Adjacent Segment Disease
Causes, Symptoms, and Treatment
Failed back surgery syndrome, or FBSS, refers to any pain that occurs after recovering from back or neck pain surgery. In many cases, the pain is directly related to the initial problem. For example, if a patient underwent a laminectomy for a compressed nerve, and the nerve remains compressed even after surgery, the pain will remain.
But not all FBSS pain is that simple. In some cases, even a successful or semi-successful surgery can still result in the development of pain. One such example is known as “Adjacent Segment Disease,” or “ASD,” and it’s a common problem that affects both men and women that undergo spinal fusion.
As many as 3% of patients with cervical spinal fusion and 9% of patients with lumbar spinal fusion may experience ASD in the first year or two after surgery, and that number may increase to 25% within 5 to 10 years. If you believe you have ASD and would like to talk to us about possible treatments, please call us today at 404-620-5523.
Define: Adjacent Segment Disease
Like failed back surgery syndrome, “adjacent segment disease” has a broad definition. Adjacent segment disease is a term that encompasses all of the complications of fusing the spine together via spinal fusion surgery.
The easiest way to understand spinal fusion is to focus on how the spine works. The spine’s job is to protect the spinal cord (the nerves that send information to the body), and also to help the body move. The spine is made up of 33 bones, known as “vertebrae.” In between most of those vertebrae is a gelatinous disc made of collagen fibers, gel, cartilage, and other cells.
The job of the disc is hold the vertebrae together and allow for the spine to move without putting pressure on the spinal cord. But many issues, such as aging (which dehydrates the discs), injury, and other diseases can cause the discs to become thinner, stiffer, or damaged. This causes:
- Bones to rub together.
- Inflammation at or near the spinal column.
- Weakening of the bone sin the spine, and more.
All of this leads to the development of chronic back pain.
The surgery used to treat this type of pain is known as spinal fusion. With spinal fusion, the surgeon uses bone grafts and inserts (“hardware”) to hold the spine together. The bone graft then starts to fuse the two vertebrae together, turning them into one piece of bone instead of two. As one piece of bone, they cannot run together, chip, herniate, or otherwise hurt the spinal column.
Which brings us to Adjacent Segment Disease.
Spinal fusion is an effective way to reduce pain in the neck, back, and legs. But the spine is not necessarily designed to have vertebrae fuse together. After spinal fusion surgery, the adjacent segments of the spine often experience and increased stress load, due to issues such as:
- Change in Posture
- Reduced Movement
- Less Support
Spinal fusion also may use hardware such as pedicle screws, grafts, and cages that may all put additional stress on the surrounding vertebrae and discs. These issues may occur anywhere on the spine or after any type of fusion, including cervical and lumbar.
For some patients, that additional demand on the adjacent discs and bones is simply too much for them to handle. They will then experience a variety of problems, including:
- Compression Fracture
- Spondylolisthesis (Vertebral Slippage)
- Adjacent Disc Degeneration, and More
Usually these occur slowly over time (although some may occur all at once), and when they do they bring more chronic pain, discomfort, and trouble with mobility.
This is why it is called “Adjacent Segment Disease.”
Although it is not technically a disease at all, patients that struggle with new or worsening pain after back surgery as a result of the effects of spinal fusion on other areas of the spine are usually diagnosed with ASD.
Causes and Risk Factors for Adjacent Segment Disease
Adjacent segment disease can happen to anyone that undergoes spinal fusion. But there are specific risk factors that indicate that some patients may be more likely to experience adjacent segment disease than others. These include:
- Location and Type of Surgery – Not all segments of the spine are at great risk for adjacent segment disease. Although almost 80% of surgeons use posterior spinal fusion, anterior cervical and lumbar fusion were at far less risk for adjacent segment disease, which is why we almost exclusively perform anterior fusions here at Spine Center Atlanta. In addition, surgery at C5–C6 and/or C6–C7 of the spine were less likely to experience ASD than other sections.
- Disc and Facet Degeneration – Patient candidates screening is critical for avoiding ASD, and unfortunately many surgeons do not necessarily screen patients for adjacent disc degeneration. If the patient has adjacent discs that also show early signs of degenerative disc disease, spinal fusion may speed up the degree of degeneration. The same is true of facet (joint) degeneration, especially in lumbar spinal fusion (as opposed to cervical spinal fusion).
- Age and Bone Health – Aging is associated with weakened discs and DDD, which in turn means that the patient is at greater risk for ASD. Similarly, patients with weak bones, such as post-menopausal women and those with osteoporosis, may be more likely to experience additional degeneration or fractures.
