Multiple rib fractures: A novel and prognostic CT-based classification system

Abstract

Background The accepted classification for multiple rib fractures is binary: flail chest or not. There is a wide spectrum of morphology with subsequent variation in the impact on chest wall mechanics and clinical outcomes. As the practice of surgical stabilisation of rib fractures evolves, there is a need for a better taxonomy. The aim of this study was to create a data-driven radiological classification system for multiple rib fractures, prognostic of both complications and surgical stabilisation of rib fracture. Methods The radiological pattern of injury was assessed for cases undergoing surgical stabilisation of rib fracture (n = 48) over a five-year period and a consecutive sample of non-operative controls (n = 48). Every rib fracture (n = 1032) was assessed on CT scans for location, displacement and comminution. An iterative classification system was developed and tested for inter-observer agreement and outcome prediction. Results The fractures occurred in a ‘series’ (≥3 consecutive ribs at a similar location) in 72% of cases: these were more likely to be displaced (p < 0.001). Variables included in the classification were the anatomical pattern (presence, length and overlap of series) and degree of displacement. The classification was prognostic for complications (p < 0.001), discriminated for fixation (C = 0.907) and had acceptable inter-observer agreement (k = 0.50). Conclusions The Sheffield Multiple Rib Fracture Classification derived categories of short/long series, and short/long flail chest, with sub-division according to the presence of displacement. It was prognostic for clinical outcomes and of surgical fixation. It may facilitate communication, comparison of outcomes and selection for management protocols.