Speaker
Description
Introduction:
Three-dimensionally (3D)-printed bioceramic scaffolds composed of beta-tricalcium phosphate (β-TCP) have demonstrated the ability to support robust bone regeneration in critically sized calvarial defects. This bone formation is facilitated through two key biological mechanisms: osteoconduction, which guides new bone growth along the scaffold, and potentially dura-mediated osteoinduction, in which the underlying dura mater plays an active role in inducing osteogenesis. However, in clinical settings such as cranioplasty, patients often present with a compromised dura mater that may be scarred, damaged, or completely absent due to prior surgery, trauma, or disease. The absence of an intact dura raises important questions about the efficacy of scaffold-mediated bone regeneration in such scenarios.
To address this clinically relevant concern, the present study investigates whether osteoconduction alone—independent of any contribution from dural osteoinductive signals—is sufficient to support bone regeneration across critically sized calvarial defects. Using a well-established in vivo model, this work aimed to evaluate the regenerative capacity of 3D-printed β-TCP scaffolds isolated from the dura mater, assessing new bone formation, scaffold integration, and vascularization. The findings from this study aim to inform the translational potential of bioceramic scaffolds in complex cranial reconstructions, especially in cases where the native osteoinductive environment is compromised or absent.
Methods:
Unilateral calvarial defects were created in rabbits (n=12) and these defects were filled with 3D-printed bioceramic scaffolds containing one of two structural modifications at the scaffold/dura interface: (a) with a solid nonporous cap or (b) with a fully porous cap. The nonporous cap abutted the dura, effectively isolating the scaffold from direct contact with the osteogenic properties of the dura while the porous cap design permitted dural-mediated osteoinduction. The rabbits were euthanized 8 weeks postoperatively and calvaria were analyzed quantitatively, volumetrically, using 3D reconstructions from microcomputed tomography, as well as qualitatively, using nondecalcified histologic sectioning to assess for differences in bone growth.
Results:
When comparing scaffolds with a porous cap to those with a solid (nonporous) cap, no statistically significant difference was detected in percent bone volume (9.3 ± 4.5 vs. 10.2 ± 4.5; P=0.71), percent volume of soft tissue presence (58.5±7.0 vs. 52.5±2.0; P=0.072), or percent scaffold volume (32.3±3.4 vs. 37.3±4.3; P=0.917). Bridging bone was generated across bone defects treated by both construct designs, independent of design (Figure). Histologic analysis revealed the generation of vascularized bone within the defect with the formation of Haversian canals.
Conclusion:
This study demonstrates that three-dimensionally (3D) printed bioceramic scaffolds composed of beta-tricalcium phosphate can promote bone regeneration across critically sized calvarial defects even in the absence of dura-mediated osteoinduction. These findings suggest that osteoconduction alone may be sufficient for effective bone healing in scenarios where the dura is compromised or absent, as often encountered in clinical cranioplasty. The results provide important insights into scaffold-based tissue engineering strategies and may guide the future design of biomaterial constructs for reliable and durable calvarial reconstruction.
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