Neuroforaminal Stenosis Defined

What is Neuroforaminal Stenosis?

Depiction of a spine with spondylosis and facet joint hypertrophy
Facet joint hypertrophy may cause radiculopathy symptoms. Medical Art Inc./E+/Getty Images

Spinal stenosis is a term that refers to a narrowing of one or more spaces in the spinal column. Generally speaking, it is related to arthritis, which means the narrowing is most often caused by degenerative changes that take place in the spinal bones over time and/or because of injury.

Spinal stenosis can occur anywhere along the length of the spine; however, it tends to be diagnosed in the lumbar (low back) and cervical (neck) areas the most.

There are 2 types of spinal stenosis: Central canal stenosis and neuroforaminal stenosis. The term “central canal stenosis” implies a narrowing of the spinal canal, which is a hollow space in the center of the spinal column The spinal cord is located inside the spinal canal. Central canal stenosis symptoms are generally experienced in parts of the body served by the affected spinal level and lower. 

Central Canal Stenosis

In the case of lumbar central canal stenosis (not cervical,) these symptoms often include neurogenic claudication which is a type of cramping pain in the legs that is brought on by walking. An increased risk for a fall is another common symptom.

Cervical spine central canal stenosis may lead to an impairment in your manual dexterity; this could affect things you do with your hands such as holding bags, purses or other items, buttoning shirts and coats, tying shoelaces and writing.

Other symptoms of cervical central canal stenosis include an overall change in your sensory perceptions, a feeling that you're weaker than you were before, changes in your gait, bowel and/or bladder dysfunction, and more.

Neuroforaminal Stenosis

Neuroforaminal stenosis is a narrowing that occurs in the foramina.

Foramina are holes that are located on either side of the spinal column; they are smaller than the spinal canal. Spinal nerves exit the foramina after branching off from the spinal cord. These nerves then traverse out to all areas of the body to pick up sensations and carry them to the brain for interpretation, and also to relay movement impulses from the brain to the muscles. 

Dr. Robert Bray, neurosurgeon at the DISC Sports and Spine Center in Marina del Rey, California says that in contrast to central canal stenosis, neuroforaminal stenosis disrupts the existing nerve only at the specific level at which stenosis is located.

In other words, in neuroforaminal spinal stenosis, if a particular vertebral level or levels (levels are called segments) do not have bony changes that result in a narrowing of the foramina, then symptoms related to that level will not be present. This does not preclude you from having symptoms at all, though. If other segments of your spine are narrowed, you may well experience related pain and other symptoms as a result.

As with central canal stenosis, neurogenic claudication (again, leg pain and cramping upon walking)  is one symptom of neuroforaminal stenosis.

In fact, it's considered the classic symptom. Neurogenic claudication is related to posture, specifically how your spinal positioning affects the space in the foramina (which was discussed above.) 

A 2017 study found that a flexed (bent forward) spine increases the space in the foramina. This tends to relieve symptoms because the nerve has more room.

What Causes Spinal Stenosis?

Passageways in the spine can be narrowed by a number of factors, says Dr. Allen Wilkins of Manhattan Physical Medicine and Rehabilitation. Among the most common are disc herniations, arthritis of the neighboring facet joints, disc bulges, and synovial cysts.

Dr. Ali Bydon, Associate Professor of Neurosurgery, Director of Spinal Column Biomechanics and Surgical Outcomes Laboratory at Johns Hopkins Medical School, and Clinical Director of Spine Surgery at Johns Hopkins Bayview Medical Center agrees, adding that disc space collapse, facet hypertrophy (which is similar to Dr. Wilkins assessment of facet arthritis above) and spondylolisthesis are others potential causes.

“Every one of these conditions become more common as people age, but may also be the result of traumatic injury," Bydon comments.

Simply the passage of time – combined with the effect that life's responsibilities have on your spine - may lie at the root of your neuroforaminal stenosis. “Neuroforaminal stenosis is caused by normal wear and tear, by aging of the joint or when a joint has been injured and does not hold up over time, among other reasons, Dr. Bray concludes.

If you're interested in treatment options for neuroforaminal stenosis, speak with your doctor. For general information, read Neuralforaminal Stenosis Treatment.

 

Sources:

Email Interview. Wilkins, A., MD. Manhattan Physical Medicine and Rehabilitation. New York. December 2013.

Freedman, B., Hoffler, C., Cameron, B., Rhee, J., Bawa, M., malone, D. Bent, M. Yoon, T. A Comparison of Computed Tomography Measures for Diagnosing Cervical Spinal Stenosis Associated with Myelopathy: A Case-Control Study Asian Spine J. Feb 2015. Accessed: March 2016. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4330215/

Lee, S., Kim, T., Oh, J., Lee, S., Soo, M. Lumbar Stenosis: A Recent Update by Review of Literature. Asian Spine J. Oct. 2015 Oct. Accessed: March 2016. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591458/

Ren, Z. Evaluation of changes in lumbar neuroforaminal dimensions in symptomatic young adults using positional MRI. Eur Spine J. Jan 2017. https://www.ncbi.nlm.nih.gov/pubmed/28116511

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