Development of a low-cost polymethylmethacrylate stand-alone cervical cage: technical note

Area of Science:

• Spinal Surgery
• Biomaterials Engineering
• Orthopedic Implants

Background:

• Cervical cages aim for stability and fusion but often face issues like subsidence and poor alignment.
• High costs of current implants contrast with their suboptimal radiological outcomes.
• There is a need for cost-effective cervical cage solutions with robust mechanical performance.

Purpose of the Study:

• To develop and mechanically evaluate a low-cost polymethylmethacrylate (PMMA) cervical cage.
• To compare the mechanical properties of the PMMA cage against a commercial polyetheretherketone (PEEK) cage.
• To assess the cost-benefit ratio of the novel PMMA cage for cervical fusion.

Main Methods:

• PMMA cages were fabricated using a newly developed casting mold.
• Static compression tests were performed on both PMMA and PEEK cages at 0 and 45 degrees.
• Key mechanical properties including compressive yield strength, yield displacement, tensile strength, and stiffness were determined.

Main Results:

• At 0 degrees, PMMA cages exhibited significantly higher compressive yield strength, displacement, and tensile strength than PEEK cages (p < 0.001).
• Stiffness was comparable between PMMA and PEEK cages (p = 0.903).
• At 45 degrees, PMMA cages demonstrated a mean compressive yield strength of 804.9 N, mean displacement of 0.66 mm, mean tensile strength of 7.92 N/mm², and mean stiffness of 1,228 N/mm.

Conclusions:

• The developed PMMA cervical cage shows comparable or superior mechanical properties to PEEK cages.
• With a short preparation time and low material cost, the PMMA cage presents a favorable cost-benefit ratio.
• Further clinical studies are required to validate the effectiveness of the PMMA cage in patient outcomes.