Risk Of Neck Injury Research Articles

Neck back and spine injuries in amateur rugby league: A review of nine years of Accident Compensation Corporation injury entitlement claims and costs

Rugby league is a popular participation sport, but there have been concerns raised regarding the possible high number of severe neck, back and spine injuries. Therefore an epidemiological overview of rugby league neck, back and spine injuries and associated costs of these injuries was undertaken in one country over nine years. The New Zealand national Accident Compensation Corporation data for moderate to serious injury entitlement claims (MSC) over nine years were analysed for the number, type and cost of neck, back and spine rugby league injuries resulting in medical treatment. There were 206 (3%) neck, back and spine MSC claims totalling NZD$1,585,927 (4%) of the total injury entitlement costs for rugby league over the nine-year period. The rate of MSC neck, back and spine rugby league injuries was 26 per 1000 total rugby league claims. Although the rate of neck, back and spine injuries varied over the nine years from 22 to 40 per 1000 injury claims, there was a significant increase over the duration of the study in the number of neck, back and spine MSC claims ( χ 2 = 849, df = 8, p < 0.001), and the cost per MSC injury claim ( χ 2 = 19,054, df = 8, p < 0.001). The frequency, severity and first 12 months cost of neck, back and spine injuries in rugby league is an issue that needs to be addressed. Unfortunately the ACC data base does not provide information on how or why the injuries occurred. A prospective injury epidemiology study needs to be conducted that will allow collection of information surrounding the mechanisms of injury and possible causative risk factors such as tackling technique. In the meantime it is suggested that coaches should ensure tackling technique is correctly taught to all rugby league players to reduce the risk of neck, back and spine injury. Team medical personnel should be trained in dealing with neck and spine injuries as well as head related injuries, and emergency procedures in dealing with players with a suspected neck or back injury should be practiced at clubs.

Retest Reliability of Force-Time Variables of Neck Muscles Under Isometric Conditions

Proper conditioning of the neck muscles may play a role in reducing the risk of neck injury and, possibly, concussions in contact sports. However, the ability to reliably measure the force-time-based variables that might be relevant for this purpose has not been addressed. To assess the between-days reliability of discrete force-time-based variables of neck muscles during maximal voluntary isometric contractions in 5 directions. Cohort study. University research center. Twenty-six highly physically active men (age = 21.6 ± 2.1 years, height = 1.85 ± 0.09 m, mass = 81.6 ± 9.9 kg, head circumference = 0.58 ± 0.01 m, neck circumference = 0.39 ± 0.02 m). We used a custom-built testing apparatus to measure maximal voluntary isometric contractions of the neck muscles in 5 directions (extension, flexion, protraction, left lateral bending, and right lateral bending) on 2 separate occasions separated by 7 to 8 days. Variables measured were peak force (PF), rate of force development (RFD), and time to 50% of PF (T(50)PF). Reliability indices calculated for each variable comprised the difference in scores between the testing sessions, with corresponding 95% confidence intervals, the coefficient of variation of the typical error of measurement (CV(TE)), and intraclass correlation coefficients (ICC [3,3]). No evidence of systematic bias was detected for the dependent measures across any movement direction; retest differences in measurements were between 1.8% and 2.7%, with corresponding 95% confidence interval ranges of less than 10% and overlapping zero. The CV(TE) was lowest for PF (range, 2.4%-6.3%) across all testing directions, followed by RFD (range, 4.8%-9.0%) and T(50)PF (range, 7.1%-9.3%). The ICC score range for all dependent measures was 0.90 to 0.99. Discrete variables representative of the force-generating capacity of neck muscles under isometric conditions can be measured with an acceptable degree of reliability. This finding has possible applications for investigating the role of neck muscle strength-training programs in reducing the risk of injuries in sport settings.

