The clinical significance of hindbrain herniation and deformity as shown on MR images of patients with Chiari II malformation.

This study investigates whether the degree of brainstem herniation and the nature of the cervicomedullary deformity seen on sagittal plane MR images correlates with the clinical syndrome in patients with the Chiari II malformation. The amount of brainstem herniation was assessed by relating the position of the midbrain and pons to the sella turcica and the anterior lip of the foramen magnum, respectively. The cervicomedullary deformity was graded into degrees of increasing severity. We found that the neurologic status of these children was not affected by either the amount of herniation or the characteristics of the cervicomedullary deformities. Because of these findings, we believe that other factors, such as disorganization of the brainstem nuclei, may be the likely cause for the breathing and swallowing difficulties experienced by children with the Chiari II malformation.