Three Types of Nerve Pain

I’ve previously written several articles here on iRunFar about nerve pain. You might say this is because nerve pain is amongst the most persistent and difficult injuries to treat.

In this modern day of well-educated, internet-savvy athletes with capable medical support, most basic soft-tissue injuries heal with the time-honored treatments of rest, ice, mobility, strength, and efficiency. I see these simple running injuries less often.

Runners with neurogenic injuries–pain and dysfunction of nerve origin–often experience:

• Chronic, persistent pain even after or during prolonged rest;
• Pain impervious to standard sports-medicine care; and
• Pain that fails to improve or even worsens with surgery.

They don’t get better easily, quickly, or sometimes ever without specific treatment. These are the folks who are more likely to walk through my door. These injuries challenge my skills and inspire learning every day. So, I write about it.

But you might also say that that those who fail to learn from history are doomed to repeat it. I am a nerve-pain sufferer, so this is also true. As of this writing, I am just emerging from the most prolonged and frustrating injury of my 26-year running career: three-plus years of bilateral ankle pain and close to a full year of almost no running. That my injury turned out to be neurogenic pain shouldn’t have been a surprise. That it felt and presented like real soft-tissue dysfunction–tight muscles, tender tendons, and stiff joints–was an impressive wolf-in-sheep’s-clothing story. But the absence of typical neurogenic pain signs was the jaw-dropper.

This turned into the Terminator Robo-Sheep that I believed would be my running’s demise. That is, until I found the electrical cable to the wolf and gently pulled the plug. Just like that, I can run again. It’s been a complex and fascinating ride. I also know that runners out there share in this experience. The rest of this article contains the new lessons I have learned.

Nerves and Neurogenic Pain Refresher

Let’s begin with a brief primer on nerves and why they are prone to creating pain and dysfunction:

• Nerves are interconnected, continuous cells and tissues that “flow” from head to toe. A single nerve, or neuron, might be only three total cells that stretch from head to toe.
• While many nerves specialize in one function, all nerves have both inputs (sensation) and outputs (actions on peripheral tissue).
• Besides sensation and action, the nervous system–the collection of all the nerve cells–is also responsible for healing and immune-system response.
• Each individual nerve is intended to have some functional mobility. It should be able to “slide and glide” amidst surrounding tissues such as skin, muscles, bones, tendons/ligaments, and fascia.
• Nerves are very sensitive and do not tolerate excessive stretching or compression. Nerves that lose their functional mobility can easily become over-stretched or compressed. With either, nerves can easily become irritated.
• A nerve needn’t be truly damaged to create pain. Irritation due to over-stretching or compression can result in neurogenic pain or symptoms.
• An issue at any point along the nerve can cause a symptom anywhere else on that same nerve. This can result in both pain and real tissue dysfunctional changes–including swelling, stiffness and weakness–several feet away from the source of dysfunction.
• Finally, that tissue dysfunction can be completely unrelated to that tissue’s normal function.

For a more thorough look at neurogenic pain, check out this article.

Three Types of Nerve Pain: Radicular, Amplified, and Dysfunctional

Let’s begin here with a story. Several years ago, a new patient came to my office three or four weeks post-operative right ankle “arthroscopy.” This means the surgeon went into the ankle to “clean up.” She was in severe pain that was clearly abnormal for both the procedure and elapsed post-operative time. Her pain had these key notes:

• Pain was constant;
• It was worse with sitting (Nerve Injury Sign #5 is pain at rest); and
• It was worse when the knee was straight and better with it bent.

Subsequent Straight Leg Raise testing–a key nerve-mobility metric–was less than 45 degrees on the painful side. Whereas, normal is at least 90 degrees, and often up to 135 degrees in women. More notably, the test replicated her symptoms.