Dynamic Analysis and Injury Prediction for Small Craft Collisions

Six staged watercraft collisions were performed to assess the corresponding boat dynamics and boat operator kinematics. Each boat was operated remotely through a series of handheld radio transmitters capable of controlling steering, throttle, and a master kill switch. Triaxial accelerometers mounted to the deck of each boat provided sensor data that was measured and recorded using several MotionMaster EDR-6DOF recorders. Hybrid-II crash test dummies were placed in occupant positions, and their resulting kinematics recorded. The triaxial deck acceleration data was used as input to a lumped-mass human dynamics model (MADYMO) to understand occupant kinematics and potential for injury. Noted results include the presence of large vertical (z-axis) deck accelerations, and the low risk of head and neck injuries during the first phase of the collisions.

Helmet Use and Risk of Neck Injury in Skiers and Snowboarders

In a case-control study, the authors examined the relation between helmet use and neck injury among Québec, Canada, skiers and snowboarders using 10 years of ski patrol data (1995-1996 to 2004-2005). Cases were defined as persons with any neck injury (n = 2,986), an isolated neck injury requiring ambulance evacuation (n = 522), or a cervical spine fracture or dislocation (n = 318). The control group included persons with non-head, non-neck injuries (n = 97,408) in an unmatched analysis. The authors also matched cases with controls injured at the same ski area, during the same activity (skiing vs. snowboarding), and during the same season. Helmet use was the primary exposure variable. For the unmatched analysis, the authors used unconditional logistic regression and adjusted for clustering by ski area and other covariates. They used conditional logistic regression for the matched analysis. Multiple imputation was used to address missing values. The adjusted odds ratio was 1.09 (95% confidence interval (CI): 0.95, 1.25) for any neck injury, 1.28 (95% CI: 0.96, 1.71) for isolated ambulance-evacuated neck injuries, and 1.02 (95% CI: 0.79, 1.31) for cervical spine fractures or dislocations. Similar results were found in the conditional logistic regression analysis and in analyses restricted to children under age 11 years. These results do not suggest that helmets increase the risk of neck injuries among skiers and snowboarders.

Preventing Minor Neck Injuries in Rear Crashes—Forty Years of Progress

This article offers a historical review of vehicle design measures that have been implemented to reduce the risk of neck injuries to the occupants of rear struck vehicles. The literature on regulations, consumer information programs, and efforts by vehicle manufacturers to address whiplash injuries is summarized along with studies evaluating the efficacy of the resulting vehicle design changes. Vehicle designs and, in particular, the designs of seats and head restraints have changed considerably over the last 40 years. With varying degrees, these changes seem to be reducing the likelihood that occupants in rear struck vehicles will suffer neck injuries in such crashes. Vehicle design has influenced the risk of neck injuries in crashes, and future design changes offer potential for further risk reduction.

Re-evaluating the Neck Injury Index (NII) Using Experimental PMHS Tests

Objective: The neck injury index, NII, developed in ISO 13232 (2005) as a testing and evaluation procedure for assessing the risk of injury to the AO/C1/C2 region of the cervical spine in motorcycle riders is reevaluated using an existing postmortem human subjects (PMHS) data set and resulting in a reformulated NII criterion applicable to PMHS tests. Methods: A recent series of 36 PMHS head/neck component tests was used to examine the risk of neck injury in frontal impacts and to assess the predictive capability of NII for impacts of various orientations. Using force and moment load cell PMHS experimental data, injury risk was assessed using NII evaluated with the ISO 13232-5 algorithms. Results: The injury risk predictions are compared with the injury outcomes from the head/neck PMHS. The NII criterion underestimated the injury incidence of the PMHS experimental group. The average predicted risk of injuries for the experimental injury tests based on NII across the MAIS levels was 0.7 percent, though there were 11 AIS 3+ injuries observed in the actual testing (30.6%). Using the experimental injury outcomes and the experimental force and moment time histories, the normalizing coefficients from NII are reevaluated to minimize the difference between NII risk assessment and the experimental injury outcome in the least squares (L2) basis. This reanalysis is compared with existing human and PMHS neck injury criteria. Conclusions: By reanalyzing the NII formulation using an existing PMHS injury data set with known forces and moments and known injury outcomes, a new NII PMHS is developed that uses PMHS loads to predict injury. This reformulation removes the dependency of the original NII formulation on the forces and moments from motorcyclist anthropomorphic test device (MATD) experiments and simulations yet retains the advantages of the multi-axial neck injury criterion.

