A Correlation Among the Most Classic Axis Injuries Classification and the New AO Upper Cervical Spine Classification System.

Abstract

Narrative review. To establish a correlation among the classic C2 classification systems and the new AO upper cervical spine trauma classification system (UCST). A multitude of classifications were historically proposed for C2 injuries, none of them with universal acceptation. The new UCST incorporated elements of these prior classifications into this new system to improve their limitations. Eight classic C2 classification systems-Anderson and D´Alonzo, Roy-Camille, Hadley et al, Grauer et al, Effendi et al, Levine and Edwards, Burke and Harris and Benzel et al were evaluated, and their injury types/subtypes were classified according to the new AO UCST. Most of the injuries were classified as type A in accordance with the new UCST, suggesting that most of the detailed descriptions of specific bone injury patterns may not be implied in different treatment strategies, being treated non-surgical. Those with ligamentous injury (type B) were attributed to some injuries with ligamentous/disc disruption without clear dislocations (type C when dislocations were present). This correlation between the classic morphologies and the new AO UCST may improve the understanding of injury patterns and help in the decision of the best treatment.