Chiari Malformation refers to a series of conditions where the lower portion of the cerebellum extends into the opening where the spinal cord exits the skull (foramen magnum). In children, its associated with spina bifida and hydrocephalus. In adults, chiari malformation tends to be more benign. Headaches worsened with coughing, laughing, sneezing, or other straining maneuvers is a common complaint. The headache tends to be occipital (back of the head) and can extend into the neck. Frequently, patients with a symptomatic chiari malformation can experience a cape-like numbness over the back which can extend into the arms and hands. At its most severe, Chiari malformation can cause weakness and numbness of the extremities due to compression of the spinal cord and development of a fluid collection within the spinal cord (syrinx). Rarely, Chiari malformation in adults can cause speech symptoms (dysarthria) and swallowing/aspiration difficulties.
Surgical treatment for Chiari malformation varies from surgeon to surgeon. All treatments involve some degree of widening of the foramen magnum. Some surgeons will simply remove the bone adjacent to the foramen magnum, while others will remove the bone and open the covering of the brain (dura). Once the dura is opened, a patch graft will be placed expanding the dura, allowing the cerebellum more room and allowing for flow of spinal fluid around the cerebellum.
At Dallas, Brain, Spine and Skull Base Surgery, we believe treatment of the Chiari malformation is best done through resection of the cerebellar tonsils. While this is an extra step in the procedure, we have found it leads to better decompression of the spinal cord and is permanent. We attribute our success in alleviating Chiari symptoms to this extra step. To date, there have been no cases where the Chiari malformation persisted after surgery or recurred at a later date. Additionally, by removing the cerebellar tonsils, we are able to reduce the size of both the incision and dural opening. This has resulted in less post-operative pain, faster recovery, and a dramatically reduced incidence of a common post-operative complication, spinal fluid leakage from the wound.
Diagnosing a symptomatic Chiari malformation can be difficult. The common symptoms of Chiari malformation can be vague and attributing them to a specific cause almost always requires advanced imaging of the brain and neck. We employ the use of magnetic resonance spinal fluid flow studies and cisternography to better assess the degree of compression at the foramen magnum and the resultant obstruction to normal spinal fluid flow. While many patients come to their first clinic visit with standard MR imaging of the brain and neck, we frequently order these more detailed exams to better characterize the effects of the Chiari malformation.