Chiari Malformations represents a family of disorders characterized by displacement of the hind portion of the brain (cerebellum, brainstem and 4th ventricle) down into the spinal canal. Because of the small space, the tonsils of the cerebellum can become impacted in the opening into the skull base (Foramen Magnum) and consequently place pressure on the spinal cord. This can also cause obstruction of the normal flow of the cerebrospinal fluid (CSF). In some situations fluid or cysts (syrinx or syringomyelia) can develop within the spinal cord. With the availability of MRI scans the diagnosis of Chiari Malformation has become more frequent. Common presenting symptoms include headache and neck pain, which are frequently worsened with coughing and sneezing. Less commonly patients can experience pain and weakness of the arms or legs, incoordination of the extremities, hoarseness, trouble swallowing and double vision.
Many patients with Chiari Malformation have no symptoms and don't require treatment. Treatment for symptomatic patients usually requires a surgery to decompress the pressure on the cerebellum, brainstem and spinal cord. Various techniques for achieving this have been performed by different surgeons. Commonly, a small amount of bone is removed from the back part of the skull and the covering of the brain (dura) is enlarged by sewing in a patch graft. This gives the brain more room and allows improved flow of the CSF past the previous area of obstruction.