Craniofacial Injuries for Helmeted and Unhelmeted Bicyclists in Germany

Paper i proceeding, 2023

Current bicycle helmet standards require impact testing mostly covering cranial or skull vault. Bicyclists are exposed to impacts to the face causing facial and basilar skull fractures, and soft tissue injuries, in addition to traumatic brain injuries. We aim to describe patterns and frequencies of craniofacial injuries grouped by anatomical and injury sites to inform new test method development in future bicycle helmet standards and subsequently promote protective designs. We analysed fully reconstructed crashes involving a bicycle from the German In-Depth Accident Study (GIDAS), crash years 2010-2022. The type and location of an injury was determined through the Abbreviated Injury Scale (2015 version), a GIDAS-own variable, and free-text information. We found that a substantial portion of craniofacial injuries were to the face for both helmeted and unhelmeted bicyclists. Facial injuries shifted from the upper face to the mid- and lower face when a helmet was worn. We identified the mid-face as the most prominent region for improving bicycle helmet safety. Hence, a new test method with an extended test area covering mid- and lower face is recommended and injury risk to commonly fractured facial bones should be assessed in future standards. Protective designs appear technically feasible: A visor in connection with a chin guard, or novel concepts using inflatable technology, can improve bicycle helmet designs for facial impact protection and could be assessed in future standards.