The rise in back pain cases has been bringing about the need for alternative treatment options to conventional spinal fusion surgery. One such promising option that has been gaining traction is the artificial disc replacement or artificial disc. Let's take a deeper look into what artificial discs are, how they work as an alternative to fusion, and the latest on their use and efficacy.
What are Artificial Discs?
Explaining the Anatomy
The human spine consists of vertebrae separated by intervertebral discs that act as cushions between the bones. These discs are made of an outer fibrous ring called the annulus fibrosus that surrounds an inner gel-like substance called the nucleus pulposus. As we age or due to injury, these discs can degenerate leading to conditions like herniation or narrowing of the spinal canal causing pain.
Artificial discs are metal and plastic prosthetic implants that are inserted between two vertebrae to replace a damaged disc. They aim to restore the height of the disc space and preserve normal spinal motion. The earliest artificial discs were developed in the 1950s but lacked long-term durability. Modern prosthetics consist of metallic endplates with a plastic or polyethylene central core.
How Do They Work as an Alternative to Fusion?
Spinal fusion involves surgically fusing together two or more vertebrae, usually with bone grafts and hardware like plates and screws, to eliminate motion at the problematic segment and stabilize the spine. While effective for pain relief, fusion removes spinal flexibility which can accelerate degeneration at adjacent levels over time.
Artificial discs, on the other hand, are intended to maintain motion between the vertebrae similar to a healthy natural disc. This helps reduce stress on the facet joints and ligaments while preserving spinal functionality. Proponents argue discs are able to more closely mimic the natural anatomy compared to fusion for relief without sacrificing mobility long-term.
Latest Developments in Artificial Disc Technology
Over the last two decades, Artificial Disc prosthetics have advanced significantly. Third generation devices feature improved materials like cross-linked polyethylene that are more durable compared to earlier silicone and metal-on-metal implants. Insertion methods with smaller incisions and instrumentation have also facilitated less invasive procedures.
With growing clinical experience, disc replacements are now commonly used in the lumbar or lower back region above and below the L4 and L5 vertebrae. Their use in the cervical or neck region is also increasing though procedures there present more technical challenges. Newer generation cervical discs feature modular designs for customized placement. Biologic prosthetics utilizing materials like collagen matrices are also under investigation.
Evidence on Efficacy and Outcomes
Several long-term randomized controlled trials comparing artificial discs versus fusion have demonstrated disc arthroplasty can provide equivalent pain relief with better functional outcomes and range of motion maintenance. Systematic reviews and meta-analyses have also validated discs confer advantages like reduced adjacent segment degeneration rates up to ten years out. However more studies evaluating outcomes beyond 15-20 years are still needed.
Complications like device migration or fracture requiring revision are reported but uncommon. As with any surgical procedure, complications specific to disc replacements include issues like nerve root injury. With proper patient selection and surgical execution by experienced surgeons however, risks are considered low. Ongoing registries are tracking long-term durability and complication data on newer generation implants.
The Future of Artificial Discs
Overall artificial discs are an exciting advance that preserve spinal flexibility. As material science and instrumentation evolves, discs have potential for use in multi-level applications and in both cervical and lumbar regions. Future prospects include biodegradable polymers, stem cell-seeded designs and motion-preserving total disc replacements. Wider insurance coverage amid growing evidence is also likely to increase patient access to discs over fusion. With continued innovation, artificial discs offer promise to reshape treatment algorithms for many spinal disorders traditionally addressed by fusion.
In summary, artificial discs have emerged as a viable alternative to fusion surgery with advantages in functionality and reduced adjacent segment effects demonstrated now up to 15 years out. Improvements in biomechanics, surgical techniques and long-term outcome data collection will further cement discs as standard of care in carefully selected patients needing motion preservation. As technology marches on, discs may help transform spine surgery outcomes for years to come.
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