The effect of helmets on the risk of head and neck injuries among skiers and snowboarders: a meta-analysis.

The prevention of head injuries in alpine activities has focused on helmets. However, no systematic review has examined the effect of helmets on head and neck injuries among skiers and snowboarders. We searched electronic databases, conference proceedings and reference lists using a combination of the key words "head injury or head trauma," "helmet" and "skiing or snowboarding." We included studies that used a control group; compared skiers or snowboarders with and without helmets; and measured at least one objectively quantified outcome (e.g., head injury, and neck or cervical injury). We included 10 case-control, 1 case-control/case-crossover and 1 cohort study in our analysis. The pooled odds ratio (OR) indicated that skiers and snowboarders with a helmet were significantly less likely than those without a helmet to have a head injury (OR 0.65, 95% confidence interval [CI] 0.55-0.79). The result was similar for studies that used controls without an injury (OR 0.61, 95% CI 0.36-0.92), those that used controls with an injury other than a head or neck injury (OR 0.63, 95% CI 0.52-0.80) and studies that included children under the age of 13 years (OR 0.41, 95% CI 0.27-0.59). Helmets were not associated with an increased risk of neck injury (OR 0.89, 95% CI 0.72-1.09). Our findings show that helmets reduce the risk of head injury among skiers and snowboarders with no evidence of an increased risk of neck injury.

Finite element analysis of occupant head and neck injury mechanism during rollover crashes

A set of state-of-the-art Finite Element (FE) vehicle restraint system, crash dummy and whole body human models was integrated and validated against several quasi-static and dynamic rollover tests. HIII dummy responses during three selected trip-over scenarios were simulated using an FE vehicle model equipped with four different hypothetical roof stiffness values. Results indicated that both previous hypotheses on rollover injury mechanism, i.e. 'diving mechanism' and 'roof crush mechanism', are flawed. The results supported that 'diving' is the major injury mechanism in rollovers, but 'roof stiffness' (not 'roof crush') affects the head and neck injury risks for far-side occupants during 'diving' type of impacts. Traditional 'diving mechanism' neglected the fact that roof stiffness can change the vehicle and occupant kinematics in rollovers, and consequently affected the occupant injury risks. More rollover tests using both the dummy and the cadaver are needed to further validate the hypothesis proposed in this study.

Simulation analysis of human neck injury risk under high-level landing impact

When a spacecraft lands on the earth by parachute, the crewmen will be subjected to a high-level landing impact which could cause their body injuries in case of emergency. The purpose of this investigation was to analyse the human neck injury risk under the high-level landing impact, and to provide useful information for the protection design of the human-seat system in the spacecraft. On the basis of impact test, a mechanical model of the human-seat system was developed, and the acceleration responses at the seat and cushion were simulated using the finite element method. After the model was calibrated and validated, the forces and moments in the human neck were calculated. The degree of the human neck injury can be judged according to the standard of the human neck injury index (N ij < 1). The results showed that when both horizontal and vertical dropping velocity reach 7.5 m/s, the compressive force and extension moment in the human neck were, respectively, 6.58 kN and 100 Nm; and the injury index of the human neck was 1.81 (more than the critical value 1). It is concluded that under the high-level landing impact, the first reason for cervical fracture is the compressive force, and the second is the extension moment. It is necessary to take measures to reduce them to levels less than tolerance limits.

