Low-back pain

Low-back pain

Low-back pain is a term describing pain located in the lumbar region. It is not a diagnosis; it only states that the person has pain in the lower part of the back.

Likewise, cervicalgia describes pain in the neck region and dorsalgia pain in the thoracic region.

Low-back pain is the most common cause of disability worldwide. Saying that someone has low-back pain, however, does not explain why it hurts. The real task is to determine its cause.

Mechanical and inflammatory low-back pain

A first essential distinction is whether the pain has mechanical or inflammatory characteristics.

Mechanical low-back pain

Mechanical low-back pain generally:

• Worsens with activity.
• Improves with rest.
• Increases as the day progresses.
• Is usually more intense at the end of the day.

Inflammatory low-back pain

Inflammatory low-back pain behaves differently:

• It worsens with rest.
• It may wake the person at night.
• It improves after the patient gets up and begins moving.
• It may be accompanied by morning stiffness.

This difference points toward completely different groups of diseases.

Causes of low-back pain

Low-back pain has many possible causes.

Mechanical causes include:

• Psychological factors, stress and tension.
• Spina bifida.
• Spondylolisthesis.
• Spondylosis or degenerative changes of the spine.
• Sciatica.

Inflammatory diseases can also cause low-back pain, particularly spondyloarthritis and ankylosing spondylitis.

Potentially serious causes must always be remembered, including:

• Vertebral metastases, such as those from prostate cancer in older men.
• Metastases from breast cancer in women.
• Abscesses and other spinal infections.

Low-back pain cannot be used as though it were the final diagnosis. Behind it may be anything from stress-related muscle spasm to inflammatory disease, infection or metastasis.

Sciatica is overdiagnosed

In my opinion, sciatica is enormously overdiagnosed.

Approximately 90% of cases called sciatica are actually myofascial syndromes caused by muscle spasm, stress, tension or anxiety.

The person may feel low-back pain extending into the buttock or leg, but this does not automatically mean that a nerve root is injured or compressed.

In these patients, there is no neurological deficit demonstrating true nerve involvement. Sciatica should therefore not be diagnosed solely because pain radiates into one leg.

First listen to and examine the patient

The medical history and physical examination guide which studies should be performed.

Before requesting tests, the physician should hear how the pain began, how it behaves, what worsens or improves it, and whether symptoms suggest a mechanical, inflammatory, neurological, infectious or malignant cause.

The patient should then be examined.

Only then can the physician decide which study is needed and which disease it is intended to confirm or exclude.

Medicine is the most inexact of all sciences

I have always said that medicine is the most inexact of all sciences, but even the most inexact science has a mathematical law.

No test has value by itself. The value of a study depends on the prior clinical probability: what the physician suspected after listening to and examining the patient.

If an expert considers that the patient may have a disease diagnosed by MRI and requests that study based on a well-founded clinical suspicion, the likelihood that the MRI will confirm the diagnosis rises substantially.

By contrast, ordering tests without listening, examining or knowing what is being sought provides very little information.

MRI does not replace clinical assessment

An MRI may show abnormalities, but finding an abnormality does not automatically mean that it is the cause of pain.

The result must be interpreted within the context of the medical history, physical examination and the disease suspected before the study was requested.

The study does not make the diagnosis by itself. Its usefulness depends on correct selection and interpretation.

How many studies does a person with low-back pain need?

A person with low-back pain might need hundreds of studies or none at all.

It depends on:

• The history described by the patient.
• Physical-examination findings.
• The disease being considered.
• The training and specialty of the evaluating physician.

Not everyone with low-back pain should be studied in the same way. What matters is not ordering many tests, but choosing the correct study for the correct clinical suspicion.

The objective is not to give everyone the generic label of low-back pain or automatically attribute the pain to sciatica. It is to determine why this particular person's back hurts.