Lower Back Pain Causes
What is lower back pain? Lower back pain may be described as a pain that is felt around the lower third of the back and at the top of the pelvis, towards the posterior side of the body. The physical discomfort felt in this region of the body may be described as persistent, sharp, sudden, or dull. The pain may be restricted to this area of the body, or it may radiate away and down the legs. Radiating pain is known as radiculopathy, and usually involves the compression of the spinal nerves due to arthritic changes in the soft tissues in and around the spine.
Lower back pain causes include a lumbar herniated disc, spinal stenosis, arthritis, osteolyelitis (spinal infection), spinal tumors, spondylolisthesis, and vertebral fractures. Here we will discuss these back conditions as well as other factors that may lead to reduced mobility and pain in your back.
Lumbar herniated disc: A lumbar disc is an intervertebral disc in the lumbar spine that separated the vertebral bodies. These discs are named according to the vertebral bodies that they are located between. For example the L4-L5 disc is labeled so because it is located between the 4th and 5th lumbar vertebrae.
Together, the outer and inner portions of the disc are somewhat malleable, allowing for some cushioning effect in the spine which protects the joints and vertebrae. The outer portion of the disc, known as the annulus fibrosis is tough and durable, like the crisscrossing fibers of a radial tire. The inner part of the disc, known as the nucleus-pulposus is more gel like and gives the disc its flexibility. Though the disc is built for flexibility, it is designed to retain its general shape so that it does not impinge on the structures around it - especially the spinal nerves.
Due aging, injury, and other factors, the wall of the annulus fibrosis may become weak and vulnerable to tears. When the annulus fibrosis breaks or tears open, its wall will bulge outwards, possibly affecting the structures around it. In addition, the gel material in the nucleus may spill through this break in the wall. If these changes occur in one of the lumbar discs, the condition may be known as a lumbar herniated disc.
These changes to the disc may be related to a sudden traumatic injury, though it is more likely that the degenerative changes occurred over a period of months or years. There are 4 changes to this degenerative process:
What causes a lumbar herniated disc? There are several lifestyle habits and decisions that a person makes throughout a long life that may predispose them to a lumbar disc herniation. Let's take a look at the two factors that we have the most control over:
- Disc degeneration: Chemical changes related to the aging process may reduce the volume of material in the nucleus or the number of layers of dense fibrous materials that compose its outer layer.
- Prolapse: The disc may become weak at one point in its outer wall, allowing the material in its nucleus press into it and cause the wall to bulge outwards. This condition may be known as a protruding disc or a bulging disc. Even if the outer wall is not broken completely, it may cause the same pathology as a herniated disc if the section of the disc protruding outwards impinges on the spinal canal and/or the spinal nerves.
- Extrusion: The third step of the herniation is when the disc wall completely breaks and the gel material in the nucleus spills through this cavity but remains within the disc.
- Sequestration or Sequestered Disc: In this final part of the herniation, the gel material of the nucleus pulposus goes all the way through the cavity and outside of the intervertebral disc.
- Poor posture: Our posture has a profound effect on the amount of stress we place on these spinal joints. Poor posture puts added weight on the discs that they were not designed to bear over a long time period.
- Lifestyle factors: a poor diet, lack of nutrition, muscle weakness, lack of regular exercise, and tobacco use greatly enhance a person's risk of degenerative disc disease and back pain.