A novel method of cadaveric data acquisition from a dissection of the male lower limb using the Perceptron ScanWorks® V5 scanner

Introduction: Under the current pressures of an expanding medical curriculum, the time allocated to anatomical training in medical education has been greatly reduced, resulting in an increasing number of doctors qualifying from medical school with an inadequate, and arguably unsafe level of anatomical understanding. Given the limited time now available for cadaveric dissection in medical training, future rectification of these deficits is becoming heavily dependent on supplementation from virtual anatomical training tools. In light of this, many attempts have been made to acquire cadaveric data for the creation of realistic virtual specimens. Until now however, the educational value of these training tools has been heavily scrutinised, with many sharing the view that they are over simplified and anatomically inaccurate. The main problems associated with the usability of pre-existing datasets arise primarily as a result of the methodology used to acquire their cadaveric data. Projects in this field have previously approached the task of cadaveric data acquisition by creating comprehensive libraries of anatomical cross-sections, from which three-dimensional processing can be technically difficult and not always successful for the reconstruction of fine or complex anatomical structures. Aim: The aim of this study therefore was to approach cadaveric data acquisition, for the purpose of creating a digital cadaveric specimen, in an unconventional manner, by obtaining three-dimensional data directly from cadaveric tissues with a Perceptron ScanWorksV5 non-contact laser scanner. Methods: To do this, a carefully planned dissection of the lower limb was performed on a 68 year old male cadaver, and laser scanning of all clinically relevant structures was undertaken at sequential stages throughout. In addition to this, colour and texture information was collected from the cadaveric tissues by high-resolution digital photography. Results: A comprehensive three-dimensional dataset was acquired from all clinically relevant anatomy of the lower limb as a result of the methodology used in this study. Data was obtained at extremely high point to point resolutions, with a measurement accuracy of 24μm, 2σ. Discussion: By obtaining cadaveric data in this way, the problems associated with the three-dimensional processing of conventional cross-sectional data, such as image segmentation, are largely overcome and fine anatomical details can be accurately documented with high precision. This data can be processed further to create an accurate and realistic virtual reconstruction of the lower limb for both three-dimensional anatomical training and surgical rehearsal in the future. Conclusion: Whilst the value of cross-sectional datasets in their own right should not be disputed, the methodology used for cadaveric data acquisition in this study has proved a very successful in collecting three-dimensional data directly form the specimen, and could be used to acquire detailed datasets for the reconstruction of other complex body regions for virtual anatomical training in the future

Life Sciences Program Tasks and Bibliography for FY 1997

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1997. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive internet web page

Life Sciences Program Tasks and Bibliography for FY 1996

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1996. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web page

Improved human soft tissue thigh surrogates for superior assessment of sports personal protective equipment

