Motorcycle helmet selection and usage for improved safety: A systematic review on the protective effects of helmet type and fastening

Cervical misalignment in motorcyclists in relation to new helmet removal recommendations shown with augmented reality resources: A biomechanical analysis

Objective

The aim of this study is to determine the best technique and position for helmet removal in injured motorcyclists by comparing cervical misalignment produced in the supine position and prone position.

Method

Comparative cross-sectional clinical simulation study to quantify CM using biomechanical analysis with the use of inertial systems. The main variable was determined for the flexion-extension motion. The extraction was tested for both positions (prone position and supine position), which were repeated 3 times for each of the 30 volunteers included, and the movement from the initial neutral position was also determined, resulting in a total of 270 biomechanical studies.

Results

A flexion was observed when moving the patient from the neutral position to the SP, due to the size of the helmet, of 1.29° ± 5.12°. Helmet removal in the supine position resulted in an average flexion-extension range of 17.51° ± 6.49°, while the same extraction in prone position recorded an average range of 10.82° ± 8.05°. For the main variable, statistically significant differences were found when comparing prone position and supine position (p = 0.0087).

Conclusions

The main conclusion of the study is that the helmet removal should be done in the position in which we find the patient, whether in prone position or supine position. Additionally, the new technique described for the prone position causes less movement of the cervical spine than the usual supine position.

Correlation between Malocclusion and Mandibular Fractures: An Experimental Study Comparing Dynamic Finite Element Models and Clinical Case Studies

Mandibular fractures are very common in maxillofacial trauma surgery. While previous studies have focused on possible risk factors related to post-operative complications, none have tried to identify pre-existing conditions that may increase the risk of mandibular fractures. We hypothesized, through clinical observation, that anatomical conditions involving poor dental contacts, such as malocclusions, may increase the risk of mandibular fractures. This work was subdivided into two parts. In the first part, Digital Imaging and Communications in Medicine (DICOM) data of four healthy patients characterized by different dentoskeletal occlusions (class I, class II, class III, and anterior open bite) have been used to develop four finite element models (FEMs) that accurately reproduce human bone structure. A vertical and lateral impact have been simulated at increasing speed on each model, analyzing the force distribution within the mandibular bone. Both vertical and lateral impact showed higher level of stress at the impact point and in the condylar area in models characterized by malocclusion. Specifically, the class III and the open bite models, at the same speed of impact, had higher values for a longer period, reaching critical stress levels that are correlated with mandibular fracture, while normal occlusion seems to be a protective condition. In the second part of this study, the engineering results were validated through the comparison with a sample of patients previously treated for mandibular fracture. Data from 223 mandibular fractures, due to low-energy injuries, were retrospectively collected to evaluate a possible correlation between pre-existing malocclusion and fracture patterns, considering grade of displacement, numbers of foci, and associated CFI score. Patients were classified, according to their occlusion, into Class I, Class II, Class III, and anterior open bite or poor occlusal contact (POC). Class I patients showed lower frequencies of fracture than class II, III, and open bite or POC patients. Class I was associated with displaced fractures in 16.1% of cases, class II in 47.1%, class III in 48.8% and open bite/POC in 65.2% of cases (p-value < 0.0001). In class I patients we observed a single non-displaced fracture in 51.6% of cases, compared to 12.9% of Class II, 19.5% of Class III and 22.7% of the open bite/POC group. Our analysis shows that class I appears to better dissipate forces applied on the mandible in low-energy injuries. A higher number of dental contacts showed a lower rate of multifocal and displaced fractures, mitigating the effect of direct forces onto the bone. The correlation between clinical data and virtual simulation on FEM models seems to point out that virtual simulation successfully predicts fracture patterns and risk of association with different type of occlusion. Better knowledge of biomechanics and force dissipation on the human body may lead to the development of more effective safety devices, and help select patients to plan medical, orthodontic/dental, and/or surgical intervention to prevent injuries.

Injury patterns and outcomes in motorcycle driver crashes in the United States: The effect of helmet use

BACKGROUND

Motorcycle crashes pose a persistent public health problem with disproportionate rates of severe injuries and mortality. This study aims to analyze injury patterns and outcomes with regard to helmet use. We hypothesized that helmet use is associated with fewer head injuries and does not increase the risk of cervical spine injuries.

METHODS

The National Trauma Data Bank was queried for all motorcycle driver crashes between 2007-2017. Univariable analysis was used to compare demographics, clinical data, injury patterns using abbreviated injury scale, and outcomes between helmeted motorcycle drivers and non-helmeted motorcycle drivers who were injured in traffic crashes. Independent factors associated with mortality were determined by regression analysis after adjustment for potential confounders.

