Material characterization and selection for 3D-printed spine models.

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Materials Science

Background:

• Cadavers and sawbones are standard for anatomical training but have limitations.
• Cadavers are expensive and difficult to obtain, while sawbones lack realistic tactile and mechanical properties.
• 3D-printed phantoms offer a potential solution for anatomical training models.

Purpose of the Study:

• To develop and evaluate 3D-printed phantoms (MedPhantom®) that emulate the tactile feel, mechanical characteristics, and visual appearance of human vertebrae.
• To provide a viable, cost-effective alternative to cadavers for surgical training in anatomy.

Main Methods:

• Developed a 3D-printing process to create MedPhantom® vertebrae with internal trabecular structures using a custom algorithm.
• Quantified tactile fidelity using a mechanical bur sweep test (75,000 RPM) measuring forces and moments.
• Assessed structural properties via a compression test (1000 RPM) measuring resultant forces.

Main Results:

• Two material compositions showed closest resemblance to human cadaveric vertebrae in the bur sweep test: 15% Gypsum® powder/100% Clear® Formlabs resin and 10% Castable® resin/90% Clear® resin.
• Optimal structural parameters for mimicking vertebrae include a 2 mm cortical wall, 4-5 mm gap size, and 0.25 mm internal cylinder radius.
• Statistical analysis confirmed significant differences between the 3D-printed samples and actual vertebrae (p < 0.05).

Conclusions:

• 3D-printed MedPhantom® vertebrae show promise as realistic anatomical training models.
• Specific material formulations and structural designs can effectively replicate the mechanical properties of human bone.
• This technology offers a scalable and accessible alternative for surgical education, potentially reducing reliance on cadavers.