Annular tears are the cause of all disc problems, including degenerative disc disease, disc herniation, bulging discs, and disc prolapses. Because annular tears are the cause of so many spine issues, it’s important to have a clear understanding of how exactly these tears affect your spine health. If you have back pain that has been difficult to diagnose, learning more about annular tears may even give you some insight into the cause of it.
The Spinal Disc
The annulus fibrosus and the nucleus pulposus form the outer and inner portion of the spinal disc, acting as a sort of cushion between vertebrae and allowing the spine to be flexible. The outer part of the disc, the annulus fibrosus, is made up of type I collagen and is wrapped around the nucleus pulposus in about 15-20 alternating layers, which adds strength to the annulus fibrosus. This part of the disc runs diagonally between the vertebrae and connects each of the vertebrae, and it is where all of the spinal disc’s nerve endings are located. In the center of the spinal disc, the annulus fibrosus meets the nucleus pulposus, and it is the job of the annulus fibrosus to contain this inner, jelly-like portion of the disc.1
Causes of Annular Tears
Annular tears, also known as annular fissures, are caused by a deficiency of one or multiple layers of the annulus fibrosus. The fact that the fibers making up the annulus fibrosus run horizontally is why tearing or separation is common for this part of the spinal disc. It is also common for these tears to happen in the postero-lateral region of the disc, meaning it begins in the back of the disc and runs along its sides. Annular tears may have concentric, transverse, or radial orientations, and tears may occur in only some or all of the layers.
Most of the time, these tears are asymptomatic and don’t cause any pain, but when these tears do have symptoms, they cause either pain localized in the area of the tear, or pain due to irritation of the spinal nerve root. The pain felt may only be felt for a short amount of time if the tear occurs suddenly, or may become chronic if the tear develops slowly over a long period of time.
This explains why tears commonly happen and the way in which they form, but what causes these tears in the first place? One of the main reasons annular tears form is due to age. As we grow older, the annulus fibrosus tears from normal wear and tear of the spine. Traumatic injuries to the back can also cause annular tears. Other risk factors include weight lifting, golf, football, cross-fit training, car accidents, slipping and falling, and lifting heavy objects while bending and twisting, especially when this is done without good form.
Generally, chronic pain from annular tears is a result of granulation tissue or the in-growth of nerve endings, but it can also allow for extrusion of the nucleus pulposus, leading to disc herniation caused by a leaky disc. This is due to the fact that the nucleus pulposus is made up of proteins that the body considers a foreign substance when it leaks out of the spinal disc and comes in contact with surrounding nerves, inflaming or irritating them. This sometimes causes irritation of the sciatic nerve, leading to sciatica.
Other radicular symptoms that can be caused by irritation of nerves include pain, paresthesia, a burning or prickling sensation that is usually felt in the hands, arms, legs, and feet, but can also be felt in other parts of the body, and weakness in certain limbs depending on the extent to which the nerves are irritated.1
How Annular Tears Are Diagnosed and Treated
In asymptomatic patients, annular tears are usually diagnosed during an imaging procedure meant for something else. In the MRI sequence, the annular tear will usually show up as being very bright compared to the rest of the annulus fibrosus, which is usually dark. This is caused by an increase in water content at the site of the annular tear compared to the normal water content of the annulus fibrosus.
If the annular tear is identified as a by-product of MRI for another issue, treatment is most likely not warranted, because it is believed that asymptomatic tears may resolve themselves over time. Although it is hypothesized that asymptomatic annular tears can eventually become symptomatic, there is no definitive evidence to prove that treating asymptomatic annular tears prevents future issues or even benefits present tears.
When annular tears do present symptoms, but there is no herniation or extrusion, the belief is that this pain is caused by inflammation of the annular tear itself or irritation of the nerves surrounding the torn area. In this case, the most common treatment is non-steroidal anti-inflammatory medication to decrease inflammation of the tear and reduce irritation of the surrounding nerves as well. Low-impact physical therapy may also be recommended in this case in order to strengthen core muscles that will help protect the spine in the future and prevent current tears from worsening. Transforaminal steroid injections may also be suggested in order to quickly mollify pain.
In the case that annular tears present symptoms and the disc herniated or extruded, pain is believed to be caused by the nucleus pulposus itself. In this situation, the patient will usually be treated for the disc herniation itself rather than treating the annular tear. Treatment may include more conservative measures such as nonsteroidal anti-inflammatory medications, physical therapy, or injections. If conservative measures fail to improve the patient’s symptoms, or if they worsen, surgical options such as laminotomy, laminectomy, foraminotomy, discectomy, fusion, or a combination of these procedures will most likely be recommended.1
Having a good understanding of the issues that may be affecting your body is one of the most important steps in getting the help you need to treat these issues. There are also many ways to prevent your discs from developing the wear and tear that causes annular tears, and taking these steps to protect your spine will help in the long run, even if you currently don’t have pain from tears.
- Tenny, S., & Gillis, C. C. (2019, November 27). Annular Disc Tear. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK459235/
