Key Points
- After a nerve injury, most pain resolves as the tissue heals. In some patients, pain persists — not because the tissue is still damaged, but because the nervous system has “learned” to keep producing pain.
- A recent systematic review from Massachusetts General Hospital (published in the Clinical Journal of Pain in 2026, first available online in September 2025) proposed the first standardized criteria for recognizing when this has happened, drawing on 28 studies of over 6,000 patients.
- Recognizing central sensitization changes what treatments will actually help — more operations often won't; targeted therapy, mind-body approaches, and specific medications often will.
Two Kinds of Nerve Pain
After a nerve injury — whether from trauma, surgery, or a chronically compressed nerve — pain generally follows one of two paths. In the first, pain resolves as the injury heals or the compression is corrected. The nerve settles, the surrounding tissue calms, and the symptoms fade on the expected timeline. This is what we hope for, and it is what happens most of the time.
In the second path, pain persists past the point where the tissue itself has healed — sometimes for months, sometimes for years. Imaging looks reasonable. Nerve testing may be normal or only mildly abnormal. And yet the pain is still there, often just as loud as it was in the acute phase, or louder.
When path two happens, something has changed in the nervous system beyond the original injury. That change has a name: central sensitization.
What Central Sensitization Actually Means
Your peripheral nerves report sensation — touch, temperature, pressure, injury — to your spinal cord and brain. Normally, when the tissue heals, those reports quiet down. The volume comes back to baseline.
In central sensitization, the amplifier stays turned up. Signals that should be quiet get amplified. Signals that should mean “warmth” or “light touch” get read as pain. And sometimes pain shows up in places where the original injury never was.
A useful analogy
Imagine a smoke detector that was triggered once by a real fire. It works. But now, months later, it goes off every time you make toast, run the shower, or clap loudly. The wiring is not broken — it has just been recalibrated to be too sensitive. That is central sensitization.
The wiring is not damaged in a way you can see on a scan. The nerves are not necessarily inflamed. What has changed is how the nervous system interprets and amplifies incoming signals. Because that change lives in the spinal cord and brain — not in the injured tissue — treatments aimed only at the injured tissue often stop working.
How Do We Know If Someone Has It? (The New Framework)
Until recently, recognizing central sensitization in a patient with nerve pain was largely a matter of clinical intuition. Experienced surgeons and pain physicians could often tell — but there was no shared, evidence-based checklist to make the process consistent from one clinic to the next.
That changed with a 2026 publication in the Clinical Journal of Pain (first available online in September 2025). Dr. Kyle Eberlin and colleagues at Massachusetts General Hospital published the first evidence-based diagnostic framework specifically for centralized pain after nerve injury. They reviewed 28 studies covering 6,189 patients and proposed five clinical criteria. Here is what each one means, in plain language.
1. You had a real nerve injury or compression to begin with
Central sensitization does not appear out of thin air. There has to have been a starting point — an accident, a surgery, a documented compressed nerve, a traumatic laceration. Central sensitization is a downstream state that develops after a genuine peripheral event. If there was no nerve injury or compression to begin with, we are talking about a different problem.
2. The pain has been going on for at least three months
Three months is longer than the tissue itself would normally take to heal. If the pain has persisted past that window, it is time to ask whether something beyond ongoing tissue injury is driving it.
3. Your sensitivity spreads beyond the original injury
This is the most telling sign. If you injured a nerve in your wrist but now your whole forearm is painful to touch, or if pressure that should feel neutral now feels like burning, the pain territory has expanded. When that happens, something is amplifying, not just transmitting. Local peripheral problems tend to cause local peripheral pain. When the map grows, that is the nervous system talking.
4. Mood, sleep, or thinking are affected
Depression, anxiety, disrupted sleep, or difficulty concentrating often travel with centralized pain. This is not a coincidence, and it does not mean the pain is “in your head.” The same nervous system that processes pain also regulates mood, sleep, and attention. When it is dysregulated in one area, it is often dysregulated across the board. Treating one dimension without the others usually leaves work on the table.
5. Numbing the nerve does not turn off the pain
This is the criterion that matters most for surgical decisions. If we inject local anesthetic at the site of the original injury and you get less than 50% relief, that tells us the pain is no longer being driven mainly by that nerve. It has moved upstream. This test is optional — not everyone needs it — but when it is available, it is one of the most useful things a surgeon can do to guide next steps.
