arthritis causes painful inflammation in the spine. Over time, it may make your vertebrae -- the small bones of the spine -- fuse together. It can also inflame other joints, like hips and knees, and it can damage your eyes, heart, and other organs. There's no cure, but treatment and taking care of yourself can often slow it down or prevent it from getting worse

Ref: https://www.webmd.com/ankylosing-spondylitis/ss/slideshow-ankylosing-spondylitis-overview