Studies in health technology and informatics
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Stud Health Technol Inform · Jan 2002
Spine-rib rotation differences at the apex in preoperative patients with adolescent idiopathic scoliosis: evaluation of a three-level ultrasound method.
This paper evaluates a new real-time ultrasound method to assess the difference between axial spinal (laminal) rotation and rib rotation at the apex of the scoliosis curve. An Aloka SSD 500 portable ultrasound machine with a veterinary long (172mm) 3.5 MHz linear array transducer was used to assess the reproducibility of the method in 13 preoperative patients with AIS. With the subject in a prone position and her head supported, readings of laminal and rib rotation were made directly on the back at 18 and 12 levels respectively The subject was repositioned after walking around the room and a second set of spinal and rib rotations obtained (repeats). ⋯ Real-time ultrasound can assess the difference between spinal and rib rotation about the apex of the scoliosis curve without the altered position detectably affecting the findings. The error (2-3 degrees) is high relative the mean apical SRRD (6-7 degrees). The apical SRRD findings have relevance to the pathogenesis of AIS.
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Stud Health Technol Inform · Jan 2002
Augmented reality and training for airway management procedures.
Augmented reality is often used for interactive, three-dimensional visualization within the medical community. To this end, we present the integration of an augmented reality system that will be used to train military medics in airway management. The system demonstrates how a head-mounted projective display can be integrated with a desktop PC to create an augmented reality visualization. Furthermore, the system, which uses a lightweight optical tracker, demonstrates the low cost and the portability of the application.
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Stud Health Technol Inform · Jan 2002
Sagittal and transversal plane deformity in thoracic scoliosis.
The aim of the study was to assess the sagittal and transversal plane deformity of the spine in thoracic scoliosis by the mean of 3-D radiographic analysis. 46 patients admitted for surgery for thoracic idiopathic scoliosis underwent preoperative radiographic assessment. All patients presented the same pattern of the coronal plane deformity: single right thoracic curve (Lenke 1, King 3). Neither lumbar nor proximal thoracic structural curve were present. The Cobb angle varied from 41gamma to 77 gamma (mean 55,4 gamma +/- 8,6 gamma). Long cassette standing antero-posterior and lateral radiographs were analysed. Three-dimensional reconstruction with Rachis 91TM software was performed for each pair of radiographs. The following parameters were assessed: sagittal thoracic Cobb angle (Th4-Th12), upper thoracic kyphosis angle (Th5-Th8), lower thoracic kyphosis angle (Th9-Th12), superior and inferior hemi-curve sagittal angles, lumbar lordosis, sacral slope, sacral incidence, vertebral plate index, segmental vertebral axial rotation throughout the thoracic and lumbar spine. Results showed great variability of parameters assessed. The non-harmonious distribution of kyphosis was demonstrated in the thoracic spine. Local Th9-Th12 hypokyphosis and adjacent local Th5-Th8 hyperkyphosis constitute the most typical sagittal pathologies. So called normokyphotic curves were composed of one hyperkyphotic and one hypokyphotic zone. Th1-Th4 segment revealed two patterns of segmental rotation distribution: a purely compensatory curve with no vertebral axial rotation or a rotated curve presenting the morphology intermediate between Lenke 1 and Lenke 2 types (or King 3 and King 5). ⋯ curves presenting the same coronal plane deformity differ in their morphology assessed in the two other planes; global thoracic kyphosis angle is a misleading parameter because it covers hypo- and hyperkyphotic zones; local distal thoracic (Th9-Th12) hypokyphosis is present in idiopathic thoracic scoliosis.
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Stud Health Technol Inform · Jan 2002
Clinical TrialIn vivo quantitative analysis of scoliotic vertebrae.
An in vivo method based on CT images and finite element meshing had been developed to quantify and visualize the bone density distribution of scoliotic vertebrae. CT examination (axial acquisition of the apical, superior and inferior adjacent vertebral bodies) had been performed on seven girls presenting an idiopathic scoliosis. Using an in-house image processing software and the pre-post processor Patran, a surfacic finite element mesh of each body slice was proposed allowing an automatic mapping of the cancellous bone slices and a volumic mesh for the bone density distribution visualization. ⋯ The shift forward by slice was made in a same way for each slice, excepted at the end plates. Besides, one can observe that the scoliotic deformation evolution seemed to modify the mechanical property distribution. The results may also suggest predictive criteria of evolution of the scoliotic deformities.
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Stud Health Technol Inform · Jan 2002
The Double Rib Contour Sign (DRCS) in lateral spinal radiographs: aetiologic implications for scoliosis.
All lateral spinal radiographs in idiopathic scoliosis show a DRC sign of the thoracic cage, a radiographic expression of the rib hump. The outline of the convex overlies the contour of the concave ribs. The aim of this study is to assess this DRC sign in children with and without Late Onset Idiopathic Scoliosis (LOIS) with 10 degrees -20 degrees Cobb angle, and to examine whether in scoliosis the deformity of the thorax or that of the spine develops first. ⋯ The DRCS primarily appears because of the rib deformation and secondarily because of the vertebral rotation, as it could be present in straight spines with no vertebral rotation. In all our school-screening referrals, (having ATI > or = 7 degrees), the thorax deformity, in terms of the DRC sign, has already been developed. 70% of these children were scoliotic. The others had a curvature of less than 9 degrees of Cobb angle (10%) or they were children with straight spines (20%) who were followed because of their existing rib hump. The non-scoliotics were 1,5-2 years younger than the ones who had already developed scoliosis, and they had both approximately a "rib index" of 1,5. The DRC sign is present in all referrals. In contrary, there is no scoliotic spine without it, as the DRC sign is always present in scoliotic lateral spinal radiographs with no exception. This observation supports our hypothesis that in idiopathic scoliosis, the deformity of the thorax develops first and then the deformity of the spine follows.