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This article is the author's final published version in Clinical Spine Surgery, Volume 36, Issue 6, July 2023, Pg. E239 - E246.

The published version is available at Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc..


STUDY DESIGN: Global cross-sectional survey.

OBJECTIVE: The objective of this study was to validate the hierarchical nature of the AO Spine Sacral Classification System and develop an injury scoring system.

SUMMARY OF BACKGROUND DATA: Although substantial interobserver and intraobserver reliability of the AO Spine Sacral Classification System has been established, the hierarchical nature of the classification has yet to be validated.

METHODS: Respondents numerically graded each variable within the classification system for severity. Based on the results, a Sacral AO Spine Injury Score (AOSIS) was developed.

RESULTS: A total of 142 responses were received. The classification exhibited a hierarchical Injury Severity Score (ISS) progression (A1: 8 to C3: 95) with few exceptions. Subtypes B1 and B2 fractures showed no significant difference in ISS (B1 43.9 vs. B2 43.4, P =0.362). In addition, the transitions A3→B1 and B3→C0 represent significant decreases in ISS (A3 66.3 vs. B1 43.9, P

CONCLUSIONS: The results of this study validate the hierarchical nature of the AO Spine Sacral Classification System. The Sacral AOSIS sets the foundation for further studies to develop a universally accepted treatment algorithm for the treatment of complex sacral injuries.

LEVEL OF EVIDENCE: Level IV-Diagnostic.

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