Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Back

Back problems affect 80% of all people at some time in their life. There is no specific category of subjects who suffer back pain more frequently than others—labourers are affected as often as clerks, men as often as women. Important contributory factors are hard physical work, lifting, static working postures, and vibration. In spite of the fact that the heaviest industrial tasks are now carried out by machines, the number of people seeking advice for back pain does not seem to have decreased. Of all sufferers, 70% return to work within a week and 90% within 3 months, regardless of the treatment they receive.

Functional anatomy and biomechanics

The spine is composed of 7 cervical (neck) vertebrae, 12 thoracic (chest) vertebrae and 5 lumbar (lower back) vertebrae, plus the sacral and coccygeal vertebrae. Each vertebra consists of a body from which a dorsal arch of bone arises. On each arch there are articular processes which allow limited mobility between adjacent vertebrae. Between the vertebral bodies are flexible plates of fibrocartilage, the disks, which facilitate movements of the spine and act as shock absorbers. Intervertebral disks have no blood or lymph supply and only a limited nerve supply.

The spinal column has supportive, protective and locomotive functions. The neck region is very mobile and the lower back region is fairly mobile, with most movement between the fifth lumbar vertebra and the first sacral vertebra. The chest region, on the other hand, is less mobile because the ribs are attached to their corresponding vertebrae. The regions of the spine that have most mobility generally give rise to most problems.

There is an anterior and an posterior longitudinal system of ligaments along the spine. In addition there are smaller ligaments around the joints and between the vertebrae and their spinous processes. These ligaments are responsible for the passive stability of the back. Active stability is contributed by the muscles of the back and the abdomen and is of great importance. These muscles can be divided into an anterior group, which includes the abdominal and psoas musculature, and posterior deep and superficial groups.

The spine is exposed to a heavy load when the body is bent forwards or turned, and the activity of the muscles of the back increases noticeably when the body is bent forwards at an angle of 30°. The same muscles have to work harder when the body is sitting rather than standing and this exposes the disks to increased pressure. In general, injudicious flexing of the spine, side bending, excessive twisting or loading asymmetrically should be avoided. During lifting, the load should be placed as near to the body as possible.

Investigation of back pain

Diagnosis of back problems depends on the expert evaluation of pain, physical examination results, back function, constitutional factors, and X-ray findings. The location, intensity, duration, and quality of pain should be considered, as well as factors that precipitate or relieve it. The function of the back should be studied with regard to its range and pattern of movements, posture, muscle tone and control, and constitutional factors should be evaluated. Changes in the shape of the spine, e.g. an exaggerated S-shaped curve (scoliosis), can, like the overall physique, be of importance.

A number of skeletal changes such as slipping of one vertebra on another, stress fractures, bony outgrowths along the edges of the vertebral bodies, and degenerative joint changes, can be identified by ordinary X-ray examination, while a ‘slipped’ disk can be seen with the help of a contrast medium. Computerized serial X-rays (tomography) can give additional information about the various tissues making up the spinal column.

Radiography should be performed in maximal flexion, extension, or any other position that evokes pain. Magnetic resonance imaging (MRI) gives both soft tissue and skeletal information, which can reveal instability or other causes of pain.

The injured person’s social situation and psychological mood can be important when a history of back problems is given, and should be evaluated by enquiring into family circumstances, education, working conditions, and so forth.

Neck

The two uppermost cervical vertebrae bear the brunt of turning (rotatory) movements while flexion and extension occur predominantly at the occiput and at the first cervical vertebra. Injuries that may affect this area include fractures and dislocations with ligamentous damage. Degenerative changes can affect the disks and give rise to bony outgrowths (osteophytes) along the edges of the vertebral bodies, resulting in pressure on nerve roots and thus pain. Injuries and diseases of the cervical spine can cause pain which not only affects the neck but can radiate to the back of the head, the shoulders, arms, and hands, as well as the lower body parts.

Traumatic injuries

Blows to the head and cervical region can fracture the cervical vertebral column and also cause dislocations with simultaneous injuries to the joint capsules, ligaments, and disks. The injuries can be either stable or unstable. The most common modes of injury are bending backwards (extension) or forwards (flexion), rotating too violently, or hitting the head so that the impact is transmitted to the cervical region (axial compression).

Bending forwards can cause a compression fracture at the front, and ligament injuries at the back, of a vertebral body. Sometimes fractures of the joint processes and injuries to the joint capsule also occur, and
ligament injuries may be present without any visible injury to the skeleton. After an injury associated with flexion it is essential to decide, with the help of X-rays, whether the injury is stable or unstable. Extension (bending backwards) produces similar injuries, with disk and ligament damage at the front and compression damage at the back of the vertebral bodies. A twisting impact can occur in isolation or in combination with flexion or extension. Unilateral damage to joint processes and ligaments can occur with a resultant dislocation.

A fracture and/or ligament injury of the cervical spine result from violent collision with an opponent or with surrounding objects, e.g. a goal post, and can be serious. Within the cervical vertebral column, the vertebral canal contains the spinal cord, which, together with its nerve roots, can be subjected to pressure and damaged by bone and ligament injuries.

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