I was one of the first people in our area to have a disc replacement for a herniated disc that was pressing on my spinal cord. That was five years ago. So far, so good. They did warn me that anything could happen — I could end up with the implant pressing on the cord or another disc going bad above or below the implant. I like to keep up on this technology, should I ever need another one. What’s the latest?

The condition you were treated for is called myelopathy. Myelopathy refers to a narrowing of the spinal canal, the opening formed by the vertebral bodies when stacked on top of one another. The spinal cord travels through the open spinal canal. Anything that narrows this opening (e.g., disc protrusion, bone spurs, hardening of the spinal ligaments) can put pressure on the spinal cord and cause serious neurologic problems.

Myelopathy from disc herniation is the main reason why disc replacements are done. In the early days of this procedure, the type of patients who qualified for the operation was limited to that clinical picture. With new and improved technology, better surgical instruments, and various sizes and styles of implants now available, the patients who can have this procedure has expanded. They are now able to use disc arthroplasty (replacement) in the lumbar spine (low back) and the cervical spine (neck).

The conditions must still be just right for the best results. There can’t be too much degeneration of the vertebral bones or facet (spinal) joints. Osteophytes (bone spurs) can be removed if they are small enough or few in number. But patients with major arthritic changes of this type may not be good candidates for disc replacement.

Surgeons are better informed of the potential pitfalls of disc replacement. They are more tuned in than ever about the importance of proper patient positioning during the surgery, how to prepare the disc space for the implant, and how to insert the implant to get the best placement and function. The surgery is still saved for patients who don’t have too much narrowing of the spinal canal and who have good spinal stability. Without those two criteria, spinal fusion is the procedure of choice.