Dear friends, besides using screws for fixation in lumbar fusion surgery, why is a “spacer” placed between two vertebrae? That is a What exactly is it, and what does it do? These are questions that is frequently asked.
Today, let’s talk about this “spacer” — the lumbar interbody fusion cage, commonly known as a Cage.
This small device plays a vital role in spinal surgery, helping many patients with lumbar spine conditions relieve pain and regain their daily activities. Next, let’s uncover the mystery of the lumbar interbody fusion cage.
A cage fusion, commonly referred to as a cage, is an implant used in spinal surgery. Its main function is to be placed between two lumbar vertebrae during surgery, helping the two vertebrae fuse together, thereby increasing the stability of the lumbar spine and relieving pain.
Main Functions of the Spinal Fusion Cage
Restore intervertebral space height: The fusion cage can restore or maintain the normal height of the intervertebral space, which helps preserve the function of the intervertebral disc and the normal anatomical relationship between adjacent vertebrae.
Provide stability: The spinal cage can deliver stability, prevent abnormal motion of the intervertebral disc, and thereby relieve symptoms and reduce stress on the spine.
Promote bone fusion: The lumbar fusion cage is typically made of biocompatible materials that can integrate with the surrounding bone tissue, helping to facilitate bone fusion so that the implant in the intervertebral space unites with adjacent vertebral bodies into one solid unit.
Stimulate bone healing: By placing the implant within the intervertebral space, the spinal lumbar cage creates a controlled bone injury. This injury triggers a biological response in the body, leading to bone cell proliferation and new bone formation.
Types of Spine Fusion Cages
Meta Cage: Usually made of titanium alloy, with excellent biocompatibility and mechanical strength.
Carbon Fiber Cage: Lighter than metal cages, helping to reduce pressure on the surrounding bone.
PEEK (Polyetheretherketone) Cage: A polymeric material with an elastic modulus similar to human bone, which helps reduce the stress-shielding effect.
Bioabsorbable Cage: This type of cage is eventually absorbed by the human body, reducing long-term foreign body reactions.
Some well-informed patients also ask: If we use autologous bone graft, why do we still need an spine cage Implant (Cage)?
Provide immediate stability: One of the main functions of the spinal fusion cage is to offer anterior and middle column support and improve intervertebral stability. Even with autologous bone graft, the cage provides immediate structural support for the surgical area, reduces abnormal motion between vertebrae, and relieves pain.
Promote bone fusion: The interbody fusion cage facilitates bone fusion. Although autologous bone has excellent osteoinductive and osteoconductive properties, the cage better maintains the height and position of the intervertebral space, creating an ideal environment for bone fusion.
Reduce the amount of bone graft needed: Using an interbody fusion cage reduces the required volume of autologous bone graft. Autologous bone harvesting may cause additional pain and complication risks, and the cage decreases dependence on autologous bone.
Improve fusion rate: Studies have shown that interbody autologous bone graft combined with cage and pedicle screw-rod fixation improves interbody fusion rates. Especially at 3 and 6 months postoperatively, the fusion rate in the autologous bone group is higher than that in the allogeneic bone group.
Improve surgical outcomes: The use of an interbody fusion cage improves surgical outcomes, shortens operative time, reduces intraoperative blood loss, accelerates postoperative functional recovery, and has high safety.
Adapt to different intervertebral space morphologies: Different intervertebral space shapes can affect cage stability. For example, a pear shaped intervertebral space is a risk factor for posterior cage migration into the spinal canal. Therefore, selecting an appropriate cage size and ensuring good contact with the endplates are extremely important.
Reduce complications: The use of an interbody fusion cage helps reduce surgery-related complications such as cage displacement. Choosing the right cage and ensuring its stability can lower these risks.
In summary, even with autologous bone grafting, the use of an interbody fusion cage (Cage) remains necessary. It provides immediate stability, promotes bone fusion, reduces the amount of bone graft required, improves fusion rates, enhances surgical outcomes, and decreases complications. Together, these functions make the interbody fusion cage an indispensable component in lumbar fusion surgery.
If you want to learn more about the fusion cage, please feel free to contact us; our team will provide you with the professional support and answers.
Post time: Mar-24-2026