Repair of complex ovine segmental mandibulectomy utilizing customized tissue engineered bony flaps.

Area of Science:

• Regenerative Medicine
• Biomaterials Science
• Craniofacial Surgery

Background:

• Craniofacial defects necessitate robust, geometrically accurate tissues for restoration.
• Compromised soft tissues require vascularized constructs for effective reconstruction.
• Tissue engineering offers a solution for creating customized, mechanically sound bony tissues.

Purpose of the Study:

• To evaluate the efficacy of a two-stage tissue engineering approach for load-bearing mandibular reconstruction in sheep.
• To compare two distinct 3D printed bioreactor geometries for bone tissue generation.
• To assess the viability and remodeling of engineered bone in a large animal model.

Main Methods:

• Utilized customized 3D printed bioreactors implanted in 5 sheep to create load-bearing mandibular defects.
• Tested two bioreactor geometries (large complex and small rectangular) filled with xenograft and autograft.
• Analyzed bone volume/total volume (BV/TV) before and after transfer to the mandibular defect.

Main Results:

• Engineered bone tissues achieved significant increases in BV/TV, from 31.8% initially to 55.3% (large) and 59.2% (small) at transfer.
• Post-transfer, the large bioreactor tissues remodeled to a final BV/TV of 64.5%.
• Viable osteoblasts were present in transferred tissues despite infection, indicating successful bone regeneration.

Conclusions:

• A vascularized, customized bony flap generated via tissue engineering is a potentially effective strategy for mandibular reconstruction.
• Optimal stabilization and local antibiotic delivery are crucial for managing complications like infection.
• This two-stage approach shows promise for complex, load-bearing craniofacial defect repair.