Chiari malformations (CMs) are structural defects in the cerebellum, the part of the brain that controls balance. Normally the cerebellum and parts of the brain stem sit in an indented space at the lower rear of the skull, above the foramen magnum (a funnel-like opening to the spinal canal). When part of the cerebellum is located below the foramen magnum, it is called a Chiari malformation.
CMs may develop when the bony space is smaller than normal, causing the cerebellum and brain stem to be pushed downward into the foramen magnum and into the upper spinal canal. The resulting pressure on the cerebellum and brain stem may affect functions controlled by these areas and block the flow of cerebrospinal fluid (CSF)— the clear liquid that surrounds and cushions the brain and spinal cord—to and from the brain.
Some CMs are asymptomatic and do not interfere with a person’s activities of daily living. In other cases, medications may ease certain symptoms, such as pain.
Surgery is the only treatment available to correct functional disturbances or halt the progression of damage to the central nervous system. Most individuals who have surgery see a reduction in their symptoms and/or prolonged periods of relative stability. More than one surgery may be needed to treat the condition.
Posterior fossa decompression surgery is performed on adults with CM to create more space for the cerebellum and to relieve pressure on the spinal column. Surgery involves making an incision at the back of the head and removing a small portion of the bottom of the skull (and sometimes part of the spinal column) to correct the irregular bony structure. The neurosurgeon may use a procedure called electrocautery to shrink the cerebellar tonsils. This surgical technique involves destroying tissue with high-frequency electrical currents.
A related procedure, called a spinal laminectomy, involves the surgical removal of part of the arched, bony roof of the spinal canal (the lamina) to increase the size of the spinal canal and relieve pressure on the spinal cord and nerve roots.
The surgeon may also make an incision in the dura (the covering of the brain) to examine the brain and spinal cord. Additional tissue may be added to the dura to create more space for the flow of CSF.
CMs may develop when the bony space is smaller than normal, causing the cerebellum and brain stem to be pushed downward into the foramen magnum and into the upper spinal canal. The resulting pressure on the cerebellum and brain stem may affect functions controlled by these areas and block the flow of cerebrospinal fluid (CSF)— the clear liquid that surrounds and cushions the brain and spinal cord—to and from the brain.
Some CMs are asymptomatic and do not interfere with a person’s activities of daily living. In other cases, medications may ease certain symptoms, such as pain.
Surgery is the only treatment available to correct functional disturbances or halt the progression of damage to the central nervous system. Most individuals who have surgery see a reduction in their symptoms and/or prolonged periods of relative stability. More than one surgery may be needed to treat the condition.
Posterior fossa decompression surgery is performed on adults with CM to create more space for the cerebellum and to relieve pressure on the spinal column. Surgery involves making an incision at the back of the head and removing a small portion of the bottom of the skull (and sometimes part of the spinal column) to correct the irregular bony structure. The neurosurgeon may use a procedure called electrocautery to shrink the cerebellar tonsils. This surgical technique involves destroying tissue with high-frequency electrical currents.
A related procedure, called a spinal laminectomy, involves the surgical removal of part of the arched, bony roof of the spinal canal (the lamina) to increase the size of the spinal canal and relieve pressure on the spinal cord and nerve roots.
The surgeon may also make an incision in the dura (the covering of the brain) to examine the brain and spinal cord. Additional tissue may be added to the dura to create more space for the flow of CSF.