We are concerned with the type associated with degenerative arthritis. In concert with this, since the disk is no longer doing its job, the joints deteriorate with added weight resulting in bone spurs. Eventually, these work in such a fashion to create a narrowing of the canal. It looks a lot like an hourglass. What happens is, once the narrowing reaches a critical level of compression of the nerves, these nerves then suffer from the lack of blood to allow them to function normally.
Decompression is the treatment of choice.
It makes more room for the nerves and the tiny blood vessels. I had a titanium horseshoe implanted to replace a bad disk. This is a disk replacement device, which results in a spinal fusion. Once this device is inserted, bone is placed in it and this knits the vertebrae so that it will stay that way forever. Nothing to worry about.