Date of Publication: 27 September 2026

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“My MRI shows a disc protrusion pressing on a nerve. Does that mean I need surgery?”

It is a question I hear surprisingly often.

For many people experiencing pain or tingling down the leg, an MRI showing a disc protrusion seems to provide an obvious explanation:

The disc is protruding.
It is pressing on the nerve.
Remove the pressure, and the problem is solved.

It sounds logical.

But sciatica is often more complex than what we see on an MRI.

What Is Sciatica?

Sciatica is a clinical syndrome, rather than simply an imaging diagnosis.

It generally describes pain radiating from the lower back or buttock into the leg, usually associated with irritation or dysfunction of a lumbosacral nerve root.

Some people experience predominantly pain. Others may experience tingling, numbness or altered sensation. In more significant cases, there may also be muscle weakness or changes in reflexes.

A lumbar disc herniation is certainly one important cause of sciatica.

But finding a disc protrusion on an MRI does not, by itself, tell us the whole story.

The MRI Is Important — But So Is the Patient

Consider this scenario.

A person develops pain and tingling down the leg. An MRI is performed and shows a lumbar disc protrusion.

It is easy to conclude:

“There's the problem. The disc is compressing the nerve, so we need to surgically decompress it.”

But now consider the clinical examination.

Their muscle strength is normal.

Their reflexes are normal.

Sensation to touch and pinprick is intact.

Neural tension tests do not reproduce their symptoms.

They have full lumbar movement.

And, importantly, there is no progressive neurological deficit.

Does the MRI finding matter?

Absolutely.

But it needs to be interpreted alongside the patient's symptoms, neurological findings and physical examination.

A Disc Herniation Is Not Necessarily Permanent

Lumbar disc herniation can certainly produce mechanical irritation or compression of a nerve root.

However, the simple explanation that “the disc is sticking out and physically crushing the nerve” doesn't tell the entire story.

Inflammatory processes surrounding the nerve root can also contribute to radicular pain.

And there is another important part of the story that many patients don't realise:

Disc herniations can change over time.

Herniated disc material can spontaneously regress or resorb as part of the body's natural biological response.

A 2023 meta-analysis involving more than 2,000 conservatively treated patients found spontaneous resorption in approximately 70% of lumbar disc herniations overall, with much of the resorption process occurring within the first six months.

Interestingly, the type of herniation matters. Extruded and sequestrated discs were considerably more likely to undergo spontaneous resorption than simple disc protrusions.

So an MRI showing a disc herniation does not automatically mean surgery.

So, When Is Surgery Necessary?

There are situations where surgical assessment is very important.

Significant or progressive muscle weakness, progressive neurological loss, or signs of cauda equina syndrome — including new bladder or bowel dysfunction or altered sensation around the saddle region — require urgent medical assessment.

Surgery may also be considered when severe and disabling sciatica persists despite appropriate conservative treatment, particularly when the clinical findings and imaging correlate.

Surgery is therefore not “good” or “bad” treatment.

The key point is that the presence of a disc protrusion on an MRI alone should not automatically be interpreted as an indication for surgery.

What If There Is No Progressive Neurological Deficit?

This is where conservative care becomes important.

And conservative care doesn't simply mean resting and waiting.

The aim is to manage symptoms, maintain movement, restore function and progressively return the person to normal activity while continuing to monitor their neurological status.

Depending on the individual presentation, conservative management may include:

• education and appropriate activity modification;

• chiropractic care and manual therapy;

• physiotherapy and other appropriate physiotherapeutic modalities; and

• exercise and rehabilitation.

The exact approach should depend on the individual rather than simply what appears on the scan.

It is to support recovery, restore function and provide an appropriate environment for the body's natural healing processes to take place.

The Bigger Question

When someone with sciatica is shown an MRI demonstrating a disc protrusion, perhaps the first question shouldn't be:

“How bad does my MRI look?”

Better questions might be:

What does my neurological examination show?

Is my neurological function stable, improving or deteriorating?

Do the MRI findings actually correspond with my symptoms?

And which management approach is appropriate for me at this stage?

Imaging is an extremely useful part of modern healthcare.

But an MRI is a picture taken at one point in time.

Understanding that distinction can change the conversation from simply trying to “fix” an image to something much more meaningful:

helping the person in front of us recover function and return to living their life.

What Does the Research Say?

The approach discussed above is supported by current clinical guidelines and published research.

1. Disc herniations can spontaneously resorb

A 2023 meta-analysis examined 31 studies involving 2,233 patients with lumbar disc herniation who received conservative treatment.

The researchers reported spontaneous disc resorption in approximately 70% of cases overall, with most of the resorption process occurring within the first six months.

Interestingly, the likelihood differed according to the type of disc herniation:

• Sequestration: 87.8%

• Extrusion: 66.9%

• Protrusion: 37.5%

• Disc bulge: 13.3%

This is an important reminder that the appearance of a disc herniation on an MRI is not necessarily permanent, and its natural history should be considered alongside the patient's clinical presentation.

Reference:
Zou T, et al. Incidence of Spontaneous Resorption of Lumbar Disc Herniation: A Meta-analysis. Clin Spine Surg. 2023. DOI: 10.1097/BSD.0000000000001490.

2. Conservative treatment is generally first-line when there is no significant neurological deficit

The World Federation of Neurosurgical Societies (WFNS) Spine Committee recommends conservative treatment as the first-line approach for lumbar disc herniation when there is no cauda equina syndrome, motor deficit or other serious neurological deficit.

Conservative management can include activity modification, appropriate medication and physical therapy or rehabilitation.

Reference:
Yaman O, et al. The role of conservative treatment in lumbar disc herniations: WFNS Spine Committee recommendations. World Neurosurg X. 2024;22:100277.

3. When should surgery be considered?

The WFNS recommendations identify severe motor deficit, progressive neurological impairment, cauda equina syndrome, or failure of appropriate conservative treatment as circumstances in which surgery may be indicated.

The NICE guideline similarly recommends considering spinal decompression when non-surgical treatment has failed to improve pain or function and the radiological findings are consistent with the person's sciatic symptoms.

In other words, the decision should not be based on the MRI alone.

References:
World Federation of Neurosurgical Societies Spine Committee. Role of surgery in primary lumbar disk herniation: WFNS Spine Committee recommendations. World Neurosurg X. 2024.

National Institute for Health and Care Excellence (NICE). Low back pain and sciatica in over 16s: assessment and management (NG59).