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Grivas TB, Vasiliadis E, Mazioti C, Papagianni D, Mamzeri A, Chandrinos M, Vynichakis G, Athanasopoulos K, Christodoulides P, Jevtic N, Pjanic S, Ljubojevic D, Savvidou O, Kaspiris A, Grunstein J. Are the Spinal Changes in the Course of Scoliogeny Primary but Secondary? J Clin Med 2024; 13:2163. [PMID: 38673436 PMCID: PMC11051170 DOI: 10.3390/jcm13082163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/03/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024] Open
Abstract
In this opinion article, there is an analysis and discussion regarding the effects of growth on the spinal and rib cage deformities, the role of the rib cage in scoliogeny, the lateral spinal profile in adolescent idiopathic scoliosis (AIS), the genetics and epigenetics of AIS, and the interesting and novel field investigating the sleep impact at nighttime on AIS in relation to the sequence of the scoliogenetic changes in scoliotics. The expressed opinions are mainly based on the published peer-reviewed research of the author and his team of co-authors. Based on the analysis noted above, it can be postulated that the vertebral growth changes in the spine during initial idiopathic scoliosis (IS) development are not primary-intrinsic but secondary changes. The primary cause starting the deformity is not located within the vertebral bodies. Instead, the deformations seen in the vertebral bodies are the secondary effects of asymmetrical loads exerted upon them, due to muscular loads, growth, and gravity.
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Affiliation(s)
- Theodoros B. Grivas
- Trauma and Orthopaedic Department, Former Head, “Tzaneio” General Hospital of Piraeus, 185 36 Piraeus, Greece
| | - Elias Vasiliadis
- 3rd Department of Orthopaedics, School of Medicine, National and Kapodistrian University of Athens, KAT Hospital, 145 61 Athens, Greece; (E.V.); (A.K.)
| | | | | | | | - Michail Chandrinos
- Orthopedic Department, Gen. Hospital of Argolida-N.M. Argous, 212 00 Argos, Greece; (M.C.); (G.V.)
| | - George Vynichakis
- Orthopedic Department, Gen. Hospital of Argolida-N.M. Argous, 212 00 Argos, Greece; (M.C.); (G.V.)
| | | | | | - Nikola Jevtic
- Scolio Centar, 403916 Novi Sad, Serbia; (N.J.); (D.L.)
| | - Samra Pjanic
- Department of Paediatric Rehabilitation, Institute for Physical, Rehabilitation Medicine and Orthopaedic Surgery “Dr Miroslav Zotovic”, 78000 Banja Luka, Bosnia and Herzegovina;
| | | | - Olga Savvidou
- First Department of Orthopaedic Surgery, School of Medicine, National and Kapodistrian University of Athens, “ATTIKON” University General Hospital, Rimini 1, 124 62 Athens, Greece;
| | - Angelos Kaspiris
- 3rd Department of Orthopaedics, School of Medicine, National and Kapodistrian University of Athens, KAT Hospital, 145 61 Athens, Greece; (E.V.); (A.K.)
- Laboratory of Molecular Pharmacology, Department of Pharmacy, School of Health Sciences, University of Patras, 265 04 Patras, Greece
| | - Jarrett Grunstein
- Chiropractic Center Livingston, 340 E Northfield Rd # 2E, Livingston, NJ 07039, USA;
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Foltz MH, Johnson CP, Truong W, Polly DW, Ellingson AM. Morphological alterations of lumbar intervertebral discs in patients with adolescent idiopathic scoliosis. Spine J 2024; 24:172-184. [PMID: 37611875 PMCID: PMC10843277 DOI: 10.1016/j.spinee.2023.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 07/26/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023]
Abstract
BACKGROUND CONTEXT Etiology of adolescent idiopathic scoliosis (AIS) is still unknown. Prior in vitro research suggests intervertebral disc pathomorphology as a cause for the initiation and progression of the spinal deformity, however, this has not been well characterized in vivo. PURPOSE To quantify and compare lumbar disc health and morphology in AIS to controls. STUDY DESIGN/SETTING Cross-sectional study. METHODS All lumbar discs were imaged using a 3T MRI scanner. T2-weighted and quantitative T2* maps were acquired. Axial slices of each disc were reconstructed, and customized scripts were used to extract outcome measurements: Nucleus pulposus (NP) signal intensity and location, disc signal volume, transition zone slope, and asymmetry index. Pearson's correlation analysis was performed between the NP location and disc wedge angle for AIS patients. ANOVAs were utilized to elucidate differences in disc health and morphology metrics between AIS patients and healthy controls. α=0.05. RESULTS There were no significant differences in disc health metrics between controls and scoliotic discs. There was a significant shift in the NP location towards the convex side of the disc in AIS patients compared to healthy controls, with an associated increase of the transition zone slope on the convex side. Additionally, with increasing disc wedge angle, the NP center migrated towards the convex side of the disc. CONCLUSIONS The present study elucidates morphological distinctions of intervertebral discs between healthy adolescents and those diagnosed with AIS. Discs in patients diagnosed with AIS are asymmetric, with the NP shifted towards the convex side, which was exacerbated by an increased disc wedge angle. CLINICAL SIGNIFICANCE Investigation of the MRI signal distribution (T2w and T2* maps) within the disc suggests an asymmetric pressure gradient shifting the NP laterally towards the convexity. Quantifying the progression of these morphological alterations during maturation and in response to treatment will provide further insight into the mechanisms of curve progression and correction, respectively.
