Why Didn't My Back Pain Injection Work?
You've had an MRI. You've seen a specialist. You've finally had an injection for your lower back pain.
You were hoping it would be the thing that settled everything down.
But you're still in pain.
So what does that mean? Did the injection fail? Is your back permanently damaged? Or have you run out of treatment options?
Not necessarily.
One of the biggest things we explain to people with persistent lower back pain is that not all back pain comes from the same structure, and not all spinal injections are designed to do the same job.
Some injections are used to investigate where pain might be coming from. Others aim to reduce inflammation and provide symptom relief.
Understanding that difference is important, particularly when an injection hasn't worked.
Why Are There Different Injections for Back Pain?
Your lower back contains several structures that can contribute to pain, including:
Spinal discs, which sit between your vertebrae.
Facet joints, which are small joints at the back of your spine.
Nerve roots, which travel out from your spinal cord.
Vertebral endplates, where the discs meet the vertebral bones.
Muscles and other surrounding tissues.
Sometimes more than one structure contributes to someone's symptoms.
And here's the important part: different structures may respond differently to different treatments.
An injection that targets one structure won't necessarily address every contributor to your pain.
1. Facet Joint Nerve Blocks: Is Your Pain Coming From the Joints in Your Spine?
Facet joints are small joints at the back of your spine that help guide and control movement.
Like other joints in your body, they can become painful.
What does facet joint pain feel like?
People with suspected facet-related pain may experience:
Pain predominantly across the lower back.
Discomfort when leaning backwards.
Pain with twisting or rotating.
Symptoms during prolonged standing.
Pain that sometimes spreads into the buttocks or thighs.
However, these symptoms are not exclusive to facet joint pain.
We cannot reliably diagnose painful facet joints based on symptoms or movement testing alone.
What is a medial branch block?
The facet joints receive pain signals through small nerves called medial branch nerves.
A medial branch block involves injecting local anaesthetic around these nerves to temporarily interrupt pain signals.
This is commonly used as a diagnostic or prognostic procedure.
The specialist is essentially asking:
"If we temporarily numb the nerves supplying these joints, does your usual back pain improve?"
The response may also help determine whether someone is suitable for a procedure called radiofrequency denervation, which aims to interrupt pain signals from these nerves for a longer period.
What if the facet joint nerve block doesn't work?
If your usual pain doesn't significantly improve while the local anaesthetic should be working, it may suggest the facet joints are less likely to be the main source of your symptoms.
However, diagnostic blocks aren't perfect.
False-positive and false-negative results can occur, meaning the response doesn't provide a definitive diagnosis.
An injection that doesn't relieve your pain isn't necessarily a wasted procedure. It may still provide information that helps guide the next steps.
2. Corticosteroid Injections: Reducing Inflammation
Corticosteroid injections work differently from diagnostic local anaesthetic blocks.
Corticosteroids are anti-inflammatory medications that may be injected into or around certain spinal structures.
The aim is to reduce inflammation and potentially relieve pain.
For example, an epidural steroid injection may be considered for someone experiencing significant sciatica associated with an irritated nerve root.
Research suggests these injections can provide small, mainly short-term improvements in some people with nerve-related leg pain.
However, they are not routinely recommended for non-specific lower back pain.
Why might a corticosteroid injection not work?
Because inflammation isn't always the only contributor to pain.
A corticosteroid injection doesn't necessarily:
Remove a disc herniation.
Reverse degenerative changes.
Remove scar tissue following spinal surgery.
Correct structural narrowing around a nerve.
Restore physical capacity lost during a prolonged period of pain.
Even when inflammation is involved, the response to steroid medication varies.
Some people experience meaningful relief, others only temporary improvement, and some experience little or no benefit.
3. Nerve-Root Injections: When Pain Travels Into Your Leg
Nerve-root injections are commonly considered when someone experiences radicular pain, often described as sciatica.
This occurs when a spinal nerve root becomes irritated or inflamed.
How do you recognise nerve-related pain?
Symptoms may include:
Shooting or burning pain travelling into the buttock or leg.
Electric-like sensations.
Pins and needles.
Numbness or altered sensation.
Sometimes weakness in certain muscles.
For example, irritation of the L5 nerve root may cause pain or altered sensation travelling down the outside of the leg towards the top of the foot.
A nerve-root injection may contain local anaesthetic, corticosteroid or both.
The medication may help reduce pain and inflammation, but it doesn't necessarily remove the underlying structure irritating the nerve.
What if the nerve-root injection doesn't work?
A lack of improvement may prompt the specialist to reconsider whether the nerve is the main contributor to the symptoms being treated.
However, it doesn't definitively rule out nerve-related pain.
