What Are Cages and Why Is Your Surgeon Putting One in Your Spine?

Your surgeon may recommend a spine fusion surgery to stop the motion of a painful segment in your spine by fusing 2 vertebrae together.

Conditions that may be treated with a spine fusion include:

Herniated Disc Video
A spine fusion may help ease symptoms of a herniated disc.
Herniated Disc Video

Often, the spinal fusion procedure includes using a cage as a space holder between your vertebrae. This cage will become a part of your spine forever, so it’s important to understand what it is and why it’s there.

Cages 101

Spine fusions are unique among all surgical procedures because they are the only type of surgery in which the goal is to hold 2 bones apart while encouraging them to grow back together.

Watch: ALIF (Anterior Lumbar Interbody Fusion) Video

Watch: Posterior Lumbar Interbody Fusion (PLIF) Video

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The bones being held apart and fused together are the 2 vertebrae at the affected level.

A cage is placed in the inter-body space and packed with bone graft to help stimulate bone growth. It restores the height of the spine and stabilizes the vertebrae as they fuse together.

See Bone Graft Options for Spine Fusion

See Autograft: The Patient's Own Bone

In a successful fusion, the bone grows around and through the cage over time, making it the only place in the body where a material is implanted and active in the reparative process. In other words, the cage and the material it is made out of play an active role in the growth of the bone that forms the fusion.

A successful fusion surgery will lead to a solid bony bridge between the vertebrae. Read more: Anterior Lumbar Interbody Fusion (ALIF) Surgery.

Unfortunately, failed back fusion surgery syndrome may occur if the bony fusion fails to grow.

See Failed Back Surgery Syndrome (FBSS): What It Is and How to Avoid Pain after Surgery

Recently, new studies have shown that the material used in the cage may affect the successful growth of the bony fusion.

Titanium cages with a nanotechnology surface favor factors that are associated with an anti-inflammatory response and the formation of bone.

As a patient, it’s important for you to talk to your surgeon about what types of materials he or she plans to use in your spine fusion surgery. Educate yourself on the types of medical devices your surgeon plans to use, and take the time to research them. After all, it’s your spine and your life—don’t be afraid to ask questions.

Learn more:

Elements of a Spine Fusion

Postoperative Care for Spinal Fusion Surgery


Olivares-Navarrete, R., Hyzy, S.L., Slosar, P.J., Schneider, J.M., Schwartz, Z., and Boyan, B.D. (2015). Implant materials generate different peri-implant inflammatory factors: PEEK promotes fibrosis and micro-textured titanium promotes osteogenic factors. Spine, Volume 40, Issue 6, 399–404.

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