Peter Dangerfield

Comparison of gait patterns between healthy and scoliotic patients using time and frequency domain analysis of ground reaction forces.

Study Design. The walking gait in 20 healthy adolescent girls and 20 adolescent girls with iodiopathic scoliosis was compared using time and frequency domain analysis of the ground reaction forces. Objectives. To investigate the support phase mechanics of walking gait in health subjects and those with scoliosis. Summary of Background Data. Previous studies have demonstrated the important role of gait in the etiology of scoliosis, although, to date, there are no detailed reports that examine kinetic gait parameters. Methods. Selected force-time parameters were used to investigate time domain patterns. The frequency content of the vertical, anterior-posterior, and medial-lateral components was used to examine frequency characteristics. Inter- and intrasubject variability and bilateral symmetry also were examined. Results. The findings indicated no significant differences between the two groups for the time domain variables. However, the frequency content of the group with scoliosis was significantly higher than that of the control group, especially in the medial-lateral component, suggesting presence of a balance control misfunction. In addition, substantially higher inter- and intrasubject variability and asymmetry was found within the frequency content of the group with scoliosis compared with the control group in the medial-lateral and anterior-posterior directions. Conclusions. Patients with scoliosis exhibit balance problems during the stance phase of gait and have significant asymmetry in the frequency characteristics. These findings could be a primary effect that contributes to the medial-lateral deformity of the spine and its initiation and progression.

Quantitative analysis of diurnal variation in volume and water content of lumbar intervertebral discs

The Cavalieri method of modern design stereology has been used in combination with magnetic resonance imaging (MRI) to obtain unbiased estimates of the volume of the lumbar intervertebral discs immediately at the end of a day of normal activity and again following a nights rest. In addition, pixel‐by‐pixel mapping of the T2‐relaxation time has been used to characterize objectively the tissues of the intervertebral discs. The mean increase in height of seven female subjects of average age 21 years (range 19–23 years) measured with a stediometer was 19.3 mm (range 8–26 mm). Image analysis showed that the mean overnight increase in volume of lumbar discs was 1300 mm3 (range 100–2700 mm3). The increase in volume of the disc was accompanied by an increase in the T2‐relaxation time of the nucleus pulposus. This suggests that the change in disc volume is most probably caused by a preferential increase in the water content of the nucleus pulposus. Clin. Anat. 11:1–8, 1998.

Learning gross anatomy in a clinical skills course

Recent developments in undergraduate medical education in the United Kingdom have produced changes in the content and delivery of component courses, including human anatomy. Anatomy can retain its place in the medical course in the new world of problem‐based learning and clinical skills teaching by gaining recognition as an integral part of the curriculum which underpins much of the practice of clinical medicine. In these new courses, anatomical information is clinically relevant and discussed in the context of medical problems and the acquisition of clinical skills. Students are encouraged to study in a manner in which information is retained (deep learning) and where understanding replaces rote learning of facts. Students take responsibility for their own learning, with appropriate support and resources. In clinical skills courses, anatomy underpins the development and retention of clinical knowledge and skills. Clin. Anat. 13:444–447, 2000.

Pathogenesis of adolescent idiopathic scoliosis in girls - a double neuro-osseous theory involving disharmony between two nervous systems, somatic and autonomic expressed in the spine and trunk: possible dependency on sympathetic nervous system and hormones with implications for medical therapy

