The anatomical features of axis ring fractures: A retrospective analysis of 217 cases

Abstract

ObjectiveRecently research reports show that the anatomical location and pattern of fracture lines in axis ring fractures are variety, however, no studies focusing on these topics have published so far. The objective of this study is to observe the radiological features of axis ring fractures with multicenter data. MethodsWe reviewed the clinical notes and imaging studies of axis ring fractures in our prospectively maintained database. Specially, CT scans and three-dimensional reconstructed images of the cervical spine were used to observe: the incidence of different anatomical structures injuries, location of fracture lines, and fracture pattern. ResultTwo hundred and seventeen patients with axis ring fractures were included. There were total 438 fracture lines on the axis ring, and the incidence of fractures of superior articular facet and/or posterior wall of C2 body, pediculoisthmic component (PIC), inferior articular facet, and lamina fracture, were 49.1%, 27.6%, 13.7%, and 9.6%, respectively. The most common fracture pattern (145 cases) was one fracture line through superior articular facet and/or posterior wall of C2 body on one side and another through the neural arch on the other side. The remaining fracture patterns included bilateral fracture lines through superior articular facet and/or posterior wall of C2 body (35 cases), bilateral PIC fractures (16 cases), and others (21 cases). A supplementary classification of axis ring fractures taking into account the anatomical areas, features, and probable mechanism was proposed. ConclusionThe anatomical location and pattern of fracture lines in axis ring fractures were more complex than expected. This study might help in understanding of radiological features of such fractures, and choosing the proper treatment.