Additional questioning revealed:

• Her ankle pain began nearly a year earlier, while “sitting in my closest, cleaning and organizing” for a couple hours. (Nerve Injury Sign #3 is that pain is disproportionate to activity.)
• Ever since, jogging and exercises classes would cause right-ankle swelling and soft-tissue stiffness and weakness. As time progressed, normal walking became symptomatic.
• Orthopedists noted soft-tissue dysfunction and an MRI was ordered. Mild degenerative changes were noted (the patient was a competitive dancer in her teens), and the arthroscopic surgery was performed.
• A year before, she was the passenger in a high-speed motor-vehicle collision. Just before impact, she turned her head all the way to the right. She began to experience neck pain and headaches after the accident.

On treatment day one, I treated her neck. After two treatments, her ankle pain was nearly abolished. It still took some time to treat chronic and severe neck pain from the motor-vehicle accident.

So, here’s a summary of what must have transpired:

• Her cervical-spine injury–through which lower-leg nerves must course–created a sensitivity point on the sensory nerves to the ankle.
• Ongoing neck dysfunction caused those nerves to create an ongoing inflammatory cascade to the nerves in the ankle that dumped inflammation, caused swelling, stiffened muscles and connective tissue, and created pain.
• This inflammatory cascade caused real tissue changes to the ankle. These tissue changes were impervious to conventional orthopedic treatment, which led to the surgery.
• Treating the source of the nerve pain in her neck was the only solution for ankle-pain relief.

This was a mind-blowing case in my young career.

Before then, I’d seen plenty of radicular pain, which occurs when a nerve becomes irritated–usually at the spinal level–and refers pain and other symptoms such as tingling, pins-and-needles, and numbness elsewhere in the body. But nerve pain tends to follow a tight course, often directly along the anatomical path of the nerve. Runners with sciatica, for instance, get referred pain that flows length of the sciatic nerve down the buttock, hamstrings, and sometimes all the way to the calf and foot. However, with radicular pain, there is nothing wrong with the tissues of the hamstring, calf, and foot. Though it may be very painful, it does not swell and neither do the surrounding joints (hip, knee, ankle, and foot) become stiff or painful.

Over time, I began to see what I now call amplified pain. This is when a runner presents with a common running malady, plantar fasciitis, for example, that has a conventional source, such as overtraining, poor footwear, or inefficient foot striking. With conventional treatment, some “plantar” patients fail to fully improve. Deeper analysis finds they also have neurogenic signs and symptoms. With amplified pain:

• Peripheral nerves, in addition to soft tissue, have become irritated (e.g. the medial-plantar nerves in addition to the fascia are overloaded). I call this the “fender-bender rule” where in a minor accident, it might look like only your car’s fender is bent, but other less-visible structures such as the tire, light, radiator are actually involved.
• These patients have nerve-mobility deficits (usually in the area of pain).
• These patients have one or more of the Six Signs of Nerve Pain.
• Their orthopedic pain gets amplified by nerve irritation. For example, foot pain that might be a 2/10 becomes 6/10, or intermittent pain becomes constant.

But the case of ankle pain and neck injury was the first time I recognized what I now call neurogenic dysfunctional pain. This is where a nerve–far away and seemingly unrelated to the function of a joint–causes severe and real tissue dysfunction at that joint. How this patient stood, walked, ran, and jumped had no impact on the pain and dysfunction of the tissues in her ankle. In essence, in cases of dysfunctional pain, the nerve–because of its proximal irritation–has almost no functional tolerance. That is, any normal activity results in a severe overreaction.

Below is a chart that outlines the three types of neurogenic pain, how much the pain is from the nerve, and how much true orthopedic-tissue dysfunction is present:

*at pain source (e.g. sciatica is leg pain, referred from a lumbar dysfunction to various points in the leg)

As we discussed, true radicular pain is nerve pain it is purest form: a “pinched” nerve in the back causes pain down the leg.

