Back Pain: What a Scan Shows and What It Does Not

Back pain is one of the leading causes of disability worldwide and one of the most over-investigated. The instinct on day three of a painful back is to get an MRI. In most cases that scan will not change treatment, and it can make things worse.

Why scans mislead

MRI studies of people with no back pain at all find disc bulges in a large proportion of adults, and the proportion rises steadily with age. Disc degeneration on a report is, for most people over 40, a normal finding, like grey hair.

The problem is what the words do. A patient told they have a slipped disc and degenerative disease becomes afraid to move, moves less, deconditions, and hurts more. Trials consistently show that early imaging in uncomplicated back pain leads to more surgery and more disability, without better pain relief.

Imaging is valuable when it will change the plan: red-flag features, progressive neurological loss, or surgery being actively considered.

What most back pain actually is

The large majority is non-specific mechanical back pain: pain arising from muscles, joints, ligaments and discs without a single identifiable structural cause. It typically improves substantially within four to six weeks.

Sciatica, where pain radiates below the knee with tingling or numbness, suggests nerve root irritation. Even most sciatica improves without surgery, though it takes longer.

What helps, according to the evidence

Keep moving

Bed rest is harmful. Staying as active as pain allows, and returning to normal activity early, produces better outcomes than resting. This is the single strongest recommendation in every guideline.

Exercise

For pain lasting beyond a few weeks, exercise is the best-evidenced treatment. The specific type matters less than doing it consistently: walking, swimming, yoga, pilates, general strengthening. Core-specific programmes are not superior to general exercise.

Heat

Superficial heat helps in the acute phase. Ice has weaker evidence.

Manual therapy

Spinal manipulation and massage give modest short-term relief, best used alongside exercise rather than instead of it.

Medication

• Paracetamol alone is of limited benefit for back pain
• NSAIDs give modest relief; use the lowest effective dose for the shortest time, with caution in kidney disease, hypertension and reflux
• Muscle relaxants may help briefly in acute spasm but cause drowsiness
• Opioids are not recommended for ordinary back pain; harms outweigh benefits
• For persistent nerve pain, drugs such as amitriptyline or duloxetine may be considered

Addressing the whole picture

Persistent back pain is strongly influenced by sleep, stress, fear of movement and low mood. This does not mean the pain is imaginary. It means treatment that ignores these factors tends to fail. Cognitive behavioural approaches and graded activity have good evidence for chronic back pain.

Red flags that need prompt assessment

• Loss of bladder or bowel control, or numbness around the groin and inner thighs, which is a surgical emergency
• Progressive weakness in a leg or foot drop
• Unexplained weight loss, fever or night sweats
• History of cancer
• Pain following significant trauma, or in someone with osteoporosis or on long-term steroids
• Severe night pain that does not change with position
• Onset before age 20 or after age 55
• Morning stiffness lasting more than an hour with gradual onset in a young adult, which may suggest inflammatory back disease

Preventing recurrence

• Regular exercise, which is the only intervention with strong evidence for prevention
• Breaking up long periods of sitting
• Reasonable lifting technique, though the evidence here is weaker than commonly claimed
• Maintaining a healthy weight
• Not smoking, which is associated with more back pain and slower healing

This article is general health information. New, severe or persistent back pain should be assessed by a doctor, and any red flag feature needs prompt medical attention.