Anaesthesia => Backache
Backache, a common condition in which sufferers experience pain in a region along the backbone, often in the lower portion of the back.
ANATOMY OF THE BACK
The backbone, or spinal column, is the main supporting structure in the human body. The spine consists of 33 bony blocks (vertebrae) standing in a stack, one on top of the other. Each vertebra is joined to the one above and below by joints and ligaments. In between each vertebra lies a disc (often called the intervertebral disc), which acts as a cushion of tissue providing a springy and movable connection between the bones. Each disc has a distinct structure consisting of two parts: a central area known as the nucleus pulposus and an outer ring, the annulus fibrosus. The former consists of jelly-like material which can easily be squashed, and can adapt to accommodate the various stresses imposed on the spine from time to time. It is kept in shape by the outer annular ring and by the vertebral bodies above and below it. All the way along the vertebral column nerves emerge from between the vertebral bodies through gaps (the intervertebral foramina) and travel outwards to various parts of the body.
Several different broad groups of disorders of the spine lead to back pain. These include injury to the spine; mechanical and structural defects of the backbone; inflammatory disorders, such as rheumatoid arthritis; and, much more rarely, tumours that occur in and around the back (see below). In some patients no cause for their back pain can be found despite extensive investigation.
One of the most common causes of back pain is a "slipped disc". This is actually a herniated intervertebral disc or prolapsed intervertebral disc. In this often very painful condition, the disc bursts or ruptures, and fragments of the outer annulus fibrosus, together with some of the inner nucleus pulposus, press on ligaments and nerves that run close to the spine. The disc protrudes outwards-it does not actually "slip". Although any disc in the entire spine can herniate or burst, the most common ones to be affected are the lowest five in the spine, possibly because these are under the most mechanical stress. The lower vertebrae are under the most stress because they support most of the body's weight, whereas the upper ones only support the weight of the head. If the protruding disc juts out far enough to press on one or more of the nerves which emerge from the intervertebral foramina, sensations of pain, numbness, and tingling will be produced, which are felt in the anatomical area supplied by that nerve. In the case of the lower back, the nerves going into the lower limbs, particularly the sciatic nerve, may be affected-resulting in the pain that radiates through the lower back and buttock into the legs (usually called "sciatica").
Although a prolapsed intervertebral disc can occur at any age, it is most frequent between the ages of 20 and 50 years, with the peak incidence being between 40 and 45 years. The pain may strike immediately or it may develop gradually over hours or days. It may also be so severe and disabling that if it happens while a person is stooping down, he or she may not be able to stand or straighten up. In most cases the back itself will show a sharp twist (scoliosis). This twisting of the spine is a reflex compensatory mechanism made by the body to try to relieve some of the pressure on a trapped nerve. Depending on severity, attacks of back pain due to rupture of an intervertebral disc may subside with immediate rest and treatment over several days to several weeks.
One of the single most common causes of back pain is wear-and-tear damage to the spine. With age, the discs lose their ability to be flexible and are gradually replaced by fibrous tissue. At the same time, the bony surfaces of the vertebrae and the intervertebral joints also show wear-and-tear and degenerate. The bony ends of the vertebrae become thickened and a rim of bony tissue develops around the edge of the disc. These changes, termed spondylosis, are the body's attempt to splint the spine in position and so prevent further damage. Damage to the small joints between the vertebrae produces the condition known as osteoarthritis. By the age of 60 almost everybody has signs of wear-and-tear spinal damage, which can be seen on X-rays; these changes are an inevitable consequence of ageing. The symptoms produced are pain and stiffness in the back, with consequent restriction of movement, so that a person can no longer bend down, or can only do so with a certain amount of pain.
The joints in and around the vertebral column function in the same way as joints elsewhere in the body and are therefore prone to strains and sprains. These will, of course, result in back pain which is usually localized to the affected area. If the strain has been severe, the affected ligaments may heal by forming large amounts of fibrous tissue. This results in impaired mobility and causes the stiff back often seen after a vertebral column injury. This can be suffered by people who strain their backs while lifting heavy weights and who may continue to suffer from a stiff back for years afterwards.
Very low back pain is not usually the result of vertebral column disease but is more likely to be due to problems with the joints connecting the sacrum, the very base of the vertebral column, to the hip bone, or ilium. Inflammation occurs at these joints-called the sacroiliac joints of the spine-in ankylosing spondylitis, a condition of the spine which produces severe stiffening and impaired mobility. The end result is a "bamboo spine", so-called because all the vertebrae eventually become fused together resulting in a completely rigid spine. This condition most often appears in young men between 15 and 25 years of age and is thought to affect around 2 per cent of the population. Regular exercise and physiotherapy have an important role to play in the prevention of the later stages of this disease.
Infections in the back are rarely a cause of back pain nowadays. When they occur, the sufferer is usually quite ill and has a fever and shivering attacks; they are caused by infection spreading to the back from another source elsewhere in the body (for example, a boil). Surgical intervention is usually required to drain this type of infection. Tuberculosis may also affect the back but again the incidence of this is falling.
Diseases of the bone itself may also give rise to back pain. The most common conditions which cause this kind of back pain are osteoporosis, which is increasingly a problem during and after the menopause, and osteomalacia. Progressive weakening of the bones in either of these conditions may result in crush fractures, when one of the vertebrae of the backbone collapses because it can no longer support the weight of the body. This usually causes sudden, severe back pain from pressure created by the fracture on the nerves around the spine, and usually requires immediate surgery.
Tumours of the spine are rare and an uncommon cause of back pain. They may be due either to growths spontaneously generated in that area, or to the spread of cancer from elsewhere in the body. The tumour may be benign or malignant, and diagnosis by back specialists usually depends on surgical removal of part or all of the tumour for examination (biopsy).
How back pain is investigated by the doctor depends very much on the symptoms described by the patient. X-rays are nearly always performed and are useful for examining the bony structure of the vertebral column. More sophisticated investigative techniques, such as CT (computerized tomography) scans or an MRI (magnetic resonance imaging) scan are needed to visualize accurately the intervertebral discs and the soft tissues of the back which include them, and to determine whether or not there has been a prolapse. It is then possible to see whether the disc has ruptured, and if it has, also whether it is pressing on a nerve root or not. X-rays can only visualize bony structures and are of little use for looking at the disc. Some specialists can also diagnose types of disc lesion by analysing the various movements made by the patient.
Treatment of back pain depends very much upon the cause and type of lesion. Modern medicine tends to advocate more conservative treatment such as lying flat in bed for at least two days and taking painkilling medication, while reserving surgery for more persistent or severe cases, or for patients whose underlying problem is a tumour. Surgical intervention is used, for example, where there is pressure on a vital nerve. Surgery usually involves either removal of part of the disc that has herniated (laminectomy); or removal of part of a vertebra in an attempt to relieve pressure caused by a herniating disc; or fusion of two or more vertebrae.
Other procedures, such as physiotherapy, chiropractic methods, traction, and manipulation, may also be recommended. Traction exerts a pulling force, using ropes, pulleys, and weights built into a special bed, to take pressure off a prolapsed disc by slightly pulling the vertebrae apart. Manipulation, which is used by physiotherapists and osteopaths, involves the use of the hands to relieve the pressure on back joints caused by prolapsed discs and other injuries.
The best treatment of all is, of course, prevention. Much back pain that develops later in life can be prevented by protecting the back sensibly when younger. People of any age, whether with a history of back pain or not, should be taught to adopt a correct sitting and working posture; always to bend at the knees, particularly while lifting a heavy weight; and to sleep in a firm bed in order to prevent stresses and strains imposed on the back because of poor back support while asleep.