Anthropometric data from three groups of adolescent girls - preoperative adolescent idiopathic scoliosis (AIS), screened for scoliosis and normals were analysed by comparing skeletal data between higher and lower body mass index subsets. Unexpected findings for each of skeletal maturation, asymmetries and overgrowth are not explained by prevailing theories of AIS pathogenesis. A speculative pathogenetic theory for girls is formulated after surveying evidence including: (1) the thoracospinal concept for right thoracic AIS in girls; (2) the new neuroskeletal biology relating the sympathetic nervous system to bone formation/resorption and bone growth; (3) white adipose tissue storing triglycerides and the adiposity hormone leptin which functions as satiety hormone and sentinel of energy balance to the hypothalamus for long-term adiposity; and (4) central leptin resistance in obesity and possibly in healthy females. The new theory states that AIS in girls results from developmental disharmony expressed in spine and trunk between autonomic and somatic nervous systems. The autonomic component of this double neuro-osseous theory for AIS pathogenesis in girls involves selectively increased sensitivity of the hypothalamus to circulating leptin (genetically-determined up-regulation possibly involving inhibitory or sensitizing intracellular molecules, such as SOC3, PTP-1B and SH2B1 respectively), with asymmetry as an adverse response (hormesis); this asymmetry is routed bilaterally via the sympathetic nervous system to the growing axial skeleton where it may initiate the scoliosis deformity (leptin-hypothalamic-sympathetic nervous system concept = LHS concept). In some younger preoperative AIS girls, the hypothalamic up-regulation to circulating leptin also involves the somatotropic (growth hormone/IGF) axis which exaggerates the sympathetically-induced asymmetric skeletal effects and contributes to curve progression, a concept with therapeutic implications. In the somatic nervous system, dysfunction of a postural mechanism involving the CNS body schema fails to control, or may induce, the spinal deformity of AIS in girls (escalator concept). Biomechanical factors affecting ribs and/or vertebrae and spinal cord during growth may localize AIS to the thoracic spine and contribute to sagittal spinal shape alterations. The developmental disharmony in spine and trunk is compounded by any osteopenia, biomechanical spinal growth modulation, disc degeneration and platelet calmodulin dysfunction. Methods for testing the theory are outlined. Implications are discussed for neuroendocrine dysfunctions, osteopontin, sympathoactivation, medical therapy, Rett and Prader-Willi syndromes, infantile idiopathic scoliosis, and human evolution. AIS pathogenesis in girls is predicated on two putative normal mechanisms involved in trunk growth, each acquired in evolution and unique to humans.

Developing professionalism through the use of wikis: A study with first-year undergraduate medical students

Aim: Learning about professionalism occurs through collaboration, with peer groups being important sources of support for students [Sandars J, Homer M, Pell G, Croker T. 2008. Web 2.0 and social software: The medical student way of e-learning. Med Teach 14:1–5. Accessed 2008 February 14]. This study aimed to discover whether the use of wikis (collaborative websites) could enhance medical students’ development of professionalism. Methods: An online wiki was made available to four problem-based learning (PBL) groups, involving 32 students. Data collection comprised a small-scale student survey and four focus groups eliciting their views about wiki use, triangulated with facilitator interviews and wiki usage statistics. Results: Several factors affected individual student and group engagement with wikis, such as positive group dynamics. Students shared web links, helping clarify PBL discussions and increase their confidence. Conclusions: Two main benefits of using wikis for the development of professionalism with medical students were revealed. First, wikis acted as a shared knowledge base for hard-to-find resources on professionalism. Second, it was precisely when students reflected on the difference between interacting in wikis and their online social spaces, or when they considered whether or not to post a resource that their sense of professionalism emerged.

Relative anterior spinal overgrowth in adolescent idiopathic scoliosis—result of disproportionate endochondral-membranous bone growth?

There is no generally accepted scientific theory for the etiology of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The text for this EFG was written by Professor Jack Cheng and his colleagues who used whole spine magnetic resonance imaging (MRI) to re-investigate the relative anterior spinal overgrowth of progressive AIS in a cross-sectional study. The text is drawn from research carried out with his co-workers including measurement of the height of vertebral components anteriorly (vertebral body) and posteriorly (pedicles) in girls with AIS and in normal subjects. The findings confirm previous anatomical studies and support the consensus view that in patients with thoracic AIS there is relatively faster growth of anterior and slower growth of posterior elements of thoracic vertebrae. The disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves. In interpretating the findings they consider the Roth/Porter hypothesis of uncoupled neuro-osseous growth in the spine but point out that knowledge of normal vertebral growth supports the view that the scoliosis deformity in AIS is related to longitudinal vertebral body growth rather than growth of the canal. In the mechanical mechanism (pathomechanism) they implicitly adopt the concept of primary skeletal change as it affects the sagittal plane of the spine with anterior increments and posterior decrements of vertebral growth and, in the biological mechanism (pathogenesis) propose a novel histogenetic hypothesis of uncoupled endochondral-membranous bone formation. The latter is viewed as part of an ‘intrinsic abnormality of skeletal growth in patients with AIS which may be genetic’. The hypothesis that AIS girls have intrinsic anomalies (not abnormalities) of skeletal growth related to curve progression and involving genetic and/or environmental factors acting in early life is not original. While the findings of Professor Cheng and his colleagues have added MRI data to the field of relative anterior spinal overgrowth in AIS their interpretation engenders controversy. Three new hypotheses are proposed to interpret their findings: (1) hypoplasia of articular processes as a risk factor for AIS; (2) selection from the normal population to AIS involves anomalous vertebral morphology and soft tissue factors—this hypothesis may also apply to certain types of secondary scoliosis; and (3) a new method to predict the natural history of AIS curves by evaluating cerebro-spinal fluid (CSF) motion at the cranio–cervical junction. What is not controversial is the need for whole spine MRI research on subjects with non-idiopathic scoliosis.

