Understanding Low Back Pain (Lumbago)

The underlying causes of low back pain (sometimes referred to as lumbago) can be complex and are not always readily apparent. This article is aimed at helping patients understand how physicians evaluate the area of pain distribution in helping to diagnose the source of a patient’s low back pain and determine initial treatment options.

90% of people afflicted by low back pain will recover completely within about six weeks. For the 10% of patients who do not recover within a few weeks, low back pain can be a painful, prolonged, costly and frustrating experience.

Before discussing the specific types of low back pain, it is important to understand a few important principles.

• Pain does not always equate to tissue damage. The severity of pain from low back problems is often unrelated to the extent of physical damage present. For example, a simple pulled muscle in the low back can cause excruciating pain that can limit one’s ability to walk or even stand, whereas a even a large herniated disc can be completely painless.
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• Diagnosis is often difficult. There are many anatomical structures in the low back that can cause severe lower back pain and/or pain that radiates into the legs and/or feet. These include:
  • Soft tissues, such as muscles, ligaments and tendons
  • Bones, which provide the structural building blocks of the spinal column
  • Facet joints, which allow the spine move
  • Discs (the outer rim of the disc, the annulus, can be a source of significant low back pain due to its rich nerve supply and tendency towards getting damaged)
  • Nerves, which branch out from the spinal cord in the low back and innervate the legs and feet

All of the above structures are interwoven to make up the structure of the spine. During embryological development there is a great deal of overlap of nerve supply to all of these structures making it nearly impossible for the brain to distinguish between problems with one structure versus another. For example, a torn or herniated disc can feel identical to a bruised muscle or torn ligament.

• Diagnostic accuracy is important. Getting an accurate diagnosis as to the underlying cause of one’s pain is important. For example, it’s not enough to know that one has sciatica – it is also important to determine the underlying cause of the sciatica, such as a herniated disc or spinal stenosis, in order to determine the best treatment options.
• Low back pain is a personal experience. Unlike many other medical conditions, the experience of low back pain is not the same for everyone. For example, two people can have the exact same condition but for one it is incapacitating and for the other it is a mere nuisance. In fact, for most people a spinal abnormality (such as a degenerated disc that can be seen on an MRI scan) is painless. Other factors - both physical and psychological - often contribute to a person’s experience of low back pain.

This article reviews three classifications of low back pain based on the area of pain distribution, or where the pain is felt (e.g. confined to the low back or radiating down the leg). The three classifications are:

• Axial low back pain (also called simple or mechanical low back pain)
• Low back pain with referred pain
• Low back pain with radicular pain (also called sciatica)

• Article written By:
• Ari BenYishay, MD

December 13, 2005

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