Chiari Malformation Surgery

Chiari Malformation, also known as Arnold-Chiari syndrome, refers to a defect in the cerebellum's structure, which is a portion of the brain that is responsible for balance-control. Under normal circumstances, the cerebellum and certain portions of the brainstem are located in an indented space towards the lower anterior part of the skull. This space is slightly above the foramen magnum. If the cerebellum is located under the foramen magnum, it is known as chiari malformation.

This malformation develops due to the space being smaller than usual. When this happens, the cerebellum and brainstem move downwards. This abnormality exerts pressure on the cerebellum as well as the brainstem, which affects the functions that these organs control. It also causes blockage of the cerebrospinal fluid.

Causes of Chiari Malformation

There are many different causes for Arnold-Chiari syndrome. Some of these are as follows:

During most circumstances, the malformation is congenital; it also can develop later in life. In adulthood, Chiari malformation develops when too much cerebrospinal fluid drains from the thoracic or lumbar region of the spine. This can happen due to injury, infection or being exposed to harmful toxins and chemicals.

Symptoms of Chiari Malformation

People suffering from this malformation experience pain in the neck, issues with their balance, numbness in the legs or arms, muscle weakness, vision problems, dizziness, problems while swallowing, hearing loss, buzzing in the ears, headaches, depression, vomiting and insomnia. In addition, the person may also have problems with hand coordination and fine motor skills.

The symptoms can vary from person to person, depending on how much cerebrospinal fluid builds up and the level of pressure being exerted on the cerebellum, nerves and the surrounding tissues. Initially, a person may not experience any symptoms; however, a number of symptoms may manifest later on. In congenital malformation, symptoms are usually present from birth.

Treating Chiari Malformation

Surgery is the only way to treat this malformation. The basic Chiari malformation surgeryinvolves making more space in the lower anterior portion of the skull, so that the cerebellum can rest without pushing the spinal cord and brainstem. This additional space is achieved by removing a small part at the skull's base that is present in the neck muscles and also by removing a first vertebra. Once this basic surgery is performed, the person will notice improvement in the symptoms.

At the moment, surgery is the only way to correct this structural defect, and to prevent damage to the spine and the central nervous system. At times, more than one surgery may have to be performed to treat this condition.

In case of adulthood Chiari malformation, posterior fossa decompression surgery is the way to treat this condition. In this Chiari malformation surgery, an incision is made at the head's rear. A part of the spine is also removed, at times. This surgery is performed by a neurosurgeon, who may use electrocautery to make the cerebellar tonsils smaller.

Spinal laminectomy is another type of surgery to correct the malformation. In this surgical procedure, the bony arched roof of the spinal canal, known as the lamina, is removed. This helps to increase the size of the spinal canal, thereby relieving pressure on the nerves and the spinal cord.

If an infant is suffering from hydrocephalus, initially a shunt is introduced to drain out excessive fluid and relieve pressure on the brain and other structures. Sometimes, hydrocephalus is treated using a procedure known as third ventriculostomy. This procedure involves making a perforation in the third ventricle's floor to help improve cerebrospinal fluid's flow.

Surgery can help bring about significant improvement in the symptoms. In most paediatric cases, nearly 50 percent of the symptoms are eliminated.