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Affiliation(s)
- Mary H Foltz
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota
| | - Casey P Johnson
- Department of Veterinary Clinical Sciences, University of Minnesota; Center for Magnetic Resonance Research, University of Minnesota
| | - Walter Truong
- Gillette Children's Specialty Healthcare; Department of Orthopedic Surgery, University of Minnesota
| | - David W Polly
- Department of Orthopedic Surgery, University of Minnesota
| | - Arin M Ellingson
- Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota; Department of Orthopedic Surgery, University of Minnesota; Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota.
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Wang H, Sun Z, Wang L, Zou D, Li W. Proximal Fusion Level Above First Coronal Reverse Vertebrae: An Essential Factor Decreasing the Risk of Adjacent Segment Degeneration in Degenerative Lumbar Scoliosis. Global Spine J 2023; 13:149-155. [PMID: 33648368 PMCID: PMC9837505 DOI: 10.1177/2192568221994082] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
STUDY DESIGN Retrospective radiological analysis. OBJECTIVE To explore whether proximal fusion level above first coronal reverse vertebrae (FCRV) could decrease risk of adjacent segment degeneration (ASD) in degenerative lumbar scoliosis (DLS). METHODS One hundred and 16 DLS patients were divided into 2 groups according to occurrence of ASD: study group (ASD positive group) and control group (ASD negative group). FCRV was defined as the first vertebrae that presents opposite orientation of asymmetric Hounsfield unit (HU) ratio from the other vertebrae within major curve. Incidence of ASD was evaluated in subgroups according to location between FCRV and upper instrumented vertebrae (UIV). RESULTS The fusion level was shorter in study group than that in control group. There were 12 patients presented FCRV 2-level proximal than SV, 32 patients presented FCRV 1-level proximal than SV, 35 patients presented the same vertebra of FCRV with SV, 23 patients presented FCRV 1-level distal than SV, 14 patients presented FCRV 2-level distal than SV. When UIV located above FCRV, no patient presented ASD, while 15.4% patients presented ASD when UIV located on FCRV. In study group, proximal scoliosis progression was detected in 1 patient (3.9%) when UIV located on FCRV, and 17 patients (29.8%) when UIV located below FCRV. CONCLUSIONS Proximal fusion level above FCRV could decrease the risk of ASD in DLS, especially for the proximal scoliosis progression. FCRV represent the transitional point of the mechanical load on coronal plane, and may be within a more stable condition than stable vertebrae measured from radiographs.
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Affiliation(s)
- Hui Wang
- Orthopaedic Department of Peking
University Third Hospital, Beijing, China,Beijing Key Laboratory of Spinal Disease
Research, Beijing, China,Engineering Research Center of Bone and
Joint Precision Medicine, Ministry of Education, Beijing, China
| | - Zhuoran Sun
- Orthopaedic Department of Peking
University Third Hospital, Beijing, China,Beijing Key Laboratory of Spinal Disease
Research, Beijing, China,Engineering Research Center of Bone and
Joint Precision Medicine, Ministry of Education, Beijing, China
| | - Longjie Wang
- Orthopaedic Department of Peking
University Third Hospital, Beijing, China,Beijing Key Laboratory of Spinal Disease
Research, Beijing, China,Engineering Research Center of Bone and
Joint Precision Medicine, Ministry of Education, Beijing, China
| | - Da Zou
- Orthopaedic Department of Peking
University Third Hospital, Beijing, China,Beijing Key Laboratory of Spinal Disease
Research, Beijing, China,Engineering Research Center of Bone and
Joint Precision Medicine, Ministry of Education, Beijing, China
| | - Weishi Li
- Orthopaedic Department of Peking
University Third Hospital, Beijing, China,Beijing Key Laboratory of Spinal Disease
Research, Beijing, China,Engineering Research Center of Bone and
Joint Precision Medicine, Ministry of Education, Beijing, China,Weishi Li, MD, Orthopaedic Department of
Peking University Third Hospital, No 49. North Garden Street, HaiDian District
100191, Beijing, China.
