An exploration of common causes of sciatica
Have you ever experienced shooting pain, tingling, and/or weakness extending down your leg? "Sciatica" is a common catch-all term used to describe such sensations that may travel down a person's leg to areas controlled by the sciatic nerve. If you are looking for Sciatica treatment in South Edmonton, this blog will give you a better understanding of the common causes of sciatica pain and how a Chiropractor can help.
The sciatic nerve is formed by a group of nerves that start in the lower back. These nerves, from spinal levels L4 to S3, exit the spine and collect in a formation called the lumbosacral plexus. The sciatic nerve branches from the lumbosacral plexus and then travels down the buttocks, enjoying a special relationship with the piriformis muscle. This relationship, as you will learn, can be important in diagnosing some types of "sciatica." From the buttock area, the sciatic nerve continues down the back of the leg and turns into the tibial and common fibular nerves.
Sciatica symptoms can be produced when some or all of the nerves contributing to the sciatic nerve are irritated, compressed, stretched, or the blood supply to the nerve is not getting through. Sciatica may or may not involve lower back pain, depending on where and what is causing the sciatic nerve to be affected. Therefore, sciatica should be considered a symptom and not a diagnosis. Because many conditions can cause sciatica, the best treatment will depend on accurately diagnosing where or how the nerve is being irritated. Here, we will discuss a few of the most common causes of sciatica: Lumbar disc problems, spinal stenosis and the real pain in the butt, piriformis syndrome.
Common Causes of Sciatica?
Lumbar Disc
Particularly in patients under 40, injured lumbar discs are one of the most common causes of sciatica. Lumbar discs are fluid-filled structures that exist between the spinal bones or vertebrae. The fluid inside the center of these discs is called the nucleus pulposus. Several layers of tissue wrap around the center to hold the nucleus in place. These layers of tissue are collectively called the annulus fibrosis. A spinal disc is like a jelly donut that cushions and disperses gravitational forces in the spine and allows the spine to be mobile. Without these discs (jelly doughnuts), spinal bones would be fused together in one stiff, rigid structure like a stick. This type of rigid spine can exist in patients with conditions such as ankylosing spondylitis and, as a result, can have very limited spinal mobility.
As you stand, gravity acts on your spine, compressing it. Lumbar discs take these compressive forces and disperse them through their fluid, which is pushed into the annulus layers of the disc. Bad posture, an unpredictable movement, a bending, lifting, twisting movement or even a cough or constipation can cause these disc fluid forces to balloon more pressure to one side of the disc. Repetitive uneven loading or a large excess pressure can cause the fluid in the disc to cause little cracks in the annulus over time. Various terms are used to describe disc problems: slipped disc, herniated disc, and bulging disc. As the annulus cracks, the inner disc nuclear fluid can start to leak out. This fluid can cause chemical irritation of the nerve root (like a sunburn) or may expand and physically compress a nerve to generate sciatica symptoms.
Numerous factors influence the health of our spinal discs, such as genetics, posture, our job, weight, diabetes, cholesterol and overall health. Genetic factors relate to the genes which are passed to us from our parents. Genes influence how your anatomy is formed. For example, joint hypermobility (think double-jointed), which is genetic, affects the disc annulus flexibility and strength. Bad posture affects how the fluid within a disc is distributed along the annulus. Sitting slouched with "bad posture" rounds the lower back and forces increased disc fluid pressure to drive backwards, increasing wear and tear to the posterior annular tissues over time. Your overall health and fitness level also determines the health of the lumbar disc. Cardiovascular health influences the quality of blood flow to the disc and significantly influences a disc's ability to repair and heal if injured. Physical fitness of our core and having good balance affect your ability to recruit muscles around the lower back to stabilize and help protect the disc. We all recognize that carrying excess weight increases the loads our spinal tissues must manage and cannot be ignored. Smoking is also a well-known factor contributing to poor disc health and healing.
