## Introduction
The choice of material for interbody fusion cages鈥攖he spacers placed between vertebrae鈥攊s a critical factor in spinal surgery. Historically, **PEEK (Polyetheretherketone)** and **Titanium** have been the two dominant materials, each offering unique biological and mechanical advantages.
## PEEK: The Radiolucent Standard
PEEK became popular due to its mechanical properties being similar to human bone.
* **Elastic Modulus:** PEEK’s modulus (~3.6 GPa) is closer to cancellous bone, reducing the risk of “subsidence” (the cage sinking into the bone).
* **Radiolucency:** PEEK is invisible on X-rays, allowing surgeons to see the bone growth *through* the cage.
* **Bio-inert:** It does not bond directly to bone, relying on a fibrous interface.
## Titanium: The Osseointegration Champion
Titanium is “bio-active,” meaning bone cells (osteoblasts) attach and grow directly onto its surface.
* **Bio-Mechanical Bond:** Provides superior early stability.
* **Surface Technology:** Modern titanium cages feature acid-etched or plasma-sprayed surfaces to increase roughness and surface area for cell attachment.
## The 2026 Trend: 3D-Printed Titanium
The latest innovation is **3D-printed porous titanium**. These cages combine the best of both worlds:
1. **Trabecular Structure:** Mimics natural bone architecture.
2. **Reduced Stiffness:** The porous design lowers the modulus of elasticity closer to that of PEEK, mitigating subsidence risks.
3. **Total Integration:** Bone grows into the entire volume of the cage, not just around it.
## Conclusion
While PEEK remains the standard for visualization, 3D-printed titanium is the future of osseointegration. Ortholyx provides both PEEK and advanced Titanium mesh cages to suit every surgical philosophy.