Chiari malformation or Arnold-Chiari syndrome is a neurological disorder involving the cerebellum region of the brain, which descends out of the skull towards the spinal region.
Some specialists use the term Arnold-Chiari interchangeably with Chiari. At times, Arnold-Chiari is used only to refer to Chiari Type II, which is often diagnosed in children.
Since the condition involves the nervous system, symptoms are varied and numerous. The major hallmark for this condition is a headache due to strong pressure in the hind portion of the head, and which becomes aggravated by physical strain, sneezing, laughing, coughing, bending and other similar activities.
This is diagnosed effectively using MRI (Magnetic Resonance Imaging), which is a non-invasive test that involves the use of a large magnet for creating a picture of internal organs. MRI shows any change in the position of cerebellar tonsils. The diagnosis involves analysis of reported symptoms, MRI results, a neurological exam and better judgement.
Since Chiari is usually described based on the size of the tonsillar herniation, a borderline condition refers to cerebellar tonsils that descends only few millimetres out of the skull.
Chiari was initially thought to be a congenital condition, but modern diagnosis has proved that many cases may not be present from birth. Some people develop symptoms in their childhood stage, while others get the medical signs during their adulthood.
An ongoing study has reportedly identified more than 100 families involving two or more members being affected by the condition, which implies that there is a genetic basis for some cases. However, this is yet to be proved conclusively.
A gene that can cause Arnold-Chiari syndrome has not yet been identified. Hence, there is no genetic test in use currently.
If the symptoms are not that severe, doctors may only suggest monitoring the situation by going for frequent MRI scans and also for treating the symptoms individually. However, in case the symptoms get worse, or if it impairs the nervous system, surgery is recommended.
The decompression surgery creates more space close to the cerebellar tonsils and also for restoring the normal flow of CSF. The procedure necessitates removal of a piece of the skull in the hind region of the head called craniectomy. Depending on the condition, it may also involve opening the covering of the brain and making a patch through a process called duraplasty.
It is important that every patient goes through a detailed consultation with their physician so that they can fully understand the possible risks and the outcomes of this surgery. The surgery carries an infection risk since it involves opening the brain.
The process recovery varies from person to person and depends on a person's overall levels of health and fitness before the surgery. Ranging from a few weeks, some patients may take a few months while others may take more than a year to recover.