Understanding your pain

What Is Central Sensitization? Why Pain Can Outlast the Injury That Caused It

A real, measurable change in how your nervous system processes pain — including why a stimulator can help without fully solving it.

If your pain has spread beyond where the original surgery was, if things that never used to hurt now do, or if you have a spinal cord stimulator that helps but doesn't fully resolve things — there's a specific, well-documented explanation for this, and it isn't psychological. It's called central sensitization, and understanding it changes how you think about your own pain — and about why failed back surgery syndrome so often involves more than the spine itself.

The definition, in plain terms

The International Association for the Study of Pain defines central sensitization as an increased responsiveness of pain-processing neurons in the spinal cord and brain to input they'd normally consider minor or ignore entirely. In simpler terms: your nervous system's volume knob for pain gets turned up, and stays up, even after the original injury — the disc, the nerve, whatever the surgery addressed — has done as much healing as it's going to do.

This was first described in the 1980s, when researchers observed that repeated pain signals reaching the spinal cord caused neurons there to fire more intensely over time — a phenomenon called "wind-up." What started as a lab observation in animal studies became one of the most important shifts in how pain science understands chronic pain in humans, and it's a large part of why failed back surgery syndrome exists as a diagnosis at all: the surgery can be technically successful while the nervous system, separately, has developed a problem of its own.

How it actually works

Pain signals normally travel a fairly predictable path: injury → nerve → spinal cord → brain, where they're processed, interpreted, and — as healing happens — gradually turned down. Two things can go wrong with that turn-down process:

The amplifiers get stuck on. Neurons in your spinal cord that relay pain signals can become more excitable at a cellular level — partly through changes in NMDA receptors, which normally act as a kind of volume limiter. When they're sensitized, that limiter stops doing its job, and signals get amplified rather than dampened.

The brakes stop working. Your brain normally sends signals down the spinal cord to dial pain back down — this is called descending inhibition. In central sensitization, this natural braking system weakens, so pain signals arrive with less of a counterbalance than they should.

The result is two recognizable patterns: allodynia, where ordinarily painless things — light touch, clothing, a gentle hug — now hurt, and hyperalgesia, where things that would normally cause mild discomfort become significantly more painful than expected.

Why a stimulator can help without being enough on its own

A spinal cord stimulator works by delivering electrical signals to interrupt pain messages traveling up the cord — and for many people, that genuinely reduces pain. But it's designed to intervene at one point along the pathway. If central sensitization has developed more broadly — involving how the brain itself interprets signals, not just how they travel up the cord — a stimulator can quiet part of the picture while the amplification happening elsewhere in the system continues. This is often exactly why people describe their stimulator as "helping, but not enough": it isn't failing at its job, it's doing one job while a second, separate problem keeps running.

Why it develops

Central sensitization doesn't appear randomly — it tends to follow a specific kind of history, and failed back surgery syndrome sits squarely inside it:

• Prolonged or repeated pain input — months or years of unresolved pain before and after surgery
• Major surgery itself, which floods the nervous system with pain signals over an extended recovery, regardless of how well the operation goes
• Ongoing inflammation, which keeps nerve endings and spinal cord neurons chemically activated
• Chronic stress and poor sleep — both common after years of pain and repeated procedures — which independently lower the threshold at which your nervous system perceives threat

This is why two people can have an almost identical spinal surgery, and one recovers normally while the other develops pain that spreads, persists, and eventually needs a stimulator — the difference often isn't the surgery itself, it's what happened to the nervous system around it, before and after.

How it can actually be worked with

Because central sensitization lives in the nervous system rather than in a specific joint or muscle, treatment aimed only at one site — another injection, adjusting the stimulator, more focus on the operated segment — often has limited effect on its own. What tends to help is different: consistent, whole-body input that the nervous system reads as safe rather than threatening.

This is part of why hands-on, whole-body osteopathic work can play a role here, alongside whatever your stimulator is already doing. A sensitized nervous system has, in effect, learned to interpret ordinary sensory input as a threat. Repeated sessions of calm, non-provoking, whole-body touch — rather than repeatedly probing the original surgical site — can give the nervous system a different kind of information over time, which is one of the mechanisms pain neuroscience education (the approach pioneered by researchers like Lorimer Moseley) is built on: changing how the nervous system interprets input changes how much pain it produces.

This isn't a fast process, because you're not treating a joint — you're gradually retraining a system that took months or years to become this sensitized. A realistic minimum here is 16 sessions: the first 4 roughly every 15 days, then about once a month after that. That pace isn't arbitrary; it mirrors how gradually this kind of nervous system change tends to happen, in both directions.

If this explains what's happening to you

If you've had spinal surgery, if you have a stimulator that helps but hasn't fully resolved things, or if the pain has spread or changed in ways that don't match the original injury — message me on WhatsApp and tell me what surgery you had, whether you have a stimulator, and what's changed since. I'll tell you honestly whether this is worth exploring for your case.