Whiplash injury prevention with active head restraint

Background Previous epidemiological studies have observed that an initial head restraint backset greater than 10 cm is associated with a higher risk of neck injury and persistent symptoms. The objective of this study was to investigate the relation between the active head restraint position and peak neck motion using a new human model of the neck. Methods The model consisted of an osteoligamentous neck specimen mounted to the torso of a rear impact dummy and carrying an anthropometric head stabilized with muscle force replication. Rear impacts (7.1 and 11.1 g) were simulated with and without the active head restraint. Physiologic rotation was determined from intact flexibility tests. Significant reductions ( P < 0.05) in the spinal motion peaks with the active head restraint, as compared to without, were identified. Linear regression analyses identified correlation between head restraint backset and peak spinal rotations ( R 2 > 0.3 and P < 0.001). Findings The active head restraint significantly reduced the average peak spinal rotations, however, these peaks exceeded the physiologic range in flexion at head/C1 and in extension at C4/5 through C7/T1. Correlation was observed between the head restraint backset and the extension peaks at C4/5 and C5/6. Interpretation Correlation between head restraint backset and spinal rotation peaks indicated that a head restraint backset in excess of 8.0 cm may cause hyperextension injuries at the middle and lower cervical spine. The active head restraint may not be fully activated at the time of peak spinal motions, thus reducing its potential protective effects.

Effects of head restraint and vehicle damage severity on neck injury risk

Domestic automobile insurance claims were investigated to correlate the driver neck injury risk with the safety rating of the head restraint, the severity of vehicle damage, and other human factors. The results of our statistical analysis reveal that the risk of neck injury for the driver is significantly different for vehicle size, use, driver gender, driver age, impact direction, accident location, and safety rating of head restraint, depending on vehicle the damage level which is assumed to imply impact severity during a rear-end crash accident. One of the unique findings from domestic insurance claims from low-speed rear-end crash accidents is the frequent reports of lower back injury together with whiplash. Thus, the risk of lower back discomfort is also included in this statistical analysis.

Hybrid III ATD in Inverted Impacts: Influence of Impact Angle on Neck Injury Risk Assessment

The purpose of this paper is to present a protocol of inverted drop-tests using a 50th percentile Hybrid III Anthropomorphic Test Device (ATD) and investigate the influence of angle and velocity at impact on neck injury risk assessment. The tests were based on existing cadaveric experimental protocols for inverted seated positions. In this study selected ATD impact orientations were also assessed in both the sagittal and coronal planes. Twenty-six tests were performed at impact velocities from 1.4 to 3.1 m s(-1). The drop tests confirmed previously described behavior of the ATD in axial loading of its head/neck/thorax complex. They also showed a significant influence of the initial impact angle on neck injury criteria currently used by researchers in rollover crashworthiness tests. At 1.4 m s(-1), the peak upper neck axial force of 4350 N was reduced by an average 1760 +/- 80 N for configurations with 30 degrees initial impact angle in any plane, compared to a reference inverted vertical configuration. The N(ij) was also significantly influenced. For a given impact velocity, an out-of-both-planes initial configuration resulted in the highest combined outputs. Based on these results, similar dynamic conditions (intrusion velocity, impact duration) may result in significantly different loadings of the Hybrid III neck.

