Chiari malformations in adults occur when there is a lack of space for the cerebellum, which is the part of the brain that controls balance and coordination. When the space at the bottom back of the skull is smaller than it should be, then the cerebellum and the brainstem may be pushed downward. The pressure on the cerebellum can block the flow of cerebrospinal fluid (CSF) and cause an array of symptoms.
For patients who show symptoms, surgical treatment is often the best option, although the course of treatment depends on the severity of the malformation. In most cases, decompression of the area surrounding the malformation is enough. Rarely, a shunt to drain the cerebrospinal fluid from the brain to the abdomen is performed to control the problem in adults.
At UPMC, we take a 360° Approach to treatment when evaluating each patient—looking at their conditions from every direction—to find the path that is least disruptive to the patient's brain, critical nerves, and ability to return to normal functioning. Our neurosurgical team may recommend a combination of surgical and non-surgical approaches to maximize the benefits of surgery while minimizing risks.
Your doctor will ask you about your symptoms and medical history, and will perform a physical exam.
Symptoms may include:
- severe head and neck pain
- loss of pain and temperature sensation
- loss of muscle strength in hands and arms
- spasticity, dizziness, or balance problems
- double or blurred vision
- hypersensitivity to bright lights
A range of tests can help diagnose and determine the severity of Chiari malformation. Although some patients are asymptomatic, others have symptoms that are not specific to Chiari malformation. Therefore, a careful examination must be conducted, and a diagnosis of Chiari malformation must be one of exclusion.
To make the diagnosis, your doctor will order imaging tests. Some of the tests used to make this diagnosis are brainstem auditory evoked potential (BAER), CT and MRI scans, myleogram, and somatosensory evoked potentials (SSEP).
There are four types of Chiari malformations, and each one should be considered separately when deciding on a course of treatment. Malformations that are asymptomatic should be left alone and do not require surgery. The goals of treatment include decompressing the nerve tissue, and creating normal CSF flow around and behind the cerebellum.
Although medications may ease the pain associated with a Chiari malformation, surgery is the only treatment that will correct functional disturbances or stop the progression of damage. Chiari I malformations (adult type) may be treated with local decompression of the bones and release of the dura. Chiari II (children) is treated similarly, although the decompression is usually followed at lower levels to decompress the spinal canal.
At UPMC, we take a 360° Approach to treatment when evaluating each patient—looking at their conditions from every direction—to find the path that is least disruptive to the patient's brain, critical nerves, and ability to return to normal functioning. Our neurosurgical team may recommend a combination of surgical and non-surgical approaches to maximize the benefits of surgery while minimizing risks.
When the disease is associated with ventral compression of the brainstem by some other associated anomaly such as basilar invagination, then the preferred surgical treatment at UPMC is the Endoscopic Endonasal Approach (EEA). This innovative, minimally invasive technique uses the nose and nasal cavities as natural corridors to access the malformation. EEA offers the benefits of no incisions to heal, no disfigurement to the patient, and a faster recovery time.
Most of the time, the treatment for a Chiari malformation in adults is performed by a small incision in the back of the head followed by the opening of a small window on the occipital bone to recreate the space to the cerebellum and brainstem.