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Cheng Y, Yang H, Hai Y, Pan A, Zhang Y, Zhou L. Hounsfield unit for assessing asymmetrical loss of vertebral bone mineral density and its correlation with curve severity in adolescent idiopathic scoliosis. Front Surg 2022; 9:1000031. [PMID: 36211282 PMCID: PMC9535087 DOI: 10.3389/fsurg.2022.1000031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundLow bone mass concomitantly occurs in patients with adolescent idiopathic scoliosis (AIS) and can persist until skeletal maturity. The purpose of this study was to assess the asymmetrical loss of vertebral bone mineral density (vBMD) and its correlation with curve severity in patients with AIS using Hounsfield unit (HU) values measured from computed tomography scans.MethodsA total of 93 AIS patients were retrospectively recruited. The HU values of the vertebral body (VB-HU) and pedicle screw trajectory (PST-HU) were measured from four vertebrae above (Apex − 4) to four below (Apex + 4) the apical vertebra (Apex) of the major curve. The VB-HU and PST-HU at the upper end vertebra, Apex, and lower end vertebra within the concave and convex sides of the major and minor curves and stable vertebrae were obtained.ResultsA significant correlation was found between the Cobb angle and VB-HU at the periapical levels of the major curve. VB-HU and PST-HU at periapical levels were significantly greater within the concavity than the convexity of both major and minor curves. The asymmetric ratios of VB-HU and PST-HU were significantly correlated with the major curve Cobb angle, peaked at the apex, and gradually diminished from the apex to the end vertebrae. The asymmetrical loss of vBMD aggravated with the progression of curve severity, presenting as VB-HU, significantly decreased within the convexity and insignificantly decreased within the concavity of the major curve.ConclusionThe asymmetrical loss of vBMD was associated with the progression of curve severity in AIS. For patients with severe AIS, the distraction of the pedicle screws at the concave side should be a priority in correcting the major curve, and supplemental anchors and larger-sized screws should be placed within the convex side around the apex of the major curve to reduce the risk of screw loosening after surgery.
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Affiliation(s)
| | | | - Yong Hai
- Correspondence: Yong Hai , Lijin Zhou
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Morphological changes of Intervertebral Disc detectable by T2-weighted MRI and its correlation with curve severity in Adolescent Idiopathic Scoliosis. BMC Musculoskelet Disord 2022; 23:655. [PMID: 35818045 PMCID: PMC9275276 DOI: 10.1186/s12891-022-05561-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 06/17/2022] [Indexed: 12/29/2022] Open
Abstract
Background Our previous studies found disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves in adolescent idiopathic scoliosis (AIS) patients. Subsequent studies showed wedging of vertebral bodies (VB) had less contribution than intervertebral discs (IVD) to the anterior–posterior vertebral column length discrepancy in severe-AIS. However, the exact morphological changes of IVD were not clearly defined. This study aimed to evaluate the morphological and pathological changes of IVD and VB in AIS girls and healthy female controls. Methods This study included 33 age-matched female controls and 76 AIS girls with a right-sided thoracic curvature. Wedge angle, height ratio and distance ratio of VB and IVD were measured on the best midline coronal and sagittal planes from reformatted MRI spine. Volumes of VB, IVD and nucleus pulposus (NP) were also evaluated on volumetric images. One-way ANOVA with Bonferroni correction and Pearson correlation tests were used. Results There was significant difference in wedge angle and height ratio of VB and IVD between AIS and controls. In severe-AIS, the position of NP was significantly shifted to the convexity when compared with non-severe AIS and controls. Whereas, the volume of IVD and NP in severe-AIS was found to be significantly smaller. In addition, Cobb angle was significantly correlated with wedge angle and height ratio, and inversely correlated with the volume of NP. Conclusions In addition to wedging of VB and IVD, there was significantly reduced volume of IVD and NP in AIS patients with severe curve, insinuating the mechanical effect of scoliosis leads to a compression on both IVD and NP before significant disc desiccation occurs. We postulate that the compression of IVD and NP can contribute to curve progression in severe-AIS, these patients are more prone to disc degeneration in adulthood if no operative treatment is offered. Further longitudinal study on these parameters is still warranted.
