An intervertebral disc prosthesis is an artificial intervertebral disc that can be used if the protruding part of the intervertebral disc is surgically removed after a herniated disc.
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Diseases of the intervertebral disc and other degenerative changes in the spine are among the most common civilization diseases of our time. The causes are a lack of exercise and predominantly sedentary work. The tiresome consequence: Chronic back problems increase in all occupational and age groups.
Sometimes an operation cannot be avoided after a herniated disc and an intervertebral disc prosthesis is used.
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Intervertebral disc surgery is usually not necessary
For most intervertebral disc patients, conservative therapies are successful. So there is no need for surgery. Targeted back exercises are sufficient in many cases.
If conservative therapy is unsuccessful, the protruding part of the intervertebral disc can be surgically removed. Disc surgery is considered if:
- the complaints persist or
- progressive nerve failures exist.
The segment in which the operated intervertebral disc is located is a complex structure consisting of two vertebral bodies with an intervertebral disc in between and the small vertebral joints further back, including the ligament connections. The absence of the protruding part of the intervertebral disc can lead to instabilities in this segment. This can make sense to use an artificial intervertebral disc.
When an intervertebral disc prosthesis makes sense
The insertion of an artificial intervertebral disc can be useful in the following situations:
Instabilities across one or two spinal segments with irritation of the nerve root when the intervertebral holes are narrowed (here the nerve roots emerge from the spinal canal),
Problems of the small vertebral joints further back,
persistent pain after intervertebral disc surgery,
(easier) vertebral sliding.
Intervertebral disc prostheses should not be used for:
poor bone substance, for example in the case of osteoporosis,
Inflammation of the movement segment concerned,
advanced spine sliding,
Complaints caused by narrowing of the spinal canal,
isolated pressure on a nerve root through displaced intervertebral disc tissue, whereby the other structures are still uninvolved.
It must be carefully considered whether a damaged intervertebral disc should be replaced by a prosthesis or not. The decision about this will affect the mobility and painlessness of the back for many years, maybe for life.
Artificial intervertebral disc has three components
For the prosthesis, which is to replace an intervertebral disc, a prosthesis model, which was developed in the former GDR, is used in most cases after several improvements. The intervertebral disc prosthesis consists of 3 components:
Two oval end plates made of metal (a very body-compatible chrome-cobalt-molybdenum alloy) and
an intermediate sliding core made of plastic (polyethylene), which enables almost normal segment movements with corresponding lateral mobility.
The steel plates are anchored to the vertebral bodies via a series of small steel teeth on the edge. The implantation is carried out without cement. The bone grows around the prosthesis and creates a firm anchorage for the implant. The prosthesis "grows into the bones".
Custom-made prostheses are available individually:
- steel plates of different sizes,
- sliding cores of different heights as well
- different angles of inclination depending on the curvature of the region of the spine to be supplied.
So the prosthesis can be adjusted to individual body measurements.
Intervertebral disc prosthesis gains mobility
If correctly indicated, the intervertebral disc prosthesis offers many advantages over other treatment methods. In contrast to the still predominantly practiced spinal stiffening, no vertebral body segment is decommissioned when an artificial intervertebral disc is provided, so that the full mobility of the spine is maintained.
The prosthesis takes over the space and function of the natural intervertebral disc and in this way guarantees stability in the affected spine segment. The neighboring segments, which have to take over the function of the disused spinal column section in the case of spinal stiffeners, are spared from overloading and the consequential damage associated therewith.
In this way, the vicious circle of "segment instability – stiffening – instability of the neighboring segment – further stiffening" is broken.
Back on her feet three days after the operation
Immediately after the procedure, the patients are already mobile without any aids. On the third day after the operation you can get up with an elastic bandage to support the abdominal muscles.
After the operation, patients usually receive additional training on mobility in daily life. The emphasis here is primarily on the walking condition that should be trained.
Strengthening and functional programs for the muscles of the trunk and spine, however, are initially not recommended. This limitation of physiotherapy follow-up treatment is necessary in order not to endanger the ingrowth of the intervertebral disc prosthesis through increased stress.
Temporary overload possible
The shape of the prosthesis is perceived as that of the intervertebral disc. This guarantees free mobility: the vertebral bodies can twist against each other by about 15 degrees. However, rotary movements are not slowed down, so that an overload can occur temporarily.
A possible complication of using an intervertebral disc prosthesis is loosening and wandering of the prosthesis. The material wear, however, is low.
With the intervertebral space endoprosthesis (intervertebral disc prosthesis) – if the indication is correct – there is an entirely viable concept for the treatment of spinal damage caused by wear. A final evaluation of the treatment with an intervertebral disc prosthesis can only be made through the scientific evaluation of the long-term results.