Human surrogates are representations of living humans, commonly adopted to better understand human response to impacts. Though surrogates have been widely used in automotive, defence and medical industries with varying levels of biofidelity, their primary application in the sporting goods industry has been through primitive rigid anvils used in assessing personal protective equipment (PPE) effectiveness. In sports, absence from competition is an important severity measure and soft tissue injuries such as contusions and lacerations are serious concerns. Consequently, impact surrogates for the sporting goods industry need a more subtle description of the relevant soft tissues to assess impact severity and mitigation accurately to indicate the likelihood of injury. The fundamental aim for this research study was to establish a method to enable the development of superior, complementary, increasingly complex synthetic and computational impact surrogates for improved assessment of sports personal protective equipment. With a particular focus on the thigh segment, research was conducted to evaluate incremental increases in surrogate complexity. Throughout this study, empirical assessment of synthetic surrogates and computational evaluation using finite element (FE) models were employed to further knowledge on design features influencing soft tissue surrogates in a cost and time efficient manner. To develop a more representative human impact surrogate, the tissue structures considered, geometries and materials were identified as key components influencing the mechanical response of surrogates. As a design tool, FE models were used to evaluate the changes in impact response elicited with different soft tissue layer configurations. The study showed the importance of skin, adipose, muscle and bone tissue structures and indicated up to 15.4% difference in maximum soft tissue displacement caused by failure to represent the skin layer. FE models were further used in this capacity in a shape evaluation study from which it was determined that a full-scale anatomically contoured thigh was necessary to show the full diversity of impact response phenomena exhibited. This was particularly pertinent in PPE evaluations where simple surrogate shapes significantly underestimated the magnitudes of displacements exhibited (up to 155% difference) when rigid shell PPE was simulated under impact conditions. Synthetic PDMS silicone simulants were then fabricated for each of the organic soft tissues to match their dynamic responses. The developed simulants exhibited a superior representation of the tissues when compared to previous single material soft tissue simulant, Silastic 3483, which showed 324%, 11,140% and -15.8% greater differences than the PDMS when compared to previously reported target organic tissue datasets for relaxed muscle, skin and adipose tissues respectively. The impact response of these PDMS surrogates were compared in FE models with previously used single material simulants in representative knee and cricket ball sports impact events. The models were each validated through experimental tests and the PDMS simulants were shown to exhibit significantly closer responses to organic tissue predictions across all impact conditions and evaluation metrics considered. An anatomically contoured synthetic thigh surrogate was fabricated using the PDMS soft tissue simulants through a novel multi-stage moulding process. The surrogate was experimentally tested under representative sports impact conditions and showed a good comparison with FE model predictions with a maximum difference in impactor displacements and peak accelerations of +6.86% and +12.5% respectively at velocities between 2 - 4 m.s-1. The value of increased biofidelity in the anatomical synthetic and virtual surrogate thighs has been proven through the incremental adoption of important surrogate elements (tissue structures, material and geometries). The predictive capabilities of each surrogate have been demonstrated through their parallel developments and staged comparisons with idealised organic tissue responses. This increase in biofidelity is introduced at modestly higher cost compared to Silastic 3483, but, given the benefits of a more representative human impact response for PPE evaluations, this is shown to be worthwhile

Life Sciences Program Tasks and Bibliography

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1995. Additionally, this inaugural edition of the Task Book includes information for FY 1994 programs. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web pag

Radiographic Assessment of Hip Disease in Children with Cerebral Palsy: Development of a Core Measurement Set and Analysis of an Artificial Intelligence System

Cerebral palsy is the most common physical disability during childhood. Cerebral palsy related hip disease is caused by an imbalance of muscle forces, resulting in progressive migration of the hip to complete dislocation. This can decrease function and quality of life. The prevention of hip dislocation is possible if detected early. Therefore, surveillance programmes have been set up to monitor children with cerebral palsy enabling clinicians to intervene early and improve outcomes. Currently, hip disease is assessed by analysing pelvic radiographs with various geometric measurements. This time-consuming task is undertaken frequently when monitoring a child with cerebral palsy. This thesis aimed to identify the key radiographic parameters used by clinicians (the core measurement set), and then build an artificial intelligence system to automate the calculation of this core measurement set. A systematic review was conducted identifying a comprehensive list of previously reported measurements from studies measuring radiographic outcomes in cerebral palsy children with hip pathologies. Fifteen measurements were identified from the systematic review, of which Reimers’ migration percentage was the most commonly reported. These measurements were used to perform a two-round Delphi study among orthopaedic surgeons and physiotherapists. Participants rated the importance of each measurement using a nine-point Likert scale (‘not important’ to critically important’). After the two rounds of the Delphi process, Reimers’ migration percentage was included in the core measurement set. Following the final consensus meeting, the femoral head-shaft angle was also included. The anteroposterior pelvic radiographs of 1650 children were then used to build an artificial intelligence system integrating the core measurement set, in collaboration with engineers from the University of Manchester. The newly developed artificial intelligence system was assessed by comparing its ability to calculate measurements and outline the pelvis and femur on a radiograph. The reliability of the dataset used to train the model was also analysed. The proposed artificial intelligence model achieved a ‘good to excellent’ inter-observer reliability across 450 radiographs when comparing its ability to calculate Reimers’ migration percentage to five clinicians. Its ability to outline the pelvis and proximal femur was ‘adequate’ with the better performance observed in the pelvis than the femur. The reliability of the training dataset used to teach the artificial intelligence model was ‘good’ to ‘very good’. Artificial intelligence systems are feasible solutions to optimise the efficiency of hip radiograph analysis in cerebral palsy. Studies are warranted to include the core measurement set as a minimum when reporting on hip disease in cerebral palsy. Future research should investigate the feasibility of implementing a risk score to predict the likelihood of hip displacement