Progression of Sagittal plane deformity and axial vertebral rotation in adolescent idiopathic scoliosis using magnetic resonance imaging (original) (raw)
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2018
Adolescent Idiopathic Scoliosis (AIS) is a three-dimensional (3D) spinal deformity affecting 0.47-5.2% of the population and is up to ten times more common in females than males. Although there are multiple types of scoliosis, AIS is the most prevalent type, accounting for 80% of cases. With increased severity of the scoliotic curve, some patients will require treatment either with bracing or spinal instrumentation, with the latter being associated with significant risks and reduced spinal flexibility. For this reason, early diagnosis and sound understanding of the 3D pathoanatomy associated with AIS, is paramount in optimal treatment outcomes. Few studies have analysed multi-dimensional anatomical changes in the vertebrae in a large cohort and prospectively over a period of time. To understand how the sagittal and axial plane deformity changes with curve progression, this study used a sequential series of magnetic resonance images (MRI) for both AIS participants and non-scoliotic controls. Wedge angles, vertebral body (VB) heights, axial vertebral rotation (AVR) and thoracic kyphosis were compared at three time-points during adolescent growth. This study found a significant hypokyphosis already evident at MRI scan 1 in the AIS cohort, and subsequent reduction or very modest increase in kyphosis over the subsequent MRI scans, when compared to non-scoliotic control participants. Further contributing factors to the scoliotic deformity include a failure of progression of an anterior wedge of VBs and a relative slower growth rate of the posterior VB height. There was an observed reduction in axial vertebral rotation (AVR) three levels above and below the apex of the curve which may indicate the transition to a compensatory curve in the scoliotic deformity. Intravertebral rotation (IVR) had a greater progressive change at periapical levels when compared to the apex, which may contribute to the non-uniform de-rotation achieved following instrumented fusion surgery. Overall this study contributes to the understanding of spinal deformity progression in AIS patients, which will hopefully aid in therapeutic planning and optimise treatment outcomes.
Progression of Vertebral and Spinal Three-Dimensional Deformities in Adolescent Idiopathic Scoliosis
Spine, 2001
Study Design. The evolution of scoliotic descriptors was analyzed from three-dimensionally reconstructed spines and assessed statistically in a group of adolescents with progressive idiopathic scoliosis. Objectives. To conduct an intrasubject longitudinal study quantifying evolution of two-and three-dimensional geometrical descriptors characterizing the scoliotic spine and vertebral deformities. Summary of Background Data. The data available on geometric descriptors usually are based on cross-sectional studies comparing scoliotic configurations of different individuals. The literature reports very few longitudinal studies that evaluated different phases of scoliotic progression in the same patients. Methods. The evolution of regional and local descriptors between two scoliotic visits was analyzed in 28 adolescents with scoliosis. Several statistical analyses were performed to determine how spinal curvatures and vertebral deformities change during scoliosis progression. Results. At the thoracic level, vertebral wedging increases with curve severity in a relatively consistent pattern for most patients with scoliosis. Axial rotation mainly increases toward curve convexity with scoliosis severity, worsening the progression of vertebral body deformities. No consistent evolution is associated with the angular orientation of the maximum wedging. Thoracic kyphosis varies considerably among subjects. Both increasing and decreasing kyphosis are observed in nonnegligible proportions. A decrease in kyphosis is associated with a shift in the plane of maximum deformity toward the frontal plane, which worsens the three-dimensional shape of the spine. Conclusions. The results of this study challenge the existence of a typical scoliotic evolution pattern and suggest that scoliotic evolution is quite variable and patient specific.
