Extruded Disc

Extruded Disc
By Tarun Jolly, MD, Ryan Cooper

Low back pain is a common problem in the United States; it has been estimated 65-80% of individuals will experience some type of back pain during their lives, and 28% of the population will experience disabling back pain1. Some 2% of all low back pain cases will be due to a condition known as a herniated disc2. A herniated disc refers to a problem with an inter-vertebral disc, whose function is to cushion the individual bones (vertebrae) that comprise the spine, and allow motion between these vertebrae4. These discs are cartilaginous structures with a gelatinous center (the nucleus pulposus) and a thick, fibrous capsule (the annulus fibrosus).

Some herniated discs are specifically said to be extruded; disc extrusion, like herniation, occurs when the nucleus pulposus pushes out through a weakening or tear in the annulus fibrosus5. More specifically, extrusion means that some part of the inter-vertebral disc has displaced outside the borders of its joint, or disc space, in such a way that the displaced nucleus has characteristically ballooned outward from a small tear in the annulus3. Sometimes displaced disc material can be disconnected from the disc itself, and said to be sequestered3. Causes can be due to age, degeneration and/or trauma. Risk factors for extrusion are the same as those for disc herniation, including: being male, middle-older age, having a congenital spinal defect, and partaking in strenuous physical activity such as bending, lifting and twisting5.

The most common location of disc extrusion is the lumbar spine, or lower back5. Many patients with an extruded disc will experience pain when the disc herniation compresses a nearby nerve root, in a condition termed a radiculopathy4. A lumbar radiculopathy will often cause mild to severe pain, as well as numbness and/or weakness in some circumstances, in the lower back and leg. The pain might range from a stabbing or pulsing sensation to a dull ache, and is most often asymmetric, occurring on just one side of the body5. The pain can progressively worsen at night and after long periods of standing or sitting. Sometimes a radiculopathy can also cause bowel/bladder incontinence which may be the sign of a more serious condition known as Cauda Equina syndrome; a surgical emergency6.

Most episodes of low back pain will resolve in 6 weeks or less, but some persistent cases may require medical intervention.
An extruded disc can be diagnosed by a doctor based on a history, a physical exam and diagnostic imaging tests. Of various diagnostic imaging tests, a doctor may obtain6, 7:

  • Plain film X-Rays to rule out other possible causes of pain, such as a tumor or fracture
  • A Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) scan, with or without contrast, to directly visualize the soft tissue of inter-vertebral disc s and compressed nerves
  • Nerve conduction studies if there is difficulty isolating the affected nerve roots
  • Discography, or direct imaging of the disc itself, can be performed by injecting contrast material into a disc or vein and performing a CT/MRI scan to visualize problems and directly assess pain

A doctor will generally begin treating low back pain with conservative methods prior to ordering any imaging tests since most patients will see improvement within weeks6. Diagnostic tests may be ordered when pain is refractory to conservative options and persists beyond 6 weeks.

Most patients with an extruded disc will not require surgery; one study suggested that as many as 95% of patients with lumbar herniation enjoyed full recovery in a few weeks5. These patients generally improve with basic conservative treatments:

  • Physical therapy, the backbone of conservative pain management for herniated discs, is often beneficial and includes strengthening exercises, spinal manipulation, hot/cold therapy, ultrasound therapy, brace support, traction and more8
  • Lifestyle changes; balanced diet and moderate exercise can eliminate strain induced by excess weight or obesity5
  • Over the counter non-steroidal anti-inflammatory medications (NSAIDS) such as aspirin, ibuprofen (Advil™) or naproxen (Aleve™) can be used for management of mild pain5
  • For the short term management of more severe pain, narcotic medications such as codeine can be prescribed5
  • Epidural steroid injections have been shown to directly reduce inflammation associated with disc herniation (and thus nerve root compression) yielding some benefit for pain9.

For those patients with pain unresponsive to conservative treatment, surgery may be indicated when pain persists5. Surgical intervention may take the form of a discectomy or fusion7. In a discectomy, a surgeon gains access to the damaged disc material via incision or a variety of more minimally invasive devices, such as endoscopes, and removes displaced material to relieve compression. Adjacent vertebrae may be fused together if the surgeon believes a risk of recurrence to be high. There are many new treatments under investigation, such as artificial discs and more minimally invasive techniques. Louisiana Pain Specialists can assist patients in identifying the best individual treatment options. After any invasive treatment, it will take some time before patients are able to resume normal activities. Patients should avoid any aggravating activities to prevent recurrence5.

In many cases, extrusions can be prevented via proper weight management and diet, regular exercise promoting maintenance of strong, flexible muscles such as walking and swimming, and by practicing good posture and proper lifting techniques5.

References

  1. Manchikanti, L. (2000). Epidemiology of Low Back Pain. Pain Physician. Vol 3(2): p. 167-192.
  2. Deyo, R.A.; et al. (1992). What can the history and physical examination tell us about low back pain? JAMA. Vol 268(6): p. 760-5.
  3. Fardon, D.; Milette, P. (2001). 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.
  4. Hsu, P.; et al. (2011). Lumbosacral radiculopathy: Pathophysiology, clinical features and diagnosis. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA.
  5. Nidus Information Services. (2010). Herniated Disk. Patient Handouts page. MD Consult Web site, Core Collection. Retrieved from www.mdconsult.com.ezproxy2.library.arizona.edu/das/patient/body/234155712-5
  6. Wheeler, S.; et al. (2010). Approach to the diagnosis and evaluation of low back pain in adults. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA.
  7. Rihn, J.; et al. (2010). Herniated intervertebral disc. First Consult, MD Consult Web site. Retrieved from www.mdconsult.com.ezproxy2.library.arizona.edu/das/pdxmd/body/234418695-2
  8. Chou, R.; et al. (2007). Nonpharmacologic therapies for acute and chronic low back pain: a review of the evidence for an American Pain Society/American College of Physicians clinical practice guideline. Ann Intern Med. Vol 147(7): p. 492-504.
  9. Legrand, E., et al. (2007). Sciatica from disk herniation: Medical treatment or surgery? Joint Bone Spine. Vol 74(6): p. 530-5.