Amplified pain stems from a local nerve that has, along with its soft-tissue neighbors, become strained or irritated. In our foot-pain example, the plantar fascia is strained (and such strain may show up in diagnostic imaging), but this tissue dysfunction might account for only 50% of the pain. The nerve irritation may amplify that foot pain from a 3/10 to a 6/10 or more.

Substantial tissue dysfunction that never seems to get better and often occurs with very little activity is the hallmark of dysfunctional pain. Tissue deficits are real and significant: palpation to the plantar fascia might reveal extreme stiffness and severe pain, yet they occur with very little activity, and persist with rest and active treatment to the painful area.

The challenge of dysfunctional pain is that it is often due to multiple insults to the nerve. While our case example had her primary irritation at the neck, we also had to treat other areas of her spine and whole-system nerve mobility for full recovery.

So why does a seemingly unrelated nerve irritation cause such dysfunction? And why does it pick that one specific area? That is somewhat uncertain. Specific tracts of neurons–those responsible for specific body areas–are thought to be directly compressed, strained, or otherwise irritated. And the nerve’s response to the insult is to send an inflammatory (“healing”) response to the area for which it is responsible. That it does that, and in such excess, defies convention and any true benefit.

This cascade of insult to injury is what is behind conditions such as complex regional pain syndrome. This is an extreme version of dysfunctional pain that causes extreme pain, hypersensitivity, swelling, and color and temperature changes in a distal limb usually without any substantial limb injury. But those who suffer from this nearly always have a trauma history involving some aspect of the spine, and usually in multiple areas. Like dysfunctional pain, successful treatment of this syndrome requires comprehensive spine and nerve-mobility treatment–among other strategies.

Joe’s Story of Dysfunctional Nerve Pain

I’ve had mild low-back and neck pain for most of my running career. It seemed to worsen when I became a physiotherapist and started performing labor-intensive manual therapy on clients as well as when I began running ultramarathons with their immense loading and fatigue challenges. Peripheral nerve pain–usually in the hamstrings or lower legs–has come and gone and, at most, made for light anecdotes and only small blips in my career radar. Neither was a major “show-stopper” for my running. I’ve had only one multi-day back sprain and any bits of nerve pain subsided quickly.

But I’ve had ankle pain for a long time. I first remember ankle pain dating back six to eight years ago. Because I’d been training for and racing ultras for a couple years, I dismissed it as part of the game. I learned some ankle-taping techniques that helped what seemed to be ankle-joint dysfunction.

My current–and super-human–ankle pain began just over three years ago. After pacing a friend in the final 30 miles of the Waldo 100k, my right ankle was very stiff. It remained stiff and painful through my preparations for, and aborted run at the 2017 Rio del Lago 100 Mile. After that race, the pain persisted despite prolonged rest. Moreover, by the summer of 2018, both ankles had severe pain. Any long trail run would result in debilitating stiffness and swelling that would make walking nearly impossible. I would hobble around as if I’d just run 200 miles.

By the fall of 2019, I could barely run due to the pain. My last long trail run resulted in significant ankle pain, swelling, and limping. Video stride analysis showed I was significantly laterally striking, which is a plausible cause for intractable ankle pain. Yet, when I fixed that and took prolonged rest, my ankle pain (namely the left ankle) actually got worse. Regardless of if or how much I ran, I’d wake up so stiff that I’d do the post-100-miler limp for several minutes. I was unable to do morning runs without substantial mobility work. And even standing and walking after sitting for a short period would be very painful.

The tissues around my left ankle were extremely stiff and sore. My lateral shin and calf muscles were tight and painful, and my retrocalcaneal bursa–a protective cushion for the Achilles tendon–was so tender than almost any contact would send me through the roof.

I spent the spring of 2020 doing nearly an hour of soft-tissue treatment before trying even a short run. Even then, the pain and stiffness would be so bad that I’d often stop after a half mile. If I did make it, the pain would subside enough to run, but the pain and stiffness following was severe.

