Both brain and spinal cord are surrounded by a liquid protective mantle, the cerebrospinal fluid (CSF). In neuromedicine it is used as an indicator of potential centers of inflammation within the central nervous system. Malignant diseases, as well as bacterial or viral infections, which can be, for example, triggers for encephalitis, meningitis or Lyme borreliosis, are found in this way.
Through targeted puncture in the lower part of the lumbar vertebrae, nerve water is taken from the patient so that conclusions can be drawn on pathological changes within the central nervous system after closer examination.
Performing a lumbar puncture
Cerebrospinal fluid is usually taken while sitting or in a lateral position during lumbar puncture. The doctor leads a puncture cannula between the 3./4. or 4./5. Lumbar vertebrae into the dural sac of the lower spinal canal. The nerve fluid is obtained by slowly draining via a cannula. Contrary to popular belief, however, the needle does not come into contact with the spinal cord as it only extends into the upper region of the lumbar spine. The spinal cord can therefore not be damaged during a lumbar puncture.
Just a few milliliters of nerve fluid are sufficient to carry out a pathological examination for possible pathological changes in the central nervous system. The insertion of the puncture needle takes place during a lumbar puncture largely without pain. In addition, a pretreatment by means of an atraumatic (tissue-sparing) needle to minimize possible pain during the actual procedure. In isolated cases, the puncture site is anesthetized by local anesthesia prior to surgery.
The nerve water analysis
After the puncture, the first results can already be seen from the staining of the extracted CSF. An undistorted point of evidence of normal, healthy nerve fluid. In contrast, colored deviations indicate an increased number of erythrocytes or leucocytes and an associated inflammatory focus or bleeding in the nervous system.
In addition, statements about cell, immunoglobin, glucose and protein content in nerve water can be made, which are crucial for the further course of treatment. If the patient is treated in a lateral position, a CSF pressure measurement can also be performed.
The use of CSF is mainly used to confirm the diagnosis of suspected multiple sclerosis (MS). In the case of a disease it comes to an increased release of the antibody Immuglobin G. This makes inflammatory plaques recognizable. Whereas in the past multiple puncture was used to control the course of the disease in multiple sclerosis after each MS episode, lumbar puncture is nowadays only used to prepare the clinical picture.
Risks and side effects of a lumbar puncture
The procedure with the hollow needle leads to a punctual damage between the area of the lumbar vertebra, which leads to a CSF negative pressure in the spinal canal. This can cause side effects such as headache, vomiting and nausea. These sequelae are also referred to as post-puncture syndrome and usually resolve some time after the procedure. Only headaches can take a few weeks to lessen.
In general, considerable obesity is a hindrance to the performance of a lumbar puncture. Patients with a coagulation disorder should also be discouraged from taking CSF as they have a particularly high risk of spinal hematoma formation. Not feasible is the removal of nerve water in people with increased intracranial pressure.