What Is Adjacent Segment Disease & How Does It Occur?

by Oct 19, 2017

Spinal fusion has a bad name for a good reason.

Actually there’s more than one reason, but this statistic gets to the heart of the matter: Within 15 years of having a fusion, there’s a 40% chance you’ll need additional surgery due to the rapid degeneration of the adjacent spine segments—what’s called adjacent segment disease (European Spine Journal, 2016).

Some would say this statistic is conservative, and I tend to agree. But my own experience bears out the original numbers: Three out of nine fusion patients who visited my office on the same day recently require a second surgery due to adjacent segment disease; all three were operated on less than five years ago.

But let’s back up. What exactly is adjacent segment disease? First, let’s define the condition and explain in detail how it’s connected to fusion.

What is adjacent segment disease?

To understand adjacent segment disease (sometimes referred to as adjacent segment degeneration or adjacent segment syndrome), you first need to understand what happens during spinal fusion. During a fusion surgery, a surgeon removes a vertebral motion segment from your spine—made up of a disc and its accompanying facet joints—in its entirety, and fills in the gap with bone graft, rods, and spacers. The newly-inserted material fuses with the vertebrae above and below to make one solid mass of bone. Spinal fusions are used to treat back pain and/or restore stability to the spine, which may have been lost in an attempt to address any number of back issues, such as leg pain from spinal stenosis.

But even if the procedure temporarily relieves back and leg pain, there are long-term consequences to removing a joint from your spine.

Looking for an alternative to fusion? Find out about an innovative new procedure that’s healthier for your spine. 

The absence of a vertebrae—and more specifically, the joint—changes the environment in which your spine operates. By stiffening a segment where there once was a joint, you create abnormal loads for the spine segments above and below the fusion. (Sometimes the effects are felt two segments away.) Those abnormal loads add stress to the nearby facet joints and discs and make them work harder, and as a result, they rapidly start to weaken, resulting in adjacent segment disease. All that wear and tear causes thickening of the spinal ligaments, which could lead to spinal stenosis; or, a disc may wear out in an effort to manage the extra load, which could lead to spondylolisthesis or a herniated disc.

If you’ve had a previous fusion, adjacent segment disease symptoms are likely quite similar to those that led up to your surgery: back pain, pain that radiates down your legs, and difficulty standing and walking.

Adjacent Segment Disease Treatment

In the early stages—before the disc has broken down or nerves become pinched—conservative treatments can help ease the pain. Physical therapy exercises, injections, anti-inflammatory medications, and modification of activities will all address the symptoms, but won’t stop the progression of the disease.

As time goes by, the more severe problems mentioned above, like spinal stenosis or a herniated disc, will likely occur, and another fusion surgery may become necessary.

An Alternative To Fusion For Adjacent Segment Disease

The best way to protect all segments of the spine is to avoid fusion altogether.

Years of data from cervical spine procedures show the importance of retaining motion in the joints: Just like lumbar fusions, patients who had fusion in the neck also had a 40% chance of needing a second surgery within 15 years due to adjacent segment degeneration. Over time, artificial disc replacement became more common (it’s a procedure that leaves the joints intact). We now know that patients who had artificial disc replacement were four times less likely to need additional surgery due to adjacent segment degeneration as opposed to a fusion (Statistics from the Journal of Neurosurgery: Spine, 2017.) The same theory applies to adjacent segment disease after lumbar fusion. And in new research published just this month, we are learning that slump sitting (sitting with bad posture, like many of us do all day long) is even more damaging after a spine fusion than we previously thought, simply because the spine can’t balance (from Hey and co-authors, Spine, 2017).

In the past, there were no alternatives to lumbar fusion for most patients, but there is one today—BalancedBack Total Joint Replacement. BalancedBack addresses the same root causes of back and leg pain as a fusion, but with one important difference: Rather than removing a joint, the BalancedBack implant replaces the function of both the damaged disc as well as the facets. Similar to a hip or knee replacement, BalancedBack allows you to keep moving like you naturally would, placing no additional mechanical stress on adjacent levels of your spine. Eliminating these added stresses decreases the risk of adjacent segment degeneration—as well as the risk of needing additional surgery to address the disease.

Do you want to know more about how you can stop the fusion cycle with BalancedBack Total Joint Replacement?

Learn how this advanced form of artificial disc technology works to address back and leg pain. Start your research today to make a more informed decision before you undergo another fusion.

About 3Spine

3Spine is a new kind of healthcare company that vertically integrates the development, clinical research, and delivery of novel healthcare technology.  The BalancedBack Total Joint Replacement is the technology platform developed by 3Spine as an alternative to fusion for the lumbar spine.

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