European Spine Journal, 1999
This is a prospective study comparing the short-and long-term three-dimensional (3D) changes in shape, length and balance of the spine after spinal instrumentation and fusion in a group of adolescents with idiopathic scoliosis. The objective of the study was to evaluate the stability over time of the postoperative changes of the spine after instrumentation with multi rod, hook and screw instrumentation systems. Thirty adolescents (average age: 14.5 ± 1.6 years) undergoing surgery by a posterior approach had computerized 3D reconstructions of the spine done at an average of 3 days preoperatively (stage I), and 2 months (stage II) and 2,5 years (stage III) after surgery, using a digital multi-planar radiographic technique. Stages I, II and III were compared using various geometrical parameters of spinal length, curve severity, and orientation. Significant improvement of curve magnitude between stages I and II was documented in the frontal plane for thoracic and lumbar curves, as well as in the orientation of the plane of maximum deformity, which was significantly shifted towards the sagittal plane in thoracic curves. However, there was a significant loss of this
Spine, 2014
Study Design. Cross-sectional study. Objective. To compare the relative contribution of the vertebral bodies and intervertebral discs with the 3-dimensional spinal deformity in adolescent idiopathic scoliosis. Summary of Background Data. There is an ongoing discussion about the causal role of skeletal growth processes in the etiopathogenesis of adolescent idiopathic scoliosis. Contradictory fi ndings have been reported on the individual contribution of the vertebral bodies as compared with the discs to the coronal deformity. As far as we know, the true 3-dimensional deformity of the discs and vertebral bodies have not yet been described. Methods. High-resolution computed tomographic scans of 77 patients with severe adolescent idiopathic scoliosis were included. Torsion and anterior-posterior and right-left asymmetry of each individual vertebral body and intervertebral disc were studied from T2 to L5, using semiautomatic analysis software. True transverse sections were reconstructed along the anterior-posterior and rightleft axis of all endplates. These "endplate-vectors" were calculated semiautomatically, taking rotation and tilt into account. Torsion was l.
Upright, prone, and supine spinal morphology and alignment in adolescent idiopathic scoliosis
Scoliosis and spinal disorders, 2017
Patients with adolescent idiopathic scoliosis (AIS) are usually investigated by serial imaging studies during the course of treatment, some imaging involves ionizing radiation, and the radiation doses are cumulative. Few studies have addressed the correlation of spinal deformity captured by these different imaging modalities, for which patient positioning are different. To the best of our knowledge, this is the first study to compare the coronal, axial, and sagittal morphology of the scoliotic spine in three different body positions (upright, prone, and supine) and between three different imaging modalities (X-ray, CT, and MRI). Sixty-two AIS patients scheduled for scoliosis surgery, and having undergone standard pre-operative work-up, were included. This work-up included upright full-spine radiographs, supine bending radiographs, supine MRI, and prone CT as is the routine in one of our institutions. In all three positions, Cobb angles, thoracic kyphosis (TK), lumbar lordosis (LL), ...
Idiopathic scoliosis: A pilot MR study of early vertebral morphological changes and spinal asymmetry
Journal of Orthopaedics, 2019
Adolescent idiopathic scoliosis (AIS) a common spinal condition affecting adolescents. Though the etiology is still unknown, it is widely thought to have a multifactorial etiology and early diagnosis remains a significant challenge. The purpose of this study is to identify early vertebral morphological changes and patterns of spinal asymmetry in these at-risk individuals who later progress to adolescent idiopathic scoliosis. This was a retrospective study of patients treated for AIS between 1997 and 2017. We utilized two study groups, a group with immature onset of spinal asymmetry and a control group. Inclusion criteria for the immature onset group was defined by a Cobb angle between 10 and 40°diagnosed prior to the age of 12 with MRI scans and XRs available for review. Qualitative assessments observed for sagittal vertebral wedging, analysis of vertebral corner anatomy, spinal harmony, and sagittal balance. These findings were then qualitatively compared between groups. Twenty patients were included in this study, ten each in the immature onset and control groups. In the immature onset group, two patients had sagittal wedging, five had abnormal vertebral corners, nine did not have spinal harmony, and nine had negative sagittal balance, compared to none of the control patients having sagittal wedging, none having abnormal vertebral corners, all having spinal harmony, and nine having positive spinal balance. This pilot MRI study identifies qualitative vertebral morphological changes in patients who progress to AIS. Our findings suggest abnormal vertebral corner anatomy, sagittal wedging, and negative sagittal balance as potential early findings in patients who develop AIS.
