Lumbar Spinal Stenosis (Central Stenosis) Overview
There are five vertebral bodies that make up the lumbar spine better known as the lower back. Nerves exiting off of the spinal cord (at the lower thoracic spine as the spinal cord ends at the upper lumbar spine) travel through the central canal. The central canal is made up of individual rings from each vertebra stacked one on top of the other. The nerves exit one at a time through the sides of these vertebral bodies. Over time, as wear and tear and other degenerative conditions, such as disc degeneration and facet arthritis, take their toll on the lower spine, these rings that make up the central canal will begin to narrow. If the narrowing is substantial, it causes nerve compression of the spine of the sac of nerves (cauda equina) which will lead to lumbar central stenosis or lumbar spinal stenosis.
Stenosis of the lumbar spine (and central stenosis), next to the herniated disc, is one of the most common conditions of the spine that is experienced over time—especially by those who are over 50 years of age with females having the majority of problems. The most common cause of lumbar stenosis is degenerative changes of the spine. The most common problem associated with stenosis is degenerative spondylolysthesis (please see section on that subject in this web site).
Lumbar spinal stenosis can also be linked to other conditions such as tumors, infections of the spine, metabolic bone disorders and other known diseases but these are exceedingly rare.
Symptoms of Lumbar Spinal Stenosis
The narrowing of the spinal canal can occasionally cause lower back pain but that is the exception rather than the rule. When someone complains of lower back pain, one might hear them refer to sciatica or their sciatic nerve (pain that radiates from the lower back and buttocks). Lower back pain from the sciatic nerve (pain in the buttocks) oftentimes is actually stenosis. The most common complaints of lumbar spinal stenosis (central stenosis) are a dull ache or “numbness” in the sacroiliac region of the spine and buttocks with prolonged standing or walking that increases with the amount of time doing that activity. Sciatica and sacroiliac syndrome symptoms will start to extend down the back of the legs with prolonged standing or walking. A general weakness or fatigue of the legs and loss of sensation can also occur (also side effects of sciatic nerve pain).
In most cases, standing and bending backwards worsens the symptoms whereas sitting or leaning forward helps to relieve them. As the individual bends forward or crouches, the space within the spinal canal increases and relieves the pressure on the sac of nerves. Generally, symptoms associated with lumbar central stenosis and stenosis of the spinal canal typically worsen over time but many times, they don’t advance at all. Occasionally, they can improve over time even without physical therapy exercises for the spine.