Today, medicine uses several methods of introducing drugs into the patient's body. One of them is intrathecal administration. The second name for this manipulation is endolumbar infusion. Unlike parenteral infusion, this method involves the delivery of the drug directly into the intrathecal space of the brain. What is intrathecal drug administration? What is the peculiarity of this method of infusion of drugs and how is it carried out in hospitals?
Why inject drugs endolumbally
Drugs are injected into the subarachnoid space after a puncture of the dura mater of the brain. Only a neurosurgeon is authorized to perform this manipulation. Initially, intrathecal administration of drugs was caused by the need for prolonged pain relief and effective hormonal therapy. Anesthetics and corticosteroid drugs are also injected into the epiduralspace.
Main advantages and disadvantages of the intrathecal method
The main advantages of this method of administering drugs neurosurgeons consider the ability to provide the maximum concentration of the active substance in the brain tissues and cerebrospinal fluid. In addition, intrathecal drugs can be administered that will not penetrate the blood-brain septum. By infusing the drug directly into the end tank, it is possible to reduce the dosage of active ingredients and minimize their systemic unsafe effects.
Among the shortcomings of the method, the complex technique of drug administration, which only experienced and highly qualified neurosurgeons possess, is of particular importance. During the procedure, the risk of a possible drop in intracranial pressure is taken into account. The intrathecal route of administration is a way to deliver liquid solutions directly to the brain. Emulsions and suspensions cannot be introduced into the CSF by this method. Another disadvantage is the possibility of brain damage, but if the rules for performing a lumbar puncture are followed, the risk is minimal.
For meningitis
The most common reason for manipulation is bacterial meningitis. This is a dangerous condition, which is characterized by inflammation of the meninges. If a patient is indicated for intrathecal administration, what does this mean? Most likely, there is an urgent need for the urgent use of antibacterial agents. To speed up the action of antibiotics and enhancetherapeutic effect, drugs are injected directly into the cerebrospinal fluid by puncturing the lumbar space.
This procedure is recommended only if more than 72 hours have passed since the parenteral infusion of antibiotics, but the patient's condition has not improved. If during this period of time there has never been a sanitation of cerebrospinal fluid against the background of ongoing therapy, intrathecal administration of antimicrobial drugs is a mandatory step.
What antibiotics can be injected directly into the CSF
Selection of antibacterial drugs for endolumbar administration under the subarachnoid membrane is based on the type of pathogen, its resistance to antibiotics of this group. For bacterial meningitis, several antibacterial drugs are used in the form of a solution for intrathecal administration. What are these medicines? The list of the most effective includes:
- "Amicacin";
- Vancomycin;
- Tobramycin;
- "Dioxydin";
- Gentamicin;
- Polymyxin.
One of these drugs may be prescribed until the results of the bacteriological study are available. In case of symptoms of toxic effects and a decrease in the level of protein in the cerebrospinal fluid, the antibiotic is canceled and another one is prescribed.
Solutions that should not be injected into the subarachnoid space
Not all antibacterial drugs are allowed to be injected into the cerebrospinal fluidspace simultaneously with other medicines. For example, a combination of penicillin drugs and Polymyxin can lead to a lightning-fast death.
In addition, endolumbar administration of antibiotics does not eliminate the need for etiotropic treatment, which the patient receives intravenously or intramuscularly. When choosing medicines, the tendency to allergic reactions, the characteristics of specific drugs, must be taken into account.
Before performing a lumbar puncture, a neurosurgeon must assess the degree of cerebral edema in a patient based on the results of an ophthalmoscopy. If the swelling is clearly expressed, intrathecal introduction into the terminal tank will not bring significant results. Moreover, swelling increases the risk of damage to brain tissue.
Introduction of cytostatics in brain tumors
In the cerebrospinal fluid, endolumbar administration of chemotherapy drugs is allowed if patients have a number of oncological diseases. These include meningeal carcinomatosis, meningeal lymphoma, neuroleukemia, and distant organ metastases.
It should not be forgotten that intrathecal administration of chemotherapy sometimes leads to complications. Some cytostatics, once in the subarachnoid space, can provoke a meningeal reaction of varying severity. Its confirmation is considered an increased protein content with a normal amount of glucose. This violation quickly passes, but in some cases leads toarachnoiditis or myelitis. There is no exact information on the frequency of complications.