Journal of Orthopaedic Surgery and Research, 2014
Background: Previous studies have demonstrated that pelvic incidence and sacral slope are significantly greater in idiopathic scoliosis patients compared with normal adolescents. However, whether these sagittal parameters are related to the progression of scoliosis remain unknown. The present was designed to determine the differences in the sagittal profiles among thoracic idiopathic scoliosis patients with different potentials for curve progression. Methods: Ninety-seven outpatient idiopathic scoliosis patients enrolled from June 2008 to June 2011 were divided to three groups according to different Cobb angles and growth potentials: (1) non-progression of thoracic curve group, Risser sign of 5 and Cobb's angle < 40°; (2) moderate progression of thoracic curve group, Risser sign of 5 and Cobb's angle ≥ 40°; and (3) severe progression of thoracic curve group, Risser sign ≤ 3 and Cobb's angle ≥ 40°. All patients underwent whole spinal anteroposterior and lateral X-ray in standing position, and the sagittal parameters were measured, including thoracic kyphosis, lumbar lordosis, sacral slope, pelvic incidence, and pelvic tilt. Results: The average thoracic scoliosis Cobb's angle in the non-progression group was significantly less than that in the moderate progression group (P < 0.01) and severe progression group (P < 0.01), but there was no statistical difference in the average thoracic scoliosis Cobb's angle between the severe progression group and moderate progression group. The average thoracic kyphosis angle in the severe progression group (9°± 4°) was significantly smaller than that in the non-progression group (18°± 6°, P < 0.01) and moderate progression group (14°± 5°, P < 0.05). No statistical differences were present in the average lumbar lordosis, sacral slope, pelvic incidence, and pelvic tilt among the three groups. Conclusions: Thoracic hypokyphosis is strongly related with the curve progression in thoracic idiopathic scoliosis patients, but not pelvic sagittal profiles.
Global malalignment in adolescent idiopathic scoliosis: the axial deformity is the main driver
European Spine Journal, 2022
Purpose To evaluate the global alignment of non-operated subjects with adolescent idiopathic scoliosis. Method A total of 254 subjects with AIS and 64 controls underwent low dose biplanar X-rays and had their spine, pelvis, and rib cage reconstructed in 3D. Global alignment was measured in the sagittal and frontal planes by calculating the OD-HA angle (between C2 dens to hip axis with the vertical). Subjects with AIS were classified as malaligned if the OD-HA was > 95th percentile relative to controls. Results The sagittal OD-HA in AIS remained within the normal ranges. In the frontal plane, 182 AIS were normally aligned (Group 1, OD-HA = 0.9°) but 72 were malaligned (Group 2, OD-HA = 2.9°). Group 2 had a more severe spinal deformity in the frontal and horizontal planes compared to Group 1 (Cobb: 42 ± 16° vs. 30 ± 18°; apical vertebral rotation AVR: 19 ± 10° vs. 12 ± 7°, all p < 0.05). Group 2 subjects were mainly classified as Lenke 5 or 6. 19/72 malaligned subjects had a mild deformity (Cobb < 30°) but a progressive scoliosis (severity index ≥ 0.6). The frontal OD-HA angle was found to be mainly determined (adjusted-R 2 = 0.22) by the apical vertebral rotation and secondarily by the Lenke type. Conclusions This study showed that frontal malalignment is more common in distal major structural scoliosis and its main driver is the apical vertebral rotation. This highlights the importance of monitoring the axial plane deformity in order to avoid worsening of the frontal global alignment.
Medical & biological engineering & computing, 2016
Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity of unknown aetiology. Increased growth of the anterior part of the vertebrae known as anterior overgrowth has been proposed as a potential driver for AIS initiation and progression. To date, there has been no objective evaluation of the 3D measurement techniques used to identify this phenomenon and the majority of previous studies use 2D planar assessments which contain inherent projection errors due to the vertebral rotation which is part of the AIS deformity. In this study, vertebral body (VB) heights and wedge angles were measured in a test group of AIS patients and healthy controls using four different image analysis and measurement techniques. Significant differences were seen between the techniques in terms of VB heights and VB wedge angles. The low variability, and the fact that the rotation and tilt of the deformed VBs are taken into account, suggests that the proposed technique using the full...