Spinal puncture: indications, contraindications, technique of carrying out

Spinal puncture is the introduction of a special needle into the subarachnoid space of the spinal cord in order to take a cerebrospinal fluid for research or for therapeutic purposes. This manipulation has many synonyms: lumbar puncture, lumbar puncture, lumbar puncture, puncture of the subarachnoid space of the spinal cord. In this article we will talk about the indications and contraindications to this procedure, the technique of its conduct and possible complications.

Indications for lumbar puncture

As mentioned above, the lumbar puncturepuncture can be performed for diagnostic or therapeutic purposes.

As a diagnostic manipulation, puncture is performed if it is necessary to examine the composition of cerebrospinal fluid, to determine the presence of infection in it, to measure the liquor pressure and permeability of the subarachnoid space of the spinal cord.

If it is necessary to remove excess CSF from the spinal canal, insert antibacterial drugs or chemotherapy in it, also perform a lumbar puncture, but already as a method of treatment.

Indications for this manipulation are divided into absolute( that is, under these conditions, the puncture is mandatory) and relative( to conduct a puncture or not to conduct, at its discretion solves the doctor).

Absolute indications for spinal puncture:

• infectious diseases of the central nervous system( encephalitis, meningitis and others);
• malignant neoplasms in the area of ​​the membranes and structures of the brain;
• diagnosis of liquorrhea( cerebrospinal fluid outflow) by introducing radiopaque substances or dyes into the spinal canal;
• hemorrhage under the spider web of the brain.

Relative indications:

• multiple sclerosis and other demyelinating diseases;
• polyneuropathy of inflammatory nature;
• septic embolism of vessels;
• fever of unknown nature in young children( up to 2 years);
• systemic lupus erythematosus and some other systemic connective tissue diseases.

Contraindications to lumbar puncture

In some cases, carrying out this diagnostic treatment can lead a patient more harm than good, and even can be dangerous for the patient's life - this is contraindication. The main ones are listed below:

• marked edema of the brain;
• sharply increased intracranial pressure;
• presence in the brain of volume formation;
• occlusive hydrocephalus.

These 4 syndromes during spinal puncture can lead to axial wedge - a life-threatening condition, when a part of the brain descends into the large occipital foramen - the functioning of the vital centers located in it is impaired and the patient may die. The probability of wedging increases when using a thick needle and removing a large amount of liquor from the spinal canal.

If puncture is a necessity, you should display the minimum possible amount of cerebrospinal fluid, and in case of signs of wedging, promptly enter the desired amount of fluid from the outside through the puncture needle.

Other contraindications are:

• pustular eruptions in the lumbar region;
• blood coagulation system diseases;
• taking medications that dilute blood( antiaggregants, anticoagulants);
• hemorrhage from an exploded aneurysm of the vessel of the brain or spinal cord;
• blockade of the subarachnoid space of the spinal cord;
• pregnancy.

These 5 contraindications are relative - in situations where the lumbar puncture is vital, it is carried out with them, they simply take into account the risk of developing any complications.

Technique of puncture

During this manipulation the patient is usually in a supine position on the side with a head tilted to the chest and pressed to the stomach, knees bent at the feet. It is in this position that the puncture site becomes as accessible to the physician as possible. Sometimes the patient is in a position not lying, and sitting on a chair, while he leans forward and puts his hands on the table, and his head in his hands. However, this provision has been used more and more rarely.

Pediatric puncture is performed between the spinous processes of 4 and 5 lumbar vertebrae, and adults slightly higher between 3 and 4 lumbar vertebrae. Some patients are afraid to perform a puncture, because they believe that the spinal cord may be touched while carrying it, however it is not! The spinal cord of an adult ends at about 1-2 lumbar vertebrae. Below it simply does not exist.

Skin in the area of ​​puncture is treated with solutions of alcohol and iodine alternately, and then inject the analgesic drug( novocaine, lidocaine, ultracaine) first intradermally, until the so-called lemon peel, then subcutaneously and deeper, during the puncture.

Puncture( puncture) is performed with a special mandrel needle( this is the rod for closing the lumen of the needle) in the plane from front to back, but not perpendicular to the waist, and at a slight angle - from the bottom upwards( along the spinous processes of the vertebrae, between them).When the needle deviates from the median line, it usually rests against the bone. When the needle passes through all the structures and enters the spinal canal, the specialist who conducts the puncture feels like a failure;if such a feeling is absent, but when removing the mandrana through the needle, the cerebrospinal fluid passes, this is a sign that the target is reached and the needle in the channel. If the needle is inserted correctly, but the spinal fluid does not flow out, the doctor asks the patient to cough or lift the head end of it to increase the pressure of the cerebrospinal fluid.

When as a result of numerous punctures appear spikes, to achieve the appearance of cerebrospinal fluid can be very difficult. In this case, the doctor will try to perform the puncture on another, above or below the standard level.

To measure the pressure in the subarachnoid space, a special plastic tube is attached to the needle. In a healthy person, the CSF pressure ranges from 100 to 200 mm Hg. To obtain accurate data, the doctor will ask the patient to relax as much as possible. The level of pressure can be estimated approximately: 60 drops of liquor per minute correspond to normal pressure. In inflammatory processes in the brain or other conditions that contribute to an increase in the volume of the cerebrospinal fluid, the pressure increases.

