The spine is made up of a total of 24 vertebrae. Thanks to its double s-shape, it is adapted to man's upright posture. Static load of the spine increases from the top to the bottom. Degenerative changes in the lower region are therefore the most frequently occurring. Each vertebra consists of a vertebral body and a vertebral arch. Each vertebral arch has articular processes which are associated with the vertebra above and below via small joints. These joints enable the vertebra to move in certain directions.
The spine is permeated by the spinal channel over its entire length. This channel contains the spinal cord. The vertebral arch’s bony ring offers the spinal cord protection against damage. Cuts in the upper and lower edge of the vertebral arch allow nerves and blood vessels to penetrate.
Hardy fibrocartilage plates – or “discs” - lie between neighboring vertebrae. These act as fixed connectors and elastic buffers between the vertebrae.
Discs are composed of an outer fibrous ring, the annulus fibrosus, and a central elastic core, the nucleus pulposus.
How does a disc prolapse occur?
A disc prolapse is the dislocation of soft core of the disc through a weak point in the fibrous ring, mostly in the direction of the spinal cord or the nerve roots. Most disc prolapses arise in the lumbar portion of the spine in patients aged between 30 and 50 years old. This dislocation leads to narrowing and compression of the nerves and blood vessels. Various symptoms may manifest themselves, depending on the nature and extent of this dislocation. Some prolapses go unnoticed, others will be associated with strong pain, while in some cases paralysis or problems of sensation may arise.
As long as there is pain and feeling is disturbed, in many cases a disc prolapse can be treated without the need for an operation, using medication-based regimes and physiotherapy. Initial rest in bed, as well as relief for and relaxation of the spine, are also important. Should paralysis be present, however, operative therapy, with removal of the prolapse, should be preferred, as nerves can be lastingly damaged through compression.
After a prolapse – whether treated conservatively or operatively – the volume of the disc diminishes. Its supporting and shock absorbing function is then in most cases lastingly destroyed. Increased loss in height of the disc can lead to a relaxation of the spinal structure. This segment loosening is usually followed by instability, which may lead to renewed compression of the nerves and of the spinal column.
A cycle of pain begins, which is associated with episodes of inflammation, the dying of disc cells, ossifications and often also with a pathological blood vessel and neuronal invasion of the affected disc.