It is believed by the doctors that the problem of spondylitis is caused by an antigen known as HLA-B27. The symptoms of this disease can be cured by using any anti- inflammatory, methotrexate, and sulfasalazine and analgesics agents. If your spondylitis problem is very severe then you might have to go for an operation only. Otherwise you can opt for a physiotherapy sessions that involve special exercises to treat your spondylitis including certain medicines.
The exercises that are recommended are basically yoga and Pilates that mobilize the joints and the spine gently. Certain medicines like the Enbrel, though expensive, has been developed lately is considered very effective for its treatment.
The best thing that would be possible is that you try and prevent the development of this disease. For this you need to introduce better and accurate sitting and standing postures for yourself instead of straining it a lot. And keep yourself physically fit and active.