Even when nerve irritation is present, injections don't always provide significant relief.
This is why we need to interpret the response alongside your symptoms, neurological examination and MRI findings.
4. What About Vertebral Endplate Pain?
This is a potential source of lower back pain that many people haven't heard of.
Your spine is made up of bones called vertebrae, with discs sitting between them.
The vertebral endplates are located where the spinal discs meet the vertebral bones.
They help distribute forces between the discs and vertebrae.
The endplate region and adjacent bone contain pain-sensitive nerve endings, meaning changes in this area can sometimes contribute to lower back pain.
Pain thought to arise from this region is sometimes described as vertebrogenic pain.
What does endplate-related pain feel like?
People with suspected vertebrogenic pain may experience:
A deep ache in the lower back.
Pain during prolonged sitting.
Discomfort bending forward.
Pain with lifting or carrying.
Difficulty tolerating certain activities or positions.
However, these symptoms are not specific to endplate pain.
Similar symptoms can occur with disc-related pain and other lower back conditions.
We cannot confidently identify endplate pain based on these symptoms alone.
What are Modic changes on an MRI?
You may have seen the term Modic changes in your lumbar MRI report.
These describe changes in the bone marrow next to the vertebral endplates.
There are three main types:
Modic type I: Bone marrow changes associated with oedema and an inflammatory-type response.
Modic type II: Fatty changes within the bone marrow, often associated with longer-term disc and endplate degeneration.
Modic type III: Bony sclerosis or hardening.
Modic changes can be associated with lower back pain, but they are also found in people without symptoms.
Research has not consistently demonstrated that Modic changes alone can identify the source of someone's pain.
Importantly, Modic type II changes are not the same as a fresh fracture or an actively healing bone injury.
An MRI showing Modic changes doesn't automatically mean the endplates are responsible for your pain.
5. Why Might a Specialist Suspect Endplate Pain After an Unsuccessful Facet Block?
Imagine you've been experiencing persistent lower back pain.
Your specialist suspects the facet joints may be contributing to your symptoms, so they perform a diagnostic medial branch block.
However, your pain doesn't significantly improve.
This may make facet-mediated pain less likely.
The specialist might then reconsider whether other structures, such as the spinal discs or vertebral endplates, could be contributing.
If your MRI also shows Modic changes, those findings may be considered alongside your symptoms.
But there's an important distinction.
A negative facet joint block doesn't prove that your pain is coming from the endplates.
The aim is to combine information from your symptoms, clinical assessment, imaging and response to previous treatments to better understand your presentation.
6. Can Endplate Pain Get Better?
Yes, pain associated with the vertebral endplate region can improve.
However, it's important to distinguish between structural changes and symptoms.
If someone has experienced an acute injury to the bony endplate, the bone may undergo healing and remodelling.
If an MRI shows longer-term changes, such as Modic type II changes, these structural findings may remain visible even when symptoms improve.
Your MRI doesn't need to look normal for your pain and function to improve.
Your experience of pain is influenced by several factors, including tissue sensitivity, physical activity, sleep, stress and the way your nervous system processes pain.
The presence of structural changes doesn't determine how much pain you will experience or what you'll be capable of doing in the future.
7. Why Rehabilitation Still Matters When Injections Haven't Worked
An injection and rehabilitation have different purposes.
An injection may aim to temporarily interrupt pain signals, investigate a suspected pain source or reduce inflammation.
Rehabilitation aims to improve your ability to move, tolerate activity and return to the things you want to do.
For example, if you've spent months struggling with lower back pain, you may have reduced how much you bend, lift, walk or exercise.
Over time, your tolerance for these activities may have changed.
This doesn't mean weakness is necessarily the cause of your pain.
It means gradually rebuilding physical capacity can be an important part of recovery.
What does rehabilitation involve?
At The Recovery Project, we don't simply prescribe the same core exercises to everyone with back pain.
We look at what you can currently tolerate and what you're trying to get back to.
This might involve:
Finding manageable starting points for walking and everyday activities.
Gradually rebuilding tolerance to bending and lifting.
Improving hip and trunk strength.
Increasing your tolerance to sitting or standing.
Progressively introducing resistance exercises.
Building confidence with movements you've been avoiding.
The aim isn't to force your way through pain.
It's to find a level of activity your back can currently manage and progressively build from there.
We don't want you avoiding movement forever. We want to help you become more capable of handling the demands of everyday life.
8. What Should You Do If Your Spinal Injection Hasn't Worked?
The next step isn't necessarily another injection.
It's worth reviewing the response with your treating clinician and understanding what the procedure was intended to achieve.
Some useful questions include:
Was the injection diagnostic or intended to provide symptom relief?
