Sciatica: symptoms, causes and when it stops being "just pain"
Most sciatica improves without surgery. The difficulty is recognising in time the cases that do not.
Before you read on. This article is general information for
patients. It cannot be used to reach a diagnosis and does not replace a
consultation: similar symptoms can have very different causes, and only an
in-person assessment — your history, your examination and your imaging — can
establish what is happening and what suits you. If something here worries you,
the right step is to discuss it with a doctor, not to draw conclusions.
Low back pain is one of the most common reasons for a medical consultation worldwide and a leading cause of time off work. Almost everyone will experience it at least once.
It is also the area where the most misinformation circulates. This article tries to organise what we actually know.
The fact that surprises almost everyone: in most low back pain, no specific structural cause is found. It is called non-specific low back pain, and it does not mean the pain is not real. It means the pain does not come from a lesion that can be operated on.
Low back pain is not the same as sciatica
| Low back pain | Radicular pain (sciatica) | |
|---|---|---|
| Where it hurts | Lower back, sometimes buttock | Travels down the leg along a path |
| Type of pain | Dull, mechanical, "heavy" | Burning, shooting, electric |
| Numbness | Rare | Common, in a specific area |
| Usual cause | Muscular, degenerative disc, facet joint | Nerve root compression |
| Surgical? | Rarely | Sometimes, with clear criteria |
Spine surgery works far better for leg pain than for pure back pain. That is one reason a serious neurosurgeon will not simply operate on isolated low back pain. If your pain travels down the leg, see our guide on sciatica.
The causes worth distinguishing
Mechanical or non-specific low back pain
By far the most common. It involves muscles, ligaments, facet joints and degenerated discs. It worsens with movement and eases with relative rest. There is no single identifiable culprit structure, which is why imaging is usually unhelpful.
Degenerative disc disease
The disc loses height and cushioning with age. This is a normal process: finding "dehydrated discs" on an MRI after 40 is as common as finding grey hair. It is not synonymous with disease.
Facet joint syndrome
The small posterior joints of the spine develop arthritis, causing pain that worsens on leaning backwards and twisting.
Spondylolisthesis and instability
One vertebra slips over another, causing mechanical pain that worsens with prolonged standing. Covered in depth in our article on spondylolisthesis.
Serious causes (uncommon, but must be excluded)
- Vertebral fracture, especially with osteoporosis or after trauma
- Spinal infection (spondylodiscitis)
- Primary tumour or vertebral metastasis
- Inflammatory disease such as ankylosing spondylitis
Do I need an MRI?
Probably not, at least not initially. This is one of the most consistent recommendations in the literature and one of the most frequently ignored.
Ordering imaging for low back pain without red flags in the first weeks does not improve outcomes and creates a problem: an MRI almost always finds something. Protrusions, disc dehydration, facet arthritis — findings that also appear in people with no pain at all.
When imaging is indicated from the start:
- Loss of strength or progressive numbness in a leg
- Numbness in the groin area or difficulty urinating → emergency
- Significant trauma, or minor trauma in someone with osteoporosis
- Fever, unexplained weight loss, history of cancer
- Night pain that wakes you and does not settle in any position
- Onset before age 20 or after age 55
- No improvement at all after 6 weeks of correct treatment
What actually works
- Keep moving. The best-evidenced recommendation there is. Prolonged bed rest makes low back pain worse. Walking is a good starting point.
- Therapeutic exercise. Core strengthening, motor control and hip work. Consistency matters more than the exact type of exercise.
- Sensible analgesia. Anti-inflammatories on a short course. Muscle relaxants have a limited, short role. Opioids are not a treatment for chronic low back pain.
- Pain education. Understanding that pain does not equal damage reduces fear of movement, one of the main drivers of chronicity.
- Managing aggravating factors: weight, smoking, inactivity, sleep and stress. All have measurable effects.
What works less well than you were told
- Prolonged bed rest
- Permanent use of back braces (they weaken the musculature)
- Traction
- Fusion surgery for non-specific back pain without demonstrated instability
When does seeing a neurosurgeon make sense?
- There is pain radiating into the leg that does not settle with conservative care
- There is a neurological deficit: reduced strength, altered reflexes, numbness in a specific territory
- Imaging shows stenosis, instability, tumour or fracture
- Pain has lasted more than 3 months without responding to proper treatment
- You want a second opinion before accepting surgery someone has proposed
A good share of these consultations end without surgery, and that is a good outcome. The purpose of the evaluation is to give you a clear diagnosis and a plan — not an operating room.
What patients ask most
How long should low back pain last before I worry?
Typical acute low back pain improves substantially within 2 to 6 weeks. If there has been no improvement at all by 6 weeks with adequate treatment, or if red flags appear at any point — loss of strength, groin numbness, difficulty urinating — it should be investigated without waiting further.
Should I get an MRI for back pain?
In the absence of red flags, not in the first weeks. An MRI almost always finds degenerative changes that also exist in people without pain, which can lead to unnecessary treatment. It is indicated when there is a neurological deficit, suspicion of a serious cause, or no improvement after correct treatment.
Is low back pain treated with surgery?
Rarely. Spine surgery works clearly better for leg pain from nerve compression than for isolated back pain. It is considered when there is demonstrated instability, symptomatic stenosis, deformity, fracture, tumour or infection — not for non-specific low back pain.
Are dehydrated discs on an MRI a bad sign?
Not on their own. Disc dehydration is part of normal spinal ageing and appears in most people after 40, many of whom have no pain at all. It is only clinically relevant when it correlates with symptoms and physical examination findings.
What is the best exercise for low back pain?
The one you can sustain. Evidence does not clearly favour one type over another: walking, swimming, clinical Pilates, core strengthening and hip work all help when done regularly. Consistency and gradual progression matter most, ideally guided by a physiotherapist.
Written and reviewed by Dr. Ricardo Bermúdez, neurosurgeon. Last reviewed: 2026-09-09.
General informational content. It is not medical advice, does not create a doctor-patient relationship, and must not be used to self-diagnose or to decide on treatment. Outcomes vary from person to person. If you have symptoms, see a doctor.
