Defining the signs and symptoms of Chiari malformation type I with and without syringomyelia

Objective: There is a lack of correlation between how Chiari malformations are defined and the plethora of signs and symptoms attributed to these malformations. The purpose of this review is to understand the signs and symptoms of Chiari malformations in relation to the newer descriptions that define these malformations. Methods: We reviewed the literature to determine what are the pertinent signs and symptoms related to Chiari malformations, with special attention to Chiari type I malformations. Results: There were several strategies identified in the literature regarding how to define the morphology of Chiari malformations based on modern imaging and pathogenetic theories. The signs and symptoms were organized based on the type and location along the neuraxis. Although suggestive, it appears that symptoms have not been clearly correlated to anatomic variations of Chiari type I malformation. In addition, we discuss how magnetic resonance imaging has found a significant number of patients that lack or have a paucity of symptoms. Conclusions: Current understanding of the signs and symptoms for Chiari malformations has been based on a dated standard definition of these malformations. There is a need to redefine these malformations in order to uncover the natural history of the disease and how symptoms relate to this disorder.