Orthopaedics and trauma Queensland annual report 2012

Orthopaedics and Trauma Queensland, the Centre for Research and Education in Musculoskeletal Disorders, is an internationally recognised research group that continues to develop its reputation as an international leader in research and education. It provides a stimulus for research, education and clinical application within the international orthopaedic and trauma communities. Orthopaedics and Trauma Queensland develops and promotes the innovative use of engineering and technology, in collaboration with surgeons, to provide new techniques, materials, procedures and medical devices. Its integration with clinical practice and strong links with hospitals ensure that the research will be translated into practical outcomes for patients. The group undertakes clinical practice in orthopaedics and trauma and applies core engineering skills to challenges in medicine. The research is built on a strong foundation of knowledge in biomedical engineering, and incorporates expertise in cell biology, mathematical modelling, human anatomy and physiology and clinical medicine in orthopaedics and trauma. New knowledge is being developed and applied to the full range of orthopaedic diseases and injuries, such as knee and hip replacements, fractures and spinal deformities.

Neurons Activated During Fear Memory Consolidation and Reconsolidation are Mapped to a Common and New Topography in the Lateral Amygdala

A key question in neuroscience is how memory is selectively allocated to neural networks in the brain. This question remains a significant research challenge, in both rodent models and humans alike, because of the inherent difficulty in tracking and deciphering large, highly dimensional neuronal ensembles that support memory (i.e., the engram). In a previous study we showed that consolidation of a new fear memory is allocated to a common topography of amygdala neurons. When a consolidated memory is retrieved, it may enter a labile state, requiring reconsolidation for it to persist. What is not known is whether the original spatial allocation of a consolidated memory changes during reconsolidation. Knowledge about the spatial allocation of a memory, during consolidation and reconsolidation, provides fundamental insight into its core physical structure (i.e., the engram). Using design-based stereology, we operationally define reconsolidation by showing a nearly identical quantity of neurons in the dorsolateral amygdala (LAd) that expressed a plasticity-related protein, phosphorylated mitogen-activated protein kinase, following both memory acquisition and retrieval. Next, we confirm that Pavlovian fear conditioning recruits a stable, topographically organized population of activated neurons in the LAd. When the stored fear memory was briefly reactivated in the presence of the relevant conditioned stimulus, a similar topography of activated neurons was uncovered. In addition, we found evidence for activated neurons allocated to new regions of the LAd. These findings provide the first insight into the spatial allocation of a fear engram in the LAd, during its consolidation and reconsolidation phase.

Pavlovian fear memory circuits and phenotype models of PTSD

Pavlovian fear conditioning, also known as classical fear conditioning is an important model in the study of the neurobiology of normal and pathological fear. Progress in the neurobiology of Pavlovian fear also enhances our understanding of disorders such as posttraumatic stress disorder (PTSD) and with developing effective treatment strategies. Here we describe how Pavlovian fear conditioning is a key tool for understanding both the neurobiology of fear and the mechanisms underlying variations in fear memory strength observed across different phenotypes. First we discuss how Pavlovian fear models aspects of PTSD. Second, we describe the neural circuits of Pavlovian fear and the molecular mechanisms within these circuits that regulate fear memory. Finally, we show how fear memory strength is heritable; and describe genes which are specifically linked to both changes in Pavlovian fear behavior and to its underlying neural circuitry. These emerging data begin to define the essential genes, cells and circuits that contribute to normal and pathological fear.

Automatic segmentation of choroidal thickness in optical coherence tomography

The assessment of choroidal thickness from optical coherence tomography (OCT) images of the human choroid is an important clinical and research task, since it provides valuable information regarding the eye’s normal anatomy and physiology, and changes associated with various eye diseases and the development of refractive error. Due to the time consuming and subjective nature of manual image analysis, there is a need for the development of reliable objective automated methods of image segmentation to derive choroidal thickness measures. However, the detection of the two boundaries which delineate the choroid is a complicated and challenging task, in particular the detection of the outer choroidal boundary, due to a number of issues including: (i) the vascular ocular tissue is non-uniform and rich in non-homogeneous features, and (ii) the boundary can have a low contrast. In this paper, an automatic segmentation technique based on graph-search theory is presented to segment the inner choroidal boundary (ICB) and the outer choroidal boundary (OCB) to obtain the choroid thickness profile from OCT images. Before the segmentation, the B-scan is pre-processed to enhance the two boundaries of interest and to minimize the artifacts produced by surrounding features. The algorithm to detect the ICB is based on a simple edge filter and a directional weighted map penalty, while the algorithm to detect the OCB is based on OCT image enhancement and a dual brightness probability gradient. The method was tested on a large data set of images from a pediatric (1083 B-scans) and an adult (90 B-scans) population, which were previously manually segmented by an experienced observer. The results demonstrate the proposed method provides robust detection of the boundaries of interest and is a useful tool to extract clinical data.

