Severity and predictors of head injury due to bicycle accidents in Western Australia

How Well Do Popular Bicycle Helmets Protect from Different Types of Head Injury?

Bicycle helmets are designed to protect against skull fractures and associated focal brain injuries, driven by helmet standards. Another type of head injury seen in injured cyclists is diffuse brain injuries, but little is known about the protection provided by bicycle helmets against these injuries. Here, we examine the performance of modern bicycle helmets in preventing diffuse injuries and skull fractures under impact conditions that represent a range of real-world incidents. We also investigate the effects of helmet technology, price, and mass on protection against these pathologies. 30 most popular helmets among UK cyclists were purchased within 9.99-135.00 GBP price range. Helmets were tested under oblique impacts onto a 45° anvil at 6.5 m/s impact speed and four locations, front, rear, side, and front-side. A new headform, which better represents the average human head's mass, moments of inertia and coefficient of friction than any other available headforms, was used. We determined peak linear acceleration (PLA), peak rotational acceleration (PRA), peak rotational velocity (PRV), and BrIC. We also determined the risk of skull fractures based on PLA (linear risk), risk of diffuse brain injuries based on BrIC (rotational risk), and their mean (overall risk). Our results show large variation in head kinematics: PLA (80-213 g), PRV (8.5-29.9 rad/s), PRA (1.6-9.7 krad/s2), and BrIC (0.17-0.65). The overall risk varied considerably with a 2.25 ratio between the least and most protective helmet. This ratio was 1.76 for the linear and 4.21 for the rotational risk. Nine best performing helmets were equipped with the rotation management technology MIPS, but not all helmets equipped with MIPS were among the best performing helmets. Our comparison of three tested helmets which have MIPS and no-MIPS versions showed that MIPS reduced rotational kinematics, but not linear kinematics. We found no significant effect of helmet price on exposure-adjusted injury risks. We found that larger helmet mass was associated with higher linear risk. This study highlights the need for a holistic approach, including both rotational and linear head injury metrics and risks, in helmet design and testing. It also highlights the need for providing information about helmet safety to consumers to help them make an informed choice.

Cranio-cervical and traumatic brain injury patterns-do they differ between electric bicycle, bicycle, and motorcycle-induced accidents?

PURPOSE

With the growing technical options of power transmission and energy-saving options in electric drives, the number of E-bike-related accidents especially in an elderly population has increased. The aim of the current study was to compare if the increased velocity in comparison to conventional bikes translates into different injury patterns in the cranio-cervical and head region.

METHODS

A retrospective cohort study was performed in patients admitted to our level one trauma center between 2009 and 2019 after being involved in an accident with either an E-bike, bicycle, or motorcycle and suffered cranio-cervical or traumatic brain injury.

OUTCOMES

cranio-cervical/intracranial injury pattern. Data interpretation was conducted in an interdisciplinary approach.

RESULTS

From 3292 patients treated in this period, we included 1068 patients. E-bikers were significantly older than bicyclists (or motorcyclists) and lay between the other two groups in terms of helmet use. Overall injury patterns of E-bikers resembled those found in motorcyclists rather than in bicyclists. E-bikers had a higher incidence of different cerebral bleedings, especially if no helmet was worn. Helmet protection of E-bikers resulted in a comparable frequency of intracranial bleeding to the helmeted bicyclists.

CONCLUSION

The overall pattern of head and cervical injuries in E-bikers resembles more to that of motorcyclists than that of bicyclists. As they are used by a more senior population, multiple risk factors apply in terms of complications and secondary intracranial bleeding. Our study suggests that preventive measures should be reinforced, i.e., use of helmets to prevent from intracranial injury.

Bicycle helmets are associated with fewer and less severe head injuries and fewer neurosurgical procedures

PURPOSE

This study explores the protective capabilities of bicycle helmets on serious head injury among bicyclists hospitalized in a Norwegian level 1 trauma centre.

METHOD

Information on helmet use, demographic variables, Abbreviated Injury Scale (AIS) and surgical procedure codes was retrieved from the Oslo University Hospital Trauma Registry for patients with bicycle-related injuries from 2005 through 2016. Outcomes were serious head injury defined as maximum AIS severity score ≥ 3 in the AIS region Head, any cranial neurosurgical procedure, and 30-day mortality.

RESULTS

A total of 1256 hospitalized bicyclists were included. The median age was 41 years (quartiles 26-53), 73% were male, 5.3% had severe pre-injury comorbidities, and 54% wore a helmet at the time of injury. Serious head injury occurred in 30%, 9% underwent a cranial neurosurgical procedure, and 30-day mortality was 2%. Compared to non-helmeted bicyclists, helmeted bicyclists were older (43 years, quartiles 27-54, vs. 38 years, quartiles 23-53, p = 0.05), less often crashed during night-time (21% vs. 38%, p < 0.001), less frequently had serious head injury (22% vs. 38%, OR 0.29, 95% CI 0.22-0.39), and less often underwent cranial neurosurgery (6% vs. 14%, OR 0.36, 95% CI 0.24-0.54). No statistically significant difference in 30-day mortality between the two groups was found (1.5% vs. 2.9%, OR 0.50, 95% CI 0.22-1.11).

CONCLUSION

Helmet use was associated with fewer and less severe head injuries and fewer neurosurgical procedures. This adds evidence to the protective capabilities of bicycle helmets.

Head injuries related to bicycle collisions and helmet use - an observational study

OBJECTIVES

In Denmark, the use of bicycles is widespread, and head injuries are often seen in cyclists involved in collisions. Despite the well-known effects of using a helmet to reduce head injuries, using helmets is not mandatory in Denmark. The primary objective of this study was to provide data regarding injury outcomes and helmet usage.

