Lumbar puncture (LP)
Lumbar puncture (LP) - is medical manipulation, designed to extract the cerebrospinal fluid and /or introducing into the subarachnoid space of the spinal cord of drugs or contrast agents (myelography).
For diagnostic purposes lumbar puncture is performed to obtain information about the cerebrospinal fluid (CSF):
- measure the cerebrospinal fluid pressure
- permeability study of the spinal cord subarachnoid space
- determine the color, transparency, and cellular composition of cerebrospinal fluid
The magnitude of cerebrospinal fluid pressure in the spinal cord subarachnoid space can be seen on intracranial pressure (normally it is 0-200 mm water column). The changes in pressure when liquorodynamic tests determine the degree of permeability subarachnoid space of the spinal cord (complete passability, partial blockade, complete blockade).
Lumbar puncture is the most accurate in comparison with other methods, to identify subarachnoid hemorrhage and its degree of severity, identify the reaction of the meninges on head injury, to detect inflammatory complications of head trauma and spinal injuries, in patients with carcinomatous meningitis identify malignant cells, increased protein content, reduced glucose concentration.
Lumbar puncture procedure technique
The patient is lying on his side with a bent hip and knee joints legs; the neck is slightly bent. Typically, a lumbar puncture is carried out in the spaces between the spinous processes of L3-L4 and L4-L5. Orient with the spinous process at the L4, which is located in the middle of the line connecting the top of the iliac crest.
Comply with all the rules of asepsis. After pre-lubricating the skin with iodine before puncture, it must be alcohol-treatment in order to prevent importation with the needle particles of iodine into the subarachnoid space.
The fine needle puncture site is administered intradermally, subcutaneously and then 3-5 ml of a 2% novocaine solution. Then, a special needle with a stylet (needle thickness 1 mm, length 10 cm, the angle of the bevel of its end 45°) produces puncture of subarachnoid space. The needle guide in the sagittal plane and a few upwardly. Going through skin, subcutaneous tissue, yellow ligament, epidural fat, dural and arachnoid mater.
After the feeling of "falling through" of the needle (puncture of the dura mater) extract mandrel. After confirming receipt of the cerebrospinal fluid, the needle is connected to the pavilion a graduated glass tube with an inner diameter of 1-2 mm for the digital measurement of cerebrospinal fluid pressure.
Outputs the cerebrospinal fluid slowly taking into account the value of liquor pressure. Cerebrospinal fluid flow rate can be adjusted easily via mandrel inserted into the lumen of the needle.
Iindications for lumbar puncture procedure
The indications for lumbar puncture in the neurotrauma are:
- subarachnoid hemorrhage during the brain (TBI) and spinal cord injuries
- meningitis and encephalitis
- spinal epidurit
- other inflammatory complications or suspicion of them
- liquorrhea after the skull base fracture (TBI)
- if necessary, check the permeability of the spinal cords subarachnoid space
Lumbar puncture is performed, if required:
- endolumbar injection of medications (such as antibiotics for purulent meningoencephalitis, etc.).
- введение контрастных йодосодержащих веществ, воздуха, кислорода, озона (для миело- и энцефалографии).
Lumbar puncture is used for therapeutic purposes for the accelerated rehabilitation of cerebrospinal fluid, recovery of liquor, including after surgery. In such cases - in the absence of contraindications - extracted to 10-20 ml of cerebrospinal fluid and more.
Contraindications to lumbar puncture procedure
For real suspicion of intracranial hematoma or posttraumatic brain abscess (especially of the temporal localization) - the lumbar puncture should be avoided.
In comatose patients lumbar puncture may be allowed only when the etiology of coma is unclear and needs of its differential diagnosis:
- alcoholic coma
- traumatic coma
- vascular coma
- intoxication coma
- diabetic coma, etc.
Lumbar puncture is contraindicated when expressed the signs of the brain stem herniation in the tentorial or foramen magnum.
At combined TBI often have additional contraindications for lumbar puncture:
- traumatic shock
- massive blood loss
- extensive damage to the soft tissues of the back
Lumbar puncture can not be done during bedsores and suppurative processes in the lumbosacral region.
Complications, that can occur during a lumbar puncture, is meningismus.
When performing a lumbar puncture during compression of the brain may develop life-threatening symptom of downward herniation of the brain stem due to reduced hydraulic backwater at the spinal level.
Lumbar puncture–related complications prevention
- Strict compliance with the indications and contraindications for its implementation
- in diagnostically of obscure cases, critical condition of the patient and increasing the lumbar pressure for the analysis should gradually (by stylet) extracts only a minimal amount of fluid (1-2 ml)
- for lumbar puncture should be use a special needles with a well-sharpened end, congruent with tightly adjoining stylet
- after lumbar puncture in all patients necessarily prescribe bed rest for 1-2 days.