Are rib fractures stable? An analysis of progressive rib fracture offset in the acute trauma setting

Abstract

Background: Rib fractures serve as both a marker of injury severity and a guide for clinical decision making for trauma patients. Although recent studies have suggested that rib fractures are dynamic, the degree of progressive offset remains unknown. The purpose of this study was to further characterize the change that takes place in the acute trauma setting.

Methods: A 4-year (2016-2019) retrospective assessment of adult trauma patients with rib fracture(s) admitted to a level I trauma center was performed. Initial and follow-up computed tomography scans were analyzed to determine the magnitude of offset. Relevant clinical course variables were examined, and location of chest wall instability was examined using the difference of interquartile range of median change. Statistical Product and Services Solutions (Version 25, IBM Corp. Armonk, NY) was then used to generate a neural network-multilayer perceptron that highlighted independent variable importance.

Results: Fifty-three patients met the inclusion criteria for severe injury. Clinical course variables that either trended or significantly predicted the occurrence of progressive offset were Abbreviated Injury Scale Thoracic Scores (3.1 ± 0.4 no progression vs. 3.4 ± 0.6 yes progression; p = 0.121), flail segment (14% no progression vs. 43% yes progression; p = 0.053), and number of ribs fractured (4 [2-8] no progression vs. 7 [5-9] yes progression; p = 0.023). The location of progressive offset largely corresponded to the posterolateral region as demonstrated by the differences of interquartile range of median change. The neural network demonstrated that ribs 4 to 6 (normalized importance [NI], 100%), the posterolateral region (NI, 87.9%), and multiple fractures per rib (NI, 66.6%) were valuable in predicting whether progressive offset occurred (receiver operating characteristic curve - area under the curve = 0.869).

Conclusion: Rib fractures are not stable, particularly for those patients with multiple fractures in the mid-to-upper ribs localized to the posterolateral region. These findings may identify both trauma patients with worse outcomes and help develop better management strategies for rib fractures.

Level of evidence: Prognostic and epidemiological, level III.