Learning that you have an annular tear can be, understandably, a traumatic, worrisome, and stressful occasion. At the same time, however, it can provide relief to some patients to find the true cause behind their symptoms, especially those who have endured chronic pain and discomfort and what may have seemed like a never-ending quest to receive a diagnosis. Because of the range of emotions that can follow hearing the words, “you have an annular tear,” many patients have difficulty even listening to what their physician is telling them, let alone comprehending all of the information that is being presented.
Whether you’re confused about your newly diagnosed condition, concerned about treating your symptoms, or worried about your prognosis, learning as much as you can about annular tears is the first step and may provide some peace of mind.
Anatomy of the Spine and Annular Tears
In order to most clearly comprehend what an annular tear is and how it is affecting you, it may prove beneficial to first have a basic understanding of what intervertebral discs are and what they are made of. Simply stated, the intervertebral discs act as shock absorbers, helping to diminish the strain and pressure that is placed on the neck and back. Without intervertebral discs, the bone structures that house the spinal cord (called the vertebrae) would grind against one another, causing excruciating pain and discomfort. Discs serve to separate and cushion articulating vertebrae, facilitate the movement of the spine, and enable the neck and back to bear weight.
The structure of an intervertebral disc can be compared to that of a jelly donut in that an exterior shell encases a gelatinous center. This shell is called the annulus fibrosus and the jellylike center is called the nucleus pulposus. Each of these components plays an important role in fulfilling the discs’ responsibilities:
· Annulus fibrosus – Primarily made of cartilage, collagen, and other fibrous materials, the annulus fibrosus is both tough and pliable. This outer shell is responsible for containing the nucleus pulposus, which requires a great deal of strength and durability to corral. The annulus fibrosus is comprised of between 15 and 25 layers of collagen, called lamellae. As you may have already guessed, an annular tear occurs in this portion of a disc.
· Nucleus pulposus – The gelatinous center of a disc, called the nucleus pulposus, is primarily made of water and collagen fibers. When weight or impact is placed on the neck or back, the nuclei pulposi are responsible for ensuring the pressure is evenly distributed throughout the discs. To make this possible, and to allow the discs to “bounce” back into shape following impact, the nucleus pulposus is highly pressurized and very tightly contained within the annulus fibrosus. When a tear develops in the annulus fibrosus, the pressure within the nucleus pulposus can force it out from its shell and into the spinal column. This is referred to as a herniated disc.
The intervertebral discs are obviously most directly affected by an annular tear, but the condition can interfere with other spinal components as well. Perhaps the component that can suffer the most from an annular tear is the central nervous system, namely the spinal cord, spinal nerves, and the nerve roots. Interference with these spinal nerves, which travel through the spinal column, can cause a great deal of discomfort in wide-ranging parts of the body.
The nervous system is particularly affected by herniated discs, which result when the nucleus pulposus seeps through an annular tear and into the spinal column. When this extruded inner disc material makes contact with a spinal nerve or the spinal cord itself, symptoms can radiate to other areas of the body. The annulus fibrosus also contains several nerves that can cause localized pain in the event of an annular tear. Specific symptoms of an annular tear will be discussed at length later on, but it is important to note that symptoms can be experienced at the site of the condition, or elsewhere in the body as in the case of a herniated disc.
Types & Causes of Annular Tears
Though any rupture in the annulus fibrosus is called an “annular tear,” there are actually several different types of annular tears that can occur. In very broad terms, the different types of annular tears can have different causes and may result in a range of symptoms of varying severity.
· Transverse tear– Also called a rim lesion or peripheral tear, this type of annular tear occurs in the outermost lamellae and is most commonly caused by traumatic injury. Discs that have a rim lesion are at risk for developing more severe annular tears that penetrate further into the disc.
· Concentric tear – Also called circumferential tears, this tear occurs between the layers of collagen that comprise the annulus fibrosus, and is sometimes easier to think of as a “split” between two lamellae. Concentric tears almost never occur in the inner-third of the annulus fibrosus and are commonly caused by traumatic injury, particularly those that involve a twisting motion of the neck or back, such as swinging a baseball bat or golf club.
· Radial tear – Also called radial fissures, these types of tears originate in the innermost lamellae and travel to the very outermost portion of the disc. In some cases, the nucleus pulposus remains contained despite the deeply-rooted rupture, while in others, the nucleus pulposus escapes and enters into the spinal column. Radial tears are most commonly caused by the natural aging process and the degenerative changes that occur within the intervertebral discs.
So how are annular tears caused? In short, degenerative changes to the spinal anatomy are the most common causes of annular tears. This is largely due to the fact that every individual who reaches and exceeds middle age is subject to the effects of the natural aging process. Over the years, many of the spine’s components can begin to break down from the weight and pressure that has continually been applied to them and from the countless movements they have been tasked with supporting. Gradually, the intervertebral discs’ annuli fibrosi can become weak and brittle and the nuclei pulposi can loser water content and become less adept at “bouncing” back into shape and evenly distributing pressure. These degenerative changes can create the perfect environment for annular tears, making this condition especially common among older individuals.
