Arnold Chiari’s anomaly is a development disorder of the occipital bone, in which the space that holds the posterior parts of the brain is smaller than usual. Also part of the cerebellum is shifted downward into the vertebral canal and fills those backup spaces that normally should surround the brain stem at the level of the great occipital foramen. This prevents normal circulation of the cerebrospinal fluid between the intracranial and cerebrospinal space and as a result leads to increased pressure inside the skull. Because of this, instead of the natural motion along the channel, the liquor begins to overcome the distance along the downwardly shifted tonsils of the cerebellum with great resistance, which couse pressure on the brain stem and spinal cord.
Because the brain stem and spinal cord are responsible for most of the body’s functions, the anomaly of Arnold Chiari manifests with wide variety of symptoms. Patients have various complaints, from a headache to an intestinal disorder.
There are 4 most common symptoms of Chiari anomaly:
This condition can remain asymptomatic for a long time. It can manifest in adolescence during a period of active growth or in adults. In this case, there is a whole list of symptoms that may indicate this anomaly:
– the headache usually begins with the occipital region;
– pain in the neck;
– numbness in the hands
– abnormal sensations in the fingers;
– awakening in the middle of the night due to numbness of the hand;
– feeling of lack of air;
– pressure behind the sternum;
Symptomatology can differ in different patients and does not necessarily correspond to the degree of wedging of the tonsils of the cerebellum. Some patients with significant levels of tonsillitis do not have any symptoms. In turn, patients with a slight incidence may experience severe symptoms. When symptoms are present, they are often fuzzy, blurred and nonspecific, and as a result, Аrnold Chiari anomaly can’t be diagnosed for a long time. The appearance of symptoms is a consequence of a disturbance of the cerebrospinal circulation and compression of the nervous structure. In some cases, damage to the head or neck as a result of trauma can trigger the onset of the disease.
Arnold Chiari Syndrome can be characterized by signs similar to other diseases. This leads to erroneous diagnosis and postpones the correct treatment.
Diagnoses that are often confused with the anomaly of Chiari:
Some patients wait for years, while it is possible to establish the correct diagnosis “Arnold Chiari Syndrome”, because there is no specific pathognomonic criterion for confirming the Chiari anomaly in addition to visualizing the diagnosis. Usually, the diagnosis is established on the basis of a comprehensive assessment of patient complaints, objective and neurological examination data, as well as MRI signs of pathology:
The main methods for diagnosing the disease “Arnold Chiari Syndrome” are:
MRI is a non-invasive method that allows you to assess the state of the brain, spinal cord and the system of liquor circulation. Also MRI allows you to assess the degree of wedging of the tonsils of the cerebellum, which can reach the level of C1-C2 cervical vertebrae. The level of tonsillitis is measured in millimeters below the large occipital foramen. At the same time, the degree of wedging observed with MRI scans does not always exactly match the severity of the neurological symptomatology. Sometimes the patient without a wedge of tonsils according to MRI shows marked symptoms, and in a patient with the descent of tonsils reaching 20 mm, the manifestations of the disease are minimal.
CT scan. It is used to visualize the bones of the base of the skull and vertebral column, but it is not informative for the diagnosis of Arnold-Chiari.
Therapeutic tactics depends on the type of malformation and the severity of the symptoms of Arnold Chiari’s syndrome.
Thus, the degree of anomaly is differentiated depending on the displacement of the cerebellar tonsils in the grete occipital foramen, disturbances in the position of the brainstem and the correlation of the structures of the craniocervical junction:
the 1st degree. It appears in adolescence or in adults, and according to statistics the peak of symptoms in adults falls on 40-50 years, which has not yet been explained.
anomaly arnold kiari 2 degrees, 3 degrees. Is manifested in early childhood or adolescence.
Anomaly of the arnold kiari of the 4th degree. It leads to the fact that newborns with such a diagnosis are not viable and die in the first days or weeks after birth.
If the symptoms are mild or moderate, the following may be effective:
When the patient has an anomaly of Arnold Chiari, we diagnose in him that the amygdala of the cerebellum is shifted downward into the large occipital foramen. At the same time, the medulla oblongata receives pressure, and this leads to neurological disorders. In the case of severe symptoms or progressive deterioration of the patient’s condition, surgical treatment is required to remove part of the occipital bone and part of the dura mater. This leads to the elimination of compression of the brain structures and the creation of space for the cerebellum and brainstem.
According to literature data and in our experience, the best treatment results are observed when patients are operated on during the first 2 years after the beginning of symptoms. Asymptomatic patients can be observed and operated later if they have symptoms. But it is important to remember that the changes, as a consequence syndrome and hydromia, are growing slowly, and patients often do not pay attention to them until gross manifestations appear. At the same time, already developed violations of the function, as a rule, are irreversible, therefore, the operation should be aimed at preventing their development. As a result of surgical treatment, most of the complaints and symptoms regress in the early postoperative period. A person returns to his functionally full life, provided that irreversible atrophic changes did not develop before the operation.
The first operation in Ukraine about the Arnold-Chiari anomaly in an adult was performed in our clinic in 1995. (after the training of Dr. Fedirko V.O. in Canada). The number of surgeries exceeded several hundred, and the efficiency of the symptomatic regression after operation is at the level of 94-97%.
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