AOSpine Classification Systems (Subaxial, Thoracolumbar).

Numerous classification systems for subaxial and thoracolumbar spine injuries were proposed in the past with the attempt to facilitate communication between physicians. The AO-Magerl, thoracolumbar system, and Subaxial Cervical Spine Injury Classification systems are all well known, but did not achieve universal international adoption. A group of international experienced spine trauma surgeons were brought together by AOSpine with the goal to develop a comprehensive yet simple classification system for spinal trauma. This article is a synopsis of the proposed subaxial and thoracolumbar classification systems. In several studies, this classification system was developed using an iterative consensus process among the clinical experts in sufficient number and quality of DICOM images of real cases searching for meaningful and reproducible patterns. Both systems are based on 3 injury morphology types: compression injuries (A), tension band injuries (B), and translational injuries (C) with a total of 9 subgroups. In the subaxial cervical spine 4 additional subtypes for facet injuries exist. Patient-specific modifiers and neurologic status were also included to aid surgeons in therapeutic decision making. The proposed classification systems for subaxial and thoracolumbar injuries showed substantial intraobserver and interobserver reliability (κ = 0.64-0.85) for grading fracture type. Grading for the subtypes varied considerably due to the low frequency of certain injury subtypes among other reasons. In summary, the AOSpine thoracolumbar and subaxial cervical spine injury systems show substantial reliability, thus being valuable tools for clinical and research purposes.