The spinal discs are responsible for the flexibility of the spine and alleviate strain on the spinal column. As we get older, the spinal discs become more prone to injury and can lead to problems in the cervical vertebrae of the neck and the lumbar region.
Spinal discs consist of a ring of connective tissue with a soft gelatinous core, which makes the spine flexible and acts as a shock absorber. When you suffer from a slipped disc, the core slips out of place and breaks through the protective ring of connective tissue. The gelatinous mass leaks out and presses against the spinal cord or the nerve roots (Fig.1).
Men aged between 30 and 50 are particularly susceptible
A herniated or slipped disc usually occurs between the age of 30 and 50. Men are almost twice as likely to suffer a slipped disc than women. For every herniated disc in the cervical region, ten occur in lumbar part of the spine. The latter are the most common reason for spinal operations, although not all herniated discs require surgery. Around 50% of operations are performed between the fifth lumbar and the first sacral vertebrae (L5/S1). The second most common operation involves the spinal disc immediately above (L4/5).
Spinal disc tearing
Herniated discs are primarily caused by degenerative changes in the spinal discs. The natural ageing process can result in tears in the connective tissue ring. If the gelatinous core of the spinal disc escapes through such a tear into the vertebral canal, this leads to a herniated or prolapsed disc.
If the core completely separates from the disc, this is known as a sequestered disc (sequestration, Fig. 4). If the ring is only weakened rather than fully torn, this can lead to disc protrusion or disc bulge (protrusion, Fig. 2). In this instance, tissue does not leak into the vertebral canal. Tissue from the disc can either mechanically press against the
nerve roots in the vertebral canal and/or chemically irritate the nerve fibres through substances caused by the condition
Frequent lifting is seldom the culprit
The timing and severity of spinal column wear are largely genetically determined. Known risk factors such as frequent lifting of heavy loads, twisting one’s back, the transmission of vibrations to the body (e.g. when driving a lorry), jobs involving frequent sitting down and nicotine consumption only play a secondary role.
Back, arm and leg pain
The typical hallmark of a herniated disc is what is known as radicular pain (i.e. radiating from the nerve roots): arm pain radiating from the cervical spine and leg pain – also known as sciatica – radiating from the lumbar spine.
In acute cases involving the lumbar, the back pain is usually secondary or precedes the leg pain. A herniated disc in the cervical spine follows a similar pattern, with the arm pain dominating the neck pain. Neurological symptoms can also occur in conjunction with this pain. Sensory disturbances in the leg or arm and the weakening or paralysis of individual muscles limit the person’s ability to walk or use their hands and arms. These kinds of neurological disorders enable doctors to locate the herniated disc with a high degree of accuracy.
Severe cases in the lumbar spine can lead to cauda equina syndrome, which is characterised by bladder and/or rectal paralysis and urinary and/or faecal incontinence. This generally requires emergency surgical treatment, whereas isolated muscle weakness or sensory disturbances in the legs or arms do not necessarily call for surgical intervention.
Radicular pain can be triggered or intensified by coughing, sneezing or through pressure on the back/stomach region. Pain can be reduced by simultaneously bending the hips and knees while in a supine position (lying on one’s back).
Article from Prof.Dr.med Max Aebi, specialist in orthopaedic surgery and traumatology of the musculoskeletal system.
Read part two of this article:
Slipped discs: Invisible in x-ray images (Part II)
Legend:
1.) nerve root compression
2.) slipped discs protrusion
3.) slipped discs extrusion
4.) slipped discs sequestration