Computer-assisted Cobb measurement of scoliosis

Abstract. This study was devised to develop a simple computerised method for measuring and quantifying the magnitude of spinal curvatures. A digitally scanned antero-posterior radiographic image was used. The vertebral column was defined as a line that can be subdivided into a number of segments, rather than into the exact number of vertebrae. The technique developed allows an observer to measure the spinal curvature with a high resolution and accuracy. One important advantage of the technique is that the assessor does not need to be skilled or experienced in measurement of a spinal curvature.

The relationship between surface and radiological deformity in adolescent idiopathic scoliosis: effect of change in body position

Three-dimensional (3D) surface deformity of the trunk in adolescent idiopathic scoliosis (AIS) is affected by changes in patient position. Initial quantification of the curve and its associated deformity, as well as subsequent monitoring, relies on both radiological and surface measurements. However, there is often a discrepancy between radiological and apparent surface deformity. The present investigation studied the dynamics of the 3D deformity associated with changes in patient position on 27 patients with AIS. The trunk deformity was quantified in three positions by measuring the angle of thoracic inclination at each vertebral level using a scoliometer. The patients all had full spine radiography in the antero-posterior erect position. Vertebral rotation and lateral spinal curvature were measured from the radiographs. Body position altered the magnitude of the surface deformity over the whole trunk, with the prone position offering the optimum relationship between 3D trunk shape and radiological deformity. This could be attributed to the ease and standardisation of positioning for prone measurements, together with increased patient comfort. It is suggested that adoption of standardised positioning and measurement of surface and radiological deformity will permit consistency of clinical judgement based on these parameters.

The role of simulation in medical education

M edical education and training have traditionally placed emphasis on student interaction with real patients in clinical settings. Although hands-on experiential learning is indispensable, medical educators have become increasingly concerned about, and committed to, the safety of patients. Making mistakes can be regarded as an expected and inevitable part of the learning process but there can be a real risk to patient safety and well-being. Furthermore, there has also been a massive increase in the numbers of students in training, especially at undergraduate level, where competition between medical students themselves and other health care groups has raised difficulties for access to patients.

Adolescent idiopathic scoliosis (AIS), environment, exposome and epigenetics: a molecular perspective of postnatal normal spinal growth and the etiopathogenesis of AIS with consideration of a network approach and possible implications for medical therapy

Genetic factors are believed to play an important role in the etiology of adolescent idiopathic scoliosis (AIS). Discordant findings for monozygotic (MZ) twins with AIS show that environmental factors including different intrauterine environments are important in etiology, but what these environmental factors may be is unknown. Recent evidence for common chronic non-communicable diseases suggests epigenetic differences may underlie MZ twin discordance, and be the link between environmental factors and phenotypic differences. DNA methylation is one important epigenetic mechanism operating at the interface between genome and environment to regulate phenotypic plasticity with a complex regulation across the genome during the first decade of life. The word exposome refers to the totality of environmental exposures from conception onwards, comprising factors in external and internal environment s. The word exposome is used here also in relation to physiologic and etiopathogenetic factors that affect normal spinal growth and may induce the deformity of AIS. In normal postnatal spinal growth we propose a new term and concept, physiologic growth-plate exposome for the normal processes particularly of the internal environments that may have epigenetic effects on growth plates of vertebrae. In AIS, we propose a new term and concept pathophysiologic scoliogenic exposome for the abnormal processes in molecular pathways particularly of the internal environment currently expressed as etiopathogenetic hypotheses; these are suggested to have deforming effects on the growth plates of vertebrae at cell, tissue, structure and/or organ levels that are considered to be epigenetic. New research is required for chromatin modifications including DNA methylation in AIS subjects and vertebral growth plates excised at surgery. In addition, consideration is needed for a possible network approach to etiopathogenesis by constructing AIS diseasomes. These approaches may lead through screening, genetic, epigenetic, biochemical, metabolic phenotypes and pharmacogenomic research to identify susceptible individuals at risk and modulate abnormal molecular pathways of AIS. The potential of epigenetic-based medical therapy for AIS cannot be assessed at present, and must await new research derived from the evaluation of epigenetic concepts of spinal growth in health and deformity. The tenets outlined here for AIS are applicable to other musculoskeletal growth disorders including infantile and juvenile idiopathic scoliosis.