Determining the clinical significance of the Chest Wall Injury Society taxonomy for multiple rib fractures

BACKGROUND The Chest Wall Injury Society (CWIS) proposals for standardized nomenclature for multiple rib fracture (MRF) classifications were derived by international expert Delphi consensus. This study aimed to validate the CWIS taxonomy using a single-instituion clinical database. METHODS Computed tomography (CT) scans, of 539 consecutive patients with MRFs admitted to a regional major trauma center over a 33-month period, were reviewed (blinded for clinical outcomes). Every rib fracture in every patient was assessed according to each of the CWIS criteria (the degree of displacement, characterization of the fracture line, location of each fracture, and the relationship to neighboring fractures). The clinical significance of the proposed CWIS definitions were determined from independently coded, routinely collected Hospital Episodes Statistics data. RESULTS The radiologic aspects of 3,944 individual rib fractures were assessed. Indicators of injury severity (severe displacement greater series length, and flail segment) were positively associated with other fractures (p < 0.001), hemopneumothorax (p < 0.001), pulmonary complications (p = 0.002), adverse outcomes (p = 0.006), mechanical ventilation (p < 0.001) and prolonged hospital and intensive therapy unit length of stay (p = 0.006, p = 0.007 respectively). Four of the CWIS-proposed definitions were correlated with pulmonary complications and adverse outcomes: the categories of displacement, the definition of individual fracture characterization, the presence of a flail segment. Two definitions for which there was CWIS consensus were not correlated with clinical outcomes: the definition of a series to describe associated fractures on neighboring ribs, the inclusion of a paravertebral sector for fracture localization. CONCLUSION The CWIS rib fracture taxonomy demonstrates clinical relevance. There were associations between the severity of category groups within three of the proposed definitions, based on the clinical outcomes observed. Clinical outcome assessment proved inconclusive for four agreed definitions. Comprehensive, multiinstitutional data collection would be required to provide validation for all the CWIS-proposed definitions.