OCCUPATIONAL APPLICATIONSTo manage upper limb musculoskeletal disorders, treatments based on reducing spinal curvatures are used empirically. Spinal posture has been shown to modify upper limb functional capacities in terms of maximum voluntary forces and fatigability. The aim of the study was to determine whether spinal curvatures also influenced upper limb joint angles during tasks associated with a risk of musculoskeletal disorders. Twenty-two healthy participants were placed in a slouched or erect sitting posture, in random order. Three standardized tasks were performed three times each in both postures. In the erect posture, shoulder flexion was consistently decreased, and shoulder abduction was decreased over most or all of the tasks analyzed. Elbow extension was increased over half of the duration of a single task. Thus, slouched or erect seated spinal posture influences proximal upper limb joint angles. Ergonomists should consider spinal posture even when focusing on proximal upper limb musculoskeletal disorders.

Predictions of vertebra positions from external data are required in many fields like motion analysis or for clinical applications. Existing predictions mainly cover the thoraco-lumbar spine, in one posture. The objective of this study was to develop a method offering robust vertebra position predictions in different postures for the whole spine, in the sagittal plane. EOS radiographs were taken in three postures: slouched, erect, and subject’s usual sitting posture, using 21 healthy participants pre-equipped with opaque cutaneous markers. Local curvilinear Frenet frames were built on a spline fitted to spinous processes’ cutaneous markers. Vertebra positions were expressed as polar coordinates in these frames, defining an angle (α) and distance (d). Multilinear regressions were fitted to explain α and d from anthropometric predictors and predictors presumed to be linked to spinal posture, the predictors’ effects being considered both locally and remotely. Anthropometric predictors were the main predictors for d distances, and postural predictors for α angles, with postural predictors still showing a marked influence on d distances for the cervical spine. Vertebra positions were then predicted by cross-validation. The average RMSE on vertebra positions was 11.0 ± 3.7 mm across the entire spine, 13.4 ± 4.1 mm across the cervical spine and 10.1 ± 3.1 mm across the thoraco-lumbar spine for all participants and postures, performances similar to previous models designed for a single posture. Our simple geometrical and statistical model thus appears promising for predicting vertebra positions from external data in several spinal postures and for the whole spine.

BACKGROUND: Transpedicular or transisthmic screws for C2 instrumentation represent the gold standard; however, the anatomy is not always compatible (hypoplastic pedicles, procidentia of the vertebral artery). Laminar screws (LS) have been proposed as a rescue technique and recently, bicortical facet screws (FS). To date, the biomechanical property of FS remains unknown. OBJECTIVE: To compare the pull-out resistance of bicortical facet (FS) vs laminar (LS) C2 screws. METHODS: Thirty-two human cadaveric C2 vertebrae were screened by CT scan imaging and dual x-ray absorptiometry before receiving both techniques and were randomized according to side and sequence (FS or LS first). Screw positioning was validated using 2-dimensional x-rays. Sixty-four mechanical tests were performed using pure tensile loading along the axis of the screws until pull-out. Mean pull-out strengths were compared using paired tests, multivariate and survival analysis (Kaplan-Meier curves). RESULTS: The morphometric data were consistent with previous studies. Over 64 tests, the mean pull-out strength of LS (707 ± 467 N) was significantly higher than that of FS (390 ± 230 N) (P = .0004). Bone mineral density was weakly correlated with pull-out strength (r = 0.42 for FS and r = 0.3 for LS). Both techniques were mechanically equivalent for vertebrae in which intralaminar cortical grip was not achievable for LS. The mean pull-out strength for LS with laminar cortical grip (1071 ± 395 N) was significantly higher than that of LS without (423 ± 291 N) (P < .0001). CONCLUSION: Our results suggest that bicortical FS of C2 offer less mechanical resistance than LS.

