Causes of Sciatica - Not Always What You Think

Anne Asher Author

Sciatica. Ugh! What a bear. If you’ve had it, you know what I mean.

When their clients ask about it, the go-to explanation for sciatica given by most of my fellow holistic types is that the one and only cause of this most uncomfortable collection of symptoms is a tight butt muscle known as the piriformis. Because the muscle is tight, they say, it presses on the sciatic nerve, giving you piriformis syndrome.

These well-meaning massage therapists, movement trainers and bodyworkers quickly review this particular sciatica cause with their client, and then offer up stretches for getting rid of the knashing, knawing discomfort: the pain, weakness, numbness, burning sensation and/or the electrical sensations that go down one leg.

Many Possible Sciatica Causes

According to high quality and definitive medical web sources, piriformis syndrome, also called sciatica nerve entrapment, shares symptoms with a whole list of back problems. When you go to an M.D. for a diagnosis based on these symptoms, she will likely make it by ruling out the other conditions on the list; this process is called differential diagnosis.

The complete list of spinal conditions with the same symptoms as piriformis syndrome is too long to cover in one post, but here are three you might consider if you’re not getting enough relief from the stretches; these are the most common causes. 

If you suspect your symptoms are caused by something other than piriformis syndrome, or if the symptoms are simply too disruptive to your life, get them checked by your licensed M.D. and/or physical therapist.

Sciatic Symptoms Cause #1: Herniated Disc

A herniated disc is the most common cause of sciatica according to the Mayo Clinic and others, affecting the shock-absorbing cushion located between spinal bones, which are called vertebrae. This cushion has a tough exterior made of fibers and a soft, liquid interior.

When the fibers on the outside of the disc rupture, the inner liquid may escape. Once it leaves the protective confines provided by the outer fibers, the liquid can, and often does, makes contact with a nearby spinal nerve root, pressuring it. That’s when you get sciatica symptoms: pain, weakness, numbness, electrical shock and/or burning going down one leg.

This type of sciatica is technically called radiculopathy. Radiculopathy is the presence of these sciatica-like symptoms when, and only when, they are created by pressure on or irritation of a spinal nerve root.

Herniated discs can be brought on by degenerative disc disease or caused by impact or injury. The former happens more in older people, whose discs have started to dry or have fully dried out. The outer fibers of dried out discs are brittle, making them prone to fraying and breaking.

Younger people are more prone to herniated disc from a forceful injury. Their outer disc fibers are generally strong and flexible enough to rebound from mild or even moderate levels of impact, but there's more fluid on the inside that may come into contact with the spinal nerve root when a rupture does occur.

Herniated disc injury from impact is most common in active adults between the ages of 30 and 50.The move to watch out for is a combination of bending the spine forward and twisting, which is something most people do when gardening, snow shoveling, lifting and moving heavy items, etc. Staying aware of how you move your body during these and similar activities will likely reduce the odds of an injury to your discs.

Sciatic Symptom #2: Spinal Stenosis

Spinal stenosis refers to a narrowing in the spaces through which the cord and spinal nerves traverse. The word stenosis is a general medical term that is applied to a number of structures in the body; it means narrowing.

Spinal Stenosis Often Starts with Osteoarthritis

Usually, but not always, spinal stenosis is a progressed form of osteoarthritis where enlargements in the size, and changes in the shape of vertebrae start to crowd the nearby nerves. These nerves normally pass through either the spinal canal (the spinal cord) or the holes on either side of the spine (spinal nerve roots.)

For the most part, osteoarthritis is a wear and tear affair; we all develop at least some during our lives. In other words, you can count on getting it as you age, even if only to a small degree. Injuries also lead to osteoarthritis.

If you’re willing to remain active at a level you can handle and can do so with minimal, or preferably no, pain or strain, you may be able to manage the symptoms and slow the progression or onset of the disease. For this, it's best to work with your licensed M.D. and/or physical therapist.

The most important step a proactive person can do to manage osteoarthritis is regularly take the joints through their full range of motion. After that, core strengthening, plus a general strength program that works most of the muscle groups are key.

