Sciatica and Centralization: Why Your Pain May Move as You Heal

Article written by Dr. Marnie Hansen, DC, for Salt Lake Spine & Pelvis

Therapies for the low back can often help with sciatica and nerve symptoms into the legs.

If you've ever had sciatica, you know how terrible it can feel. Maybe it started as low-back pain and then began shooting into the buttock, down into the thigh, calf, or even your foot. Sometimes you might notice your leg or foot hurts way worse than your low back. You might also get numbness, tingling, weakness, aching, burning sensations, or even muscle spasms that show up unexpectedly.

Or that fabulous electric zinger that stops you in your tracks.

Then, suddenly... as you start getting better, something strange happens:

The pain moves locations entirely!

It can be quite unpredictable, and oftentimes annoying, making you wonder if this one problem has now led to two or three. But... funny enough, it's good news to me when I hear this! It's exactly what I look for in the process of healing sciatica and nerve referral into the extremities.

And it's often exactly what I'm hoping to see.

Meet Centralization

There's a term we use in spine-focused care called centralization. To sum it up, it means that the pain that was traveling down your leg, and away from your spine, is now switching directions and traveling back up towards it.

For example:

Foot pain inches up to the → calf, which slowly retreats up to the → thigh, then it creeps back up to a → buttock, and at last centralizing, or landing back at the → low back (where sometimes it likes to hang on for a while, but more on this later...).

I like to describe this mechanism to patients as being similar to how a thermometer works. If you imagine your sciatic nerve as a long thermometer running from your low back, down your leg to your foot, you can get a good visual on how this works. When the nerve is pinched, compressed, restricted, or interfered with at the spine, low back, or by the numerous structures and tissues around the low back and hips, symptoms can travel further down that thermometer.

In short, when the nerves coming from your low back are irritated, you can think of the nerve being "hot," or spiking the thermometer (down the leg).

On the flip side, when there is less pressure or irritation to the nerve, the thermometer effect travels back up to the leg and centralizes at the low back in most cases. As the irritation reduces, the symptoms can start climbing back up the leg to its starting point, or central origin.

Hence the term "centralization."

At this point, you might actually say with some relief (and equal irritation):

"My leg feels so much better now…but, darn it, my back still really hurts."

When I hear this on my table, it is an encouraging sign that the body is doing its job. And to be clear, the end goal is definitely not for the pain to stay in the back forever. But it can often hang out there for a while before resolving. In my practice, I see this frequently, and notice that it's that last 90% or so of functional and structural healing that can take the longest to work through.

The optimal goal is for the entire system to calm down, as everything in the body is connected, and it can wind up and compensate around a central injury. Yet, when the symptoms that were traveling all the way down into the calf or foot reverse direction and head back up to the low back, I definitely pay attention.

Why Does Sciatica Travel So Far Down The Leg?

The sciatic nerve is an amazing nerve.

It is the largest nerve in your body, and it is formed from the nerve roots that exit the spine at the low back and sacrum, and masterfully branch into the pelvis, glutes, and eventually down your legs.

That's quite the journey.

And along its often arduous journey, it has to traverse its way through connective tissue and fascia, running under and over muscles, through ever-moving joints, and dodging its way around your discs. At any point on its trek down the leg, it can be compressed, pulled at, irritated, or pressurized. These structures can influence how freely your nerve moves through its landscape and how stressed out it can become in doing so.

It has to travel quite the gauntlet, or an obstacle course of tissues and bones, you could say!

(And healthy tissues equal easier nerve travel, or nerve glide)

Nerves from the low back and sacrum branch off the spinal cord, exit the spine, and branch into the sciatic nerve that travels down the leg.

The starting point of the sciatic nerve's journey is first navigating through the spine. In order to travel down the leg, it has to first exit the spine. In order to do this, it has to travel right next to your lumbar discs, which are the tough yet flexible cushions between your spinal bones. They help to absorb the gravitational force placed on your spine as it bends, twists, and moves throughout the day.

They are the body's built-in shock absorption, and they are marvelous.

A disc can sometimes bulge or herniate, meaning that some of its tissue bulges or protrudes further out than usual. My patients laugh when I mention those toys we used to squeeze as kids, and the eyes bulged out... a disc bulge or herniation is similar to that. Abdominal pressure and ergonomics put day-in, day-out stress on the discs, and they can sometimes weaken and bulge.

When this happens, typically there is some sort of tissue inflammation that happens around the nerve root traveling nearby. In many cases, this can lead to symptoms down into the leg.

But here's the real kicker... and it's important:

A disc bulge does not mean there will be pain or symptoms to follow.

This is important to remember. A systematic review published in the American Journal of Neuroadiology showed that a large number of people who did not have back pain will have disc bulges at some point in their life. And the percentages steadily increase with age. For example, they estimated that 30% of twenty-somethings will have no back or sciatic pain but already have disc bulging. By the age of 50, that number climbs up to around 60%, and further rises to 84% by the time people are in their 80's.

