Annular Tear

By Tarun Jolly, MD, Ryan Cooper

Back pain is the second most common medical complaint in the United States; low back pain has been estimated to effect as many as 84% of adults1. This pain can come from a variety of causes including: the tearing of an intervertebral disc, or an annular/disc tear, from traumatic injury, or age-related degeneration2. These tears usually occur in the lumbar spine and result in lower back pain, however they are not limited to this region; tears can occur in the thoracic and cervical spine creating pain in the upper back, neck and upper extremities3.

Intervertebral discs separate and cushion the individual bones, or vertebrae, that comprise the spine4. These discs are compressible structures consisting of a gelatinous center (the nucleus pulposus) contained within a thick, fibrous capsule (the annulus fibrosus), which supports the weight of the upper body and creates joints which give the spine flexibility and allow for back motion5.

Annular tears occur in the layers of the fibrous outer capsule allowing the nucleus pulposus to leak out fibrosus. When this occurs, the weakened integrity of the disc can allow for bulges to form which can impinge upon nearby nerves causing pain4. If the outer capsule is torn completely, a disc herniation has occurred which can also impinge nearby nerves and cause pain2. Any impingement of nerve roots around the spinal cord in this fashion is known as a radiculopathy4. In some cases this impingement can even cause numbness over affected skin and/or weakness in affected muscle groups. Pain from a torn disc can vary from a sharp stabbing to a dull ache and generally affects only one side of the body4.

Annular tears can begin to accumulate as early as adolescence and are often asymptomatic; one study estimates that as many as 20% of teenagers show some sign of degeneration with imaging5. With growth and stress, degeneration peaks sometime during middle age. Risk factors for degeneration and tears include:

  • Age1, 5 – the nucleus pulposus dehydrates with time and shrinks, altering the balance of the disc and creating risk for tears
  • Strain/strenuous work1 – placing excessive loads on an intervertebral disc via heavy lifting or awkward bending or twisting can increase the risk of tearing
  • Smoking1
  • Obesity1 – increased weight places extra stress on the discs, increasing risk of tearing
  • Psychological factors1 – conditions such as depression and anxiety can lead to somatization disorders in which pain is experienced with no apparent physical cause

Many of these risk factors can be prevented or avoided.

Diagnosis and Treatment

Diagnosing an annular tear begins with a visit to a doctor; a proper history and physical exam for back pain may indicate the need for diagnostic testing when conservative home treatment proves ineffective and pain persists for several weeks1, 6. Typically an X-Ray is ordered first to rule out other possible causes of pain, such as a clear fracture. A computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan may also be ordered to directly visualize nerve root compression and/or a tear itself, which often shows up as a high intensity signal distinct from other parts of a disc1, 5, 6. It may also be necessary to inject a contrast material directly into the disc before performing a CT/MRI to better visualize the disc and determine the exact cause of pain. This procedure is termed discography, and is the gold standard in disc tear detection. Finally, if there is difficulty determining the nerve roots responsible for the pain, nerve conduction studies can be done1, 6.

Once an annular tear has been identified, it can be categorized as one of the following7:

  • Grade 1, normal: a clear boundary exists between the annulus fibrosus and the nucleus pulposus
  • Grade 2, moderate degeneration: the separation of the annulus fibrosus and nucleus pulposus becomes less well-defined, with clefts of nucleus forming into the fibrosus
  • Grade 3, severe degeneration: the boundary between the annulus fibrosus and nucleus pulposus has all but disappeared with major clefts reaching the outer borders of the fibrosus

Extensive diagnostic efforts are often unnecessary as most patients will improve with conservative treatment measures before ever requiring a scan1. Over-the-counter anti-inflammatory/pain relief medications such as aspirin, ibuprofen (Advil™) or naproxen (Aleve™) are often the first choice of therapy for long-term swelling and pain management8. However, some patients may experience more severe pain during the natural healing process and may require short-term prescription pain relief in the form of narcotics or other opiate medications. When a radiculopathy results from a disc tear, significant compression can occur from swelling, which is the body’s natural response to injured tissue; thus steroid injections can be considered to reduce inflammation for longer periods of time9. Physical therapy can also be prescribed to help strengthen affected muscles and joints to improve stability and reduce pain, and acupuncture has been shown to help with pain management as well8.

While most patients will respond to these conservative treatments, some will experience persistent pain that may require surgical intervention10. The most common surgical intervention, and the gold standard treatment for disc tears and herniations, is the open discectomy. In this procedure, portions of the damaged disc can be removed to reduce pressure on the nerve roots and thus alleviate pain. Advances in technology and understanding of disc tears have also allowed for the development of more minimally invasive surgical techniques as well10. Much smaller incisions can be made allowing access for a variety of devices used to relieve compression of nerve roots. Examples include thermal devices which can heat/freeze disc material, lasers and radio waves which can obliterate disc material, or other manual methods such as suction which can be used to decompress a disc and/or seal a tear5.

Louisiana pain specialists are trained to assist patients in managing back pain, and can assist patients in finding appropriate therapy.

Patients and doctors alike should always be on the lookout for certain alarm symptoms if disc damage is suspected. A damaged lumbar disc can compress a certain group of nerve roots called the Cauda Equina, leading to impotence, incontinence (urinary or bowel) and numbness under the groin. This condition requires immediate surgical intervention to prevent long-term damage1.

Given the prevalence of back pain, new approaches to the treatment of annular tears and related disc disorders are currently under investigation. Studies of glucosamine and chondroitin supplementation are showing a potential for benefit, as are implantations and replacements of entire intervertebral discs; however, research remains limited to date5.

References

1 Wheeler, S.; et al. Approach to the diagnosis and evaluation of low back pain in adults. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2010.

2 Fardon, D.; Milette, P. Nomenclature and Classification of Lumbar Disc Pathology: Recommendations of the Combined Task Forces of the North American Spine Society, American Society of Spine Radiology, and American Society of Neuroradiology. Spine. Vol 26, E93-E113. 2001.

3 Rihn, J.; et al. Herniated intervertebral disc. First Consult, MD Consult www.mdconsult.com.ezproxy2.library.arizona.edu. Posted July 29, 2010. Accessed April 10, 2011.

4 Hsu, P.; et al. Lumbosacral radiculopathy: Pathophysiology, clinical features and diagnosis. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.

5 Raj, P. Intervertebral Disc: Anatomy-Physiology-Pathophysiology-Treatment. Pain Practice. Vol 8, 18-44. 2008.

6 Steiger, T.; et al. Diagnostic testing for low back pain. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.

7 Osti, O; et al. Annular Tears and Disc Degeneration in the Lumbar Spine. The Journal of Bone and Joint Surgery. Vol 74, 678-682. 1992.

8 Chou, R. Subacute and chronic low back pain: pharmacologic and noninterventional treatment. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2010.

9 Chou, R. Subacute and chronic low back pain: nonsurgical interventional treatment. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2009.

10 Chou, R. Subacute and chronic low back pain: surgical treatment. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2010.