Chemotherapy with Methotrexate
This drug is used in the treatment of a number of neurooncological diseases. Intrathecal administration of "Methotrexate" at a dosage of 0.25 mg of the active substance per 1 kg of the patient's body weight begins a week after surgery. This drug, like any other cytostatic, has side effects.
The disadvantage of "Methotrexate" is its increased toxicity. After endolumbar injection, patients have an increase in edema at the site of surgical treatment and intracranial hypertension. In addition to Methotrexate, another drug is used that can be injected directly into the subarachnoid space - this is Cytosar, which has a similar composition and principle of action. Analogues of these drugs are mistakenly considered "Velcade", "Bortezomib". These chemotherapy drugs should not be injected into the CSF. In the instructions for use of this antitumor agent, the risk of a lethal outcome is noted if it is administered intrathecally. Chemotherapy with this agent can only be carried out by the parenteral route.
Preparing for the procedure
Before injecting drugs endolumbally, the doctor must assess the patency of the CSF space after puncture of the hard shell. For this purpose, neurosurgeons conduct liquorodynamic tests. This preparatory stage is of particular importance if the patient is diagnosed with tumor or metastatic lesions.spinal membranes. If the cerebrospinal fluid pathways are blocked, medications will not be able to reach the lesions via the endolumbar route. In addition, the myelotoxic effect of the drug may increase due to the impossibility of uniform distribution in the cerebrospinal fluid.
How to administer drugs intrathecally?
The method of using drugs by infusing them into the subarachnoid space consists of several steps:
- The dose of the main active drug must be diluted in 2-3 ml of saline (0.9% sodium chloride).
- After completion of the lumbar puncture performed at the level of the vertebrae L3-S1 (the needle pierces the epidermis, the interspinous and yellow ligaments of the vertebral processes and the dura mater), the cannula of the syringe is moved to the pavilion of the puncture needle.
- Inject 5-6 ml of cerebrospinal fluid into the syringe, then inject 2-3 ml of the drug into the cerebrospinal fluid.
- The syringe is then refilled with cerebrospinal fluid and the remaining contents are slowly injected.
- The puncture needle is removed.
- If the patient's condition is satisfactory, he is advised not to get out of bed for the next half hour.
Intrathecal drug delivery systems
In order to reduce spasticity that accompanies some diseases of the brain and spinal cord, special devices are used for endolumbar insertion. With a pump and a catheter placed inend tank, injected with the substance baclofen, better known under the trade name "Lioresal".
The system for intrathecal administration was developed several years ago by Rostov neurosurgeons. Their invention was appreciated by leading Russian experts in the field of neurooncology. Thanks to the development, patients with severe spastic syndrome that occurs against the background of malignant lesions of the brain and spinal cord, various injuries, multiple sclerosis, stroke, meningitis, have the opportunity to stop pain and improve their quality of life. Due to severe pain syndrome, patients developed severe disorders of the musculoskeletal system, secondary irreversible fibrotic changes in the joints.
Before the use of intrathecal implantable systems, physiotherapy methods were used in the treatment, oral muscle relaxants were used, which had only a partial therapeutic effect.
Treatment of chronic pain with opiates
These systems for endolumbar drug administration are also used as palliative care for cancer patients. The presence of severe pain syndrome, which is assessed on a visual analogue scale at the level of 60-100%, is the main indication for the use of opioid narcotic drugs ("Morphine") as analgesics. The system is installed in patients who have reached the age of majority and who have provided written consent to use the system.
The operation is performed as follows:
- First, the individual sensitivity of the patient to the "Morphine" administered by the endolumbar route is determined. To find out whether the microdose of the drug was effective, special equipment with ultrasonic sensors helps.
- If the test is positively passed and there are no contraindications to the implantation of the pump, implantation is started.
- A catheter connected to a programmed pump is inserted intrathecally under the skin within the spinal column.
- After installing the system, the doctor proceeds to set up the implanted device (fixes the rate of medication delivery, provides the ability to turn the pump on and off, and also activates the option to urgently add a dose of the drug when pain increases).
The device needs to be refilled approximately once every few months, and the patient will be notified: if the drug has run out, the intrathecal pump will beep. Chemotherapy using this system is not yet carried out, but neurooncologists are already working on this issue.
