Based on the history, clinical examination, and MRI findings, the diagnosis of Chiari I malformation was made. The patient is taken to the operating room, where general anesthesia is induced. The patient is then positioned prone with the head supported in a three-pin head holder. The occipital area is shaved and prepped in a sterile fashion. A midline incision is created from the inion to C2.
Dissection continues until the suboccipital area is exposed.
A craniectomy of the suboccipital area is performed to visualize the dura and C1 area. A straight or Y-shaped incision is made into the dura over the cerebellar hemisphere. Drainage from the Foramen of Magendi is evaluated. Fine electrocautery may be needed to shrink the cerebellar tonsils in effort to restore normal CSF pathway. A patch graft of either bovine pericardium, synthetic material, or periosteum is then created to enlarge the posterior fossa at the foramen magnum and upper cervical spine.