Computational protocol: Effectiveness of Bicycle Safety Helmets in Preventing Facial Injuries in Road Accidents

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Protocol publication

[…] The evaluation was based on the data of the German In-Depth accident study (GIDAS). The German In-Depth accident study is a collaborative project of the federal office of road engineering (Bundesanstalt fur Strassenwesen; BaSt, Germany) and the research association of automobile technology (Forschungsvereinigung Automobiltechnik e.V.; FAT, Germany). A random selection method is used at the universities of Hannover and Dresden to register road accidents involving personal injury and evaluating these accidents medically and technically. According to this method, about 2,000 road accidents involving personal injuries are being reported every year in Greater Hannover and Dresden since the 1st of July 1999. A research team consisting of technicians and medical specialists go to the accident site and collect information about traces of the accident, vehicle deformation, injuries, and the cause of the accident. Based on 500 to 3000 data registered per accident, the accident can be reconstructed in detail by the use of a 3D laser technique (, ). After the accident, the team went to the hospital where the patient was undergoing treatment and recorded the clinical diagnosis. All data were compared to the official accident profiles for the catchment area and analyzed. Thus, GIDAS data were representative of the actual conditions in the surveyed areas ().In this study 24,892 accidents were registered from 1999 to 2011, of which 22,347 could be fully reconstructed. The excluded data were: Not completely reconstructed accidents, all traffic participants except bicyclists, fatally injured people. Also, cases with unknown facial injuries or unknown fact of wearing a helmet were excluded. All together we could analyze data from 5,350 cyclists. We evaluated the following data: collision opponents (), type of collision (), collision speed (relative speed of the collision partner in km/h), age, gender, the use of a protective helmet, and the presence of a facial fracture (orbital bone, zygomatic bone, nasal bone, maxilla, and mandible). Fractures of the nasal bone, the orbital bone, the zygomatic bone, and the maxilla were grouped together as fractures of the mid-face.The bicycle is not only use as a cheap mode of transport. The community who use a bicycle for sport activities is increasing. Thus, every year redesigned and faster bicycles were produced by industry. So, there is a large offer on different bicycle types, e.g. city bikes, mountain bikes, road racing bikes, cyclo-cross bikes, BMX bikes, trick riding bikes and E-bikes. The normal road cyclist is generally not mandated to wear specific clothing. A standard bicycle helmet is the sole protection and is developed to protect the head in case of fall or collision. They are not designed to protect the face. So, they have no chin guard or face shield. Bicycle helmets were different in two types, depending in manufacturing method: In-mold-method and selective-sticking-method. The standard bicycle helmet is a soft-shell helmet and is produced in the selective-sticking-method. In this process the two components (inner plastic foam and outer plastic) were sticked at selective points. So, the acting energy cannot distribute and leads much higher energy in several points. A better protection will be accepted by using the in-mold-method. This technique guaranteed an all-over solid compound from the inner plastic foam and the outer plastic. In case of fall the energy will be a consisted distribution of energy. Hard-shell helmet, micro-shell helmet and some skater helmet are produced in this way (). Some of those helmets have also an additional chin guard or face shield. Therefore, these kinds of helmets are used for mountain biking, speed biking and road racing biking.Our data from the GIDAS had no details about the helmet. So, we did not know if the bicyclist wore a soft-shell helmet or hard-shell helmet. Because the data are from road accidents, we believe that most of the helmets were simple soft shell helmets.This was a multicentrically and retrospectively evaluated comparative study. Data from the included groups were compared to the entire cohort of cyclists.The data were evaluated retrospectively. SPSS Statistics (SPSS for Windows, Version 21.0, SPSS Inc, Chicago, USA) was used for statistical analysis. To get an overview of the data, a descriptive analysis was performed ( and ). As related to our issue, we used the binary logistic regression model to analyze the variable “wearing a helmet” to the occurrence of a fracture (). In the same analysis, we looked for other risk factors for sustaining a facial fracture (). A binary logistic regression model was performed to analyze the association between the fracture location, wearing a helmet, the relative speed of the opponent and the age (). The level of significance was set to P ≤ 0.05. […]

Pipeline specifications

Software tools V-FAT, SPSS
Applications Miscellaneous, qPCR
Diseases Facial Injuries, Craniocerebral Trauma, Fractures, Bone