Myelography

Myelography is a method of diagnosis, carried out by introducing a contrast medium into the subarachnoid space of the spinal cord followed by fluoroscopy. This technique allows you to diagnose a number of diseases of the nervous system that are invisible when performing a simple X-ray study. The usual radiography of the spine shows only its bone structure, and it is not possible to evaluate the state of the spinal cord, its membranes and roots on the radiograph. It is these structures that will be shown by myelography.

Of course, a more modern method of visualization, allowing to see not only the spinal cord, but all the structures around it, is a computer or magnetic resonance imaging, but to this study there are a number of contraindications, and not every patient is available. Here in these cases the myelography comes to the aid of the doctor and the patient. About what this study is, what indications for its conduct, whether special preparation is needed for it, whether complications are possible after it, and this article will be discussed.

When myelography is shown

This study is prescribed in the following cases:

• with the aim of discovering the causes of pain, weakness, numbness of the limbs;
• if there is a suspected presence of neoplasms in the region of the canal of the spinal cord or posterior cranial fossa;
• for the diagnosis of intervertebral hernias;
• with the aim of detecting pathological changes in the vessels of the spinal canal;
• To diagnose damage to the roots of the spinal cord;
• to identify signs of inflammation in the spinal cord and its membranes;
• with suspected narrowing (stenosis) of the canal of the spinal cord.

With the help of myelography, the following diseases can be confirmed:

• syringomyelia (cavities are found in the spinal cord);
• meningocele (bulging of the dura mater);
• traumatic spinal cord injuries;
• inflammation of the spinal cord of the spinal cord, or spinal arachnoiditis;
• infection of the spinal cord and surrounding tissues;
• tumors of the central nervous system.

In addition, myelography can be prescribed to a patient before and after surgery on the spine and spinal cord to determine the effectiveness of treatment.

Contraindications to the study

There are a number of conditions when the myelography should be temporarily delayed or completely abolished. These are:

• heart disease, kidney, liver in decompensation;
• pregnancy (if the doctor and the future mother decide to do the research, it is necessary to take measures to protect the fetus from X-rays);
• acute infectious diseases with severe fever;
• anatomical or posttraumatic defects of the spine, slowing the introduction of contrast medium;
• inability to stay in a fixed position;
• pustular eruptions on the skin in the puncture area;
• intracranial hypertension;
• allergic reactions to components of radiopaque substance.

How to prepare for myelography

Before the examination, the doctor will ask the patient in detail about the medicines he takes. The danger for the examinee during myelography is represented by such groups of drugs as hypoglycemic (in particular, metformin), blood thinning (for example, warfarin), anticonvulsants and antidepressants. For a few days before the diagnosis, these medications should be discontinued and replaced with other drugs of similar action recommended by the doctor.

The patient should inform the doctor in detail about all the episodes of allergy that he had. Of particular importance is the allergy to iodine and barium, since many contrast substances in their basis have these microelements.

The doctor should also be aware of all the chronic diseases the patient has. First, with some of them, myelography is completely contraindicated, and secondly, knowing about these diseases, specialists conducting research, can foresee the development of certain complications and timely, and most importantly - adequately respond to them.

It is extremely important for women to notify a doctor of a possible or pre-existing pregnancy, since X-rays can have a negative impact on the health and development of the fetus.

2-3 days before the study, the patient should exclude from his diet products that cause fermentation and increased gas formation in intestines (cabbage, buns, etc.) - the presence in it of a large amount of gas can "lubricate" the picture during the research. The amount of liquid consumed, on the contrary, should be increased. 8 hours before myelography is not recommended to eat any food, but to drink when you feel thirst still follows.

Before the puncture, sensitive patients can be prescribed sedatives, in addition, all the subjects are treated with a cleansing enema.

During the study, the patient takes off his clothes partially or completely, and puts on a special hospital shirt. He also removes glasses, jewelry, dentures, watches and other items that can distort the image.

Diagnostic equipment

To carry out myelography, you need a special table capable of changing the angle of incidence, an X-ray tube, a monitor that will receive an image in fluoroscopy. Converts x-ray radiation into a video image of a special device - a fluoroscope. To improve the picture quality of the monitor, use an amplifier.

You will also need a puncture needle with a mandrel (a removable core that clogs the lumen of the needle to prevent premature leakage of spinal cord liquid), a solution of antiseptic (iodine, alcohol or other), solutions of painkillers (1% lidocaine solution), contrast agent. As the last, as a rule, use gas (nitrous oxide or oxygen) or special radiopaque preparations.

To detect hypersensitivity to a contrasting substance, the subject is tested for an allergic test: 2 ml of this drug is administered intravenously. If there are symptoms of intolerance, myelography is not performed or carried out using the contrast that the patient tolerates well.