METHODS

Participants were bicyclists who sustained head injuries in bicycle collisions and were assessed by the Copenhagen Emergency Medical Services between 1 January 2016; and 15 June 2019. Patients with suspected head injury were identified in an electronic prehospital patient record. Data were linked to the Danish National Patient Registry to retrieve the diagnosis and were categorized into head injury or no head injury based on the diagnosis. Adjusted logistic regression analyses were reported with odds ratios and corresponding confidence intervals to assess the risk of head injury while adjusting for risk factors like age, sex, alcohol consumption, occurrence during weekends and traumatic brain injury.

RESULTS

A total of 407 patients were included in this study. Within this entity, 247 (61%) had sustained a head injury. The use of a helmet was reported in one-third of the included patients. Among the head-injured patients, 13% sustained moderate to severe head injuries. Patients with suspected alcohol involvement were significantly less likely to report the use of a helmet. Helmet use reduced the risk of head injury with an odds ratio of 0.52, (95% CI 0.31 - 0.86). In high-energy trauma, the use of a helmet showed a significant reduction in the risk of sustaining a head injury with an odds ratio of 0.28, (95% CI 0.12 - 0.80).

CONCLUSIONS

In this study, using a helmet was associated with a significantly decreased risk of head injury; this association was even more significant in high-energy trauma.

Bicycle injuries: A systematic review for forensic evaluation

Bicycles are employed as means of transportation across various age groups, from young students to the elderly, for work, education, health, and leisure trips. Despite not achieving high speeds, bicyclists remain vulnerable to severe and even fatal injuries when they are involved in traffic accidents. Although the rising awareness of ecological issues and traffic law enforcement mean that cyclists are increasingly susceptible to road traffic crashes and injuries. Injuries resulting from a traffic accident involving cyclists can show distinct and specific characteristics depending on the manner of occurrence. The aim of this study is to provide a systematic review of the literature on injuries sustained in cyclists involved in road accidents describing and analysing elements useful for forensic assessment. The literature search was performed using PubMed, Scopus, and Web of Science from January 1970 to March 2023. Eligible studies have investigated issues of interest to forensic medicine about traffic accidents involving bicycles. A total of 128 studies satisfied the inclusion criteria and were categorized and analyzed according to the anatomical regions of the body affected (head, neck, thoraco-abdominal, and limb injuries), and the assessment of lesions in reconstruction of the bicycle accident was examined and discussed. This review highlights that injuries resulting from a traffic accident involving cyclists can show distinct and specific characteristics depending on the manner of occurrence and the energy levels involved in the crash. The assessment of injuries offers valuable insights that integrated with circumstantial and engineering data perform the reconstruction of accident dynamics.

A Review of Cyclist Head Injury, Impact Characteristics and the Implications for Helmet Assessment Methods

Head injuries are common for cyclists involved in collisions. Such collision scenarios result in a range of injuries, with different head impact speeds, angles, locations, or surfaces. A clear understanding of these collision characteristics is vital to design high fidelity test methods for evaluating the performance of helmets. We review literature detailing real-world cyclist collision scenarios and report on these key characteristics. Our review shows that helmeted cyclists have a considerable reduction in skull fracture and focal brain pathologies compared to non-helmeted cyclists, as well as a reduction in all brain pathologies. The considerable reduction in focal head pathologies is likely to be due to helmet standards mandating thresholds of linear acceleration. The less considerable reduction in diffuse brain injuries is likely to be due to the lack of monitoring head rotation in test methods. We performed a novel meta-analysis of the location of 1809 head impacts from ten studies. Most studies showed that the side and front regions are frequently impacted, with one large, contemporary study highlighting a high proportion of occipital impacts. Helmets frequently had impact locations low down near the rim line. The face is not well protected by most conventional bicycle helmets. Several papers determine head impact speed and angle from in-depth reconstructions and computer simulations. They report head impact speeds from 5 to 16 m/s, with a concentration around 5 to 8 m/s and higher speeds when there was another vehicle involved in the collision. Reported angles range from 10° to 80° to the normal, and are concentrated around 30°-50°. Our review also shows that in nearly 80% of the cases, the head impact is reported to be against a flat surface. This review highlights current gaps in data, and calls for more research and data to better inform improvements in testing methods of standards and rating schemes and raise helmet safety.

Risks for bicycle-related injuries in Al Ain city, United Arab Emirates: An observational study

Traffic-related injuries are a serious health problem. Traffic safety is a priority reflected in the United Nations Sustainable Development Goals. Data on current hazards for bicycle-related injuries from the United Arab Emirates are lacking. The aim of our observational study was to assess the behavior of bicyclists on the roads in Al Ain City, United Arab Emirates and compare our current results with a previous study from 2004.We adapted and tested a structured data collection form. Different sectors of Al Ain were randomly selected to cover the whole city during different times. Bicyclists were observed without direct contact.Out of 1129 bicyclists, 97.6% were males and 13.2% children. 39.4% were cycling on main roads with high-density traffic, 33.1% were cycling against the traffic, 39.3% were cycling at night, and 96.8% of them were not using lights. Only 2.1% of the bicyclists used helmets. A higher proportion of female than male cyclists used helmets (25.9% vs 1.5%; P < .001, Fisher exact test). There was an increase in cycling with the traffic (P < .001) and in use of helmets (P < .025) compared with the previous study.Unsafe practices of bicyclists and low use of helmets despite legislation persist in Al Ain. There is a need to raise bicycle safety awareness and improve enforcement of bicycle helmet legislation. This should be directed toward expatriate workers, children, parents, and maids. Environmental changes, namely building separate bicycle lanes, can increase safety for cycling.