Injury to the human neck is a frequent consequence of automobile accidents and has been a significant public health problem for many years. The term `whiplash' has been used to describe these injuries in which the sudden differential movement between the head and torso leads to abnormal motions within the neck causing damage to its soft tissue components. Although many different theories have been proposed, no definitive answer on the cause of `whiplash' injury has yet been established and the exact mechanisms of injury remain unclear. Biomechanical research is ongoing in the field of impact analysis with many different experimental and computational methods being used to try and determine the mechanisms of injury. Experimental research and mathematically based computer modelling are continually used to study the behaviour of the head and neck, particularly its response to trauma during automobile impacts. The rationale behind the research described in this thesis is that a computational model of the human head and neck, capable of simulating the dynamic response to automobile impacts, could help explain neck injury mechanisms. The objective of the research has been to develop a model that_,, can accurately predict the resulting head-neck motion in response to acceleration impacts of various directions and severities. This thesis presents the development and validation of a three-dimensional computational model of the human head and cervical spine. The novelty of the work is in the detailed representation of the various components of the neck. The model comprises nine rigid bodies with detailed geometry representing the head, seven vertebrae of the neck and the first thoracic vertebra. The rigid bodies are interconnected by spring and damper constraints representing the soft-tissues of the neck. 19 muscle groups are included in the model with the ability to curve around the cervical vertebrae during neck bending. Muscle mechanics are handled by an external application providing both passive and active muscle behaviour. The major findings of the research are: From the analysis of frontal and lateral impacts it is shown that the inclusion of active muscle behaviour is essential in predicting the head-neck response to impact. With passive properties the response of the head-neck model is analogous to the response of cadaveric specimens where the influence of active musculature is absent. Analysis of the local loads in the soft-tissue components of the model during the frontal impact with active musculature revealed a clear peak in force in the majority of ligaments and in the intervertebral discs very early in the impact before any forward rotation of the head had occurred. For the case of rear-end impact simulations it has been shown for the first time that the inclusion of active musculature has little effect on the rotation of the head and neck but significantly alters the internal loading of the soft-tissue components of the neck.

Developing computational models of the human spine has been a hot topic in biornechanical research for a couple of decades in order to have an understanding of the behaviour of the whole spine and the individual spinal parts under various loading conditions. The objectives of this thesis are to develop a biofidefic multi-body model of the whole human spine especially for dynamic analysis of impact situations, such as frontal impact in a car crash, and to generate finite element (FE) models of the specific spinal parts to investigate causes of injury of the spinal components. As a proposed approach, the predictions of the multi-body model under dynamic impact loading conditions, such as reaction forces at lumbar motion segments, were utilised not only to have a better understanding of the gross kinetics and kinematics of the human spine, but also to constitute the boundary conditions for the finite element models of the selected spinal components. This novel approach provides a versatile, cost effective and powerful tool to analyse the behaviour of the spine under various loading conditions which in turn helps to develop a better understanding of injury mechanisms.

This study is concerned with whiplash injuries resulting from the sudden acceleration and deceleration of the head relative to the torso in vehicle collisions. Whiplash is the most common automobile injury, yet it is poorly understood. The objective of this thesis is to develop a representative rigid linkage lumped parameter model using Lagrangian mechanics to capture the relative motion of the head and cervical spine. Joint locations corresponding to the intervertebral centers of rotation are used to simulate the normal spinal movements and an inverse analysis is applied to determine the viscoelastic parameters for the spine, based on cadaver test results. The model is further validated using ANSYS dynamic finite element analysis and experimentally validated using a newly designed and fully instrumented whiplash test fixture. Our findings reveal the effectiveness of the simplified model which can be easily scaled to accommodate differences in collision severity, posture, gender, and occupant size.

This study is concerned with whiplash injuries resulting from the sudden acceleration and deceleration of the head relative to the torso in vehicle collisions. Whiplash is the most common automobile injury, yet it is poorly understood. The objective of this thesis is to develop a representative rigid linkage lumped parameter model using Lagrangian mechanics to capture the relative motion of the head and cervical spine. Joint locations corresponding to the intervertebral centers of rotation are used to simulate the normal spinal movements and an inverse analysis is applied to determine the viscoelastic parameters for the spine, based on cadaver test results. The model is further validated using ANSYS dynamic finite element analysis and experimentally validated using a newly designed and fully instrumented whiplash test fixture. Our findings reveal the effectiveness of the simplified model which can be easily scaled to accommodate differences in collision severity, posture, gender, and occupant size.

