What is it?
Merriam-Webster Dictionary Definition: Any of various degenerative diseases of the spine.
thefreedictionary.com: Degeneration of the spinal column, especially a fusion and immobilization of the vertebral bones.
The term is used by many medical professionals as a synonym for spinal osteoarthritis and more specifically, for spondyloarthropathy. In this article, my aim is to focus on arthritis (arthrosis) involving the zygophyseal joints of the spine. At this point, you are probably asking yourself, "zygo…what?".
Let's go all the way back to the beginning, and start off by defining what ARTHRITIS is. Literally, and most simplistically, inflammation of a anatomic/physiologic joint connecting (articulating) structure. Arthritis itself is a huge subject. There are literally dozens of kinds of arthritis. Many of us are familiar with rheumatoid or autoimmune arthritis and know of family members that suffer from it. This is caused by the joints in your body being attacked by your immune system. Degenerative arthritis, on the other hand, is the result of wear and tear, and sometimes added to by trauma. Degenerative and post traumatic spinal arthritis involving the zygapophyseal joints is the focus of this article. It should be noted that traumatic arthritis is not synonymous in the medical world with degenerative arthritis, even though there is no doubt that both contribute to varying degrees in causing symptoms.
Spondyloarthropathies include many types of autoimmune and genetic subtypes. Fusing or ankylosing of the spine, perhaps the most infamous among them. Ankylosing Spondylitis is the name of this genetic disorder. While many kinds of entities, immune and otherwise, can effect the joints we are discussing, for the sake of brevity this article is limited to the degenerative and traumatic forms that are most commonly encountered.
So you've have an inflamed joint. What does this have to do with the Zygo… thing? The zygapophyseal (alternative spelling zygapophysial) joints, also called apophyseal or facet joints, are the surfaces coming together and articulating the roof (back, dorsal or posterior) sections of each vertebrae. These joints therefore allow for flexibility but also provide stability to the spine. They do so by connecting each vertebrae to adjacent vertebrae above and below at spinal roof's outer edges. This occurs in paired, symmetrical fashion along the entire length of the spine. Exceptions being the connection of the skull and first vertebra, and the first and second vertebrae. Even the sacrum, the large central bone between the rear portion of your pelvic blades, those that you sit on, has these joints. However, they are fused shortly after birth in most individuals. Sitting just below and away from each joint is the articular pillar (pedicle). Coming off of the edge formed by the pillar and upper portion of each joint is a wing shaped structure extending outward called the transverse process. Muscles attach to the transverse process, and not all vertebrae have them. Nearby and partially below the transverse process sits the opening for each nerve root on each side of the spine. These openings are called foramina [Latin for little window]. The zygapophyseal joints form the majority of the roof (dorsal or posterior) surface of this opening as they connect the respective roofs of each vertebrae. The floor (ventral or anterior) aspect of this opening is formed by the upper outer portions of each vertebral body, and by the vertebral discs sandwiched respectively between each vertebral body.
The vertebral disc, when it herniates, can compromise the foramina (little window) as well as the spinal canal. Enlargement of the zygapophyseal joint due to inflammation can do the same from above. Therefore, the nerve root can become impinged as the foramina narrows. This is called foramina stenosis (Greek root meaning narrowing). The same process can occur within the spinal canal, containing the spinal cord. Below lumbar vertebrae number one, the spinal cord ends and nerve roots are found sitting as they drop down and exit the spine. When impingement occurs within this large central canal, it is called spinal stenosis. Both foraminal and spinal stenosis, individually or in combination, can cause serious problems. These include pain, weakness, and when occurring rapidly, loss of sensation and paralysis.
The enlarging zygapophyseal joint can also literally push its upper partner forward (ventrally or anterior). This shifting of one vertebrae above the other in an posterior to anterior or dorsal to ventral direction is called listhesis. This can cause further problems as it alters spinal postural mechanics and also narrows the foraminal opening. Listhesis can also be caused by trauma, birth defects in the spine, and other disorders.
Inflammation of the zygapophyseal joint, caused by damage to or loss of it's internal cartilage and joint edges, is an often overlooked cause of pain. There are many ways to go about treating pain caused by this intra-articular pathology. Diagnosis isn't always clear at the onset as a great deal of back and neck pain ends up recovering with limited or no intervention at all.
When pain in any part of the spine persists for weeks, it is best addressed by a physician. In many cases, physical therapy can be of tremendous benefit. In addition, medications such as ibuprofen and treatment with heat alternating with ice packs can be of great benefit. If the pain continues to persist for months, it's time to involve a physician expert in spinal pain. Imaging studies are likely to be a waste of time as X-rays, CT scans and/or MRIs can readily reveal degenerative pathology having absolutely nothing to do with the cause of pain. That is to say, imaging can reveal arthritis but it can just as easily reveal normal appearing spine. Due to limitations inherent in imaging studies, they may easily miss abnormalities in the zygapophyseal joint that will eventually appear on these same studies, but years later. Tenderness over zygapophyseal joints on physical exam correlates highly with these joints being the source of pain. However, even this is not fool proof. Carefully performed, X-ray guided local anesthetic blockade of the small nerves going to these joints is the gold standard. The term for this kind of nerve block is Median Branch Block. Even this is not perfect, but is far more likely to yield to successful treatment and management of chronic pain that can be caused by these joints. In addition to physical therapy and regular postural muscle strengthening exercises, treatment with a technique deriving from Median Branch Blockade, Radiofrequency neural branch ablation, when indicated can provide substantially longer duration pain reduction. Without some sort of muscle strengthening and maintenance routine, the results of this procedure significantly shorter in duration.
Article by Dr. John Sherry II