Child injuries and violence: responding to a global challenge

Injuries and violence are a significant cause of child death and physical and psychological disability. Every year injuries and violence kill approximately 950 000 children (aged less than 18 years) and injure or disable tens of millions more as discussed in the recent World report on child injury prevention.1 This burden is particularly tragic because much of it is avoidable. Known, effective prevention and treatment strategies remain greatly underutilized, especially in low- and middle-income countries where 95% of child injury deaths occur. This month’s Bulletin theme issue seeks to promote greater attention to this significant public health problem and to explore ways in which this burden can be lowered. Several strategic directions are addressed. There is a need to increase the knowledge base on the extent and outcome of injury, as well as risk factors that should be targeted with prevention efforts. Celko et al. (374–381) identify risk factors for burns in the Czech Republic as a basis for subsequent prevention efforts. Rozenfeld & Peleg (362–368) determine the extent of violence-related injury in Israel, including identifying risk factors using the National Trauma Registry, a tool that has facilitated injury research in that country. Bordin et al. (336–344) show that severe punishment is related to mental health problems in poor urban Brazilian children and identify potential interventions, such as efforts to support parents emotionally that may help them adopt better child-rearing practices. Mikton & Butchart (353–361) undertake a systematic review of what works in child maltreatment prevention, pointing out evidence for promising interventions such as home visitation and parental education. These four articles demonstrate the scientific foundation of injury control, as emphasized by Haddon in the public health classic, here reviewed by Ruyan & Baker (402–403). Injury control must be better addressed in health policy and integrated into other major agendas. Harvey et al. (390–394) emphasize that there are many proven interventions that need to be put into action. To do so, injury prevention must be integrated into child health and survival initiatives and also into the broader development agenda. In terms of trauma care, Mock et al. (382–389) review several local success stories, point out early efforts to implement system-wide improvements and emphasize that existing global trauma care efforts should better address the special needs of injured children. To be able to influence policy, there must be stronger advocacy in injury control. This point is brought home in the round table discussion in which Pless (395–401) emphasizes the need to convince health departments that injury is a health problem and is therefore part of their role. He advises child safety advocates to push for more government action and to “be prepared to operate at the political level”. To undertake sustainable injury control work, there must be sufficient individual and institutional capacity. Hyder et al. (345–352) emphasize this point in their efforts to improve local ability to gather and handle injury data in a multicountry study. This study has helped to develop the injury knowledge base and has led to better injury surveillance capabilities in the countries involved. At this stage, what is needed more than anything else in injury control are model country programmes. One of the most compelling arguments to bring to the attention of policy-makers is the documentation of successful programmes in similar countries. Pervin et al. (369–373) evaluate the effectiveness of Viet Nam’s recent mandatory motorcycle helmet law and show high compliance with the law among adults. However, compliance is lower for children (although improved since the new law) due to parental misperceptions that children face a higher risk of neck injuries with helmet use as well as a loophole in the law for children not wearing helmets. This study demonstrates the overall success of a helmet law, identifies specific challenges and provides valuable information for other countries to use in their own efforts to promote universal motorcycle helmet use. The increased attention that this Bulletin issue brings to the field of injury control is timely and will be followed closely by several important events: the release of the Global status report on road safety (June 2009); the Violence Prevention Alliance’s fourth milestones meeting (September 2009); and the first global ministerial conference on road safety in Moscow (November 2009). We hope that this special Bulletin issue convinces those in child health and development that child injury and violence should be on their agendas. We also hope that the issue stimulates more research on what works to prevent and treat injuries, especially in low- and middle-income countries, as well as increased advocacy and partnerships to confront child injury. We especially hope that this issue will encourage countries and governments to implement injury control policies and programmes that will actually lower the currently unacceptable toll of child injury. ■

Rear-impact neck protection devices for adult wheelchair users

Many wheelchair users remain in their wheelchairs during transit. Safety research for wheelchair users has focused mainly on frontal impact. However, although they are generally less severe, rear-impact injuries are expensive and difficult to treat and whiplash injury protection for adult wheelchair users remains poorly understood. In this article, 10 g (16 km/h) rear-impact sled tests conducted with the Biofidelic Rear Impact Dummy II or BioRID-II (Denton ATD Inc and Chalmers University of Technology; Gothenburg, Sweden) seated in a rigid wheelchair with no head restraint showed that Abbreviated Injury Scale-score 1 neck injury risk evaluated with the neck injury criterion (NIC) and Nkm criterion is substantially above proposed threshold levels. A prototype wheelchair head restraint was developed and tested together with an existing commercial head restraint (Rolko; Borgholzhausen, Germany) in the same 10 g (16 km/h) rear impact. Both head restraints reduced the injury scores substantially. NIC test scores for the head restraints with no gap ranged from 18 to 24 (approximately 20%-30% chance of neck injury symptoms of duration >1 month) compared with test scores for no head restraints that ranged from 34 to 37 (approximately 95% chance of neck injury). The corresponding extension-posterior Nkm scores with no gap ranged from 0.30 to 0.35 (approximately 5% chance of neck injury) compared with no head restraint of 1.16 (approximately 45% chance of neck injury symptoms). However, the number of sled tests performed was small (three with no head restraint and six with a head restraint), and these results should be considered mainly trends. Preliminary results also showed that the horizontal gap between the head and the wheelchair head-restraint cushion should be as small possible.