The overall aim of this thesis was to study the daily process of coping, potential prognostic factors for recovery and evaluating an individually tailored behavioural medicine intervention in the acute stage of Whiplash Associated Disorders (WAD). The studies comprised three samples of patients with acute Whiplash Associated Disorders (WAD). All patients were included within the first month after the whiplash occurrence and were recruited from hospital emergency wards in six Swedish communities. Study I and II included 51 participants generating 260 daily coping diaries (WAD-DCA) during seven days in the acute stage of WAD. In Study I daily stressors and primary appraisal were analysed and in Study II patterns between stressors, appraisals, coping strategy profiles, daily activity level and well-being were described. The results showed a large variety of situations that the individuals perceive as stressful, not only pain itself. High self-efficacy was associated with high degree of physical/mental well-being. Threatening stressors and catastrophic thoughts were associated with low degree of physical and mental well-being. In Study III potential prognostic factors for good as well as poor recovery were studied more closely in a mildly affected sample (MIAS) (n=98) from within the first month after the accident up to one year later. Pain-related disability at baseline emerged as the only indicator of prognosis after 12 months in MIAS. Study IV (n=55) was a randomised control study, were current clinical recommendations of standard self-care instructions (SC) for the management of acute WAD was compared to an individually tailored behavioural medicine intervention delivered via Internet or face-to-face. The results showed that SC was not as effective as the behavioural medicine intervention. By early identification of situation-specific factors and potential behavioural (physical, cognitive and affective) determinants of activity performance, it seems possible to tailor a self-management intervention that decreases pain-related disability, fear of movement and catastrophising and increases self-efficacy. The use of innovative methods such as the Internet of distributing treatment interventions showed to be a good alternative to more traditional forms. The results of this thesis uncover new insights in understanding the individual’s specific perspective as applied in a behavioural medicine approach in acute WAD.

The research described in this thesis focuses on the biomechanics of cervical spine injury diagnosis and rehabilitation management. This research is particularly relevant to the diagnosis of minor neck injuries that typically arise from motor vehicle accidents and are classified as "whiplash injuries". The diagnosis and treatment of these chronic neck problems has been particularly difficult and frustrating and these difficulties prompted calls for the objective evaluation of the techniques and procedures used in the measurement and assessment of neck dysfunction. The biomechanical aspects of the clinical diagnosis of minor cervical spine injuries were investigated in this work by reconfiguring an existing detailed biomechanical model of the human neck to simulate injuries to particular structures, and to model abnormal muscle activation. The investigation focused on the range of motion assessment and the methods of testing and rehabilitating the function of the deep neck muscles because the model could be applied to provide further insight into these facets of neck injury diagnosis and management. The de Jager detailed head-neck model, available as a research tool from TNO (The Netherlands), was chosen for this study because it incorporated sufficient anatomical detail, but the model required adaptation because it had been developed for impact and crash test dummy simulations. This adaptation significantly broadened the model's field of application to encompass the clinical domain. The facets of the clinical diagnosis of neck dysfunction investigated in this research were range of motion and deep muscle control testing. Range of motion testing was simulated by applying a force to the head to generate the primary motions of flexion/extension, lateral flexion and axial twisting and parametric changes were made to particular structures to determine the effect on the head-neck movement. The main finding from this study of cervical range of motion testing was that while motion can be accurately measured in three dimensions, consideration of the three dimensional nature of the motion can add little to the clinical diagnosis of neck dysfunctions. Given the non-discriminatory nature of range of motion testing, the scientific collection and interpretation of the three dimensional motion patterns cannot be justified clinically. The de Jager head-neck model was then further adapted to model the cranio-cervical flexion test, which is used clinically to test the function of the deep muscle groups of the neck. This simulation provided confirmation of the efficacy of using a pressure bio-feedback unit to provide visual indication of the activation of the deep flexor muscles in the neck. However, investigation of the properties of the pressure bio-feedback unit identified significant differences in the stiffness of the bag for the different levels of inflation that must be accounted for if comparisons are to be made between subjects. Following the identification of the calibration anomalies associated with the pressure bio-feedback unit, the motion of the point of pressure of the head on the headrest and the force at this point of contact during the activation of the deep flexor muscle group were investigated as an alternative source of feedback. This output, however, was found to be subject specific, depending on the posterior shape of the skull that determined the point of contact during the head rolling action. Clinically, an important outcome of the alternative feedback assessment was that the prescribed action to target the deep flexor muscle group will feel different for each individual, ranging from a slide to a roll of the head on the headrest, and this must be accounted for when explaining the action and during rehabilitation management.

Diss. (sammanfattning) Umeå : Umeå universitet, 2008. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Univ., 2008. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 4 uppsatser.

CHARLES UNIVERSITY IN PRAGUE Faculty of Physical Education and Sport Dissertation thesis March 2014 Ondřej Fanta ABSTRACT Title: Detection of head biomechanical response during extreme loading Objectives: The aim of the work was to monitor the current state of knowledge on the issue of closed head injuries, in contact and contactless respectively impacts, to establish appropriate biomechanical indicators for the detection and analysis of internal mechanical response under external mechanical load and to assess the specific circumstances that may affect the resulting injury criteria especially with regard to the actual reaction of the organism before impact. Methods: To the processing research were included and cited in particular impacted world-class publications and bibliography in the number of more than 80sources. The measurements and analysis of contact impacts were taken on the constructed impactor and the analysis of the contactless collisions were taken on the impacts simulator. The monitored biomechanical values were in particularly kinematic data describing the movement of the head towards the neck, values of acceleration of the head, head injury criteria and activity of selected muscles of the neck. Results: It consists diagram of the process of head injury and analysis of two main branches -...