Patient-Specific Bioimplants and Reconstruction Plates for Mandibular Defects: Production Workflow and In Vivo Large...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Craniomaxillofacial Surgery

Background:

• Extensive craniomaxillofacial bone defects pose reconstruction challenges due to limited donor sites.
• Patient-specific implants are crucial for accurate anatomical restoration.
• Poly(trimethylene carbonate) (PTMC) and β-tricalcium phosphate (β-TCP) composites are explored for bone regeneration.

Purpose of the Study:

• To evaluate patient-specific composite bioimplants (PTMC+TCP) in a large animal model for mandibular reconstruction.
• To compare the efficacy of PTMC+TCP and neat PTMC bioimplants against autologous bone and empty defects.

Main Methods:

• In vivo study using twelve Göttingen minipigs with 25 mm mandibular continuity defects.
• Defects were treated with PTMC+TCP bioimplants, PTMC bioimplants, autologous bone, or left empty, supported by patient-specific titanium plates.
• Postoperative assessment at 24 weeks included ossification evaluation and histopathological analysis.

Main Results:

• Both PTMC and PTMC+TCP bioimplants promoted ossification by 24 weeks.
• PTMC+TCP implants showed direct bone apposition, good osteoconduction, and osteoinductivity.
• Neat PTMC implants were covered by fibrous tissue.
• PTMC+TCP implants exhibited high rates of necrosis and infection, potentially linked to resorption or β-TCP particle size.

Conclusions:

• Composite PTMC+TCP bioimplants demonstrate osteoconductive and osteoinductive potential in large mandibular defects.
• Challenges with PTMC+TCP implants, including necrosis and infection, require further investigation regarding resorption and β-TCP characteristics.
• Clinical translation necessitates validation in relevant large animal models and load-bearing sites, as findings from small animal models may not be directly applicable.