As with herniated disc (Sciatica Cause #1, above) and spondylolisthesis (Sciatica Cause #3, below), where there’s spinal stenosis, there’s likely to be pressured or irritated nerves. Once that pressure occurs, you guessed it – sciatica, well, actually, radiculopathy, symptoms ensue.

Neuroforaminal Stenosis: Radiculopathy Symptoms

Note: The above is only true for the neuroforaminal type stenosis, which is stenosis that affects those holes on either side of spinal bones; again, this is where the spinal nerve roots pass through before they branch off into individual nerves throughout the body.

The difference between radiculopathy and sciatica is that radiculopathy symptoms can only be created by a spinal nerve root that gets compressed or irritated in some way. Sciatica, on the other hand, may be caused by radiculopathy, but not necessarily.

Central Canal Stenosis: Myelopathy Symptoms

The type of stenosis that affects the spinal canal is called central canal stenosis. Even though central canal stenosis is easier to say than neuroforaminal stenosis, it’s usually much more challenging and serious; the symptoms it leads to are called myelopathy, not sciatica or radiculopathy, and they occur when the spinal cord, not the nerve root on either side, becomes compressed or irritated.

Sciatica Cause #3: Spondylolisthesis

Spondlolylisthesis – a mouthful to say for sure – describes a type of spinal instability where a lumbar vertebra – I’m talking about the bone, not the disc- slips forward relative to the bone that’s just below or just above.

The L-5 bone, which is the last vertebra in the spinal column and located just above the sacrum bone, is the area most often affected by spondylolisthesis.

Spondylolisthesis starts simply enough – with a stress fracture injury to an obscure area of the back of the spinal bone known as the pars. Left untreated, a pars injury, also called a pars defect, may destabilize the bone to the point where a spondylolisthesis develops.

This injury most often affects teen athletes whose sports involve repetitious movement of the spine. But it can also be due to aging and/or genetics. 

Middle aged people who are overweight may be more at risk because the extra belly weight can pull the pelvis into a forward tilt, a position that pressures the pars even more.

Okay, then, how does spondylolisthesis cause sciatica?

As the top bone slips forward, the area on either side of the bone that surrounds the spinal nerve root becomes smaller.

With less “clear sailing” space, the spinal nerve roots are more likely to “bump into” the bone that surrounds them. 

The nerve roots are extremely sensitive; when they come into contact with bone, you'll likely get nerve sensations and other symptoms as mentioned several times above. This is another example of radiculopathy.

Which leg you feel these nerve sensations in will depend on where the compressed nerve root is located: An irritated or pressured left spinal nerve root will send symptoms down the left leg; a pressured right spinal nerve root will result in symptoms down the right leg.

Quick Recap of the Technicalities

Myelopathy symptoms generally come from central canal stenosis, while radiculopathy symptoms are often due to neuroformainal stenosis, herniated disc or spondylolisthesis. 

Sciatica is a Catch-All Phrase

Sciatica is not technically a medical term; rather, it's a sort of catch-all phrase that many people, even some doctors, use to quickly refer to the symptoms like pain, weakness, numbness, burning or electrical sensation that go down just one leg. Regardless of the cause, these symptoms indicate the need to speak with your doctor and/or physical therapist. 

All that said, it’s entirely possible to have a herniated disc and a tight butt muscle at the same time.

Making the distinction between “sciatica” and the actual cause of your symptoms may guide you to the right action and help resolve the symptoms faster. It will likely also help you choose movements and exercises that are exactly tailored to what's going on with your spine. A physical therapist may be very helpful for this.

So there you have it – the sciatica story few holistic types know. Knowledge is power!

Sources:

Hicks, B., et. al. Piriformis Syndrome.  Continuing Education Activity. StatPearls [Internet] Last Update: August 4 2023.

Mayo Clinic Staff. Sciatica. Mayo Clinic Website. January 31 2024.

Categories: : Chronic Pain & the Medical System, Sciatica