This stresses the fact that our spine changes as we age, and pain from a bulging disc isn't always a guarantee. Evidence of a bulge on imaging doesn't always mean it will be an issue for us.

Sciatica and Centralization: Can a Herniated Disc Heal?

Yes.

The body is inherently smart in its adaptation and repair process when given the right environment and right set of tools to heal. Most herniations will improve with the right care over time. Studies have shown that the material that breaks off from the herniation can even shrink or be reabsorbed by the body over time.

In the spirit of "Happy Gilmore," I sometimes describe the disc repair process to my patients as the disc "going home." Obviously that's not a technical medical term, but it gets smiles and laughs where they are much needed. It can be a great way for my patients to picture the inflammation calming down and irritation reducing around the disc, nerve, and spine as we improve how everything feels and moves.

If you have injured a disc before, that history matters. Episodes of previous low back pain or injury are one of the strongest predictors of it happening again. And the discs are no exception in this. Previous injury can leave the tissues vulnerable to reinjury.

It doesn't mean you have to repeat the cycle of back pain and sciatica over and over again. It simply means your history has pointed out some very useful information on where your body may need a little support or retraining.

Coming in hot: The Compensations

This is the part where patients can get slightly tripped up with their care. But in all seriousness, it's very normal, and once you see the patterns of what is happening, you can better understand it.

Your low back is like the bridge between your lower and upper body. It is connected to your core, your neck, and even your feet, through fascia, muscles, bones, nerves, and other structures. It works in cooperation with your body's larger ecosystem.

When you experience an injury or pain, you naturally change how you walk, sleep, sit, stand, bend, or move, right? Some muscles work harder while others rest. Your pelvis might rotate or tilt, or your mid-back might "lock up." Even your head and neck are a part of the compensation process.

Think about how you limp and shift your posture to protect a sore or sprained ankle for a week or two. Eventually, your knee, hip, or back might start aching or complaining. Not necessarily because of a prior injury to those areas (though that can add to it), but because your movement system as a whole adapted to protect the injured ankle.

When I think about how the body compensates around an injury, I like to think of the spiral patterns of fascia that travel up and down the body. In my practice for example, I will see a hip surgery on the right, then a left shoulder becomes painful a year or two later as it did extra work in the hip's recovery process. I sometimes describe these compensation patterns as being like a "snake effect" up or down the spine, as compensation patterns frequently travel in diagonal patterns and shift around the kinetic chain as the body heals.

This isn't to say that every single new ache or pain is automatically a good sign. But symptoms changing and traveling to different parts of the body in the recovery process can give us some very good information. I pay close attention when leg symptoms retreat toward the spine, movement patterns change and improve, strength returns, and flexibility balances out from side to side. That's progress!

Why I Look at the Whole Spine

When someone pays a visit to my office with low back pain or sciatica, I assess the whole body and look at more than just the one problematic spot. I want to know how the pelvis is moving, how the person walks, how they stand. I look at how the neck moves, what the mid-back is doing, and evaluate for what kind of compensations might have developed above or below the painful area.

In most cases, I find something.

Depending on the individual, I use different therapies. For low backs, I might use the flexion-distraction table to traction the spine and provide relieving assisted stretching at the low back muscles. I'll also use pelvic/SOT blocking, deep muscle stimulation, soft tissue work, mobility exercises, and progressive strengthening to help restore more functional movement throughout the spine and beyond.

In my office, we are not just simply chasing pain, but we are looking at the entire environment the body is reacting to, and assessing all the elements that the pain can arise from.

Watch the "Thermometer"

If you are struggling with sciatica, the first step you can take today is noticing exactly where your symptoms are, and to what degree you feel them. For example: does the pain go all the way to the foot? And when does it do that? What makes it better? How far up the leg does the pain retreat back up the leg, and when does it do that?

Or has the pain finally moved up out of the leg, and set up camp in your back? Is the leg pain finally quiet while the low back is still grumpy? That information, and tracking it, matters a lot!

Healing isn't always linear, and symptoms can fluctuate a lot as tissue inflammation and tension calm down. As your body adapts and movement patterns change or improve, things will feel different in different places.

When symptoms of sciatica begin to retreat up the leg and toward the spine, you are likely experiencing what is called Centralization. Pay attention to that. Watching that "thermometer effect" travel upward is one of the first clues that you are headed in the right direction.

There is an important exception to make note of: new or worsening leg weakness or numbness around the groin/saddle area, fever, loss of bowel or bladder control, major trauma, or progressively worsening or severe symptoms all warrant an ER visit rather than waiting for symptoms to centralize. Do get a prompt medical evaluation in these situations.

In my office, the best news is no news. When a patient looks at me after a few weeks and just shrugs and says, "I feel fine," as if they forgot what they came in for in the first place, that tells me that the body has done its job and the brain isn't receiving those pain signals anymore, and is ready to move onward and upward! That is a great day.

If you would like a postural evaluation and suspect you may be experiencing symptoms of back pain or sciatica, don't ignore it! Get checked!

If you liked this article and want to learn more, we are happy to help! Click here for a complimentary consultation to see if our services could be the right fit for you.