Getting PEEK to Stick to Bone: The Development of Porous PEEK for Interbody Fusion Devices

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Spinal Fusion Technology

Background:

• Interbody fusion cages are crucial for spinal fusion, with polyether-ether-ketone (PEEK) being a common material.
• Smooth PEEK surfaces may impede osseointegration and successful spinal fusion.
• A need exists for improved PEEK cage designs that promote bone ingrowth.

Purpose of the Study:

• To introduce and evaluate the first commercially available porous PEEK interbody fusion cage (COHERE®).
• To assess the potential of porous PEEK to enhance osseointegration and spinal fusion outcomes.
• To compare the performance of porous PEEK against traditional smooth PEEK and titanium implants.

Main Methods:

• Development of a porous PEEK cage with a structure mimicking trabecular bone.
• Biomechanical testing comparing expulsion resistance and adhesion strength.
• In vitro cell culture studies assessing cell attachment, proliferation, and mineralization.
• Preclinical animal studies evaluating bone ingrowth and fixation strength.
• Clinical case studies in cervical spinal fusion.

Main Results:

• Porous PEEK demonstrated superior expulsion resistance and adhesion strength compared to smooth PEEK and titanium-coated PEEK.
• In vitro studies showed enhanced cell attachment, proliferation, and mineralization on porous PEEK.
• Animal studies revealed bone ingrowth comparable to porous titanium, resulting in double the fixation strength of smooth PEEK.
• Clinical cases indicated effectiveness in cervical spinal fusion.

Conclusions:

• The porous PEEK fusion cage design effectively supports bone ingrowth and enhances implant fixation.
• This novel material offers a promising alternative to traditional smooth PEEK cages for improving spinal fusion rates.
• Clinical application suggests the COHERE® device is effective for achieving cervical spinal fusion.