Head and neck injury risks in heavy metal: head bangers stuck between rock and a hard bass

Objective To investigate the risks of mild traumatic brain injury and neck injury associated with head banging, a popular dance form accompanying heavy metal music. Design Observational studies, focus group,...

Research Study on Neck Injury Lessening with Active Head Restraint Using Human Body FE Model

Objectives: The objective of this study is to examine the effectiveness of the active head restraint system in reducing neck injury risk of car occupants in low-speed rear impacts. Methods: A human body FE model “THUMS” was used to simulate head and neck kinematics of the occupant and to evaluate loading to the neck. Joint capsule strain was calculated to predict neck injury risk as well as NIC. The validity of the model was confirmed comparing its mechanical responses to those in human subjects in the literatures. Seat FE models were also prepared representing one with a fixed head restraint and the other one with an active head restraint system. The active head restraint system was designed to move the head restraint forward and upward when the lower unit was lower unit was loaded by the pelvis. Rear impact simulations were performed assuming a triangular acceleration pulse at a delta-V of 25 km/h. Results : The model reproduced similar head and neck motions to those measured in the human volunteer test, except for active muscular responses. The calculated joint capsule strain also showed a good match with those of PMHS tests in the literature. A rear-impact simulation was conducted using the model with the fixed head restraint. The result revealed that NIC was strongly correlated with the relative acceleration between the head and the torso and that its maximum peak appeared when the head contacted the head restraint. It was also found that joint capsule strain grew in later timing synchronizing with the relative displacement. Another simulation with the active head restraint system showed that both NIC and joint capsule strain were lowered owing to the forward and upward motion of the head restraint. A close investigation of the vertebral motion indicated that the active head restraint reduced the magnitude of shear deformation in the facet joint, which contributed to the strain growth in the fixed head restraint case. Conclusions: Rear-impact simulations were conducted using a human body FE model, THUMS, representing an average-size male occupant. The cervical system including the facet joint capsules was incorporated to the model. The validity of the model was examined comparing its mechanical responses to those in the literature such as the whole body motion of the volunteer subject and the vertebral motion in the PMHS tests. Rear-impact simulations were conducted using the validated THUMS model and two prototype seat models; one had a fixed head restraint and the other one was equipped with an active head restraint system. The active head restraint system works moving the head restraint forward and upward when the lower unit is loaded by the pelvis. The head and neck kinematics and responses were analyzed from the simulation results. The force and acceleration rose at the pelvis first, followed by T1 and the head. The early timing of force rise and its magnitude indicated that the pelvis force was a good trigger for the active head restraint system. The results showed that the head was supported earlier in a case with the active head restraint system, and both NIC and joint capsule strain were lowered. The study also analyzed the mechanism of strain growth in the joint capsules. Relatively greater strain was observed in the direction of the facet joint surface, which was around 45 degrees inclined to the spinal column. The forward and upward motion of the active head restraint were aligned with the direction of the joint deformation and contributed to lower strain in the joint capsules. The results indicated that the active head restraint could help reduce the neck injury risk not only by supporting the head at an early timing but also through its trajectory stopping the joint deformation.

