If you have degenerative disc disease that is still causing neck or lower back pain even after medical treatments, you are probably considering your surgical options. While you only need to choose between two types of degenerative disc disease surgery—spinal fusion surgery or artificial disc replacement surgery—your choice is extremely important to your long-term health and happiness. In this article, we describe both types of degenerative disc disease surgery so that you can make the best choice between anterior cervical discectomy and fusion vs artificial disc replacement.
When we are young, the tough and rubbery discs between spinal bones act as a shock absorber for the spine. They also act as spacers, allowing the nerve roots and nerves to pass through natural spaces and holes in the spinal column. Intervertebral discs also allow the column of spinal bones to move somewhat independently, in effect, allowing the neck or back to bend, flex, and twist.
Unfortunately, spinal discs tend to break down as we age, and can be made worse by injuries or diseases. When this breakdown causes symptoms, it is called degenerative disc disease. In short, degenerative disc disease is neck or back pain caused by degenerating spinal disc.
While degenerative disc disease can theoretically occur in any intervertebral disc, it usually occurs at one or more discs in the neck or lower back. The 7 spinal bones at the top of the spinal column make up the cervical spine. Each spinal bone (i.e., vertebra) is named C1 to C7, from top to bottom. C1 is located at the bottom of the skull, while C7 is just above the top of the rib cage. As you might have guessed, the cervical spine is what allows the neck to move in all the ways that it does. Most people with cervical degenerative disc disease have disc disease at the spinal disc between C5 and C6 spinal bones; however, cervical degenerative disc disease can occur at any disc in the cervical spine, from the disc below C2 to the disc below C7.
Cervical degenerative disc disease causes symptoms in the neck and sometimes in the arms. At some point, the wear-and-tear of aging affects in one or more discs in the cervical spine prevents the neck from moving freely and painlessly. Consequently, people with cervical degenerative disc disease often experience neck stiffness or pain, and many people develop pain in the shoulder blades. The pain often occurs when the neck is held in one position for a long time. If the cervical degenerative disc disease pinches a nerve or nerve root in the cervical spine, it may send pain shooting down an arm. Cervical degenerative disc disease symptoms, also known as cervical discogenic pain, are a significant cause of discomfort and disability.
Just as the cervical spine stops at the top of the rib cage (and the thoracic spine begins), the lumbar spine starts at the bottom of the rib cage (where the thoracic spine ends). The 5 vertebral bones in the lumbar spine, L1 through L5, are much larger than the vertebral bones in the cervical spine. This makes sense when you consider how much more body weight they have to support compared to the spinal bones in the neck. These relatively large lumber vertebrae need hearty and resilient discs to support weight, absorb shock, and provide flexibility. In lumbar degenerative disc disease, one or more of the intervertebral discs in the lumbar spine breaks down and causes symptoms. Lumbar degenerative disc disease most commonly occurs in the disc between L4 and L5 spinal bones but can occur at any place between L1 and S1 (the top of the sacrum).
Lumbar degenerative disc disease mainly causes symptoms in the lower back, in and around the lumbar spine. Early in lumbar degenerative disc disease, lower back pain may simply feel like a dull ache. Occasionally the achy lower back pain may spread to the buttock, groin or upper leg. As lumbar degenerative disc disease progresses, patients experience back pain flare-ups. Unlike the dull, constant, achy lower back pain that normally occurs in early lumbar degenerative disc disease, flare-up pain is sharp, sudden, and severe. Like cervical pain, lumbar degenerative disc disease symptoms occur when the person maintains the same position for a long time. Likewise, lower back pain and stiffness tend to subside once the person moves. That being said, a flare-up may occur out of the blue or can be brought on by bending the lower back. Without effective treatment for lumbar degenerative disc disease, lower back pain worsens and flare-ups tend to occur more often.
Most people with degenerative disc disease receive non-surgical treatments first. Unless there is some emergent need for spine surgery (e.g., cauda equina syndrome), conservative, non-surgical neck and lower back pain treatments are first-line therapies. Non-surgical treatments for degenerative disc disease include heat and/or ice, pain medications such as ibuprofen or naproxen, physical therapy, manual manipulation, massage therapy, and steroid injections in and around the degenerated disc. Fortunately, conservative, non-surgical treatments help most people with neck or lower back pain achieve symptom relief. When conservative treatments fail, however, spine surgery is usually the only effective solution.
If degenerative disc disease causes truly uncontrollable pain that cannot be treated with conservative treatments, spine surgery is indicated. In short, the diseased disc needs to be removed surgically, i.e., a discectomy, to stop the symptoms of degenerative disc disease. The two solutions for uncontrollable pain are spinal fusion surgery or artificial disc replacement. In both surgeries, the diseased disc is completely removed (discectomy), which relieves neck or lower back pain. However, the second part of each surgery and their long-term effects are quite different.
Spinal fusion surgery, the diseased disc is removed, leaving a space between the vertebral discs, one above and one below. This space cannot remain as it is, so the two spinal bones are fused together. The spinal bones can be fused with hardware, bone grafts, artificial bone material or some combination of these. The vertebral bones do not fuse immediately—they have to “heal” or “knit” over time, somewhat like broken leg bones held near each other in a cast eventually fuse together. Once the bones have solidly fused, the spine in that area is quite rigid and supports the weight or the head or body above it. On the other hand, the fused spinal bones cannot move relative to one another, so overall movement of the spine is reduced. In cervical spinal fusion surgery, this means the head is supported, but the neck may not be as flexible as it once was. In lumbar spinal fusion surgery, it is the lower back that cannot bend and flex like it once did, but the fusion can support the weight of the body.
In artificial disc replacement, as in spinal fusion surgery, the diseased disc is removed, temporarily leaving a space between the vertebral discs. However, instead of fusing the bones together, in artificial disc replacement the surgeon inserts an artificial disc into that open space. Much like the natural disc, the artificial disc acts as a shock absorber, a spacer, and allows the vertebral bones above and below to move rather freely relative to one another. Healing is a bit faster after artificial disc replacement than it is after spinal fusion surgery because no bones have to “knit” together. Increased freedom of motion between the affected spinal bones means greater range of motion in the neck (cervical spine) or lower back (lumbar spine).
Choosing which degenerative disc disease surgery is right for you is an extremely important decision that should involve your spine surgeon, your loved ones, and probably a bit of research. Understand not everyone is a candidate for artificial disc replacement. People with osteoporosis, certain forms of cancer, or other diseases of the bone, for example, are only candidates for spinal fusion surgery—artificial disc replacement may not be an option. That said, people who are eligible for either type of spinal surgery should closely compare artificial disc replacement vs. spinal fusion.
Spinal fusion has been around for longer than artificial disc replacement has, all spine surgeons can perform the spinal fusion surgery, and spinal fusion provides good pain relief. On the other hand, spinal fusion surgery recovery takes a relatively long time, in some cases the bones do not fuse successfully, and when they do fuse, spinal motion and flexibility may be limited.
Artificial disc replacement has only been available for about a quarter of a century, not all spine surgeons routinely perform artificial disc replacement, and the devices may need to be replaced after 70 years. On the other hand, recovery times are relatively fast with artificial disc replacement, artificial disc replacement relieves neck and lower back pain to the same extent as spinal fusion surgery, and artificial disc replacement restores considerable strength, mobility and flexibility to the cervical or lumbar spines.