Study DesignSystematic Review.ObjectiveTo describe the historical classifications of thoracolumbar injuries and their evolution into the AO Spine Thoracolumbar Injury Classification System.MethodsA systematic review of MEDLINE, EMBASE and Cochrane Databases was performed in keeping with Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.Results445 articles were crystallized to 14 included studies. Simple categorization systems offered by Bohler or Watson-Jones merely identify fracture morphology. Holdsworth and Denis conveyed a sense of the stability of injuries by noting columns of stability, but still failed to take into consideration important factors such as neurological status or specific integrity of key stabilizing structures. The AO Spine Thoracolumbar Injury Classification System provides 3 hierarchical categories: type A consisting of compression type injuries, type B composed of distraction injuries and the unstable type C comprising displacement injuries. This communicates the severity of the fracture to clinicians and, with the addition of modifiers, can be synthesised into a scoring system to guide management. This classification is based upon biomechanical stability and increasing likelihood of clinicians offering operative rather than non-operative intervention as fracture severity escalates.ConclusionsA combination of evaluating fracture morphology, integrity of the posterior ligamentous complex and neurological status of the patient in the context of individual patient modifiers is integral to guide surgical decision making. The AO Thoracolumbar Injury Classification System accounts for all of the aforementioned and is the derivative and advancement on existing historical systems. Further nuanced development of scoring systems to guide operative or non-operative management is still required.