RESULTS

A total of 315,258 patients were included for analysis, 66 % of these patients were helmeted. The sample was 92.5 % male and the median age was 41 years. Non-helmeted motorcycle drivers were more likely to sustain severe head trauma (head abbreviated injury scale ≥ 3: 28.5 % vs. 13.3 %, p < 0.001), had higher intensive care unit-admission (38 % vs. 30.2 %, p<0.001), mechanical ventilation (20.1 % vs. 13 %, p<0.001) and overall mortality rates (6.2 % vs. 3.9 %, p<0.001). Cervical spine injuries occurred in 10.6 % of non-helmeted motorcycle drivers and in 9.5 % of helmeted motorcycle drivers (p<0.001). Helmet use was identified as an independent factor associated with lower mortality [OR 0.849 (0.809-0.891), p<0.001].

CONCLUSION

Helmet use is protective for severe head injuries and associated with decreased mortality. Helmet use was not associated with increased rates of cervical spine injuries. On the contrary, fewer injuries were observed in helmeted motorcycle drivers. Public health initiatives should be aimed at enforcement of universal helmet laws within the United States and across the world.

The forgotten protection factor: A nationwide score-based assessment of motorcycle eye protection legislation

INTRODUCTION

Motorcycle accidents cause millions of deaths and injuries globally. It is estimated that billions of dollars would be saved in the United States alone if safety equipment, such as helmets and eye protection, was ubiquitously worn. Legislation concerning eye protection specifically is understudied and poorly characterized.

METHOD

We reviewed all motorcycle-related safety equipment laws in all 50 states of the United States for information regarding eye protection. We graded the rigor of each statute using our six-category Eye Safety Metric and performed a comparative analysis of statutes across all jurisdictions.

RESULTS

Fourteen states did not have any statutes regarding eye protection. Among states that did, 23 states had weak statutes (0-2 points), 20 states had moderately stringent statutes (3-4 points), and 7 states had strong statutes (5-6 points). States in western United States tended to have less strict eye protection laws. Twenty-six states had eye protection exemptions for windshields, which are a poor form of eye protection. Six states that had universal helmet laws had no laws requiring eye protection.

CONCLUSIONS

We characterized eye protection legislation across the country and found great diversity in the stringency of laws across all jurisdictions. Despite only two states lacking helmet laws, we found that 14 states lacked eye protection laws. These findings from our Eye Safety Metric can be used as a springboard for future research, which can be used to determine the need for and significance of eye safety legislation for motorcyclists and to inform legislative decision-making.

PRACTICAL APPLICATIONS

With this research, we hope to further the understanding of legislation regarding eye protection for motorcyclists and help policymakers identify states that need improved eye safety standards.

Evaluation of full-face, open-face, and airbag-equipped helmets for facial impact protection

OBJECTIVE

Two-wheeler riders frequently sustain injuries to the head and face in real-world crashes, including traumatic brain injury, basilar skull fracture, and facial fracture. Different types of helmets exist today, which are recognized as preventing head injuries in general; however, their efficacy and limitations in facial impact protection are underexplored. Biofidelic surrogate test devices and assessment criteria are lacking in current helmet standards. This study addresses these gaps by applying a new, more biofidelic test method to evaluate conventional full-face helmets and a novel airbag-equipped helmet design. Ultimately, this study aims to contribute to better helmet design and testing standards.

METHODS

Facial impact tests at two locations, mid-face and lower face, were conducted with a complete THOR dummy. Forces applied to the face and at the junction of the head and neck were measured. Brain strain was predicted by a finite element head model taking both linear and rotational head kinematics as input. Four helmet types were evaluated: full-face motorcycle and bike helmets, a novel design called a face airbag (an inflatable structure integrated into an open-face motorcycle helmet), and an open-face motorcycle helmet. The unpaired, two-sided student's t-test was performed between the open-face helmet and the others, which featured face-protective designs.

RESULTS

A substantial reduction in brain strain and facial forces was found with the full-face motorcycle helmet and face airbag. Upper neck tensile forces increased slightly with both full-face motorcycle (14.4%, p >.05) and bike helmets (21.7%, p =.039). The full-face bike helmet reduced the brain strain and facial forces for lower-face impacts, but not for mid-face impacts. The motorcycle helmet reduced mid-face impact forces while slightly increasing forces in the lower face.

