Study on Syringomyelia Associated with Chiari Malformation Through Magnetic Resonance Imaging

Objective: To study the relationship between the extent of cerebellar tonsil herniation and the size of syrinx in patients with syringomyelia associated with Chiari malformation, and to explore the regular rule of its occurrence. Methods: Retrospective analyses were made on the MRI data of CM/SM in 162 cases. The length of cerebellar tonsil herniation and the length and width of cavity were measured. Then the measurement data obtained were analyzed statistically. Results: The patients with the length of cerebellar herniation below the lower border of the foramen magnum shorter than 5 mm accounted for 13.58%; those patients with the length of cerebellar herniation equal to 5～15 mm constituted 75.31%; and the patients with the length of cerebellar herniation longer than 15 mm accounted for 11.11%. The correlation coefficient between the extent of cerebellar tosil herniation and the length of cavity was rl=-0.0961, P=0.3517 and the coefficient for the width of the cavity was r2=-0.0055, P= 0.9578 . Conclusion: Syringomyelia was found more frequently in patients with a herniation of 5～15 mm than in those with a smaller or larger herniation . There was no significant linear correlation between the extent of cerebellar tonsil herniation and size of syrinx.