These are only a few of the risk factors, and in some cases the risk factors may be unknown. Some of these risks for ASD can also be screened out prior to surgery, but not all surgeons perform such a screening.
While there are risks for adjacent segment disease, the causes are still up for debate. Although researchers have a rough idea of what causes ASD (change in posture, reduced range of motion, etc.), they are not entirely sure why some patients experience adjacent segment disease while other patients with a similar risk profile do not.
The most likely causes supported in the research are just that – increased stress on adjacent disc space, and spondylosis (degenerative disc disease) due to aging. But there may be other causes as well, including:
- Misalignment – Post-operative misalignment is a very common cause of spinal fusion failure and ASD, as it adds additional stress on the adjacent discs. Misalignment may be due to healing, or to surgical error.
- Antidepressant Use – There is some evidence that regular use of antidepressants may be a contributing factor in the development of adjacent segment disease, but the reason is currently unclear. It may not specifically be antidepressants, but rather the way depression enhances feelings of pain.
- Missing Decompression – Not all surgeons use decompression techniques on the spine when performing spinal fusion. Yet patients that did not undergo any decompression procedures were more likely to have developed ASD.
Often the cause of adjacent segment disease can be diagnosed, which is why it is important to see a specialist in failed back surgery syndrome and ASD. Spine Center Atlanta is a nationally recognized revision and FBSS spinal center, and Dr. Chappuis and his team are happy to take on your case and try to diagnose the cause of your agent segment disease.
Symptoms of Adjacent Segment Disease
It is theoretically possible to experience problems with the adjacent segments without experiencing pain. If there is no pain, then it is usually not yet considered to be adjacent segment disease. Instead, it may be referred to as “Adjacent Segment Degeneration.”
Adjacent segment disease, on the other hand, is when the degeneration or damage causes pain. Thus pain after spinal fusion on or near the adjacent segments of the spine is the primary symptom of ASD.
Adjacent segment disease is a type of failed back surgery syndrome, or FBSS, which refers to any issue that causes pain to develop after spine surgery on the neck or back. While only diagnostic tools can determine whether or not your FBSS is ASD, there are some signs that you likely have adjacent segment disease, rather than some other type of back surgery:
- Slow Over Time – ASD tends to occur slowly over time as the discs and vertebrae start to degenerate or become damaged. Other forms of FBSS may occur during or right after recovery.
- Different Pain or Location – Although pain may be experienced in the same location with ASD, there is a good chance that the pain with ASD will differ in some way. This is because the adjacent segment disease means that the issues developed in a different area of the spine than the area addressed in surgery.
- Radiculopathy and Nerve/Spine Symptoms – Different injuries mean different symptoms. You may also experience pain and sensations that you did not experience before, such as tingling, shooting paints, numbness, weakness, and more.
The pain itself may be different than you experienced in the past. The exact symptoms of adjacent segment disease are directly related to the area of injury.
Diagnosis of Adjacent Segment Disease
Adjacent segment disease tends to be easier to diagnose than other types of FBSS, because the degeneration is usually apparent with common diagnostic tools. Diagnosis may include:
- CT Scan
- Diagnostic Injections
- Surgical Consultation
Generally, the orthopedic specialist will look at your risk factors, the time it has been since your spinal fusion surgery, and the clinical presentation of the symptoms. All of these help determine whether or not adjacent segment disease is likely.
Treatment for Adjacent Segment Disease
Treatment for adjacent segment disease is possible, and the results are often very positive. Although the risk factors associated with ASD may still be present after any other type of procedure, there are some techniques that may be effective, including:
- Neural Decompression – Laminectomy (neural decompression) has been shown to be an effective way to decrease pain associated with ASD. Some forms of decompression can also be performed as a minimally invasive procedure, which means fewer complications and scarring.
- Additional Fusion – For select candidates, additional spinal fusion may be worthwhile. It depends largely on which discs are degenerating. In some cases, an additional spinal fusion may be enough to fix the problem. However, due to the risk factors, this is not recommended for all patients.
- Arthroplasty – Disc replacement surgery may also be a consideration. There are now many effective disc replacement hardware devices that can effectively relieve some of the pain associated with ASD.
Every case should also be reviewed individually, to determine the degree of degeneration, the possible causes and risk factors that led to the ASD, and more. Only by diagnosing the issue can a treatment be recommended.
Led by Dr. James Chappuis, Spine Center Atlanta has become the leading source for failed back surgery syndrome treatments, including adjacent segment disease. Led by nationally renowned orthopedic surgeons, Spine Center Atlanta sees clients from both the local Atlanta area and across the United States, and can assist you in determining ASD treatment.
For more information, or to book an appointment, please call us today at 404-351-5812.