainer. These studies investigated the individual components of this strategy. The porous space maintainer showed similar soft tissue healing and response to non-porous space maintainers in a rabbit composite tissue defect. In humans, the porous space maintainers were well tolerated and maintained a soft tissue envelope for closure after implantation of a bone regeneration technology. The antibiotic-releasing space maintainers showed release of antibiotics from 1-5 weeks, which could be controlled by loading and fabrication parameters. In vivo, space maintainers releasing a high dose of antibiotics for an extended period of time increased soft tissue healing over burst release space maintainers in an infected composite tissue defect model in a rabbit mandible. Finally, stabilization of bone defects could be improved through scaffold structures and delivery of a bone forming growth factor. Additionally, a vascularized bone flap was transferred and demonstrated increased bone tissue maintenance over time in a mandibular defect. These studies illustrate the possibility of the two stage strategy for repair of composite tissue defects of the craniofacial complex.