SIGNIFICANCE OF RESULTS

The chin guards of full-face helmets and the face airbag protect by reducing facial load and brain strain for lower face impact; however, the full-face helmets' influence on neck tension and increased risk for basilar skull fracture need further investigation. The motorcycle helmet's visor re-directed mid-face impact forces to the forehead and lower face via the helmet's upper rim and chin guard: a thus-far undescribed protective mechanism. Given the significance of the visor for facial protection, an impact test procedure should be included in helmet standards, and the use of helmet visors promoted. A simplified, yet biofidelic, facial impact test method should be included in future helmet standards to ensure a minimum level of protection performance.

Helmet Use and Jaw and Tooth Injuries in Motorcyclists Admitted to a Referral Hospital

Background and Aim

The use of helmets has been reported to reduce the incidence and severity of head injuries in motorcyclists. However, there remains a significant gap in knowledge regarding the effectiveness of helmets, especially in preventing jaw and tooth injuries.

Patients and Methods

In this retrospective analytical study record, all traffic accidents that occurred continuously from 2017 to 2019 in which the motorcyclists were on at least one side of the collision based on inclusion criteria. Data from injury variables in medical records were merged with data related to helmet use in the trauma registration system in Excel software. Then, the final analysis was performed with STATA software version 14 at a significance level of < 0.05.

Results

In total, 1807 people participated in the study, and 160 (9.37) people used helmets. The incidence rate of jaw and tooth injuries was 86 (5.04%). Logistic regression implied that the odds ratio for helmet use was 0.7, which considering the p value of 0.419, shows no significant relationship between wearing helmets and jaw and tooth injuries.

Conclusion

Helmets alone cannot prevent jaw and tooth injuries, and designers should design helmets that protect the head and the jaw and tooth. In prevention programs and campaigns for motorcyclists, every age, gender, job, grade group and marital status are target groups.

The burden of unhelmeted motorcycle injury: A nationwide scoring-based analysis of helmet safety legislation

INTRODUCTION

Motorcycle collisions comprise a large portion of motor vehicle injuries and fatalities with over 80,000 injuries and 5,500 fatalities per year in the United States. Unhelmeted riders have poor medical outcomes and generate billions in costs. Despite helmet use having been shown to lower the risk of neurological injury and death, helmet compliance is not universal, and legislation concerning helmet use also varies widely across the United States.

METHODS

In this study, we systematically reviewed helmet-related statutes from all US jurisdictions. We evaluated the stringency of these statutes using a legislative scoring system termed the Helmet Safety Score (HSS) ranging from 0-7 points, with higher scores denoting more stringent statutes. Regression modeling was used to predict unhelmeted mortality using our safety scores.

RESULTS

The mean score across all jurisdictions was 4.73. We found jurisdictions with higher HSS's generally had lower percentages of unhelmeted fatalities in terms of total fatalities as well as per 100,000 people and 100,000 registered motorcycles. In contrast, some lower-scoring jurisdictions had over 100 times more unhelmeted fatalities than higher-scoring jurisdictions. Our HSS significantly predicted unhelmeted motorcycle fatalities per 100,000 people (β = -0.228 per 1-point increase, 95% CI: -0.288 to -0.169, p < .0001) and per 100,000 registered motorcycles (β = -6.17 per 1-point increase, 95% CI: -8.37 to -3.98, p < .0001) in each state. Aspects of our score concerning helmet exemptions for riders and motorcycle-type vehicles independently predicted higher fatalities (p < .0001). Higher safety scores predicted lower unhelmeted fatalities.

CONCLUSION

Stringent helmet laws may be an effective mechanism for decreasing unhelmeted mortality. Therefore, universal helmet laws may be one such mechanism to decrease motorcycle-related neurological injury and fatality burden. In states with existing helmet laws, elimination of exemptions for certain riders and motorcycle-type vehicles may also decrease fatalities.

Effect of different helmet types in head injuries: a case-control study in northern Ghana

BACKGROUND

Motorcycle helmet use is low in Ghana and many helmets are non-standard. There are limited data on the effectiveness of the different helmet types in use in the real-world circumstances of low-income and middle-income countries. This study assessed the effect of different helmet types on risk of head injury among motorcycle crash victims in northern Ghana.

METHODS

A prospective unmatched case-control study was conducted at the Tamale Teaching Hospital (TTH). All persons who had injuries from a motorcycle crash within 2 weeks of presentation to TTH were consecutively sampled. A total of 349 cases, persons who sustained minor to severe head injury, and 363 controls, persons without head injury, were enrolled. A semistructured questionnaire was used to interview patients and review their medical records. Multivariable logistic regression was used to estimate odds for head injury.

