Anterior Cervical Osteotomy: A Narrative Review and Proposal of a Mechanism-Based Decision Framework (The ACO Triad)

Study DesignNarrative review and conceptual framework proposal.ObjectiveTo reframe anterior cervical osteotomy (ACO) as a biomechanical continuum and propose a mechanism-based decision framework "the ACO Triad" integrating alignment, stability, and safety.MethodsA comprehensive literature review was performed across PubMed, Embase, and Web of Science to identify studies representative of distinct ACO biomechanical mechanisms. Unlike traditional hierarchical classifications based on resection volume, techniques were analyzed and synthesized into a four-tier continuum based on their dominant correction mechanism: from disc-level release to vertebral-body translation.Key Content and FindingsThe literature review suggests that sagittal alignment outcomes are governed by the mechanism of apical control (hinging vs. translation) rather than the volume of bone removed. We organized strategies into four tiers: Tier I leverages disc-level release for segmental hinging; Tier II utilizes targeted retro-corporeal decompression; Tier III encompasses traditional corpectomy, which exhibits a "correction ceiling" and stability trade-offs with longer spans; and Tier IV (e.g., VBSO, ACAF) utilizes vertebral body translation for indirect decompression. The "ACO Triad" framework explains the trade-offs: while corpectomy (Tier III) increases resection, it may compromise stability (load-sharing) and safety in adhesive disease. Conversely, translation techniques (Tier IV) decouple decompression from resection, altering the safety profile.ConclusionsAnterior cervical osteotomy is best understood as a mechanism-driven continuum. By integrating alignment, stability, and safety, the ACO Triad provides a rational foundation for surgical decision-making, shifting planning from a resection hierarchy toward biomechanical intent.