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Hounsfield Unit for Assessing Vertebral Bone Quality and Asymmetrical Vertebral Degeneration in Degenerative Lumbar Scoliosis. Spine (Phila Pa 1976) 2020; 45:1559-1566. [PMID: 32756284 DOI: 10.1097/brs.0000000000003639] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Retrospective analysis. OBJECTIVES The aim of this study was to demonstrate the correlation between degenerative lumbar scoliosis (DLS) and osteoporosis based on Hounsfield unit (HU) measurement from computed tomography (CT) scans, and to investigate the asymmetrical vertebral degeneration in DLS. SUMMARY OF BACKGROUND DATA The correlation between DLS and osteoporosis measured by dual-energy x-ray absorptiometry (DEXA) is debated, since T-scores measured by DEXA scan can be overestimated due to abdominal vessel wall calcification, degenerative bony spurs, and facet hypertrophy. The reliability and accuracy of HU to determine osteoporosis are shown in many reports, but it has never been used to assess the vertebral bone quality for DLS patients. METHODS Nighty-five DLS patients were retrospectively reviewed. Regions of interest for HU were measured on three coronal images of the lumbar vertebrae. HU measurement of the whole vertebrae from L1 to L5 was obtained, then HU measurement within concave and convex sides were obtained separately in L5, upper and lower end vertebrae, apex vertebrae, neutral vertebrae, stable vertebrae. RESULTS HU value presented a gradually increasing trend from L1 to L5. No correlation was detected between Cobb angle and mean HU value of the 5 lumbar vertebrae, or between Cobb angle and HU value of every lumbar vertebrae separately. HU value was higher within concavity than that within convexity of the same vertebrae both in major and compensatory curve. Asymmetric HU ratio in apex vertebrae positively correlated with Cobb angle. Stable vertebrae were the first proximal vertebrae that present opposite orientation of asymmetric HU ratio from the other lumbar vertebrae. CONCLUSION Progression of degenerative scoliosis presents no correlation with osteoporosis based on HU measurement but could increase the asymmetrical vertebral degeneration, especially in apex vertebrae. Distraction of the pedicle screws at concave side, instead of compression of pedicle screws at convex side, should be a priority to correct lumbosacral curve. LEVEL OF EVIDENCE 3.
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Chevrefils C, Périé D, Parent S, Cheriet F. To distinguish flexible and rigid lumbar curve from MRI texture analysis in adolescent idiopathic scoliosis: A feasibility study. J Magn Reson Imaging 2017; 48:178-187. [PMID: 29281150 DOI: 10.1002/jmri.25926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/30/2017] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Imaging in side bending, supine, traction, fulcrum, and push prone are examples of methods used to evaluate the curve reduction of scoliotic spine. However, being able to determine spine curve flexibility from MRI would eliminate the need of additional X-ray radiation related to radiograph acquisition in side-bending. PURPOSE/HYPOTHESIS To find specific texture features of lumbar postural muscles on MRI that can distinguish flexible from rigid lumbar scoliotic curves. We hypothesized that the changes occurring in postural muscles with scoliosis can be seen with MRI. STUDY TYPE Retrospective study case control. POPULATION With Institutional Review Board approval and informed consent, 15 adolescents with idiopathic scoliosis and scheduled for surgery were involved. FIELD STRENGTH/SEQUENCE T1 -weighted MR images were performed on a 1.5T system using a spin echo sequence in the axial direction. ASSESSMENT The spinal erector, quadratus lumborum and psoas major muscles were analyzed using textural features. STATISTICAL TESTS Principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were used to classify the lumbar postural muscles and calculate performance metrics. The lumbar flexibility index, measured from suspension tests, was used as ground truth measurement. RESULTS The five discriminant features (out of 34 tested features) obtained from PCA were able to keep over 90% of the variability of the dataset. The right and left spinal erector and the left psoas major had the highest performance metrics to classify the spinal curve flexibility, with an accuracy over 0.80, a sensitivity over 0.82, a specificity over 0.68, and a Matthews correlation coefficient over 0.57. DATA CONCLUSION This study analyzed MRI using texture information of muscle to distinguish flexible from rigid scoliotic curves. Some postural muscle such as the spinal erector and the psoas major are more likely to reflect the curve flexibility of a scoliotic participant. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017.