RESULTS

After adjusting for confounders, the odds of head injuries were 93% less in motorcyclists with full-face helmet (FFH) (adjusted OR, AOR 0.07, 95% CI 0.04 to 0.15) or open-face helmet (OFH) (AOR 0.07, 95% CI 0.04, 0.13), compared with unhelmeted motorcyclists. Half-coverage helmets (HCH) were less effective (AOR 0.41, 95% CI 0.18 to 0.92). With exception of HCH, the AORs of head injury for the different types of helmets were lower in riders (FFH=0.06, OFH=0.05 and HCH=0.47) than in pillion riders (FFH=0.11, OFH=0.12 and HCH=0.35).

CONCLUSION

Even in this environment where there is a high proportion of non-standard helmets, the available helmets provided significant protection against head injury, but with considerably less protection provided by HCHs.

When the Helmet Is Not Enough: Forensic Multidisciplinary Reconstruction of a Deadly Motorcycle Accident

We report the case of a 54-year-old man who died in a motorcycle accident due to loss of control of the vehicle on a viaduct. No other vehicles were apparently involved, except for a car hit by the motorcycle after it fell. A post-mortem CT scan (computed tomography scan) was performed showing complex head trauma with a subarachnoid hemorrhage and multiple skull and facial bone fractures. A forensic cinematic reconstruction performed by an engineer was needed to exclude other incident causes other than the loss of control. The multidisciplinary approach that included autopsy findings, a cinematic reconstruction, a helmet test and an examination played a key role in clarifying the dynamics of the accident, allowing us to explain how the death occurred despite the motorcyclist’s helmet use. The cause of death was identified as a penetrating head trauma with cerebral material exposure, produced by the impact of the head against a fixed bolt in the guardrail base. Despite the use of the helmet, the impact force was enough to render the protection ineffective and allowed the bolt to penetrate through the helmet and the skull.

Full-face motorcycle helmets to reduce injury and death: A systematic review, meta-analysis, and practice management guideline from the Eastern Association for the Surgery of Trauma

BACKGROUND

While motorcycle helmets reduce mortality and morbidity, no guidelines specify which is safest. We sought to determine if full-face helmets reduce injury and death.

METHODS

We searched for studies without exclusion based on: age, language, date, or randomization. Case reports, professional riders, and studies without original data were excluded. Pooled results were reported as OR (95% CI). Risk of bias and certainty was assessed. (PROSPERO #CRD42021226929).

RESULTS

Of 4431 studies identified, 3074 were duplicates, leaving 1357 that were screened. Eighty-one full texts were assessed for eligibility, with 37 studies (n = 37,233) eventually included. Full-face helmets reduced traumatic brain injury (OR 0.40 [0.23-0.70]); injury severity for the head and neck (Abbreviated Injury Scale [AIS] mean difference -0.64 [-1.10 to -0.18]) and face (AIS mean difference -0.49 [-0.71 to -0.27]); and facial fracture (OR 0.26 [0.15-0.46]).

CONCLUSION

Full-face motorcycle helmets are conditionally recommended to reduce traumatic brain injury, facial fractures, and injury severity.

Analysis of different safety devices in the prevention of motorcycle-related craniofacial trauma - A retrospective study

Introduction:

Motorcycle accidents are one of the most frequent causes of trauma. Safety devices and helmets can influence the severity of injuries. Our retrospective study wants to evaluate the different effectiveness of Open-face and Full-face helmets in the prevention of craniofacial trauma.

Materials and Methods:

The sample consists of 440 patients admitted to two Level I Trauma Centres in Northern Italy, between January 2002 and February 2019, because of motorcycle-related craniofacial trauma. For each patient personal data were collected, as well as type and site of fractures, type of helmet, if worn, Comprehensive Facial Injury (CFI) score and Abbreviated Injury Score (AIS-Head) for head injuries. Inferential statistical analysis was then conducted.

Results:

Two hundred and eighty-eight patients wore Open-face helmets (69.7%) and 125 patients wore Full-face ones (30.3%). Mean CFI score (Standard deviation - SD) observed in patients with Open-face helmets was 7.0 (SD: 6.8) and surgery was required in 149 cases (51.7%); while it was 4.9 (SD: 6.0) in patients with Full-face helmets for whom surgery was required in 43 cases (34.4%) (P < 0.0001 and P = 0.002, respectively). Multivariate analysis shows that severity of facial trauma is a significant risk factor for head injury severity with OR 1.90 (95% confidence interval: 1.43 - 2.51) and P < 0.0001.

Discussion:

Full-face helmets are definitely considered to be more protective for facial trauma, which is also a significant risk factor for the severity of head injuries. The type of helmet chosen influences the need of surgical treatment in case of craniofacial trauma.