Bulging Disc

By: Tarun Jolly, MD, Ryan Cooper In many individuals, whether due to age-related degeneration or a traumatic tear, a bulge can develop from an intervertebral disc that compresses nearby nerves causing pain; this compression is termed a radiculopathy1. A bulging disc is not necessarily a form of herniation, but rather a simple extension of disc tissue beyond the borders of the intervertebral joint2. Intervertebral discs separate and cushion the individual bones, or vertebrae, that comprise the spine1. The spine itself forms from individual vertebral bones stacked upon one another to surround and protect the spinal cord. Intervertebral discs are composed of a tough, fibrous outer layer called the annulus fibrosus and filled with a soft, gelatinous inner layer called the nucleus pulposus. Intervertebral discs have three major functions:

  1. they connect individual vertebrae to one another
  2. they provide for movement between vertebrae
  3. they absorb weight, or ‘load,’ placed on the spine.

With time, these discs can change in size (volume) and structure that can effect many functions of the disc and increase the risk of bulging11. In the case of a bulge, the disc simply overlaps the boundaries of the vertebrae, most commonly occurring in the lumbar spine (lower back), but can also be seen in the cervical spine (neck) and rarely in the thoracic spine (upper back)2. A bulge compressing nerves in the cervical region will typically cause neck and upper extremity pain, while a bulge compressing nerves in the lumbar region will cause lower back and/or lower extremity pain. Notably, a bulging disc reflects a radiographic finding more so than any specific diagnosis, such as a disc herniation3. While often seen in the presence of annular tears and herniations, a bulge doesn’t imply that any problem exists; in fact, many bulges can be asymptomatic. In the general population, it has been estimated that as many as 52% of individuals have a bulged disc but will report no symptoms4.

Diagnosis and Treatment

Despite the high prevalence of asymptomatic bulging, if a radiculopathy is present as the result of a bulged disc, diagnosis of the pathology causing the bulge is made by a doctor based on a comprehensive history, physical exam, and, in some instances, imaging and other diagnostic studies5, 6. Imaging is usually indicated for severe pain or after 4-6 weeks of conservative therapy has failed to show any improvement in mild symptoms. Imaging is the only manner with which to confirm the presence of a bulged disc; this is typically done via magnetic resonance imaging (MRI) or computed tomography (CT). Imaging allows the visualization of a bulge; however trained doctors are needed to determine the actual cause of the bulge, which is most often a disc herniation or degenerative disc disease. With disc herniation, slow degeneration or acute trauma can cause tears in a disc, weakening the integrity and allowing the nucleus pulposus to penetrate the annulus fibrosus7. The spilling of this fluid into the spinal canal can lead to a radiculopathy. With degenerative disc disease, or spondylosis, non-specific changes and weakening of disc integrity over time and with age allow for structural changes and bulging7. This too can lead to nerve root compression and a radiculopathy. A trained doctor must always rule out the possibility of tumors, infection, fractures and other potential problems as well. Most bulged discs will not require treatment, as many individuals may never experience any symptoms. Treatment is only necessary when a radiculopathy is present. A treatment regimen generally begins with conservative measures, as the majority of cases resolve on their own in less than a month5. One recent study showed complete resolution of pain in up to 80% of patients following conservative therapy for bulged discs of cervical origin8. Examples of conservative treatment include:

  • 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 management9.
  • For patients experiencing more severe pain, short-term prescription pain relief in the form of narcotics or other opiate medications may be appropriate9.
  • Steroid injections can be considered to reduce inflammation for longer periods of time8.
  • 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 management9. Traction, a physical therapy designed to spread the vertebrae apart and expand intervertebral spaces can relieve compression as well8.
  • In some instances, simple avoidance of aggravating physical activity for short periods of time and/or temporary immobilization of an affected area may be of some benefit8.

Surgical treatment is generally avoided, and patients must rely on conservative treatment, until the underlying pathology contributing to the bulging disc has been identified4. Once identified, the underlying pathology can be treated. Open discectomy is the most common, and currently the gold standard, for treating herniations; in this procedure part of the damaged disc is removed to alleviate pain and pressure10. Fusion of adjacent vertebral bones is also sometimes recommended to prevent recurrence of herniations. Surgery is not guaranteed to relieve all pain, and should be delayed until it has been determined that any benefits outweigh the potential risks of spine surgery. Louisiana Pain Specialists can assist patients in developing an optimal treatment plan. In lieu of disc discectomy and fusion, which ultimately reduces mobility, artificial disc replacement surgery is a technique in development for the treatment of radiculopathies8. Because this is an emerging technique, however, few studies exist regarding the long-term outcomes and durability of artificial discs.

References

1 Hsu, P.; et al. Lumbosacral radiculopathy: Pathophysiology, clinical features and diagnosis. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011. 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 Milette, P. The Proper Terminology for Reporting Lumbar Intervertebral Disc Disorders. American Journal of Neuroradiology. Vol 18, 1859-1866. 1997. 4 van Rijn, J.; et al. Observer Variation in MRI Evaluation of Patients Suspected of Lumbar Disk Herniation. American Journal of Roentgenology. Vol 184, 299-303. 2004. 5 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. 6 Steiger, T.; et al. Diagnostic testing for low back pain. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011. 7 Robinson, J.; Kothari, M. Clinical features and diagnosis of cervical radiculopathy. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2010. 8 Robinson, J.; Kothari, M. Treatment of cervical radiculopathy. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2010. 9 Chou, R. Subacute and chronic low back pain: pharmacologic and noninterventional treatment. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2010. 10 North American Spine Society 2009: Lumbar (open) Microscopic Discectomy. Patient Handouts page. Available at www.knowyourback.org/Pages/Treatments/SurgicalOptions/LumbarDiscectomy. Accessed April 15, 2011. 11 Buckwalter, J. A.. Aging and Degeneration of the Human Intervertebral Disc. Spine. Vol 20, 1307-1314. 1995.