The Long-Term Risk of Spinal Fusion
The purpose of a spinal fusion is to stop movement. A one-level fusion removes the disc between two vertebrae and uses screws and other hardware to force the two vertebrae together, which then fuse into one structure. A two-level fuses three vertebrae, three-level fuses four vertebrae, and so on. So is it really that big of a deal if we lose movement and flexibility in a few vertebrae?
Yes, it’s a big deal, and the risks are long-term. Let me explain.
The Spine Structure
The spine consists of a column of stacked bones called vertebrae, and the column stretches from the neck all the way down to the tailbone. There are five segments: cervical (7 bones), thoracic (12 bones), lumbar (5 bones), sacrum (5 fused bones), and coccyx (the 4 fused bones that make up the tailbone). Their purpose is to provide structure for the body and to protect the big bundle of nerves that threads through the middle of the column called the spinal cord. Between each vertebra, we have intervertebral discs, which cushion the vertebrae as we move and absorb shock.
While the terminology spinal column likely brings to mind a stick-straight structure, the spinal column is not straight. It actually has gentle snake-like curves to the front and back that provide counterbalance and aid with movement, balance, and shock absorption. In short, the spinal column is made for flexibility and movement.Get a Second Opinion on Your MRI or X-ray and Avoid Unnecessary Surgery
Fusion Can Cause Adjacent Segment Disease
A fusion forces the adjacent vertebral segments (those above and below the fusion) to take on the extra stress and become overloaded with additional work they were never intended to do. When this occurs, this is called adjacent segment disease (ASD), and it may be accompanied by pain, bone spurs, arthritis, and so on. As it advances you are likely to start hearing your doctor throw out the F word again—another fusion. And next thing you know, you’re chasing your ASD up or down your spine. So, yes, one fusion is one fusion too many. And if you’ve already had one fusion, this doesn’t mean you have to say yes to another one. In fact, the long-term fusion risk is that it will just create bigger and bigger problems down the road. See the video below for visuals and more information on ASD.
The Long-Term Risk Of Spinal Fusion
A 2018 study investigated the occurrence of adjacent segment disease (ASD) following short lumbar fusion surgery. Specifically, how often does ASD following fusion result in additional fusions? The study defines “short fusion” as three or fewer fused levels. Researchers followed 479 subjects after short fusions. A total of 37 subjects (7.7%) underwent surgeries for ASD that developed after their initial fusion surgery.
The study found that subjects whose initial fusion included three segments were 2.7 times more likely to undergo ASD fusion surgery than those with one or two fused segments. So the more lumbar levels you have fused, the more likely you are to need additional fusions. Additionally, subjects with rheumatoid arthritis fared even worse, with a 4.5 times greater risk of more fusions.
Adjacent segment disease aside, long-term fusion risk includes many additional important issues, including:
- Indicators such as pain, quality of life, and disability have been shown to be no better with a fusion than they are with conservative approaches alone.
- Physical therapy (PT) was shown to be just as effective at relieving pain and function as a back fusion.
- Two- and five-year post-surgery outcomes were no better for patients with fusions than for those who only underwent a laminectomy (decompression).
Fusing a spine to treat pain is NEVER a good thing and should be avoided at all costs. As a patient, please be smarter and get multiple opinions from both spine surgeons and non-surgeons who don’t know each other. Know ALL your options.