Ankylosing spondylitis (AS) is a progressive systemic chronic inflammatory rheumatic disease that causes arthritis of spine and sacroiliac joints and finally results in contracture or bony fusion of these joints. The ankylosed spine has increased propensity to fracture due to rigidity. long lever arms. and osteoporosis. https://balboasurfandsstylers.shop/product-category/waist-bags/