Sagittal sacro-pelvic morphology and spino-pelvic balance in pediatric lumbosacral spondylolisthesis : development of a postural model = Morphologie sacro-pelvienne et équilibre spino-pelvien sagittal dans le spondylolisthésis lombosacré pédiatrique : développement d'un modèle postural

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Assessment of Regional Bone Density in Fractured Vertebrae Using Quantitative Computed Tomography

Study DesignCohort study.PurposeThe aim of this study is to propose and evaluate a new technique to assess bone mineral density of fractured vertebrae using quantitative computed tomography (QCT).Overview of LiteratureThere is no available technique to estimate bone mineral density (BMD) at the fractured vertebra because of the alterations in bony structures at the fracture site.MethodsForty patients with isolated fracture from T10 to L2 were analyzed from the vertebrae above and below the fracture level. Apparent density (AD) was measured based on the relationship between QCT images attenuation coefficients and the density of calibration objects. AD of 8 independent regions of interest (ROI) within the vertebral body and 2 ROI within the pedicles of vertebrae above and below the fractured vertebra were measured. At the level of the fractured vertebra, AD was measured at the pedicles, which are typically intact. AD of the fractured vertebral body was linearly interpolated, based on the assumption that AD at the fractured vertebra is equivalent to the average AD measured in vertebrae adjacent to the fracture. Estimated and measured AD of the pedicles at the fractured level were compared to verify our assumption of linear interpolation from adjacent vertebrae.ResultsThe difference between the measured and the interpolated density of the pedicles at the fractured vertebra was 0.006 and 0.003 g/cm3 for right and left pedicle respectively. The highest mean AD located at the pedicles and the lowest mean AD was found at the anterior ROI of the vertebral body. Significant negative correlation exist between age and AD of ROI in the vertebral body.ConclusionsThis study suggests that the proposed technique is adequate to estimate the AD of a fractured vertebra from the density of adjacent vertebrae

Reliability and development of a new classification of lumbosacral spondylolisthesis

A classification of lumbosacral spondylolisthesis has been proposed recently. This classification describes eight distinct types of spondylolisthesis based on the slip grade, the degree of dysplasia, and the sagittal sacro-pelvic balance. The objectives of this study are to assess the reliability of this classification and to propose a new and refined classification. Standing posteroanterior and lateral radiographs of the spine and pelvis of 40 subjects (22 low-grade, 18 high-grade) with lumbosacral spondylolisthesis were reviewed twice by six spine surgeons. Each radiograph was classified based on the slip grade, the degree of dysplasia, and the sagittal sacro-pelvic balance. No measurements from the radiographs were allowed. Intra- and inter-observer reliability was assessed using kappa coefficients. A refined classification is proposed based on the reliability study. All eight types of spondylolisthesis described in the original classification were identified. Overall intra- and inter-observer agreement was respectively 76.7% (kappa: 0.72) and 57.0% (kappa: 0.49). The specific intra-observer agreement was 97.1% (kappa: 0.94), 85.0% (kappa: 0.69) and 88.8% (kappa: 0.85) with respect to the slip grade, the degree of dysplasia, and the sacro-pelvic balance, respectively. The specific inter-observer agreement was 95.2% (kappa: 0.90), 72.2% (kappa: 0.43) and 77.2% (kappa: 0.69) with respect to the slip grade, the degree of dysplasia, and the sacro-pelvic balance, respectively. This study confirmed that surgeons can classify radiographic findings into all eight types of spondylolisthesis. The intra-observer reliability was substantial, while the inter-observer reliability was moderate mainly due to the difficulty in distinguishing between low- and high-dysplasia. A refined classification excluding the assessment of dysplasia, while incorporating the assessment of the slip grade, sacro-pelvic balance and global spino-pelvic balance is proposed, and now includes five types of lumbosacral spondylolisthesis

A Modified Sagittal Spine Postural Classification and Its Relationship to Deformities and Spinal Mobility in a Chinese Osteoporotic Population

BACKGROUND: Abnormal posture and spinal mobility have been demonstrated to cause functional impairment in the quality of life, especially in the postmenopausal osteoporotic population. Most of the literature studies focus on either thoracic kyphosis or lumbar lordosis, but not on the change of the entire spinal alignment. Very few articles reported the spinal alignment of Chinese people. The purpose of this study was threefold: to classify the spinal curvature based on the classification system defined by Satoh consisting of the entire spine alignment; to identify the change of trunk mobility; and to relate spinal curvature to balance disorder in a Chinese population. METHODOLOGY/PRINCIPAL FINDINGS: 450 osteoporotic volunteers were recruited for this study. Spinal range of motion and global curvature were evaluated noninvasively using the Spinal-Mouse® system and sagittal postural deformities were characterized. RESULTS: We found a new spine postural alignment consisting of an increased thoracic kyphosis and decreased lumbar lordosis which we classified as our modified round back. We did not find any of Satoh's type 5 classification in our population. Type 2 sagittal alignment was the most common spinal deformity (38.44%). In standing, thoracic kyphosis angles in types 2 (58.34°) and 3 (58.03°) were the largest and lumbar lordosis angles in types 4 (13.95°) and 5 (-8.61°) were the smallest. The range of flexion (ROF) and range of flexion-extension (ROFE) of types 2 and 3 were usually greater than types 4 and 5, with type 1 being the largest. CONCLUSIONS/SIGNIFICANCE: The present study classified and compared for the first time the mobility, curvature and balance in a Chinese population based on the entire spine alignment and found types 4 and 5 to present the worst balance and mobility. This study included a new spine postural alignment classification that should be considered in future population studies

Spondylolisthésis et spondylolyse (Adulte et pédiatrique)

Par définition, la spondylolyse est une solution de continuité de l’arc postérieur de la vertèbre. Le spondylolisthésis est le glissement antérieur (ou postérieur) d’une vertèbre sur une autre (fig. 2). Dans le cadre de ce chapitre, nous nous limitons aux formes présentant une anomalie de l’arc postérieur. Cette anomalie doit être entendue comme non dégénérative, non traumatique, non pathologique et non iatrogénique