A computer image analysis system for microvessel density measurement in solid tumours

Microvessel density (MVD) is a widely used surrogate measure of angiogenesis in pathological specimens and tumour models. Measurement of MVD can be achieved by several methods. Automation of counting methods aims to increase the speed, reliability and reproducibility of these techniques. The image analysis system described here enables MVD measurement to be carried out with minimal expense in any reasonably equipped pathology department or laboratory. It is demonstrated that the system translates easily between tumour types which are suitably stained with minimal calibration. The aim of this paper is to offer this technique to a wider field of researchers in angiogenesis.

A comparison of the histochemical and image-derived proteoglycan content of articular cartilage

There are several methods for determining the proteoglycan content of cartilage in biomechanics experiments. Many of these include assay-based methods and the histochemistry or spectrophotometry protocol where quantification is biochemically determined. More recently a method based on extracting data to quantify proteoglycan content has emerged using the image processing algorithms, e.g., in ImageJ, to process histological micrographs, with advantages including time saving and low cost. However, it is unknown whether or not this image analysis method produces results that are comparable to those obtained from the biochemical methodology. This paper compares the results of a well-established chemical method to those obtained using image analysis to determine the proteoglycan content of visually normal (n=33) and their progressively degraded counterparts with the protocols. The results reveal a strong linear relationship with a regression coefficient (R2) = 0.9928, leading to the conclusion that the image analysis methodology is a viable alternative to the spectrophotometry.

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As Drs Patel and McGhee intimate, the original nerve mapping technique they described 1 was tedious and time-consuming, requiring the capture of hundreds of separate images and many hours of manual montaging to form a confluent map. The maps they published also had distracting component image delineation. It is for these reasons that a number of research groups have sought to develop automated techniques for generating these nerve maps (Table 1).2–6...

The TFOS International Workshop on Contact Lens Discomfort: report of the contact lens interactions with the ocular surface and adnexa subcommittee

The report of this subcommittee concerns the impact of contact lenses (CLs) on the ocular surface, with a particular emphasis on CL discomfort (CLD). We define the ocular surface, its regional anatomy, and the physiological responses of each region to CL wear.

Geometric sensitivity of patient-specific finite element models of the spine to variability in user-selected anatomical landmarks

Software to create individualised finite element (FE) models of the osseoligamentous spine using pre-operative computed tomography (CT) data-sets for spinal surgery patients has recently been developed. This study presents a geometric sensitivity analysis of this software to assess the effect of intra-observer variability in user-selected anatomical landmarks. User-selected landmarks on the osseous anatomy were defined from CT data-sets for three scoliosis patients and these landmarks were used to reconstruct patient-specific anatomy of the spine and ribcage using parametric descriptions. The intra-observer errors in landmark co-ordinates for these anatomical landmarks were calculated. FE models of the spine and ribcage were created using the reconstructed anatomy for each patient and these models were analysed for a loadcase simulating clinical flexibility assessment. The intra-observer error in the anatomical measurements was low in comparison to the initial dimensions, with the exception of the angular measurements for disc wedge and zygapophyseal joint (z-joint) orientation and disc height. This variability suggested that CT resolution may influence such angular measurements, particularly for small anatomical features, such as the z-joints, and may also affect disc height. The results of the FE analysis showed low variation in the model predictions for spinal curvature with the mean intra-observer variability substantially less than the accepted error in clinical measurement. These findings demonstrate that intra-observer variability in landmark point selection has minimal effect on the subsequent FE predictions for a clinical loadcase.

A sonographer's guide to the assessment of heart disease

The book is mostly designed for students of echocardiography, teachers of echocardiography and cardiac sonographers working in routine clinical practice, but will also be very useful to echocardiologists and cardiac registrars. The goal of the text is to provide a comprehensive review of transthoracic echocardiography in the assessment of various cardiac pathologies. Refresher notes on cardiac anatomy and the relevant cardiac physiology and pathophysiology are included to expand the cardiac sonographer’s knowledge in this area and further their understanding of various diseases, disease processes and associated findings.