OCCUPATIONAL APPLICATIONS Modifying the spinal curvature is an empirical approach to treating upper limb musculoskeletal disorders, often attributed to the balance between physical stress and individual functional capacities. We completed an experimental biomechanical study to quantify the effect of seated spinal posture on upper limb functional capacities. Isometric maximum muscle voluntary forces (MVFs) were measured at participants' shoulder, elbow, and wrist. Fatiguability was also assessed during a repetitive painting task. Participants were asked to assume both slouched and erect spinal postures, in a random order. In the erect posture, participants achieved higher shoulder and elbow isometric MVF levels and took longer to reach a fatigue threshold. Thus, spinal posture tends to remotely influence upper limb functional capacities, especially at the shoulder and elbow. Ergonomists should consider spinal posture even when focusing on musculoskeletal disorders of the upper limb. TECHNICAL ABSTRACT Background: Musculoskeletal disorders are a major public health issue, and current treatments often remain unsatisfactory. Treatments based on spinal curvature modifications are empirically used for upper limb musculoskeletal disorders. Purpose: To determine whether a slouched or erect sitting posture has an effect on upper limb functional capacities, with tests and outcomes focused on the risk of upper limb musculoskeletal disorders. Methods: Randomized experimental study, crossover design. Twenty-two right-handed healthy participants from the local area were assessed in a research laboratory. Participants' spinal curvatures were increased or decreased, through verbal instructions and light touch, to place them in a slouched or an erect posture that was stable and easily maintained, in a random order. Isometric maximum muscle voluntary forces (MVFs) were measured. Participants also performed a repetitive task that simulated painting, with fatigue level assessed using the CR10 Borg scale. Upper limb positioning, task setting, and instructions to participants were standardized, and the investigator was blind to the results of MVF measurements. The main outcomes were normalized differences in MVF values and time-to-reach "7" on the CR10 scale. Results: There were significantly higher MVF values in the erect posture for the shoulder and elbow, with respective mean (SD) normalized differences of 11.4 (18.2)% and 11.8 (19.2)%; differences approached significance at the wrist [7.7 (18.5)%]. The normalized difference in time-to-reach "7" on the CR10 scale was significantly higher in the erect posture (by 11.4%). Conclusions: Spinal posture modified individual upper limb functional capacities and could thus influence the risk of upper limb musculoskeletal disorders.

To our knowledge, FE neck models including active 1D or 3D muscles have been mainly used for impact simulations and have yet to be used to investigate the effects of volumetric deformation, transve...

Current approaches towards subject-specific FE modelling and virtual testing would benefit from easy-to-use personalization and positioning tools. The PIPER project aims to provide these tools for full human body FE models used in automotive safety as an open-source, easy-to-use software framework that is independent from both model and FE code. In this context the positioning of the spine is of particular interest, while remaining complex because of its high number of dofs. This abstract presents the development of a spline based spinal posture predictor tool relying on linear interpolation between known physiological postures, and its implementation within the PIPER tool.

In passive automotive safety, advanced Human Body Models for injury prediction based on the Finite Element (FE) method (e.g. Thums or GHBMC families) have the potential to represent the population variability and to provide more accurate injury predictions than alternatives using global injury criteria. However, these advanced HBMs are underutilised in industrial R&D. Possible reasons include difficulties to position the models - which are typically only available in one posture - in actual vehicle environments, and the limited representation of the population variability (size, weight, limited availability for specific populations such as children, etc.). As the models and methodologies to use them are not standardized or widely shared, research achievements have been slow to result into safety benefits for the whole community. The main objective of the PIPER project was to develop user friendly tools to position and personalize these advanced HBMs, and to share them widely with the community. By facilitating the generation of population and subject-specific HBMs and their usage in production environments, the PIPER tools will enable new industrial R&D applications for the design of restraint systems as well as in research. After a specification phase to which the community could participate, the project developed an Open Source software framework to facilitate the positioning and personalizing of human body models for safety. The framework can be used with the leading HBMs and, because of its modularity, it could be further extended by users. It already provides many modules developed by the partners including state of the art real time simulation techniques for positioning, advanced morphing techniques to match various population dimensions, or smoothing approaches. The project also developed a new Open Source child model which can be used to describe children of age between 1.5 and 6 years during impacts and interactions with child restraint systems. The model performance has been extensively checked against and the model has its own dedicated module in the PIPER framework to facilitate the age change. Other project results included the development of generic car environments to facilitate comparisons and future work on accident reconstructions, and various software tools and geometrical datasets. A first evaluation was performed within the project through a few crash applications that were selected for their safety relevance. Performed by both industrial and academic partners, these included among others pedestrian to generic vehicle impact, postural changes due emergency manoeuvres (pre-crash) followed by a crash and child accident reconstructions. Scaling and/or positioning were performed in each application and adult models from the GHBMC and Thums families were used besides the PIPER child model. The results demonstrated the usability and the potential of the software and child model. Most results were documented in tutorials for future users. After selecting open source licenses, the PIPER framework and child model were first released at the final workshop of the project on April 25, 2017. Numerous academic and industrial users had already raised their interest during the project and provided useful inputs at various dissemination events and the workshop was well attended by both industry and academia. The initiation of an Open source project (www.piperproject. org) to continue promote the PIPER's vision and results beyond the end of the EU project was also announced at the workshop. Links to the project results, documentation, and other information can be found on the Open Source project Website.