WHIPS (Volvo Cars' Whiplash Protection System)—The Development and Real-World Performance

Objectives: Present the performance of WHIPS and identify possible next steps of soft tissue neck injury reduction potentials, based on rear-end real-world crash data. Methods: Front-seat occupants (above 14 years of age) have been analyzed regarding influencing factors on reported incidences of soft tissue neck injuries. The outcome of 1858 occupants in cars equipped with WHIPS and 663 occupants in Volvo cars of model year 1999 without WHIPS are studied with respect to WHIPS injury-reducing effect for different impact severities and injury durations. The occupants in WHIPS are further studied with respect to seating position and sitting posture, such as turned head and head-to-head restraint distance. Results: Soft tissue neck injury risk reductions are seen for occupants in WHIPS as compared to prior Volvo cars; mean values ranging from 21 to 47% depending on impact severity and symptom duration. Sitting posture (turned head and increased backset) increases soft tissue neck injury risks. Based on the self-reported injury data, a significantly lower risk was found for occupants facing straight forward with the head in close proximity to the head restraint as compared to the risk for occupants with rotated head and a larger backset. Even though the highest risk of soft tissue neck injuries is found in higher impact severity, the large amount of soft tissue neck injuries sustained at low impact severity emphasizes the need of focusing measures for crash avoidance. Conclusions: This study presents the development and real-world performance of WHIPS as well as identifies situations for further focus and challenges for the next generation of soft tissue neck injury protection and prevention, including areas such as occupant posture and crash avoidance.

Relationship of Dynamic Seat Ratings to Real-World Neck Injury Rates

Objectives: The Insurance Institute for Highway Safety assigns consumer safety ratings to passenger vehicle seats based on laboratory sled tests that simulate rear-end collisions. The purpose of this research was to determine how well these ratings correlate to driver neck injury risk in real-world crashes. Methods: Insurance claims for cars and SUVs struck in the rear by the front of another passenger vehicle were examined for evidence of driver neck injury. Logistic regression was used to compare neck injury rates for vehicles with different seat ratings while controlling for other important variables. Results: Driver neck injury rates were 15% lower for vehicles with seats rated good compared with vehicles with seats rated poor. Rates of driver neck injuries lasting 3 months or more were 35% lower for vehicles with seats rated good compared with vehicles with seats rated poor. Conclusions: Seat/head restraints that perform better in dynamic sled tests have lower risk of neck injury than seats that rate poor, especially when considering long-term injuries. However, the relationship of dynamic seat ratings to neck injury rates is not linear. Further research is needed to determine whether the criteria for rating seats can be amended so as to be more uniformly predictive of real-world neck injury.

A Numerical Investigation of Factors Affecting Cervical Spine Injuries During Rollover Crashes

Factors affecting the risk of cervical spine injury in rollover crashes were investigated using a detailed finite element human head-neck model. Analyze systematically neck responses and associated injury predictors under complex loading conditions similar to real-world rollover scenarios and use the findings to identify potential design improvements. Although many previous experimental and numerical studies have focused on cervical spine injury mechanisms and tolerance, none of them have investigated the risk of cervical spine injuries under loading condition similar to that in rollovers. The effects of changing the coefficient of friction (COF), impact velocity, padding material thickness and stiffness, and muscle force on the risk of neck injuries were analyzed in 16 different impact orientations based on a Taguchi array of design of experiments. Impact velocity is the most important factor in determining the risk of cervical spine fracture (P = 0.000). Decreases in the COF between the head and impact surface can effectively reduce the risk of cervical spine fracture (P = 0.038). If the COF is not 0, an impact with lateral force component could sometimes increase the risk of cervical spine fracture; and the larger the oriented angle of the impact surface, the more important it becomes to reduce the COF to protect the neck. Soft (P = 0.033) and thick (P = 0.137) padding can actually decrease the neck fracture risk, which is in contrast to previous experimental data. A careful selection of proper padding stiffness and thickness, along with a minimized COF between the head and impact surface or between the padding and its supporting structure, may simultaneously decrease the risk of head and neck injuries during rollover crashes. A seatbelt design to effectively reduce/eliminate the head-to-roof impact velocity is also very crucial to enhance the neck protection in rollovers.

Helmet use and the risk of neck or cervical spine injury among users of motorized two-wheel vehicles

Objective:To quantify the effects of wearing a helmet on head and facial injury among users of motorized two-wheel vehicles and to determine if helmet use increases the risk of neck...