Technology and Health Care - Volume 15, issue 6

Authors: Then, C. | Menger, J. | Benderoth, G. | Alizadeh, M. | Vogl, T.J. | Hübner, F. | Silber, G.

Article Type: Research Article

Abstract: The most common complication associated with immobilization is pressure sores caused by sustained localized tissue strain and stress. Computational simulations have provided insight into tissue stress-strain distribution, subject to loading conditions. In the simulation process, adequate soft tissue material parameters are indispensable. An in vivo procedure to characterise material parameters of human gluteal skin/fat and muscle tissue has been developed. It employs a magnetic resonance imaging (MRI) device together with an MRI compatible loading device. Using the derived data as constraints in an iterative optimization process the inverse finite element (FE) method was applied. FE-models were built and the …material constants describing skin/fat and muscle tissue were parameterized and optimized. Separate parameter sets for human gluteal skin/fat and muscle were established. The long-term shear modulus for human gluteal skin/fat was G ∞ , S / F = 1182 Pa and for muscle G ∞ , M = 1025 Pa . The Ogden form for slightly compressible materials was chosen to define passive human gluteal soft tissue material behaviour. To verify the approach, the human skin/fat-muscle tissue compound was simulated using the derived material parameter sets and the simulation result was compared to empirical values. A correlation factor of R 2 = 0.997 was achieved. Show more

Keywords: Human tissue, separation of fat and muscle, material parameters, bed sore

DOI: 10.3233/THC-2007-15601

Citation: Technology and Health Care, vol. 15, no. 6, pp. 385-398, 2007

Authors: Currò, Vincenzo | Buonuomo, Paola Sabrina | Zambiano, Annaluce | Vituzzi, Andrea | Onesimo, Roberta | D'Atri, Alessandro

Article Type: Research Article

Abstract: The aim of this study is to verify the usefulness for parents of a web evaluation framework composed of ten quality criteria to improve their ability to assess the quality level of medical web sites. We conducted a randomised controlled trial that included two groups of parents who independently evaluated five paediatric web sites by filling out two distinct questionnaires: group A with the evaluation framework, group B without it. 40 volunteers were recruited from parents referring to the General Paediatrics Out-patients Department who satisfied the following eligibility criteria: Internet users, at least 1 child under 12 months old, no …professional skill in Internet and medicine. The survey was taken between February 2, 2000 and March 22, 2000. Parents evaluated each web site and assigned a score, compared with a gold standard created by a group of experts. Suggesting evaluation criteria to parents seem useful for an improvement of their ability to evaluate web sites. Show more

Keywords: Web quality, information, parents, clinical trial

DOI: 10.3233/THC-2007-15602

Citation: Technology and Health Care, vol. 15, no. 6, pp. 399-406, 2007

Authors: Citak, M. | Board, T. N. | Sun, Y. | Look, V. | Krettek, C. | Hüfner, T. | Kendoff, D.

Article Type: Research Article

Abstract: Introduction: In computer assisted orthopaedic surgery, rigid fixation of the Reference Marker (RM) system is essential for reliable computer guidance. A minimum shift of the RM can lead to substantial registration errors and inaccuracies in the navigation process. Various types of RM systems are available but there is little information regarding the relative stabilities of these systems. The aim of this study was to test the rotational stability of three commonly used RM systems. Materials and methods: One hundred and thirty Synbones and 15 cadavers were used to test the rotational stability of three different RM systems (Schanz’ …screw, RM B and RM C adjustment systems). Using a specially developed testing device, the peak torque sustained by each RM system was assessed in various anatomical sites. Results: Comparison of means for Synbone showed that the RM C was the most stable (mean peak torque 5.60 ± 1.21 Nm) followed by the RM B system (2.53 ± 0.53 Nm) and the RM A (0.77 ± 0.39 Nm) (p<0.01). The order of stability in relation to anatomical site was femoral shaft, distal femur, tibial shaft, proximal tibia, anterior superior iliac spine, iliac crest and talus. Results from the cadaver experiments showed similar results. Bi-cortical fixation was superior to mono-cortical fixation in the femur (p<0.01) but not the tibia (p=0.22). Conclusion: The RM system is the vital link between bone and computer and as such the stability of the RM is paramount to the accuracy of the navigation process. In choosing RM systems for computer navigated surgery surgeons should be aware of their relative stability. Anatomical site of RM placement also affect the stability. Mono-cortical fixation is generally less stable than bi-cortical. Show more