Supine to standing Cobb Angle change in idiopathic scoliosis: The effect of endplate preselection

Introduction Standing radiographs are the ‘gold standard’ for clinical assessment of adolescent idiopathic scoliosis (AIS), with the Cobb Angle used to measure the severity and progression of the scoliotic curve. Supine imaging modalities can provide valuable 3D information on scoliotic anatomy, however, due to changes in gravitational loading direction, the geometry of the spine alters between the supine and standing position which in turn affects the Cobb Angle measurement. Previous studies have consistently reported a 7-10° [1-3] Cobb Angle increase from supine to standing, however, none have reported the effect of endplate pre-selection and which (if any) curve parameters affect the supine to standing Cobb Angle difference. Methods Female AIS patients with right-sided thoracic major curves were included in the retrospective study. Clinically measured Cobb Angles from existing standing coronal radiographs and fulcrum bending radiographs [4] were compared to existing low-dose supine CT scans taken within 3 months of the reference radiograph. Reformatted coronal CT images were used to measure Cobb Angle variability with and without endplate pre-selection (end-plates selected on the radiographs used on the CT images). Inter and intra-observer measurement variability was assessed. Multi-linear regression was used to investigate whether there was a relationship between supine to standing Cobb Angle change and patient characteristics (SPSS, v.21, IBM, USA). Results Fifty-two patients were included, with mean age of 14.6 (SD 1.8) years; all curves were Lenke Type 1 with mean Cobb Angle on supine CT of 42° (SD 6.4°) and 52° (SD 6.7°) on standing radiographs. The mean fulcrum bending Cobb Angle for the group was 22.6° (SD 7.5°). The 10° increase from supine to standing is consistent with existing literature. Pre-selecting vertebral endplates was found to increase the Cobb Angle difference by a mean 2° (range 0-9°). Multi-linear regression revealed a statistically significant relationship between supine to standing Cobb Angle change with: fulcrum flexibility (p=0.001), age (p=0.027) and standing Cobb Angle (p<0.001). In patients with high fulcrum flexibility scores, the supine to standing Cobb Angle change was as great as 20°.The 95% confidence intervals for intra-observer and inter-observer measurement variability were 3.1° and 3.6°, respectively. Conclusion There is a statistically significant relationship between supine to standing Cobb Angle change and fulcrum flexibility. Therefore, this difference can be considered a measure of spinal flexibility. Pre-selecting vertebral endplates causes only minor changes.

Enhancing paramedics procedural skills using a cadaveric model

Background Paramedic education has evolved in recent times from vocational post-employment to tertiary pre-employment supplemented by clinical placement. Simulation is advocated as a means of transferring learned skills to clinical practice. Sole reliance of simulation learning using mannequin-based models may not be sufficient to prepare students for variance in human anatomy. In 2012, we trialled the use of fresh frozen human cadavers to supplement undergraduate paramedic procedural skill training. The purpose of this study is to evaluate whether cadaveric training is an effective adjunct to mannequin simulation and clinical placement. Methods A multi-method approach was adopted. The first step involved a Delphi methodology to formulate and validate the evaluation instrument. The instrument comprised of knowledge-based MCQs, Likert for self-evaluation of procedural skills and behaviours, and open answer. The second step involved a pre-post evaluation of the 2013 cadaveric training. Results One hundred and fourteen students attended the workshop and 96 evaluations were included in the analysis, representing a return rate of 84%. There was statistically significant improved anatomical knowledge after the workshop. Students' self-rated confidence in performing procedural skills on real patients improved significantly after the workshop: inserting laryngeal mask (MD 0.667), oropharyngeal (MD 0.198) and nasopharyngeal (MD 0.600) airways, performing Bag-Valve-Mask (MD 0.379), double (MD 0.344) and triple (MD 0.326,) airway manoeuvre, doing 12-lead electrocardiography (MD 0.729), using McGrath(R) laryngoscope (MD 0.726), using McGrath(R) forceps to remove foreign body (MD 0.632), attempting thoracocentesis (MD 1.240), and putting on a traction splint (MD 0.865). The students commented that the workshop provided context to their theoretical knowledge and that they gained an appreciation of the differences in normal tissue variation. Following engagement in/ completion of the workshop, students were more aware of their own clinical and non-clinical competencies. Conclusions The paramedic profession has evolved beyond patient transport with minimal intervention to providing comprehensive both emergency and non-emergency medical care. With limited availability of clinical placements for undergraduate paramedic training, there is an increasing demand on universities to provide suitable alternatives. Our findings suggested that cadaveric training using fresh frozen cadavers provides an effective adjunct to simulated learning and clinical placements.