Spinal Stenosis
Spinal stenosis is a condition characterized by the narrowing of a spinal canal. Narrowing of a canal in which a nerve travels can cause nerve compression and result in sciatica symptoms. There are a few types of stenosis which you might read about on an imaging report, such as central stenosis, lateral recess stenosis, or foraminal stenosis. These terms are used to describe the area of a narrowed canal. Age-related degenerative changes in the spine are a primary cause of spinal stenosis. Bony changes, such as bone spurs (osteophytes), can start to block holes that nerves are passing through. Similarly, ligaments can thicken or buckle and reduce the size of a canal which a nerve is passing through. Herniated or bulging disc material can also balloon outwards, narrow a canal, compromise nerve passage, and lead to sciatic symptoms.
The facet joint is a spinal structure often affected by age-related degenerative changes that can cause spinal stenosis. Facet joints are small joints formed between adjacent vertebrae that work with our disc tissues to provide stability and allow spinal movement. With age comes wear and tear, and these joints can experience enlargement from osteoarthritis. Enlarged facet joints can then encroach on the neural foramina and cause nerve compression and sciatic symptoms.
Stenosis symptoms are often affected by posture in that different positions can cause an improvement or worsening of sciatic symptoms. The symptoms of spinal stenosis may worsen or become more pronounced in certain positions or activities. For instance, standing, walking, or bending backwards to the side can change canal anatomy dynamics and contribute to stenosis, further nerve compression and induce sciatica symptoms. Conversely, leaning slightly forward or sitting flexed may relieve sciatic symptoms by opening up the spinal canal and reducing pressure on nerves. You might have noticed older people leaning over their grocery carts as they walk through the supermarket. This leaned-forward posture opens symptomatic spinal canals and is a hallmark sign of spinal stenosis called a "shopping trolley sign" in orthopedics.
Piriformis Syndrome
Earlier, we described the passage of the sciatic nerve and referenced an important clinical relationship of the sciatic nerve to the piriformis muscle. The piriformis muscle is a small, pear-shaped muscle located deep in the buttocks attached to the back of the hip and is responsible for rotating the hip laterally (outwards). Given the piriformis muscle's location deep within the hip, it lies in close proximity to the sciatic nerve. The sciatic nerve runs just underneath the piriformis; however, in 10-15% of people, the sciatic nerve pierces through the piriformis instead of travelling underneath it. These individuals likely have a higher incidence of piriformis-induced sciatica.
The piriformis muscle may become tight or irritated through daily use, leading to compression or irritation of the sciatic nerve as it passes beneath or through the muscle. In piriformis syndrome, the actual sciatic nerve is irritated as opposed to a nerve root, which is affected by spinal stenosis and lumbar disc injuries we discussed above. The symptoms of piriformis syndrome can appear similar to spinal stenosis and lumbar disc injuries but can exist without back pain. Understanding the anatomy affected to produce a patient's sciatica symptoms is key to providing appropriate treatment.
Piriformis syndrome is the most commonly over-diagnosed injury when dealing with sciatica.
Importantly, not all cases of sciatica are caused by spinal stenosis, lumbar discs, or piriformis syndrome. If you're experiencing sciatica symptoms, consult a healthcare professional who can evaluate your situation, provide an accurate diagnosis and rule out serious pathology which could be causing sciatica symptoms. If you're in Edmonton and seeking chiropractic relief from sciatica, our office can determine the underlying cause of your pain and thus provide this first key step toward effective treatment.
Chiropractic care aims to uncover and address the root causes of your sciatica. Radix, the name of our clinic, means root. We want to get to the root of the issue affecting your tissues, not just mask the symptoms. Whether your sciatica is related to a lumbar disc issue, spinal stenosis, or piriformis syndrome, a Chiropractor can help alleviate sciatica symptoms and improve your overall quality of life. Our office will organize X-rays if needed and can refer you for an MRI and provide direct referrals to other medical professionals if your sciatic symptoms are beyond what chiropractic care can manage. Our chiropractic approach uses a blend of postural education, physical therapy exercises, lifestyle recommendations, muscle massage, and safe spinal adjustments to educate our patients on their condition, restore proper alignment, reduce inflammation, and promote healing.
Don't stay sidelined by sciatica!