Why Spinal Injections Don’t Fix Back or Leg Pain Long-Term Unless You Rehab Too

Spinal injections can absolutely have their place. They can take the edge off pain, calm inflammation, and make it easier to move again. But they don’t fix what’s driving your pain and that’s why, without rehab, relief is usually short-lived.

Here’s what’s really going on 👇

1. The Mechanism Mismatch

Steroid injections reduce inflammation around irritated nerves. That’s helpful if your pain is caused by chemical irritation from a fresh disc bulge or swelling. But most long-term back or leg pain isn’t purely inflammatory it’s mechanical. When the nerve root is being physically compressed or has adapted to being irritated, an injection can’t undo that pressure or those nerve changes.

2. What Is a Nerve Root?

A nerve root is the section of a nerve that exits your spinal cord through small openings between the vertebrae, called foramina. Each nerve root carries messages between your spinal cord and specific areas of your body for example, the lower lumbar nerves communicate with the legs.

When everything is healthy, these nerves glide freely as you move. But if a disc bulges or there’s swelling, the nerve root can become compressed or inflamed. This irritation can cause pain, tingling, or weakness that travels down the path of the nerve often called sciatica.

Spinal injections can sometimes help calm this inflammation and reduce chemical irritation. However, if the nerve root is being physically compressed by disc material or bone, or if it’s become hypersensitive from long-term irritation, reducing inflammation alone isn’t enough. That’s where movement and rehab come in.

3. Inflammation May Not Be the Main Driver

In the early stages of a disc injury, injections can help by reducing inflammation around the nerve. But as time goes on, the body often reabsorbs much of the disc material, leaving behind scar tissue or nerve hypersensitivity and these don’t respond to steroids.

This explains why someone might get temporary relief from an injection, only to have their pain return weeks or months later. The cause has shifted from inflammation to mechanical pressure and nerve sensitivity, which need an active approach to fix.

4. Nerve Sensitisation Explained

When you’ve had back or leg pain for a while, the nerves and the nervous system can become overprotective this is called nerve sensitisation.

If a nerve root has been compressed or inflamed for too long, it starts reacting to normal movement or pressure that wouldn’t usually cause pain. That’s called peripheral sensitisation when the nerve itself becomes hypersensitive.

Over time, the spinal cord and brain can also start to amplify those pain messages that’s central sensitisation. The pain continues even when the tissue has healed, because your nervous system has “learned” to keep sending out danger signals.

This is why scans don’t always match symptoms. Someone can have a large disc bulge but no pain, while another person with a small change can be in severe discomfort the difference is in the sensitivity of the nervous system, not the amount of damage.

The good news? Sensitisation can be reversed. Gradual, guided movement and strength training help teach the body that movement is safe again, allowing the alarm system to quiet down and pain to settle.

5. How Movement Helps a Disc Heal

When a disc bulges or herniates, part of its inner gel-like centre (the nucleus pulposus) pushes out through the outer layer. This can press on a nerve root and cause pain.
But your body is designed to heal and movement plays a major role in helping that process.

• Movement improves circulation and fluid exchange:
  Discs rely on movement not blood flow for nutrients. Gentle movement acts like a pump, helping the disc stay hydrated and healthy.

• When the nerve in your lower back is under pressure from a disc, tight ligament, or too much movement between the vertebrae the small stabilising muscles in your spine (especially one called the multifidus) can help take that pressure off.

• These deep muscles act like your spine’s built-in support system, keeping each segment steady and preventing too much strain on the nerves.

  When they get weak (which is common after back pain), the spine becomes less stable and reduce the space where the nerve sits. That extra pressure can make symptoms worse.

• Strengthening the multifidus and surrounding muscles through guided movement helps create more space, improves stability, and takes load off the irritated nerve.

• Over time, this makes it easier for the body to heal and for the nerve to calm down which is why strength-based rehab is so much more effective long-term than relying on rest or injections alone.

• Pressure changes help reabsorb the bulge:
  The alternating pressure from walking or controlled exercise helps herniated material retract back toward the centre. Your immune system also clears away disc fragments naturally through phagocytosis.

• Movement reduces inflammation:
  Controlled loading disperses inflammatory chemicals and improves circulation, reducing swelling around the nerve root.

• It rebuilds confidence and coordination:
  Avoiding movement can make pain worse. Gradual, guided exercise restores strength and teaches the body that bending and lifting are safe again.

So while rest can help early on, movement is what helps a disc reabsorb and heal.

6. Injections Don’t Change Movement or Loading

Even if inflammation is part of the problem, injections don’t fix how you move. Weakness, poor load management, and repeated compression all keep the cycle going. Rehab rebuilding strength and control is what stops it from coming back.

7. The Temporary Relief Trap

It’s common to feel better for a few weeks after an injection. That’s great use that time to move, build confidence, and start your rehab. But if you stop there, the pain usually returns. The injection was never meant to be a cure it’s a tool to help you start rebuilding.

The Takeaway

Spinal injections can be useful for short-term relief, especially when pain is high. But the real progress happens once you use that relief to move better, strengthen your body, and change the habits that keep the nerve irritated. The injection settles things down your rehab keeps it that way.

If you’re struggling with ongoing back pain, sciatica, or leg pain after a spinal injection, it doesn’t mean your body is broken or the treatment failed. It just means you’re ready for the next step rebuilding strength, restoring movement, and regaining confidence.

At The Recovery Project in Cromwell, we help people move beyond short-term relief with personalised rehab programs designed to get you strong, capable, and pain-free for the long run.