Do nursing students have the recall of bioscience necessary to study pharmacology?

Background: For medical and allied health students, bioscience knowledge underpins the successful scaffolding of learning in their developmental and advanced level units. Many of these students complete theory-based Bioscience units, followed by a unit in Pharmacology, which specifically requires knowledge of anatomy, physiology and microbiology. In general, studies of recall report relatively large losses over short retention intervals (months), which accumulate, but level off, for longer retention intervals (years) (Custers, 2010). However, there are no studies that specifically test the recall of bioscience knowledge by allied health students. Methods: We are tracking the recall of bioscience in nursing students prior to, and during, their Pharmacology unit. In each semester, students complete short, basic, knowledge-based MCQ quizzes on concepts from (i) the gastrointestinal system and (ii) fundamental microbiology. Students were given 5 days warning about the microbiology quizzes but were given no warning prior to the gastrointestinal system quiz. Performance in these quizzes was compared to individual student’s results in the final examination on these topics in the first semester of their degree. Results: At the start of the study, the nursing students performed better in the exam MCQs on the gastrointestinal system than on microbiology. In the exam, the students’ mean marks for the gastrointestinal system ranged from 69–83%, and this was successively reduced to 63%, 53% and 49% after 4, 9 and 16 months, respectively. The mean exam marks for microbiology was 48–58%, and this did not change significantly after 4 (63%), 9 (59%) or 16 months (47%). This suggests that warning the nursing students that they were to be quizzed on microbiology may have helped their recall. However, after 16 months regardless of the subject, the nursing students undertaking the Pharmacology unit recalled less than half of the bioscience quiz answers. Conclusions: Nursing students may not have the recall of bioscience necessary to study pharmacology, and this may limit their success in pharmacology. Reference: Custers, E. J. F. M. (2010). Long-term retention of basic science knowledge: a review study. Advances in Health Science Education, 15, 109–128.

A loss of bioscience knowledge in nursing students

Background: Knowledge of the human biosciences is fundamental to the development of competent nurse practitioners (Smales, 2010) with the requisite knowledge and skills, necessary for high quality patient care and good patient outcomes (Logan and Angel, 2011). Many of these students study bioscience units which cover topics in anatomy, physiology, pathophysiology and microbiology. Studies of science recall in general and medical education, report up to 33% loss of knowledge in the first year which declines to 50% in the subsequent year (Custers, 2010). Objectives: The objectives were to test the recall of bioscience knowledge by nursing students and to ascertain their perceptions of the testing. Questions explored: What would the results be for multiple choice questions in fundamental microbiology and gastrointestinal anatomy and physiology (A&P) undertaken by nursing students 4, 9 and 16 months after their first bioscience exam on these topics? Would pre-warning the students of a microbiology quiz and not a gastrointestinal A&P quiz affect the findings? How would the students respond to the testing when surveyed? Recall results: The nursing students performed better in the final exam on gastrointestinal A&P than on fundamental microbiology. There was an approximate 20% loss in knowledge of gastrointestinal A&P after 4 months and this did not change significantly over the next 12 months. Although there was an improved performance in microbiology quizzes after 4 months, there was no significant difference in results over the next 12 months. Survey results: More than 50% of students thought the testing helped them focus for the lectures and made them aware they had some pre-knowledge of the lecture topics. Discussion: Although there was a loss of knowledge of gastrointestinal A&P, it appears that warning the students about the microbiology quiz may have helped their recall. The majority of students valued the testing as a useful learning exercise. References: Custers, E. J. F. M. (2010). Long-term retention of basic science knowledge: a review study. Advances in Health Science Education, 15, 109-128. Smales, K. (2010). Learning and applying biosciences to clinical practice in nursing. Nursing Standard, 24(33), 35-39. Logan, P.A., & Angel, L. (2011). Nursing as a scientific undertaking and the intersection with science in undergraduate studies: implications for nursing management. Journal of Nursing Management, 19(3), 407-417.