Long-term comparison of two β-TCP/PLCL composite scaffolds in rabbit calvarial defects

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Regenerative Medicine

Background:

• Bone graft substitutes are crucial in orthopedic and spinal surgery for improved patient outcomes.
• Developing advanced materials like β-tricalcium phosphate/poly(L-lactide-co-ε-caprolactone) (β-TCP/PLCL) copolymers aims to enhance bone regeneration.
• Elastic porous scaffolds offer potential advantages in surgical application and integration.

Purpose of the Study:

• To compare the surgical usability and bone regeneration potential of a novel elastic porous β-TCP/PLCL composite scaffold against a commercial β-TCP/PLCL bone graft substitute.
• To evaluate the degradation, tissue integration, and host response to both materials in a rabbit calvarial defect model.

Main Methods:

• A bilateral 12-mm calvarial defect model was created in 12 rabbits.
• Both composite and commercial scaffolds were implanted after soaking in bone marrow aspirate.
• Artificial intelligence (AI)-assisted micro-CT and histopathology were used for quantitative and qualitative analysis at 24 and 48 weeks.

Main Results:

• Both scaffolds demonstrated good tissue ingrowth and vascularization, with 10%-16% new bone formation.
• Implant material was visible at 48 weeks, indicating slow degradation for both materials.
• A foreign body reaction was observed in both groups, more pronounced in the composite scaffold, but the composite scaffold offered superior intraoperative usability.

Conclusions:

• The novel composite scaffold exhibits enhanced usability during surgery compared to the commercial chronOS Strip.
• Both β-TCP/PLCL materials support bone regeneration but undergo slow degradation and elicit foreign body responses.
• Further research may be needed to optimize the composite scaffold to mitigate the foreign body reaction while retaining its usability benefits.