Causes of the L4 syndrome
In most cases the cause of L4 syndrome is a herniated disc. There are various forms of this. First, a part of the intervertebral disc shifts to the outside and presses on the nerve root.
In severe cases, the disc can burst open and a part of it comes out. Another cause of L4 syndrome can also be a narrowing of the spinal canal, in which the spinal cord runs, at the site of the fourth lumbar vertebra. Cysts in this area can also irritate or compress the nerve root. In rare cases, benign or malignant tumors that occur at this site can also be a cause of L4 syndrome.
Diagnosis of the L4 syndrome
To diagnose the L4 syndrome it is important to talk to your doctor and to describe the symptoms in detail. Then some tests, such as the Lasegue test, are performed, which indicate that the nerve root is irritated. If the L4 syndrome is confirmed, the cause will be searched for.
Since the most common cause of L4 syndrome is a herniated disc, this is clarified with a magnetic resonance imaging (MRI) examination.Changes in the intervertebral disc and also a bulge of the disc, which can push in the nerve root, become visible. If magnetic resonance imaging cannot be performed, for example, because of metallic prostheses in the body, computer tomography is performed. The Laseque test is intended to show whether there is irritation of the nerve roots.
To perform the test, the patient lies flat on his back. The stretched leg is lifted by bending the hip joint. If a stabbing pain in the leg occurs at a flexion angle of 40-60°, this is called a positive Lasegue sign.
On the basis of the exact localization of the pain, one can conclude at what level the nerve root damage is. In the L4 syndrome, the pain would be felt on the thigh above the patella or on the inside of the lower leg. However, a positive Lasegue sign can also occur when there is irritation of the nerve root due to inflammation of the meninges or irritation of nerves elsewhere in the nerve tract.
At the spinal cord, nerve tracts emerge in the nerve root and then move to the various muscles of the body. When these nerves are activated, the muscle contracts and thus performs its function. The muscles that receive their nerve tracts from a particular nerve root are called identification muscles.
If this root is damaged, the corresponding muscles suffer functional limitations. Therefore, functional disorders of certain muscles can be used to draw conclusions about damaged nerve roots. The most important characteristic muscle of the L4 syndrome is the muscle quadriceps femoris, colloquially known as the quadriceps.
It runs from the hip scoop, along the thigh to the knee. If it is tensed, this leads to flexion of the hip and extension of the knee. If there are problems with these movements, this can be an indication of an L4 syndrome.
Periradicular therapy is called PRT. This means that treatment is performed directly around the nerve root. The structures in the back are shown by a CT scan.
Afterwards, a syringe is injected in a controlled manner into the nerve root. Under CT supervision, it can be ensured that no parts of the spinal cord or the nerves and blood vessels running here are damaged. After the syringe has been introduced, an anaesthetic, i.e. a local anaesthetic and an anti-inflammatory drug such as cortisone, is injected through the skin.
This is intended to relieve the pain of L4 syndrome. Cortisone also has a decongestant effect on the irritated area. This reduces the pressure on the nerve root and the cause of the symptoms can be improved, at least for a short time.