Technique of research

In most cases, myelography is performed on an outpatient basis. If a patient has a serious somatic pathology, it is performed in a hospital with mandatory observation by a neurologist within 24 hours after the examination.

The contrast is introduced into the subarachnoid space with a syringe connected to the needle.

Depending on the direction of contrast distribution, there are 2 types of myelography: ascending and descending. In the first case, spinal puncture is performed in the lumbar spine, in the second - in the cervical spine.

During the puncture, the examinee is lying on the side with the chin tilted to the chest and legs bent at the knee and hip joints and pressed against the abdomen. Less often, puncture is performed in the patient's position while sitting elbows on the table in front.

The skin in the area of ​​the alleged puncture is treated three times with solutions of antiseptics, after which it is stratified by this solution with an anesthetic solution. The puncture needle under the control of a fluoroscope is administered to an adult at the level between the spinous processes of 3 and 4 lumbar vertebrae along the median line of the back at a slight angle upward (parallel to the spinous processes). When the needle goes through all the structures, pierces the arachnoid shell and is in the subarachnoid space, the doctor performing the puncture will feel like a failure. After this, the mandrin is removed from the needle and the spinal fluid is separated by drop. Several ml of this liquid are immediately sent to the laboratory for analysis, then a syringe is connected to the needle and a contrast agent is injected. Then the needle is removed, the skin is disinfected again, and the patient changes position on the table - he lies face down on his stomach.

Again, under the control of a fluoroscope, the radiologist slowly tilts the table - when the lumbar puncture is performed, it tilts the head end, and when puncturing the cervical spine, it lowers the legs. The angle of inclination is small - it is no more than 10 ° C.

In the process of performing the tilt on the monitor, the radiologist watches the spread of the contrast medium along the spinal canal - flow around the spinal cord and other structures. The doctor pays attention to the slightest deviations from the norm and, if necessary, takes pictures of a particular site. To obtain high-quality images, the patient should lie on his side and do not move at the time of imaging. Even a slight jerk will increase the likelihood of blurring the image.

At a high risk of developing unwanted reactions to the introduction of contrast after taking pictures, the patient can be injected with a solution of sodium thiosulfate.

When the examination is completed, the doctor returns the table to the initial (horizontal) position and allows the subject to turn over on his back.

In a number of cases, while the contrast material is in the canal of the spinal cord, the patient is given a computer tomography (in this version, it is called "CT-myelography").

If a contrast agent which is soluble in fats is used in the course of myelography, the doctor evacuates it from the spinal canal at the end of the study. Within 24 hours after this, the patient must comply with bed rest on a firm, level surface (this is important!).

The time of the study varies within half an hour-hour. CT-myelography takes another 20-30 minutes.

Some time the radiologist describes and analyzes the received roentgenograms. After that, he gives a description, and sometimes the pictures themselves to the patient. The results of the study are usually discussed with the patient not by a radiologist, but by the attending physician.

At the end of the study, the patient should lie in the supine position for 12 to 24 hours with a slightly raised head end. To accelerate the process of removing contrast from the body, the patient is recommended to consume large amounts of water. If, after rest, he does not stay in the office, but goes home, it is necessary that someone accompanies him.

Patient's sensations

Probably the reader is worried about the question "what does the subject feel during myelography?" When performing a puncture, a person feels light pressure in the waist. At the time of the introduction of contrast - a brief burning sensation, heat, headache and dizziness. Some patients note the appearance of a salty taste in the mouth. At the time of discontinuation of the drug, the subject may experience nausea and / or vomiting. In some cases, during the study, patients complain of inordinate pain.

Complications of myelography

In the vast majority of cases, myelography is transferred by patients well, without any undesirable effects. However, occasionally some complications arise.

• Every fifth patient after mielography faces such side effects as nausea, vomiting and headache. These symptoms increase in the vertical position of a person, therefore, in order to reduce the risk of their development, research to comply with bed rest during the day and settle with a slightly elevated head end.
• In the case of taking the patient before the study of metformin, after the study may be a violation of the kidneys. It is necessary to follow the urination: during 8 hours you must urinate. If this does not happen, tell your doctor.
• In some cases, develop encephalopathy or serous meningitis, there may be convulsions: so manifest neurotoxic effects of contrast, caught in the subarachnoid space of the brain.
• In isolated cases, damage to the structures of the spinal canal at the time of lumbar puncture or the introduction of contrast.

In conclusion, it should be noted that myelography is a highly informative and sufficiently safe method of diagnosis, the expediency of which is determined by the attending physician in each specific case. Nevertheless, the study assumes direct intervention in the central nervous system, therefore it is carried out exclusively after the written consent of the patient to it.

Medical animation on the theme "Myelography":