What Is Spinal Stenosis?

What Is Spinal Stenosis?

One of the first places to look for an answer to “what is spinal stenosis?” is the dictionary: The word stenosis means a narrowing or constriction of the diameter of a bodily passage or orifice. The definition of spinal stenosis, then, is the narrowing of the passages of the spinal cord and nerves. This condition may occur in the neck (called cervical stenosis) or in the lower back (lumbar spinal stenosis); depending on where you have it, the condition will present slightly differently.

In this article, we’ll be taking a closer look at lumbar spinal stenosis, including its symptoms and causes, and spinal stenosis treatment options.

What is lumbar spinal stenosis?

Running down the center of your back is the spinal column, made up of the interlocking vertebrae that support your body and allow you to move. The spinal canal is in the center of these vertebrae, forming the space that encloses the bundle of nerves known as the spinal cord. The bundled spinal cord stops just above your lower back area—the lumbar spine—where the individual nerve roots branch out, looking something like a horse’s tail (cauda equina). Each nerve in turn exits the spinal canal at a particular vertebral body, through openings on each side called foramen.

Spinal stenosis occurs when a nerve or nerves are painfully compressed because the areas they pass through have narrowed. Specifically, compression can happen in three areas:

  • The canal itself might become narrow, compressing the nerve bundle and therefore affecting multiple nerves. This is called central stenosis.
  • The small openings on the sides of the canal, called the foramen, may narrow, reducing the space available for individual nerves exiting there. This is called foraminal stenosis.
  • The tract where the nerve root exits the central canal may narrow; this is called lateral recess stenosis.

All three are closely related, with foraminal stenosis being the most common type. Most of the time, patients have more than one type occurring at the same time, though usually one is more severe than another. For example, you may have foraminal and central stenosis, with the foraminal being more severe and the central only moderate. The degree of severity for each depends on what caused the original stenosis. A large disc herniation would cause more significant narrowing of the lateral recess area, for instance. (You could then either call that condition a disc herniation or lateral recess stenosis, because the lateral recess area has been narrowed by a disc fragment. Most medical professionals would refer to it as disc herniation.)

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Lumbar spinal stenosis is an extremely common condition affecting a large portion of the general population, usually anywhere from age 35 through end of life. The three types of spinal stenosis listed above—central, foraminal, and lateral recess—are usually attributed to normal degenerative changes that occur as we get older. In fact, many people commonly think of this condition as arthritis of the spine, brought on by wear and tear over time. These degenerative types of spinal stenosis are typically brought on by a combination of factors:

  • A herniated disc (sometimes called a bulging disc) may be pushing outward, interfering with the surrounding nerves.
  • Buckling or inflamed ligaments (tough connective tissue) in the spinal canal, which sometimes occurs due to aging, weak discs, can take up additional space and impact nearby nerves or the spinal canal.
  • A bone spur (an outgrowth of bone) on the spine may be impinging on nearby nerves. Bone spurs are commonly associated with osteoarthritis.
  • Loss of disc height is common. The disc looks like a flat tire, causing the vertebra to be too close to one another or even slip forward (spondylolisthesis) or backward (retrolisthesis) on one another.
  • Cyst formations are fluid-filled sacs that develop as a result of degeneration in the facet joints and create pressure inside the spinal canal.

All of the above will reduce the natural space that is usually afforded to these spinal components, leaving less room for nerves to pass through.

Degenerative stenosis is by far the most common type of spinal stenosis, but there are other, rarer, types of stenosis as well. These include congenital stenosis, in which someone is born with a very narrow canal; iatrogenic stenosis, which is physician-induced and usually occurs following spinal surgery; and pathologic, which is stenosis caused by a tumor, infection, or trauma.

What are the symptoms of spinal stenosis?

In most cases, spinal stenosis comes on slowly. (Though sometimes a herniated disc can make it progress more rapidly.) People with all types of lumbar spinal stenosis usually experience similar symptoms: back pain, leg pain, and varying degrees of numbness, weakness, or tingling down the back or in one leg (usually one leg is worse than the other). Standing upright and lying down flat accentuate the problem, making it necessary to sit down frequently. Over time, walking may become increasingly uncomfortable, and you may find yourself bending forward slightly to help relieve the pain. In extreme cases, it may also cause bowel and bladder dysfunction, and sexual dysfunction.

A doctor can diagnose spinal stenosis with an MRI.

What are spinal stenosis treatment options?

There are varying degrees of spinal stenosis, ranging from mildly stenotic to severely stenotic. Treatment options depend on a patient’s symptoms as well as their general health and age. Physiological age (health and fitness) is even more important than chronologic age and a better indicator for how well someone will tolerate surgery.

Some conservative treatment options for this condition include:

  • Anti-inflammatories, which may be useful for reducing inflammation and can help reduce pain.
  • Epidural steroid injections, which can be helpful in the early stages of stenosis but become less effective over time. But if your condition is too severe, most doctors will avoid putting needles in an area with so little space.
  • Therapy, which may provide only temporary relief, because stenosis is an anatomical problem. Therapy for stenosis is often less effective than it would be for other medical conditions.
  • Chiropractic care helps some people manage the symptoms of spinal stenosis without having to undergo surgery.

Typically, foraminal stenosis is harder to treat nonsurgically because the canal is so narrow—much narrower than the central canal. It doesn’t take much to interfere with nerve passage in this already-small space, and there are few good ways to open it further.

Surgery As An Option

Although conservative care options are available for spinal stenosis, many people with more advanced lumbar spinal stenosis opt for surgery if the condition is interfering with their life, either in terms of necessary mobility or simply enjoying their favorite activities.

Surgery involves “decompression” to remove or address the offending material pressing on the nerves, i.e., removing small parts of an inflamed ligament or a bone spur, or even taking out some of a diseased disc if need be. Once the material is removed, the surgeon will assess the stability of the spine. More often than not (especially in the case of foraminal stenosis), by removing the bone or disc material, the surgeon will have created an instability (iatrogenic instability). If the spine is deemed “unstable,” fusion or another stabilization surgery may be required.

Are there alternatives to fusion?

Surgeons fuse because they have to, not because they want to. One of the problems with fusion is that taking away the mobility of even a single level in your spine places added stress on the adjacent levels, both above and below the fused location. This often leads to rapid degeneration of one or both levels, which means you’ll likely need another fusion surgery down the road.

But there is another option. BalancedBack Decompression Arthroplasty can be used to re-stabilize your spine after a decompression for stenosis, instead of fusing the unstable segments with screws, rods, and spacers. The BalancedBack procedure preserves your mobility by giving you a completely new joint (disc and facets), which means there’s no fusion stress placed on the areas above and below the affected level—decreasing the likelihood of repeat surgery.

Still have questions about spinal stenosis? Visit our Knowledge Center to learn more.

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