DOI: 10.3233/THC-2007-15603

Citation: Technology and Health Care, vol. 15, no. 6, pp. 407-414, 2007

Authors: Davarani, S. Zeinali | Shirazi-Adl, A. | Hemami, H. | Mousavi, S.J. | Parnianpour, M.

Article Type: Research Article

Abstract: The effects of external resistance on the recruitment of trunk muscles and the role of intrinsic and reflexive mechanisms to ensure the spinal stability are significant issues in spinal biomechanics. A computational model of spine under the control of 48 anatomically oriented muscle actions was used to simulate iso-resistive trunk movements. Neural excitation of muscles was attained based on inverse dynamics approach along with the stability-based optimization. The effect of muscle spindle reflex response on the trunk movement stability was evaluated upon the application of a perturbation moment. In this study, the trunk extension movement at various resistance levels while …extending from 60° flexion to the upright posture was investigated. Incorporation of the stability condition as an additional constraint in the optimization algorithm increased antagonistic activities for all resistance levels demonstrating that the co-activation caused an increase in the intrinsic stiffness of the spine and its stability in a feed-forward manner. During the acceleration phase of the movement, extensors activity increased while flexors activity decreased in response to the higher resistance. The co-activation ratio noticed in the braking phase of the movement increased with higher resistance. In presence of a 30 Nm flexion perturbation moment, reflexive feed-back noticeably decreased the induced deviation of the velocity and position profiles from the desired ones at all resistance levels. The stability-generated co-activation decreased the reflexive response of muscle spindles to the perturbation demonstrating that both intrinsic and reflexive mechanisms contribute to the trunk stability. The rise in muscle co-activation can ameliorate the corruption of afferent neural sensory system at the expense of higher loading of the spine. Show more

Keywords: Dynamic simulation, stability, spine, iso-resistive extension, spindle reflex

DOI: 10.3233/THC-2007-15604

Citation: Technology and Health Care, vol. 15, no. 6, pp. 415-431, 2007

Authors: Joshi, Ashish | Lichenstein, Richard | Rafei, Keyvan | Bakar, Adnan | Arora, Mohit

Article Type: Research Article

Abstract: Objective: The goal of the study was to investigate the feasibility and acceptance of an interactive computer assisted asthma education program in the pediatric emergency department (ED) for children with acute asthma exacerbations. Methods: A pre-post non- randomized study was designed for children age 3 to 18 years at the University of Maryland Hospital for Children, Baltimore. An interactive computer-assisted educational program, Patient Education and Motivation Tool (PEMT), was designed using learning theories, to teach children about asthma and its management. Sixty nine children were enrolled during an ED visit for acute asthma between May 2006 and November …2006. Socio-demographic and asthma knowledge information was gathered using questionnaires. An attitudinal survey was used to assess the acceptance of the program. Results: Eighty one percent (n=56) of the children found PEMT very easy to use, and seventy five percent (n=52) agreed to use it in near future. There was a significant thirteen percent improvement in knowledge of asthma after the completion of this computer assisted asthma education program (p=0.01). Conclusion: PEMT is highly acceptable and is an effective way to provide asthma education in an ED setting. Show more

Keywords: Asthma, children, computers, education, behavior

DOI: 10.3233/THC-2007-15605

Citation: Technology and Health Care, vol. 15, no. 6, pp. 433-444, 2007