Why criterion #5 matters
A well-placed nerve block that provides less than 50% relief is a strong signal that another operation on that same nerve is unlikely to solve the pain. That is not a small thing — it can spare a patient a second, third, or fourth surgery that was not going to work, and redirect care toward approaches that address the amplification directly.
Why This Distinction Actually Matters
Two people can walk into a clinic with the same complaint — burning pain, six months after a nerve was injured — and be in very different situations. The framework helps make the distinction visible.
Person A — mostly peripheral
- Nerve compression at a specific site
- Well-localized pain that follows the nerve's territory
- Sleep, mood, and thinking largely intact
- Diagnostic block gives more than 50% relief
- Standard nerve compression care — often surgery — is likely to help
Person B — significant central component
- Original injury has healed on imaging and exam
- Pain has spread beyond the nerve's territory
- Sleep, mood, or concentration are affected
- Diagnostic block gives less than 50% relief
- More surgery on that nerve alone is unlikely to help — different tools are needed
Historically, this distinction was made by clinical intuition — and it was often made well, by experienced clinicians. What is new is that we now have a shared framework for making it more consistently, and for explaining the reasoning to patients in a way that is transparent rather than opaque.
What Treatments Actually Help
Once central sensitization is recognized as part of the picture, the treatment strategy shifts. The goal moves from “fix the injured tissue” (which may already be healed) to “calm the amplification.” Several approaches, used together, tend to work best.
Pain-focused physical therapy
Not just strengthening. A therapist experienced in centralized pain will use graded exposure — carefully reintroducing movement to a nervous system that has learned to treat movement as dangerous. This retrains the amplification loop as much as it retrains the muscles.
Pain reprocessing therapy (PRT) and related mind-body approaches
PRT is a specific, evidence-based approach designed for exactly this kind of pain. In a 2021 randomized trial published in JAMA Psychiatry, two-thirds of participants with chronic back pain were pain-free or nearly pain-free at one-year follow-up. It is not appropriate for pain being driven by ongoing tissue damage — but for centralized pain, it is one of the best-studied non-pharmacologic options we have. See our full write-up on mind-body resources for chronic pain for specific programs and how to find a trained provider.
Certain medications
Low-dose antidepressants (such as duloxetine) and anticonvulsants (such as gabapentin or pregabalin) target the central amplification rather than peripheral tissue. Used at the right dose and for the right patient, they can dial down the volume enough for the other pieces of the plan to work.
Sleep, stress, and mood work
The same nervous system regulates all of these. Poor sleep amplifies pain; pain disrupts sleep; both worsen mood; low mood raises pain sensitivity. Improvement in any one of these areas tends to help the others, which is why comprehensive care almost always addresses more than one at a time.
Surgery when it is indicated
Even patients with a strong central component sometimes still have a treatable peripheral piece. The distinction is not surgery versus no surgery. It is: do not expect surgery alone to solve a pain that is being maintained centrally. A thoughtful plan may include surgery on a residual peripheral problem plus the central-focused work above. What it should not do is repeat operations on the same nerve when the nerve block already told us that will not work.
What This Means If You Are the Patient
Your pain is real. Central sensitization is not “made up” pain, and this framework is not a polite way of telling you it is not. It is a genuine dysfunction of the pain system, and there are documented physical changes in the spinal cord and brain that go with it. The brain generates pain, whether the amplification is coming from the injured tissue or from the wiring itself — and the pain feels the same either way.
Recognizing it is not a diagnosis of exclusion or a shrug. It is a specific state with specific treatments. When surgeons and pain physicians identify a central component, they are not saying “we can't find anything.” They are saying “we found something, and here is what actually works for it.”
Ask your surgeon or pain physician whether the Raasveld-Eberlin criteria have been considered in your case. The framework is new enough that it may not have made it into every clinic yet, but any thoughtful nerve surgeon or pain physician will be familiar with the underlying concepts.
If your nerve block has already given you less than 50% relief and you are still being offered more of the same procedure, that is worth a second opinion. That is exactly the situation the framework was designed to catch.
Frequently Asked Questions
Second Opinion on Persistent Nerve Pain
If you have persistent pain after a nerve injury or nerve surgery — and are wondering whether more surgery is really the next step — I am happy to see you for a thorough evaluation. Not everyone needs another operation. Everyone deserves an honest answer.
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This article is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Discussion of the Raasveld-Eberlin 2026 diagnostic framework is educational; application to any individual case requires evaluation by a qualified physician. Full disclaimer.
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