Epidural Space

Diagram of the Epidural Space
Diagram of the Epidural Space. (c) Anne Asher 2007

Epidural Space

The epidural space is an area of spinal anatomy that is located between the spinal cord and the vertebral canal.  In other words, it is outside the cord but inside the canal.

Three layers of tissue cover the spinal cord, and between each is a "space." The epidural space is the area between the outermost tissue layer and the inside surface of bone in which the spinal cord is contained.

The epidural space runs the length of the spine.

The epidural space contains fat tissue along with blood vessels and nerve roots.

The other two "spaces" are in the spinal cord itself.  They are named the sub-dural and sub-arachnoid spaces, after some (but not all) of the other tissue coverings that surround the spinal cord. 

Epidural Injections for Neck or Back Related Pain

If you’ve ever had an injection to help reduce inflammation and/or relieve nerve pain and symptoms that go down one arm or leg, your doctor may have inserted the needle into your epidural space.  In this treatment, the needle goes right over a compressed spinal nerve root (which is where the pain likely starts) and distributes medication.  The medication may be a local anesthetic, a steroid drug, or a combination of the two.

Even though with an epidural injection you’ll have a needle stuck in you, doctors consider this treatment to be non-invasive, i.e. non-surgical.

  Another common name for a non-invasive medical treatment is “conservative.”

Related: What is Facet Joint Hypertrophy?

Intralaminar Epidural Injections

Epidural injections are among the most of common back treatments, and the most common type given for neck or back related pain is called the intralaminar injection.

 

The lamina is a part of the bony ring located in back of the vertebral body.  In an interlaminar injection, the needle is aimed upwards toward your head and in between two interconnected lamina.

A 2012 review entitled,"The effectiveness of lumbar interlaminar epidural injections in managing chronic low back and lower extremity pain," conducted by Benyamin, et. al. and published in the July-August issue of the journal Pain Physician evaluated 26 medical studies to see how effective interlaminar epidural injections were for relieving symptoms due common spine problems.

The researchers found good evidence that epidural injections can help pain from a compressed nerve root (radiculitis) that comes about because of a disc herniation - when the medication used was local anesthtics and steroids.  But they did not find evidence that the injection would help the disc herniation itself.

Related: Spinal Epidural Injections

The researchers also found fair evidence that epidurals  with local and steroids can help symptoms of a compressed nerve root that are radiculitis related to stenosis.

   They also found fair evidence for spine pain not related to disc herniation (called "axial" pain) when local anesthetic was used - either alone or with a steroid medication.  All injections studied and reported on were done with fluoroscopy, which means these were image-guided procedures.

Related: Causes of Cervical Radiculopathy

Sources:

Benyamin R.M., Manchikanti L., Parr A.T, Diwan S., Singh V., Falco F.J., Datta S., Abdi S., Hirsch J.A. The effectiveness of lumbar interlaminar epidural injections in managing chronic low back and lower extremity pain. Pain Physician. Jul-Aug 2012. Accessed Jan 2016.

Mosby's Medical Dictionary. 7th edition. 2006. Mosby Elsevier. St. Louis, Mo.

Stedman's Medical Dictionary. 28th Edition. 2006. Lippincott, Williams, Wilkins. Baltimore. Moore, K., Dalley, A. Clinically Oriented Anatomy. 5th edition. 2006. LIppincott, Williams & Wilkins. Baltimore.

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