For a study, it was determined that a sophisticated understanding of the biomechanics of the atlantoaxial complex was required to determine the best treatment for traumatic atlas fractures with or without transverse atlantal ligament (TAL) injury. The “rule of Spence” (ROS) was developed in 1970 as part of a groundbreaking effort to standardize the treatment of burst-type atlas fractures. According to the ROS, radiographic evidence of lateral mass displacement (LMD) larger than 6.9 mm (i.e., the distance between the C1 lateral masses and the C2 superior articular processes) may indicate a torn TAL and the necessity for surgical therapy. Since then, ROS has been commonplace in the literature on atlas injuries in the spine.
However, current research efforts and imaging breakthroughs had proven that the ROS was wrong on both fronts: it neither correctly predicts a TAL injury nor informs surgical decision-making in the decades following the original report by Spence et al. A review was to outline the history of the ROS, demonstrate its limitations, present findings from the existing literature on ROS and LMD thresholds, and discuss the current landscape of TAL injury management techniques, which included parameters like the Atlanta dental interval and type of injury according to the Dickman classification system and the AO Spine upper cervical injury classification system. The ROS was groundbreaking in its initial investigation and subsequent advancement of biomechanical and clinical knowledge of atlas fractures and TAL injuries; however, it is now time to retire its legacy as a rule.
