Back pain

Summary

Back pain is second only to headache as the most common cause of pain. It can be acute, intermittent or chronic and is mostly caused by minor injuries, slipped discs, facet joint problems or arthritis. Ageing, a sedentary lifestyle, poor posture, obesity, genetic factors, certain work environments, pregnancy, smoking and even psychological factors can put one at risk of backache. Good back hygiene and regular exercise can prevent or postpone back problems.

Some symptoms – such as back pain combined with bladder or bowel control problems – are cause for contacting a doctor immediately. Otherwise, wait about a week before you go to the doctor with back pain, in case it resolves by itself. Eighty to 90 percent of back pain resolves spontaneously within six weeks.

Less than 5 percent of back pain patients will need an operation. Always ask for a second opinion if back surgery has been recommended.

Back pain can occur anywhere along the spine, but the most common site is the lower back or lumbar region. The lower part of the back bears the weight of the upper body, as well as any weight you’re carrying. It also twists and bends more than the upper back.

Back pain may be acute, recurrent or chronic. Most cases of back pain are acute – i.e. the pain starts suddenly and intensely – and usually last a short time (less than a month). Acute back pain is not usually caused by a serious medical condition and most cases resolve within a few days. Recurrence is however common and takes the form of repeated episodes of acute pain with pain-free intervals. Chronic back pain is present all the time, persists beyond three months and even slight movements can trigger it. Recurrent or chronic pain is usually more intractable than acute pain and often requires specialist advice.

In about 85% of acute back pain cases the exact cause cannot be identified. There are many different possible causes; the following are some of the more common ones:

Sprains, strains and minor injuries: in most cases the cause of back pain is not serious damage or disease, but having lifted a heavy object or made an abrupt movement. This is often called "simple" back pain. 
A strain or tear to the muscles, tendons or ligaments can produce painful muscle tension and spasm. The pain usually lasts only a few days. Although this pain often begins suddenly, and one particular movement can trigger it, the underlying cause may have been developing for some time. Inactivity and improper movements are usually at the root of simple back pain. (See risk factors.)

Intervertebral disc lesion: wear and tear or strain may cause a spinal disc to bulge, tear or rupture (herniate). The disc's gelatinous filling protrudes and presses against sensitive nerves from the spinal cord. This is commonly referred to as a "slipped disc".

Facet joint problems and osteoarthritis: this is the usual cause of recurrent or chronic lower back pain. Spinal movement is made possible by joints between the vertebrae that consist of two flat faces or "facets". If these degenerate, the two halves of the joint grate painfully against each other. 
Initially, the disc degenerates or wears down and increases the stress on the facet joints behind it. These joints become inflamed and later wear out (osteoarthritis). The inflamed joints cause backache.
Later, the arthritic joints become big and swollen (like an old lady’s arthritic finger joints) and these enlarged joints protrude into and narrow the spinal canal. This is called spinal stenosis and causes pinching of the nerves that run down the buttocks and legs, resulting in nerve pain (sciatica) and weakness down the legs.
The pain is typically worse when standing and walking (spinal claudication) and relieved by sitting or bending forward. It is often easier to walk in a stooped position, for example when using a shopping trolley.
 

Other causes

Pathological back pain can sometimes be due to an infection (spondylodiscitis) and tumours. Back pain may also be referred from problems in other organs, usually near the spine. These conditions include peptic ulcers, kidney problems, pancreatitis, infections, inflammatory bowel disease, pregnancy, menstruation and other gynaecological problems such as ovarian cysts. In older people, low back pain may be a symptom of Paget's disease.

Backache can be caused by an accident or an injury to the spine, degenerative disease, metabolic diseases, infections or a tumour Use this list as a basis for the possible causes of back pain.

 If you experience any of the following symptoms, you could have a back problem:

• pain in the back
• restriction of back movements
• back pain accompanied by numbness of one or both legs
• back pain radiating to the foot or knee
• dizziness or disturbance of vision related to neck posture
• difficulty standing up after sitting for prolonged periods
• back pain after standing for a long period of time

Structure of the back 

The back's system of bones, muscles, ligaments, tendons and nerves work together to bear the weight of your body and the loads you carry. The structure of the back provides considerable strength and flexibility, but because the spine is so central to the body's movements, even small amounts of damage can often cause pain.

The spine consists of 33 bony segments, the vertebrae. There are seven cervical, 12 thoracic, five lumbar, five sacral and four coccygeal vertebrae. The two latter groups – the sacrum and coccyx – are fused and immobile. Between the cervical, thoracic and lumbar vertebrae lie the discs: tough, spongy "cushions" that act as shock absorbers for the vertebrae and give the spine flexibility. Strong elastic ligaments hold the vertebrae and discs firmly together in a column. Muscles attach to the vertebrae by fibrous connections called tendons. The complex layers of back muscle contract to move your back and upper body.

The spine column also protects the spinal cord, which runs down through a canal formed by the vertebrae. Nerves (roots) from the spinal cord branch out and leave the spine through spaces between the vertebrae at the levels of the discs.

Who gets back pain and who is at risk?

Back pain is second only to headaches as the most common site of pain. Four out of five adults will experience at least one bout of back pain in their life.

