Ankylosing spondylitis still be progressive even though after suffering 20 years?

Yes: With time there can less activity - what we call burned out as. With time symptoms can be related to the damage from ankylosing spondylitis. The as needs to be evaluated regarding the amount of activity vs the mechanical damage effects. There are laboratory studies, examination techniques and imaging techniques such as MRI that help tract the inflammatory activity. Also treatments vary.

Yes: Though the full form of ankylosing spondylitis tends to be less painful (since the spine fuses itself), it is not normal. Minor trauma can break it, and it tends to be unstable, often injuring the spinal cord. If if fuses in a deformed position, this risk goes up. It some cases the deformity (kyphosis) will increase through microscopic fractures caused by gravity and poor bone quality.