Chiari Malformation (Update on Diagnosis and Treatment).

Chiari Malformation Type I (CMI) is a congenital malformation diagnosed by MRI findings of at least 5 mm of cerebellar ectopy below the foramen magnum. CM1 is frequently associated with syringomyelia. Herein, we discuss the history of CMI and syringomyelia, including early pathological and surgical studies. We also describe recent investigations into the pathogenesis and pathophysiology of CMI and their practical implications on management and surgical intervention. We also highlight the recent development of the Common Data Elements for CMI, providing a framework for ongoing investigations. Finally, we discuss current controversies of surgical management in CMI.