The following factors can increase your risk for back problems:

Ageing: Discs begin gradual deterioration from age 30. With age, the discs lose moisture and shrink. This puts more stress on the facet joints which become arthritic, with resultant back pain.

Sedentary lifestyle: Being unfit increases your risk for back pain, especially if you attempt an unaccustomed activity. Lack of exercise leads to the following conditions which may threaten your back:

• muscle inflexibility: restricts the back's ability to bend and rotate.
• weak back muscles: increases load on the spine and the risk of disc bulge.
• weak stomach muscles: increases strain on the back and cause the pelvis to tilt abnormally.
• obesity: increases weight on the spine and pressure on the vertebrae and discs. A large belly pulls the spine forward and out of alignment, increasing the risk of back strain.

Poor posture and spending long periods in one position, such as working at a computer or slouching in front of the TV.

Genetic factors: Some people are genetically susceptible to back pain, usually because they inherited spinal structural abnormalities. Mutation of the COL9A2 gene may be linked to about 10% of sciatica cases. This gene plays a role in producing collagen, an important protein component of the discs. The defective gene may cause disc deterioration, leading to sciatica.

Work that stresses the back: risky activities include lifting, forceful movements, bending and twisting into awkward positions, repetitive movements and vibration (as occurs with long-distance truck driving).

Improper body mechanics during sporting activities can damage the back, e.g. a jerky golf swing or incorrect use of exercise equipment. Cyclists often experience lower back pain, which is often resolved by adjusting the angle of the bicycle seat. Some research suggests that, over time, high-impact exercise such as rugby or aerobics may increase the risk for degenerative disc disease. Hyperextension of the spine as in gymnastics and cricket (especially in the case of bowlers) may lead to a stress fracture (spondylolysis).

Pregnancy makes women prone to back pain due to shifting of abdominal organs, forward redistribution of body weight and loosening of ligaments in the pelvic area prior to delivery.

Smoking: possibly because it decreases blood circulation to the tissues of the back. The association may also be due to a generally unhealthy lifestyle.

Psychological factors: research indicates that in many people, pre-existing depression and feelings of helplessness may have a negative influence on one’s perception of pain and one’s ability to cope with back problems. People with depression are also more likely to have vague physical symptoms, including back pain.

Physical examination and medical history

Your doctor will take a medical history, and will likely ask about the frequency, duration and nature of the pain (whether piercing, throbbing, burning, etc.); when it began; whether it was triggered by an event, such as lifting something heavy; what worsens the pain (e.g. coughing, walking) and what relieves it (e.g. lying down, exercise). Tell your doctor about any previous back pain episodes and injuries involving your back, neck or hips.

Your doctor will then give you a full physical examination.

Most cases of back pain will not require complex tests for initial assessment and treatment. However, if pain is severe and does not respond to treatment, or if you have significant leg pain, some imaging tests may be necessary. These may include the following:

X-rays can help show bone alignment and the presence of degenerative joint disease, tumours, infection or injury in some cases. Plain X-rays will not show soft tissue pathology such as the lumbar discs or nerves.

Magnetic resonance imaging (MRI) or computerised tomography (CT) scans generate images that help reveal conditions involving the soft tissues e.g. herniated discs. MRIs can also help detect other causes of back pain, including infection and cancer.

Bone scan: a scan is taken after a radioactive substance (tracer) has been injected into a vein to help detect bone tumours, stress fractures or osteoporotic insufficiency fractures.

Discography: discs suspected of being the source of pain are injected with dye and X-rayed. This technique is generally used only to identify the injured disc as source of the back pain before the patient undergoes surgery.

Myelography: a dye injected into the spinal canal shows up herniated discs or other lesions on X-rays or a CT scan. This procedure has largely been replaced by MRI scans.

Electrodiagnostic studies: electrical tests, such as EMG (electromyography), are used to study nerve conduction pathways, and can confirm nerve compression caused by spinal conditions (herniated discs or stenosis) and peripheral conditions (diabetic neuropathy or peripheral nerve compression).

Other tests 
Blood and urine samples may be used to test for conditions such as infections, cancer or arthritis.

Contact your doctor promptly if back pain results from a fall or blow to the back. Otherwise, contact your doctor if pain does not improve after about a week.

Infrequently, back pain can signal a serious medical problem. Consult your doctor if you have back pain and:

• bladder or bowel control problems (such as difficulty passing urine)
• numbness in the groin or in the vicinity of the anal region
• weakness, numbness or "pins and needles" in the legs
• fever
• rapid weight loss
• a history of cancer
• abdominal pain
• pain running down one or both legs
• you feel unsteady on your feet
• the pain is increased by lying down
• the pain wakes you at night
• the pain is unrelated to movement
• the pain is localised in the upper back (thoracic spine)
• a history of corticosteroid use
• a history of intravenous drug use
• a history of urinary tract infection
• in children, any severe back pain that persists for more than three days

Reviewed by Dr Pradeep Makan, orthopaedic surgeon, Melomed Gatesville and Life Vincent Pallotti Hospital in Cape Town and part-time lecturer in the department of orthopaedic surgery at the University of Cape Town, 2010.

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