To assess the permeability of the subarachnoid space, special tests are performed: Stukeya and Kvekkensted. The Kvekkensted sample is performed as follows: determine the initial pressure, then compress the jugular veins of the subject for a maximum of 10 seconds. The pressure during the sample increases by 10-20 mm of water column, and 10 seconds after the restoration of blood flow is normalized. Stool sample: in the navel area, press down with your fist for 10 seconds, as a result of which the pressure also rises.

Blood in liquor

There are 2 reasons for the impurity of blood in the cerebrospinal fluid: bleeding under the arachnoid and damage to the vessel during the puncture. To differentiate them from each other, the liquor is collected in 3 test tubes. If the admixture of blood is a hemorrhage, the liquid will be uniformly colored in a scarlet color. If, however, the liquor from the 1st to the 3rd test tube becomes purer, it is likely that the blood appeared as a result of injury to the vessel when puncturing. If the hemorrhage is small, staining the cerebrospinal fluid in a scarlet color may be barely noticeable or not noticeable at all. In this case, changes will necessarily be revealed in the laboratory study.

Investigation of CSF

As a rule, cerebrospinal fluid is collected in 3 test tubes: for general analysis, biochemical and microbiological examination.

In the general analysis, the lab technician assesses the density, pH, color, fluid transparency, counts cytosis( the number of cells in 1 μl), determines the protein content. If necessary, identify other cells: tumor cells, epidermal cells, arachnoendothelium and others.

The density of cerebrospinal fluid is normally 1,005-1,008;It increases with inflammation, decreases - with excess fluid.

Normal pH value is 7.35-7.8;it rises in the case of paralysis, neurosyphilis, epilepsy;decreases with meningitis and encephalitis.

Healthy liquor is colorless and transparent. Its dark color is indicative of jaundice or melanoma metastases, yellow is a sign of an elevated level of protein or bilirubin in it, as well as a transferred hemorrhage into the subarachnoid space.

Muddy liquor becomes with an elevated white blood cell count( above 200-300 in 1 μl).In bacterial infection, neutrophilic cytosis is determined, in the case of a virus infection, the lymphocyte is detected, in the case of parasitosis, eosinophilic, in the case of hemorrhage, an increased content of erythrocytes is found in the cerebrospinal fluid.

The protein should normally not be more than 0.45 g / l, but with inflammatory processes in the brain, neoplasms, hydrocephalus, neurosyphilis and other diseases, its level is significantly increased.

In the biochemical study of CSF, the level of many indicators is determined, among which the most important are the following:

• glucose( its level is approximately 40-60% of the blood level and is 2.2-3.9 mmol / l, decreases with meningitis, it rises -with strokes);
• lactate( normal for adults 1,1-2,4 mmol / l; increases with meningitis of bacterial nature, brain abscesses, hydrocephalus, cerebral ischemia, decreases with viral meningitis);
• chlorides( normal - 118-132 mol / l, increased concentration in tumors and brain abscesses, as well as echinococcosis, decreased - with meningitis, brucellosis, neurosyphilis).

The microbiological examination is carried out by staining a smear of cerebrospinal fluid according to one of the possible methods( depending on the suspected pathogen), by sowing the liquid on the nutrient medium. Thus, the causative agent of the disease and its sensitivity to antibacterial drugs.

How to behave to the patient after a spinal puncture

To prevent possible outflow of liquor through the puncture hole, the patient should be kept bed resting, being in a horizontal position, within 2-3 hours after the puncture. To prevent the development of complications of the operation or facilitate their condition in the case of their appearance, bed rest should be extended to several days. Exclude weight lifting.

Complications of spinal puncture

Complications of this procedure develop in 1-5 patients out of 1000. These are:

• axial wedge( acute - with increased intracranial pressure, chronic - with repeatedly performed punctures);
• meningism( the appearance of meningitis symptoms in the absence of inflammation as such, is the result of irritation of the meninges);
• infectious diseases of the central nervous system due to violation of asepsis rules during puncture;
• severe headaches;
• damage to the spinal cord roots( there are persistent pains);
• bleeding( if there was a clotting disorder or a patient taking blood thinning medications);
• intervertebral hernia, resulting from damage to the disc;
• epidermoid cyst;
• meningeal reaction( a sharp increase in the cytosis and protein level at a normal glucose level and the absence of microorganisms in the crop, resulting from the introduction of antibiotics, chemotherapy, analgesics and radiocontrast agents into the spinal canal, as a rule, rapidly and without a trace regress, but in some casesbecomes the cause of myelitis, radiculitis or arachnoiditis).

So, spinal puncture is the most important, very informative medical-diagnostic procedure, to which there are both indications and contraindications. The expediency of conducting it is determined by the doctor, and he also assesses possible risks. The overwhelming number of punctures is tolerated by patients well, but complications sometimes develop, in the case of which the examinee should immediately tell about it to the treating doctor.

Educational program on neurology, lecture on "Lumbar puncture":

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