Risk Factors
While annular tears that are caused by traumatic injury cannot necessarily be prevented, some of those that result from certain degenerative changes can. The leading cause of disc deterioration is the natural aging process, which is, obviously, unavoidable. However, other risk factors that contribute to the degenerative changes that occur within the spine can be avoided, including:
· Obesity – Being overweight forces the spine to work in overdrive. The intervertebral discs are especially affected since they are tasked with absorbing impact and supporting body weight. The intervertebral discs of an obese individual are taxed at greater levels than those that support the weight of a healthy individual, sometimes leading to premature or exacerbated degeneration.
· Immobility – Leading a sedentary lifestyle can prove detrimental to spinal health, not only in obese individuals, but in those who fall into a healthy weight category as well. Remaining largely immobile can lead to the weakening of the muscles and ligaments that support the neck and back. Over time, these tissues can atrophy, making them unable to provide the spine with the support it requires. When an inactive individual does tax their spine with facilitating movement or supporting weight, excess pressure is placed on the vertebrae and intervertebral discs because of the lack of support from the muscles in the neck and back.
· Alcohol abuse or tobacco use – Both of these unhealthy habits can interfere with the intervertebral discs’ ability to properly absorb nutrients, making them more prone to injury and deterioration. In the case of tobacco products, nicotine, carbon dioxide, and a plethora of other chemicals can prove harmful. The exact effects that alcohol abuse has on the intervertebral discs are not entirely known or understood, but it is thought that excessive alcohol consumption can contribute to the dehydration of both the annuli fibrosi and the nuclei pulposi. Malnourished or dehydrated discs are unable to properly support the spine, eventually contributing to the degenerative changes that can occur.
· Physically demanding jobs or activities – Occupations that require repeated mechanical movements, such as bending, lifting, and twisting, can significantly contribute to spinal deterioration. The physical demands these jobs place on the neck and back can cause the intervertebral discs to deteriorate at a faster rate and can contribute to the development of an annular tear. Taking part in physically demanding activities can have similar effects on the intervertebral discs, especially participating in high-impact sports, such as football or gymnastics.
The cervical spine in the neck and the lumbar spine in the lower back are most commonly affected by the degenerative changes that can be accelerated as a result of these risk factors. These are the most mobile portions of the spine and are also responsible for supporting the greatest amounts of weight (the skull, in the case of the cervical spine, and the upper body, in the case of the lumbar spine). The thoracic spine in the middle back is relatively more stable and receives additional support from the rib cage, making it less susceptible to disc deterioration.
Annular Tear Symptoms
As previously stated, patients’ symptoms can vary depending on which type of annular tear has developed. Transverse, concentric, and radial tears that affect the outer third of the disc’s lamellae can all cause what is called discogenic pain. This symptom occurs when the nerve fibers located in the outer lamellae are disrupted by the annular tear, and typically presents as a constant ache. Activities that increase the pressure within a disc (such as sneezing, sitting, or tilting the head) can exacerbate discogenic pain while activities that reduce pressure (like lying down) may provide relief.
Annular tears that affect the inner lamellae, namely radial tears, can cause both discogenic pain and radiculopathy, which is pain that travels along the length of a nerve. Radiculopathy is typically caused by the extrusion of the nucleus pulposus into the spinal canal, which is where the spinal nerves and nerve roots are located. In addition to pain, radiculopathy can also include numbness, tingling, and muscle weakness.
While the mere presence of the nucleus pulposus in the nerve-filled spinal column is certainly enough to cause neural compression, the problem is made even worse by a chemical found within the inner disc material called phospholipase A2 (PLA-2). This enzyme causes an inflammatory response, leading to further irritation of the spinal nerves and what is called chemical radiculopathy, which also causes pain, numbness, tingling, and muscle weakness. The location of these symptoms is dependent on which region of the spine contains the affected disc.
Neural compression in the cervical spine can cause symptoms to travel along the length of the affected nerve and into the following areas:
· Neck
· Upper back
· Shoulders
· Arms
· Hands
· Fingers
The following areas can be affected by neural compression within the lumbar spine:
· Lower back
· Hips
· Buttocks
· Legs
· Feet
· Toes
Disc herniation in the lumbar spine can often cause compression of the sciatic nerve, leading to a set of radiculopathic symptoms that are collectively referred to as sciatica. Sciatica typically affects only one side of the body, though it is not unheard of for patients to experience sciatica bilaterally. In addition to the basic radiculopathic symptoms, sciatica can also include sharp pain that shoots down the side of the leg, difficulty sitting, walking, or standing, and increased discomfort when leaning backward, coughing, laughing, or sneezing.
At AOMSI diagnostics, we provide the most accurate spinal imaging available in the healthcare marketplace. This imaging has been proven in peer-reviewed medical journals to be the most accurate, reliable and specific spinal imaging when compared to traditional spinal imaging modalities.
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