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In the last newsletter in our Low Back Pain Series, I discussed muscle strains, spasms and facet joint irritation and how these conditions may cause referred pain down the leg, a symptom known as sciatica. Today, I will discuss in more detail, sciatica as a symptom and some of the other sources of sciatica.  

Sciatica, by definition, refers to pain that travels down the Sciatic nerve, or along the back of the thigh.  The cause of sciatica is from something putting pressure on the sciatic nerve or nerve roots that make up part of the sciatic nerve, most commonly, a herniated disc or a bone spur.  It is important to note that sciatica is a symptom and not a diagnosis.  The cause of the sciatica is the diagnosis.  When someone reports “I have sciatica” they are really saying, they have pain going down their leg.  This is neither a clear understanding of the problem nor does it guide one to the appropriate treatment.  

Compression of the sciatic nerve may come from an injury to the disc, degenerative changes in the spine, muscular tightness, infection, a vascular lesion, trauma, a tumor in the pelvic viscera, pregnancy or other neurological conditions which affects the function of the nervous system.  Let us take a look at each of these in more detail.  

Disc injury. 

The intervertebral disc most commonly gets injured in the posterolateral aspect of the disc, the back portion of the disc to the sides, right or left.  A disc can bulge, herniate or extrude.  With all of these, inflammation, which is really a chemical irritation, comes along as tissue is injured.  Any amount of inflammation may also cause some compression of the nerve root that is exiting the spinal cord at the level of injury.  The compression and chemical irritation on the nerve root will cause referred pain down the leg or the symptom of sciatica.  The more extensive the injury is at the disc level, one would think the more severe the symptoms of sciatica, however, some research has shown that MRI findings of disc bulges do not necessarily correlate with pain level of the patient.  

Degenerative or anatomical changes in the spine. 

I have grouped several degenerative or anatomical conditions together here and include the following: bone spurs, lumbar spinal stenosis, spondylolisthesis, spondylosis, degenerative joint or disc disease.  Osteophyte formation, or bone spurs, occur where there is more force on bone.  When there has been a small tear in a disc, the force transducing properties of the disc material are now compromised.  Instead of the disc absorbing some of the forces through the spine, the vertebrae at the level of damage, may now start to absorb some of these forces.  In reaction, bone starts to grow and does so in the form of little bone spurs around the edges of the vertebrae, along the edges of the facet joints or anywhere on the vertebrae that is absorbing more force.  Lumbar spinal stenosis occurs when there is some compromise to the shape of the spinal canal adding pressure to the spinal cord or spinal nerves.  Stenosis may result from degenerative disc changes, degenerative joint changes, congenital anomalies of the vertebrae or inflammation of a posterior intervertebral ligament called the ligamentum flavum.  A spondylolisthesis is the physical movement of a vertebrae to the front or back adding traction to the spinal cord or nerve roots.  A spondylosis is a break in 1 or more parts of the vertebrae adding traction or pressure to the spinal cord or nerves.  As previously discussed, degenerative disc or joint disease can also put pressure on the nerve roots as they exit.  For more info on degenerative disc or joint disease, please read our blog post on DDD/DJD.  

Muscular tightness. 

There are a few areas along the path of the sciatic nerve that may compromise its function.  Often, the piriformis muscle, a muscle in the posterior hip, acts to externally rotate the hip and may compress the sciatic nerve when stretched.  When the piriformis is lengthened or stretched, the act of stretching can produce numbness or tingling down the leg or sciatica symptoms.  Also, the upper part of the hamstrings come into close contact with the sciatic nerve and may also produce similar pain patterns.  

Infection.

In some cases, there can be an infection that occurs around a portion of the sciatic nerve resulting in the pain down the posterior portion of the leg.  In this case, it is important to identify if there are any skin lesions down the posterior thigh or buttocks or if the patient has had any difficulties with urination or bowel movements.  Although uncommon, hair follicle infections do happen in this area resulting in sciatica.  

Vascular lesions. 

Some patients may form aneurysms in the lower portion of the aorta or its branches, the right and left femoral arteries, the major blood vessels to the legs and visceral organs.  An aneurysm forms when there is a small tear in the inner walls of the vessel causing blood flow to become turbulent or restricted.  This damage can cause a section of the vessel to enlarge and put pressure on the structures in the area, the sciatic nerve included.  This cause would be very difficult to identify without imaging and the sciatica would not respond to care in a chiropractic office. 

Trauma 

Trauma resulting in a fracture to the spine, sacrum, pelvis or femur can add compression to the sciatic nerve resulting in sciatica.  Proper identification and treatment via immobilization will be essential here to recovery and prevention of long term sciatica.  

Other pelvic tumors. 

There may be other tumors or masses that form within the pelvic region.  For example, tumors on the ovaries, uterus, large intestine, kidneys, bladder, prostate or spine.  Depending on the location of the tumor, the symptoms of sciatica may come and go or may also be present with other symptoms or the tumor origin.  Again, these symptoms will not go away with chiropractic care and will persist throughout the course of treatment, which may look like failed care.  This is why it is important to refer for further assessment or imaging when pain persists.  

Pregnancy

Pregnancy is a very common cause of sciatica.  The position of the baby may put pressure on both or one sciatic nerve for entire pregnancies or portions of a pregnancy.  This can be quite debilitating for the mother.  In these cases, the movement of the baby can change the symptoms.  Chiropractic care can help maintain mobility in the spine as well as loosen the muscles around the pelvis making sciatica symptoms quite manageable during pregnancy.  

Other neurological conditions like multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS) are examples where there is an underlying condition that exists causing the sciatica.  These will need to be managed by a family physician or neurologist.  Chiropractic care may aid in other symptoms of these conditions but won’t take away the nerve pain.  

As you can see there are multiple different sources that cause leg pain or sciatica.  The initial chiropractic assessment helps us determine one or a few sources as the potential source of the sciatica.  Chiropractic care can help treat many of the most common sources of sciatica, but can also identify when chiropractic care may not be the best option.  If you are experiencing any of the symptoms discussed above, please use the link below to book an initial assessment or if you have been in to see us in the past, we would love to help you get back to health.