How Does the Surgeon Perform the Surgery for Arnold-Chiari Syndrome

In order to cure Arnold-Chiari syndrome and its manifestations, a surgery known as posterior fossa decompression has to be performed. The invasive procedure helps remove the bone situated towards the back of the skull and the spine. The objective of the surgery is to completely stop or control the progression of the symptoms caused due to tonsillar herniation, besides relieving the compression of the brain stem and the spinal cord, and restoring the normal flow of cerebrospinal fluid (CSF). The surgery lasts for two to three hours, while hospital recovery may take anywhere between two to four days.

Surgery is performed in case there is abnormal collection of cerebrospinal fluid in the spinal cord, or if there is a Chiari malformation blocking CSF flow. During the consultation, the neurosurgeon will provide a brief explanation about the procedure to the patient and also the associated benefits and risks, besides clarifying any questions. Some pre-surgical tests such as blood test, chest X-ray, electrocardiogram, and CT scan will have to be done before the surgery.

Process of Surgery

Preparing the Patient: The surgeon will make the patient lay on the operating table and administer anaesthesia, thereafter. This would be followed by the doctor placing the patient's head in a three-pin, skull-fixation device that holds the head in position during the course of the surgery.

Making the Incision: The surgeon makes a skin incision down the middle region through the neck muscles, so that the skull and also the top of the spine become visible. This incision is usually three inches long, where the skin and the muscles are slightly lifted from the bone and then folded back.

Bone Removal: The surgeon will remove a small portion of the skull and push it towards the back of the patient's head. The process is called suboccipital craniectomy. In a few instances, the bony arch of the vertebra is also removed by a process called laminectomy. These steps are done for exposing the protective covering of the brain and the spinal cord, called dura. As a result of the process, the compression on the tonsils is reduced.

Opening the Dura: The surgeon will then open the dura to get a view of the tonsils and the cistern. Few surgeons also conduct a Doppler ultrasound study during the operation to determine whether it's necessary to open the dura. For some patients, the process of bone removal can alone restore the normal flow of CSF.

Reducing the Tonsils (optional): Based on the size of herniation, the stretched as well as the damaged tonsils are shrunk via a process called electrocautery. This shrinkage will ensure that there is no further blocking the cerebrospinal fluid flow.

Attaching the Dura Patch: A small patch made of synthetic material or the patient's pericranium, which is a piece of deep scalp tissue just to the exterior of the skull, is then sutured into its place. This patch will further enlarge the dura opening and also the space present around the tonsils. The dural patch is then sutured under watertight conditions. Later, the suture line is coated by a dural sealant to prevent cerebrospinal fluid leakage.

Closing the Incision: Post the surgery, the neck muscles and the skin are sutured together. A dressing is next placed over the area where the incision has been performed.