Did you experience any temporary improvement?
Did your back pain improve but your leg pain remain?
How long did any relief last?
What activities are still difficult?
Are there other potential contributors to your symptoms?
What can we do to improve your physical function?
Your response to an injection is one piece of the puzzle, not the whole picture.
If you develop new or progressive leg weakness, seek prompt medical assessment. New bladder or bowel dysfunction or numbness around the saddle area requires emergency assessment.
9. Does an Injection Not Working Mean My Back Pain Is Permanent?
No.
An injection not working doesn't mean you've run out of options.
It doesn't automatically mean your spine is getting worse.
And it doesn't mean rehabilitation won't help.
Persistent back pain can be complex, particularly when an MRI shows several changes that could potentially contribute to symptoms.
Sometimes further medical investigation or treatment is appropriate.
Other times, the next step is to focus on rebuilding movement, strength and tolerance to activity.
Recovery isn't always about fixing one structure.
It's about helping you return to the activities that matter to you, even when some structural changes remain.
Frequently Asked Questions About Spinal Injections and Back Pain
Why didn't my facet joint injection work?
If you had a diagnostic medial branch block, a lack of pain relief may suggest the facet joints aren't the primary source of your symptoms.
However, diagnostic blocks aren't perfect, and the result needs to be interpreted by your specialist.
If you had a corticosteroid injection into the facet joint itself, the purpose and interpretation are different.
What's the difference between a nerve block and a corticosteroid injection?
A nerve block usually uses local anaesthetic to temporarily interrupt pain signals.
A corticosteroid injection uses anti-inflammatory medication to try to reduce inflammation and pain.
Some spinal injections contain both medications.
Why am I still in pain after a corticosteroid injection?
Corticosteroid injections don't help everyone. Pain can have several contributors, and inflammation may not be the main driver of your symptoms.
Even when inflammation is present, the injection may only provide temporary relief or no meaningful improvement.
How long does a spinal steroid injection take to work?
Some people notice relief within a few days, while others may take one to two weeks to experience the full benefit.
The response depends on the type of injection and the condition being treated.
Can Modic type II changes cause lower back pain?
Modic type II changes can be associated with lower back pain, but they are also found in people without symptoms.
Their presence on MRI doesn't automatically confirm that they are causing your pain.
Can vertebral endplate pain get better?
Yes. Symptoms associated with the vertebral endplate region can improve, even if some structural changes remain visible on MRI.
Rehabilitation may help improve physical capacity and tolerance to everyday activities.
Does an injection not working mean my back pain is permanent?
No. An unsuccessful injection doesn't mean your back pain is permanent.
It may mean the suspected pain source needs reassessment or that a different management approach is required.
Should I exercise if my spinal injection hasn't worked?
For many people with persistent lower back pain, appropriate exercise can be beneficial.
The starting point and progression should reflect your symptoms, medical history and physical capacity.
Follow the post-procedure advice from your treating clinician and seek reassessment if symptoms are significantly worsening or new neurological symptoms develop.
Looking for Back Pain Rehabilitation in Cromwell?
At The Recovery Project in Cromwell, Central Otago, we combine osteopathy, exercise rehabilitation and strength training to help people experiencing persistent and recurring lower back pain.
Whether you're recovering from a disc injury, dealing with ongoing symptoms after spinal surgery or struggling with back pain that hasn't responded to injections, we look beyond your MRI to understand how your symptoms affect your everyday life.
Our approach focuses on understanding your current capacity, developing meaningful goals and progressively building towards them.
Because an injection not working doesn't mean your back can't get better.
Book an appointment with The Recovery Project to discuss your symptoms and rehabilitation options.
References and Further Reading
National Institute for Health and Care Excellence (NICE). (2016, updated 2020). Low back pain and sciatica in over 16s: Assessment and management (NG59).
https://www.nice.org.uk/guidance/ng59Cohen, S. P., et al. (2020). Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group. Regional Anesthesia & Pain Medicine, 45(6), 424–467.
https://doi.org/10.1136/rapm-2019-101243Oliveira, C. B., et al. (2020). Epidural corticosteroid injections for lumbosacral radicular pain. Cochrane Database of Systematic Reviews, 2020(4), CD013577.
https://doi.org/10.1002/14651858.CD013577Hopayian, K., Raslan, E., & Soliman, S. (2023). The association of Modic changes and chronic low back pain: A systematic review. Journal of Orthopaedics, 35, 99–106.
https://doi.org/10.1016/j.jor.2022.11.003World Health Organisation (WHO). (2023). WHO guideline for non-surgical management of chronic primary low back pain in adults in primary and community care settings. World Health Organisation.
https://www.who.int/publications/i/item/9789240081789
