For children experiencing symptoms and who have been diagnosed with a Chiari malformation, surgery allows the creation of more space for the brain and spinal cord. Without surgery, symptoms can be expected to continue or even worsen over time.
The goal of surgery is to increase the amount of space at the base of the brain. A small portion of bone at the bottom of the skull must be removed to create this extra space. The bone that is removed will not be put back, but the muscle and skin covering this bone are thick enough to provide protection for the brain.
A small incision or cut (approximately four inches in length) is made in the skin in the back of the head. The muscles that cover the bone at the bottom of the skull are gently moved out of the way and small drills are used to cut the bone away from the skull. After this bone is removed, the neurosurgeon may use an ultrasound machine to see if enough space has been made. If enough space is present, the surgery is complete and the incision is sewn closed.
If additional space is required, an opening must be made in the thick covering of the brain, called the dura mater. Most neurosurgeons then sew a patch of material over this opening to keep spinal fluid from running out of the back of the head. Opening the dura mater and sewing in this patch makes all the space that is needed. In addition, some neurosurgeons may shrink the part of the brain tonsils that is crowding into the upper spinal canal. As these brain tonsils do not have any function, it is safe to shrink this brain tissue.
Children who receive the surgery have a very good chance of being helped, but follow-up visits are required to ensure that symptoms do not return.