Complications of Ankylosing Spondylitis: What Is Spinal Fusion?

Doctors often refer to spinal fusion as “bamboo spine.”

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Early on with ankylosing spondylitis, or AS, you might think you can tolerate the symptoms. Some back pain and stiffness is certainly uncomfortable and inconvenient, but you can find ways to cope. The problem is, AS is a progressive condition. Without treatment, your AS can progress to a serious complication: spinal fusion, or ankylosis.

“Spinal fusion is when parts of the spine fuse together and become immobile,” says Anca D. Askanase, MD, MPH, rheumatologist at Columbia University Irving Medical Center. “That could involve parts of the spine, or it can involve the whole spine. Traditionally, it's described as the bamboo spine.”

Imagine a bamboo stalk. Whereas a traditional spine has several pieces (vertebrae) that allow the spine to curve and bend, a bamboo stalk is one rigid stick. When AS progresses, inflammation and damage to the spine causes the vertebrae to fuse together, becoming immobile and rigid like a bamboo stalk.

What Makes Ankylosis So Destructive

There are two major problems with spinal fusion: its effect on your quality of life, and its effect on the physical health of your body.

Spinal fusion affects quality of life by severely limiting mobility. This can be even worse if the spine fuses in an unnatural, hunched-over position. As a result, simple things like eating or getting dressed can be particularly challenging.

Furthermore, spinal fusion can compromise the health of the rest of your body. “If there's kyphosis, which is the bent-over position, the internal organs become squished a little bit,” says Dr. Askanase. “The breathing capacity is diminished, the heart function is impaired, the organs are affected, and that's the time when a surgical intervention may be in order.”

Treating Spinal Fusion

It’s easier to prevent ankylosis than it is to treat it. Unfortunately, once fusion occurs, the only option to correct it is with surgery.

“Spine surgery is not simple surgery. They are complicated, complex, long surgeries, whose outcomes are not always as perfect as we'd like them to be,” says Dr. Askanase. “They are attempts at maintaining function, [but] there's nothing better for any organ or any part of the body than keeping the one that we had started with functional.”

Getting an early diagnosis for AS and sticking to medications and lifestyle modifications should prevent spinal fusion for most people. Learn more here about medication options to treat AS.

“With our better understanding of the disease, with our better understanding of the treatment options, both lifestyle and medication options, the risk of spinal fusion is much lower than ever before,” says Dr. Askanase.