Axial Spondyloarthritis (SpA) is a kind of inflammatory arthritis which includes ankylosing spondylitis. Common symptoms of axial SpA are inflammatory back pain, morning stiffness, peripheral arthritis, enthesitis. Controlling aforementioned symptoms are one of the goal in treatment, and another goal is preventing bony ankylosis of axial skeleton such as spine. Ankylosis can limit range of motion and lower the quality of life.

Non-steroidal antiinflammatory drug (NSAID) and Tumor necrosis factor (TNF)-a inhibitor are the current treatment options for axial SpA. These medications can improve pain and stiffness of axial SpA patients, however preventing bony ankylosis is not proven. Current study showed attenuating inflammation at early stage could prevent further bony destruction and ankylosis in axial SpA. Present study is designed to discover the therapeutic effect of NSAID whether NSAID could recover the early inflammatory bony change (bone marrow edema at MRI) and prevent further bony change.

Inclusion Criteria:

1. 2009 Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial spondyloarthritis
2. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) > 4
3. definite bone marrow edema on Sacroiliac joint MRI

Exclusion Criteria:

1. Patients who have underling cancer / infectious disease / kidney disease / liver disease / cardiovascular or cerebrovascular disease
2. Patients who is using TNF-a inhibitor
3. Patients with side effects of NSAID
4. Patients with history of peptic ulcer
5. Patients who can't keep NSAID treatment