Definition herniated disc
A slipped disc is a wear-related disease of the spine. Due to years of incorrect or excessive strain, the gelatinous ring of the intervertebral disc loses its elasticity and can shift.
Introduction
Although most people suffering from persistent back pain assume that they have a slipped disc, everyday clinical experience shows that a slipped disc is a rather rare cause of severe back pain. In many cases a herniated disc even causes no pain at all. Persons who develop a herniated disc due to many years of incorrect or excessive strain may notice sensory disturbances such as numbness or tingling and increasing muscle weakness.
In addition, it can also lead to the development of pain in the affected spinal segment. Persons who observe a corresponding symptomatology should urgently consult a specialist as soon as possible. If a herniated disc is present, the symptoms can only be alleviated after a detailed diagnosis and the initiation of appropriate treatment measures.
Diagnosis
The diagnosis of a suspected herniated disc usually involves several steps. Above all, the detailed doctor-patient conversation (short: anamnesis) can help to sort out the symptoms present in the affected person and make an initial suspected diagnosis. During this conversation, the affected patient should describe the symptoms as precisely as possible.
In the diagnosis of a herniated disc, pain in one or more spinal segments plays a decisive role. Depending on the severity of the herniated disc, this pain can also radiate into the arms, buttocks or legs. In addition, the herniated disc can cause sensory disturbances (such as numbness or tingling) due to nerve root compression.
In advanced stages, many of the affected patients also show limitations in muscle strength (muscle weakness). Depending on the exact location of the herniated disc, coughing or sneezing may increase the symptoms. The doctor-patient consultation in the course of diagnosis of a herniated disc also includes questions regarding urination and stool behaviour.
The reason for this is the fact that a deep herniated disc can, under certain circumstances, lead to disturbances in urination (so-called urinary incontinence) or bowel movement (so-called faecal incontinence). These complaints are often accompanied by pronounced sensory disturbances in the area of the anus and/or the genitals. In addition, restrictions in sensitivity may occur on the inner side of the thighs.
Following the doctor-patient consultation, an orienting physical examination takes place. During this examination, muscle strength, sensitivity and reflexes are tested in particular. In addition, if a deep disc herniation is suspected, the diagnosis includes various exercises that test the functionality of the characteristic muscles of the most important spinal segments.
In patients who can walk on their toes and heels without any problems, paralysis of the relevant muscles can already be specifically excluded with the help of this simple diagnostic method. If the suspicion of the presence of a herniated disc is confirmed during the physical examination, the diagnosis must be continued. Above all, imaging procedures that are suitable for imaging the spine including the intervertebral discs play a decisive role in the diagnosis of a herniated disc.
The preparation of ordinary x-rays is of little help in the diagnosis of a herniated disc. For this reason, a computed tomography (CT) or magnetic resonance imaging (MRI) of the herniated disc must be ordered for an exact diagnosis. Due to the better imaging of the intervertebral discs, magnetic resonance imaging is considered the imaging method of choice in the diagnosis of a herniated disc.
Since an advanced herniated disc can often lead to impairment of sensitivity and/or muscle strength, diagnostic measures should be extended to patients with corresponding symptoms. In particular, the so-called electromyography (EMG) and electroneurography (ENG) can help to determine whether sensitivity disorders and paralysis symptoms are associated with a herniated disc. With the help of electromyography, the treating physician can measure whether individual muscles are electrically excited via the associated nerve fibres.
If necessary, electroneurography can be used to determine which nerve root is affected by the herniated disc. In the course of diagnosis of a herniated disc, this information is particularly important for the choice of the most appropriate treatment strategy. In addition, various infectious diseases that can cause symptoms similar to those of a herniated disc should be excluded.
If a herniated disc is suspected, the MRI serves to confirm the diagnosis, it is the means of choice for imaging in case of a herniated disc. The MRI is particularly suitable for imaging tissue structures, nerves and the intervertebral discs themselves. Images of the various spinal segments are produced to assess which part is affected.
It is advantageous that the patient is not exposed to radiation during the MRI. A disadvantage, however, is that the preparation of an MRI takes a long time and one has to lie completely still during this time. Without an MRI, however, the herniated disc cannot be diagnosed with certainty, which is why an MRI should always be performed if there is any suspicion.
In general, it should be assumed that computed tomography or magnetic resonance imaging to diagnose a herniated disc is only useful if the results of the orienting physical examination confirm the initial suspected diagnosis. In patients with pronounced loss of sensitivity and/or limitations in muscle strength, the diagnosis cannot be made without MRI. The reason for this is the fact that without MRI neither the exact location nor the severity of the herniated disc can be determined.
In addition, a surgical indication cannot be made correctly without MRI. Conventional X-rays are considered an unsuitable imaging method for the diagnosis of a herniated disc. Although X-rays in several planes can adequately depict the bony structures of the spinal column, it is not possible to assess tissue structures or nerve fibres.
For this reason, the diagnosis of a herniated disc in the case of a conspicuous physical examination must include the performance of a computed tomography (CT) or magnetic resonance imaging (MRI). In general, magnetic resonance imaging is considered to be the method of first choice in the diagnosis of a herniated disc. Only in the case of questionable findings, which are determined in the course of the doctor-patient conversation and / or physical examination, the X-ray may be useful.
In people who, for example, complain of severe back pain immediately after a trauma, fractures of the bony spinal structures can be excluded by X-ray. When a herniated disc is diagnosed, various tests can be performed. The classic test to confirm the diagnosis of a herniated disc should allow statements about sensitivity, reflexes and muscle strength.
Already during a detailed doctor-patient consultation, the described symptoms should be used to determine which vertebral segment a possible herniated disc could affect. Based on this information, a suitable test should then be carried out during the physical examination. To exclude possible sensory disturbances, the treating physician must coat both sides of the body simultaneously.
If the affected patient experiences different sensations on both sides of the body, the test is considered positive. Subsequently, the muscle strength of the extremities must be tested by comparing the sides. During this test, the doctor applies pressure to the extremities and asks the patient, for example, to lift the legs against this pressure.
If the diagnosis is “advanced herniated disc”, this test would reveal a difference in the sides. In addition, the classic characteristic muscles of certain spinal segments can be tested with the help of the so-called toe and heel gait. In a patient who can walk on toes and heels without problems, a muscle paralysis can be excluded.
If the suspicion of the presence of a herniated disc is confirmed by one of these tests, the diagnosis may have to be supplemented by imaging procedures. The Lasègue test is also groundbreaking: the patient lies stretched out on his back and the doctor slowly begins to bend the stretched leg in the hip joint. If the test can no longer be continued from about 70-80° of flexion due to severe shooting pain in the leg, it is considered positive.
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