Multiple professional visits revealed no specific diagnosis. Plain film x-rays were 100% normal. Standard soft-tissue and joint techniques offered no relief. Cursory examinations of nerve mobility revealed general sciatic-nerve tension, but nerve-mobility exercises seemed to have no effect.

In late spring, a month of rest only helped partially. Then I wore a walking boot for four-plus weeks, which helped a lot. I began short walks. They were tolerable but not completely pain-free. Forward progress inched along. By summer, I was walking every day and ready for a test. I ran a single mile with no pain. But several hours later, it stiffened up and the next day I felt significant pain. Strikeout.

Then, as it often happens, a patient teaches me something. One of my clients with lower-leg pain had nerve-tension signs. After low-back and pelvic treatment were ineffective, I treated her neck and she got much better. I began to self-treat my neck with self-mobilizations to the upper neck joints and cranial bones, plus neck and nerve stretching. The next morning, my ankle felt as pain-free and mobile as it had been all year. I ran three miles, pain-free.

I treated it again, this time more aggressively. A few hours after my self-manhandling, my ankle ached and throbbed worse than ever. Normal walking was impossible. I was super-discouraged until I remembered a key rule of neurogenic injury: if you make nerve pain worse, you’ve truly found the source.

After a day’s rest, I did more gentle treatment and progressed that treatment whole-body: performing low-back and even coccyx techniques. Four pain-free miles of running immediately followed. Subsequent work discovered I had dysfunctions–stiff tissues–in my neck, mid-back and lower back, all requiring treatment!

Since then, I’ve gotten progressively better. I still wake up a little stiff, but that stiffness abates in only a few steps. Morning runs are now possible and enjoyable. Most importantly, there is no latent punishment for running: no swelling or day-after disability. Recently, I’ve progressed my running to short bouts of sprinting and a 15-mile mountain trail run with nearly 4,000 feet of climb and descent with little pain during and after.

While this might seem miraculous, it is not. I simply applied treatment to the area of greatest need. I have decreased compressive strain on the nerve. And once you make a nerve happy, it often recovers rapidly.

Clues That Your Running Injury is Neurogenic

Beyond the Six Signs, how do you know if your running injury might be neurogenic? Here are three more clues:

1. Spine Pain. A hallmark of nerve dysfunction is spine pain. If the spine itself is painful, it may be harboring nerve tension or compression that is causing issues downstream. Runners very often consider it “part of the game,” even disregarding frequent, severe headaches. If you have spine pain as well as a persistent orthopedic-seeming injury, it may result in a neurogenic dysfunctional pain leg injury.
2. Presence of Other Nerve Symptoms. These include non-painful but abnormal nerve-irritation signs such as tingling, pins-and-needles, and numbness.
3. Increased General Stiffness (Nerve Tension). If you have a persistent leg injury but also experience a gradual worsening in mobility–in the spine, but possibly also in the neck, shoulders, hips, or hamstrings–this may be a global sign of increased nerve tension. Because the nervous system is a continuous fascial system, a focal dysfunction in the neck may cause both pain downstream in the leg as well as restricted motion in the entire body. Consider any substantial decrease in normal range a red flag for neurogenic dysfunction.

Conclusion: It All Matters

The most important takeaway is that we cannot blow off other aches and pains because they don’t seem to impact our running. Neck and back pain from stressful work, poor posture, or sitting too long might create or amplify a debilitating leg injury. And those chronic headaches or crazy-stiff and achy hamstrings can be more than just an annoyance.

How we run plays the biggest role in how we feel on the run. But, so does how we live. Our whole-body integrity is of crucial importance and something we must maintain for healthy, happy running.

Invest a bit of extra time in spinal and whole-body mobility. Monitor posture. Keep tuned in to what your body is telling you. Take care of the whole picture and you might be able to run far for a long time.

Call for Comments

• Do you have a running injury that has been diagnosed as neurogenic? Can you share your experience?
• Do you currently have an issue that seems like a normal running injury but isn’t responding to normal treatments?