Interbody fusion

Interbody fusion places the bone graft or cage between the vertebra in the area usually occupied by the intervertebral disc.

Cervical interbody fusion

Lumbar interbody fusion (LIF).

The continuous development of materials with elastic properties close to that of the cortical bone improves induction of osteogenesis and simplifies the technique of interbody fusion.

Interbody fusion is commonly utilized for arthrodesis and stability among patients undergoing spine surgery. Over the last few decades, interbody device materials, such as titanium and polyetheretherketone (PEEK), have been replacing traditional autografts and allografts for interbody fusion. As such, with the exponential growth of bioengineering, a large variety of cage surface technologies exist. Different combinations of cage component materials and surface modifications have been created to optimize interbody constructs for surgical use.

Muthiah et al. performed a comprehensive review of the literature on titanium and PEEK as medical devices between 1964 and 2021. We searched five major databases, resulting in 4974 records. Articles were screened for inclusion manually by two independent reviewers, resulting in 237 articles included for review.

Interbody devices have rapidly evolved over the last few decades. Biomaterial and biomechanical modifications have allowed for continued design optimization. While titanium has a high osseointegration capacity, it also has a high elastic modulus and is radio-opaque. PEEK, on the other hand, has a lower elastic modulus and is radiolucent, though PEEK has poor osseointegration capacity. Surface modifications, material development advancements, and hybrid material devices have been utilized in search of an optimal spinal implant that maximizes the advantages and minimizes the disadvantages of each interbody material ¹⁾.