Discogenic Back Pain: A Common Problem in the Community

Lower back (or lumbar) pain is one of the most common sources of discomfort and disability. There are many causes of lower back pain including spinal muscle pain, spinal nerve pain, narrowing of the spinal canal (spinal stenosis), spine arthritis (facet degeneration and sacroiliac joint dysfunction), infection and tumors. There are also a number of non-spine related causes of low back pain, such as gallstones, pancreatitis, renal stones, or even aortic dissection. However, one of the most common, but rarely understood types of back pain is called discogenic back pain. This refers to lower back pain caused by problems with an intervertebral disc, such as injury or degeneration. Intervertebral discs lie between adjacent vertebrae in the spine, forming a cartilaginous joint to allow slight movement of the vertebrae while also acting as ligaments that hold the vertebrae together. If an injury occurs to one of these discs, it can result in serious discogenic back pain.

Symptoms of discogenic back pain

Problems with spinal discs usually cause pain in the lower back and/or buttock. The pain is usually sharp and closely related to changes in posture, commonly worse when getting out of a chair or bending forward. Occasionally, the pain is associated with numbness in the legs, but without a loss of strength or sensation. For young adults, the most common cause of discogenic back pain is injury through sports or lifting heavy objects. Elderly patients can develop discogenic back pain even without an injury because of natural wear-and-tear (degeneration) of the lumbar discs. Because lumbar discs are made of cells that have no ability to self-heal or regenerate, the pain they contribute to overall back pain experienced may never completely subside. Any back pain lasting more than six months is deemed chronic back pain. Chronic back pain involving discs that can not self-heal means it will increase if not treated, as the disc deteriorates over time. At later stages, if not treated properly, neurological complications such as nerve compression become more likely.

How is discogenic back pain diagnosed?

Discogenic back pain can be difficult to diagnose. Besides reviewing a patient’s history, a physical examination and an x-ray or magnetic resonance imaging (MRI) are often used. We can spot the abnormalities that would explain the lower back pain 95% of the time. A spinal injection test – called a discogram – can also be used to confirm which disc is generating the pain. There are other injection tests – such as facet joint block, sacroiliac joint block, trigger point injection and nerve root injection – that help identify or clarify causes of discogenic pain.

Treatment strategies

After confirming the primary source of the back pain, treatment is relatively straightforward.

For patients who have only suffered from back pain for a short period of time, we recommend painkillers, anti-inflammatory drugs, physical therapy, bracing, alternative therapies and lifestyle modifications. This is known as “first-line treatment.” However, if discogenic back pain patients fail to respond to first-line treatments, they are normally encouraged to seek surgical options.

There are several strategies for surgical treatment. Epidural steroid injections involve inserting a fine needle into the spine from the back with x-ray guidance. Local anesthetics combined with long-acting corticosteroids are then injected onto the disc’s surface. Alternatively, radiofrequency intra-discal therapy, (also known as biaculoplasty), adopts a similar approach to spinal injections, except that two probes are positioned on both the left and right sides of the disc under fluoroscopic guidance. A radiofrequency is passed through the probes into the posterior annulus, (the disc’s fibrous outer ring), creating an increase in temperature that builds up to between 45-60 degrees Celsius. This can relieve pain for weeks to months.

Lumbar spine fusion is often considered the ultimate procedure of last resort for discogenic back pain. It is usually required when the above treatments fail to relieve the pain. Spinal fusion is a surgical procedure performed under general anesthesia that aims to directly connect two vertebrae. With the advance of modern surgical capabilities and technologies, this surgery has become commonplace. It is conducted in a minimally invasive way. The disc will be replaced by a plastic cage packed with artificial bone graft. Stabilization is achieved with screws locking the back side of the spine. The risks related to spinal fusion are usually very small, and a patient’s normal length of stay in the hospital is around five days. In most cases, six months after lumbar spine fusion surgery, the back should function normally.

References:

Baldwin, N.G.; “Lumbar Disc Disease: The Natural History”; Neurosurgery Focus, 2002. 13(2): p. E2.

Buenaventura, R.M., et al; “Systematic Review of Discography as a Diagnostic Test for Spinal Pain: An Update”; Pain Physician, 2007. 10(1): p. 147-64.

Kapural, L., J.P. Cata, and S. Narouze; “Successful Treatment of Lumbar Discogenic Pain Using Intradiscal Biacuplasty in Previously Discectomized Disc”; Pain Practice, 2009. 9(2): p. 130-4.

Poh, S.Y., et al; “Two-year Outcomes of Transforaminal Lumbar Interbody Fusion”; J Orthop Surg (Hong Kong), 2011. 19(2): p. 135-40.

Waterman, B.R., P.J. Belmont, Jr., and A.J. Schoenfeld; “Low Back Pain in the United States: Incidence and Risk Factors for Presentation in the Emergency Setting”; Spine J, 2012. 12(1): p. 63-70.