Chiari I Malformation


A Chiari I Malformation is a congenital (present at birth) condition in which the base of the bony skull and a portion of brain tissue (cerebellum) are disproportionately sized to one another. The hallmark of this condition is herniation or forced displacement of a segment of the cerebellum through a misshapen or inadequately sized opening at the base of the skull into the upper spinal canal. This results in compression of the brainstem and disturbance of spinal fluid circulation resulting in a myriad of mild to severe symptoms.


Despite its congenital nature, symptoms often do not begin until adulthood. Women are more frequently, although not exclusively, afflicted. Symptoms may gradually develop or occur following trauma. Symptoms are dependent on the specific area of herniation, and can be so diverse and numerous, it's difficult to believe a single structural problem can be to blame. Due to its complex nature, the condition is often unrecognized or misdiagnosed. Patients may initially complain of a headache which may be confused with a migraine. More mysteriously, they may also complain of nausea; vomiting; dizziness; vertigo; sensitivity to sound, light and smells; widespread pain; weakness; clumsiness; balance issues; difficulty with memory and concentration; urinary urgency and frequency; disturbances with bowel habits; fatigue; and many others.


Diagnosis is made through a detailed, focused, multidisciplinary neurological examination and confirmed by a diagnostic study (magnetic resonance imaging) of the brain using a specific, unique protocol. Because symptoms mimic so many other conditions, Chiari I Malformation patients often wait years for an accurate diagnosis. Timely diagnosis and treatment lessens the chance of more permanent neurological damage.


Some patients with Chiari I Malformations are symptom free and require no treatment. Others may see symptoms improved through medications and other non-surgical methods. However, when symptoms become evident, and other clinical criteria are met, generally surgery is warranted.

In this operation, the opening at the base of the skull is enlarged, creating more room for the brain in order to relieve compression of the brainstem and spinal cord. Circulation of spinal fluid is thus improved and symptoms are relieved.