Our Summary

This paper reviews the advancements and challenges in the design of spinal interbody cages (ICs) - tools used in spine surgeries to help bones fuse together. Since the late 1980s, these devices have been used to restore the space between vertebrae, contain bone grafts (transplanted bone tissue), and restore stability to the spine. They have evolved to be more successful than just using bone grafts alone, leading to less pain after surgery, shorter hospital stays, fewer complications, and higher rates of bone fusion.

In the mid-1990s, the design of ICs was typically a threaded titanium-alloy cylinder filled with bone graft. This design was better than bone grafts alone or non-threaded cages, but it had issues with stability and a high chance of the cage sinking into the bone (cage subsidence). Since the early 2000s, a non-threaded box-shaped design made of titanium or a plastic material called polyether ether ketone has become more common. This design is more stable but there are still issues with cage subsidence, fusion rates, and surgical complications that need to be improved.

The paper then discusses recent research on ICs over the past 3 years, focusing on trends in improving cage design, materials, alternatives to bone grafts, and coatings that could enhance bone fusion.

FAQs

  1. What are spinal interbody cages and what purpose do they serve in spine surgeries?
  2. How have the designs of spinal interbody cages evolved since they were first used in the late 1980s?
  3. What are some of the current challenges and areas of research in improving the design and effectiveness of spinal interbody cages?

Doctor’s Tip

A helpful tip a doctor might tell a patient about spinal fusion is to follow post-operative instructions carefully, including proper lifting techniques, avoiding heavy lifting or bending, and attending physical therapy as recommended. It is important to give your body time to heal and follow up with your healthcare provider regularly to monitor progress and address any concerns.

Suitable For

Patients who are typically recommended spinal fusion surgery with the use of interbody cages include those with:

  1. Degenerative disc disease: This condition involves the breakdown of discs in the spine, leading to pain and reduced mobility. Fusion surgery can help stabilize the spine and reduce pain.

  2. Spinal stenosis: This condition involves the narrowing of the spinal canal, which can cause pressure on the spinal cord and nerves. Fusion surgery can help relieve this pressure and improve symptoms.

  3. Spondylolisthesis: This condition involves the slipping of one vertebra over another, which can cause pain and instability in the spine. Fusion surgery can help realign the vertebrae and stabilize the spine.

  4. Herniated discs: When a disc in the spine ruptures or bulges, it can put pressure on nearby nerves, causing pain and other symptoms. Fusion surgery can help stabilize the spine and relieve pressure on the nerves.

  5. Spinal fractures: Fusion surgery may be recommended for patients with spinal fractures that are not healing properly or are causing instability in the spine.

Overall, patients who have not responded to conservative treatments such as physical therapy, medication, or injections may be candidates for spinal fusion surgery with the use of interbody cages. It is important for patients to discuss their specific condition and treatment options with their healthcare provider to determine if spinal fusion is the right choice for them.

Timeline

Before spinal fusion surgery, a patient typically undergoes a series of diagnostic tests such as X-rays, MRI, and CT scans to determine the extent of the spinal condition. They may also undergo physical therapy, pain management, and other conservative treatments to alleviate symptoms. Once surgery is recommended, the patient will meet with a surgeon to discuss the procedure, risks, and recovery process.

During spinal fusion surgery, the surgeon will access the spine through an incision in the back or neck, remove damaged discs or vertebrae, insert the interbody cage filled with bone graft, and secure it in place with screws or plates. The surgery typically takes several hours and the patient will be monitored in the hospital for a few days before being discharged.

After spinal fusion surgery, the patient will begin a rehabilitation program to regain strength, flexibility, and mobility. They may need to wear a brace for a period of time and attend physical therapy sessions to help with recovery. It can take several months for the bones to fully fuse together, and the patient will need to follow post-operative guidelines to prevent complications and ensure a successful outcome.

Overall, the timeline of a patient’s experience before and after spinal fusion surgery involves pre-operative testing and preparation, the surgical procedure itself, and a period of recovery and rehabilitation to achieve optimal outcomes.

What to Ask Your Doctor

Some questions a patient should ask their doctor about spinal fusion and the use of interbody cages include:

  1. What type of interbody cage will be used in my spinal fusion surgery?
  2. How will the interbody cage help with the fusion process?
  3. What materials are used in the interbody cage and why were they chosen?
  4. What are the potential risks and complications associated with the use of interbody cages?
  5. What is the expected success rate of fusion with the specific interbody cage being used?
  6. Are there any alternative options to using interbody cages in my surgery?
  7. How long will the interbody cage need to remain in place after surgery?
  8. How will the interbody cage affect my recovery and rehabilitation process?
  9. Are there any restrictions or limitations I should be aware of after receiving an interbody cage?
  10. What advancements have been made in interbody cage design and materials that could benefit my surgery?

Reference

Authors: Jain S, Eltorai AE, Ruttiman R, Daniels AH. Journal: Orthop Surg. 2016 Aug;8(3):278-84. doi: 10.1111/os.12264. PMID: 27627709