The aim of this report is to provide an overview of the final version of the PIPER framework and application. The software, along with its documentation, and not the report, constitutes the main part of the deliverable. The software and documentation were already distributed at the Final Workshop and online (under the Open Source license GPLv2 or later for the software, and the GNU FDL 1.3 license for the documentation). The documentation includes detailed descriptions of the framework principles, user interface, metadata, along with the modules and their parameters. It also includes application scenarios (called workflows). Information about the use of the modules is complemented by Tutorials that were developed as part of WP1 (online on the wiki) and explanatory videos were developed as part of WP4 (videos of the final workshop, now available on YouTube). The headers in the source code files (also available online) list the main contributors to the software. The report will therefore not provide details about information that is already available elsewhere but will only provide a very brief summary of the functionalities available. Some of the descriptions are excerpts of the manual.

As shown by the main topic of the VPH2016 conference, Translating VPH to the clinic, is now a critical objective of the VPH research community. At the same time EuroNCAP, the European consumers' association for vehicle safety rating, very recently introduced the use of Human Body Models (HBM) simulations to define some of the test conditions in their consumer test protocols for pedestrian impact scenarios. Although they may at first seem somewhat unrelated, such different research areas as the clinical and automotive crashworthiness research benefit from the same advances in numerical methods and computational capacity for imaging and modelling. Further, both research communities may share very similar challenges, not only in their approach to the modelling of the biomechanical behaviour of the human body, but also in their need to transfer this research into tools that will effectively prove their societal benefits in a safety and regulation constrained socio-economic environment. With relatively similar aims and scopes, expectations in the field of in-silico clinical trials, or virtual testing, are high in both industries. The PIPER project is a 3.5 year EC funded research project that aims to deliver tools that will allow a user to personalise and position any Finite Element (FE) HBM, in a virtual vehicle environment, for virtual testing. The challenge is scientific, as state-of-the art methods had to be designed and implemented to e.g. develop Statistical Body Shape Models (SSM) from clinical imaging data, or to ensure that deformed FE models would still meet solvers' quality metrics for simulations. The promotion of such tools was identified as critical and strong choices (open-source, meta-tools - independent from the FE model/code, contribution of the end-users to all stages of the project) were made to ensure a successful public-private research partnership. This abstract presents some of these key aspects, with an emphasis on their possible usefulness and transfer to the VPH community.

The Harms technique is now considered as the gold standard to stabilize C1–C2 cervical spine. It has been reported to decrease the risk of vertebral artery injury. However, the risk of vascular injury does not totally disappear, particularly due to the proximity of the trans-isthmic C2 screw with the foramen transversarium of C2. In order to decrease this risk of vertebral artery injury, it has been proposed to use a shorter screw which stops before the foramen transversarium.

Objective Concussion is a prevalent brain injury in sport and the wider community. Despite this, little research has been conducted investigating the dynamics of impacts to the unprotected human head and injury causation in vivo, in particular the roles of linear and angular head acceleration. Setting Professional contact football in Australia. Participants Adult male professional Australian rules football players participating in 30 games randomly selected from 103 games. Cases selected based on an observable head impact, no observable symptoms (eg, loss-of-consciousness and convulsions), no on-field medical management and no injury recorded at the time. Primary and secondary outcome measures A data set for no-injury head impact cases comprising head impact locations and head impact dynamic parameters estimated through rigid body simulations using the MAthematical DYnamic MOdels (MADYMO) human facet model. This data set was compared to previously reported concussion case data. Results Qualitative analysis showed that the head was more vulnerable to lateral impacts. Logistic regression analyses of head acceleration and velocity components revealed that angular acceleration of the head in the coronal plane had the strongest association with concussion; tentative tolerance levels of 1747 rad/s2 and 2296 rad/s2 were reported for a 50% and 75% likelihood of concussion, respectively. The mean maximum resultant angular accelerations for the concussion and no-injury cases were 7951 rad/s2 (SD 3562 rad/s2) and 4300 rad/s2 (SD 3657 rad/s2), respectively. Linear acceleration is currently used in the assessment of helmets and padded headgear. The 50% and 75% likelihood of concussion values for resultant linear head acceleration in this study were 65.1 and 88.5 g, respectively. Conclusions As hypothesised by Holbourn over 70 years ago, angular acceleration plays an important role in the pathomechanics of concussion, which has major ramifications in terms of helmet design and other efforts to prevent and manage concussion.

"A framework towards personalisation and active muscle integration in a 3D finite-element neck model for orthopaedic applications." Computer Methods in Biomechanics and Biomedical Engineering, 17(sup1), pp. 74–75 AcknowledgementsThis work was supported by the European Commission [grant number FP7-PEOPLE-RG-2009-256575]. The imaging protocol was co-sponsored by the University of Aberdeen and NHS Grampian.

"Evaluation of neck muscles activation patterns during simple isometric tasks." Computer Methods in Biomechanics and Biomedical Engineering, 16(sup1), pp. 170–171Keywords:: neckmusculoskeletalmodellingmuscleactivation AcknowledgementThe authors gratefully acknowledge the funding of this study by the European Commission (FP7-PEOPLE-2009-RG) as part of the DEMU2NECK project.