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Affiliation(s)
- Claudia Chevrefils
- Computer Engineering Department, École Polytechnique de Montréal, Montreal, Canada.,Research Center, Sainte-Justine University Hospital, Montreal, Canada
| | - Delphine Périé
- Research Center, Sainte-Justine University Hospital, Montreal, Canada.,Mechanical Engineering Department, École Polytechnique de Montréal, Montreal, Canada
| | - Stefan Parent
- Research Center, Sainte-Justine University Hospital, Montreal, Canada
| | - Farida Cheriet
- Computer Engineering Department, École Polytechnique de Montréal, Montreal, Canada.,Research Center, Sainte-Justine University Hospital, Montreal, Canada
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Gervais J, Périé D, Aubin CÉ. Sensitivity of MRI signal distribution within the intervertebral disc to image segmentation and data normalisation. Comput Methods Biomech Biomed Engin 2013; 17:1383-90. [PMID: 23432015 DOI: 10.1080/10255842.2012.748756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
There is a lack of early biomarkers of intervertebral disc (IVD) degeneration. Thus, the authors developed the analysis of magnetic resonance signal intensity distribution (AMRSID) method to analyse the 3D distribution of the T2-weighted MR signal intensity within the IVD using normalised histograms, weighted centres and volume ratios. The objective was to assess the sensitivity of the AMRSID method to the segmentation process and data normalisation. Repetition of the semi-automatic segmentation by the same operator did not influence the quality of the contour or our new MR distribution parameters whereas the skills of the operator influenced only the MR distribution parameters, and the instructions given prior to the segmentation influenced both the quality of the contour and the MR distribution parameters. Bone normalisation produces an index that jointly highlights IVD and bone health, whereas cerebrospinal fluid normalisation only suppresses the effect of the acquisition gain. This robust AMRSID method has the potential to improve the diagnostic with earlier biomarkers and the prognosis of evolution.
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Affiliation(s)
- Julien Gervais
- a Department of Mechanical Engineering , Ecole Polytechnique , Montréal , Québec , Canada
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Gervais J, Périé D, Parent S, Labelle H, Aubin CE. MRI signal distribution within the intervertebral disc as a biomarker of adolescent idiopathic scoliosis and spondylolisthesis. BMC Musculoskelet Disord 2012. [PMID: 23206365 PMCID: PMC3551775 DOI: 10.1186/1471-2474-13-239] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background Early stages of scoliosis and spondylolisthesis entail changes in the intervertebral disc (IVD) structure and biochemistry. The current clinical use of MR T2-weighted images is limited to visual inspection. Our hypothesis is that the distribution of the MRI signal intensity within the IVD in T2-weighted images depends on the spinal pathology and on its severity. Therefore, this study aims to develop the AMRSID (analysis of MR signal intensity distribution) method to analyze the 3D distribution of the MR signal intensity within the IVD and to evaluate their sensitivity to scoliosis and spondylolisthesis and their severities. Methods This study was realized on 79 adolescents who underwent a MRI acquisition (sagittal T2-weighted images) before their orthopedic or surgical treatment. Five groups were considered: low severity scoliosis (Cobb angle ≤50°), high severity scoliosis (Cobb angles >50°), low severity spondylolisthesis (Meyerding grades I and II), high severity spondylolisthesis (Meyerding grades III, IV and V) and control. The distribution of the MRI signal intensity within the IVD was analyzed using the descriptive statistics of histograms normalized by either cerebrospinal fluid or bone signal intensity, weighted centers and volume ratios. Differences between pathology and severity groups were assessed using one- and two-way ANOVAs. Results There were significant (p < 0.05) variations of indices between scoliosis, spondylolithesis and control groups and between low and high severity groups. The cerebrospinal fluid normalization was able to detect differences between healthy and pathologic IVDs whereas the bone normalization, which reflects both bone and IVD health, detected more differences between the severities of these pathologies. Conclusions This study proves for the first time that changes in the intervertebral disc, non visible to the naked eye on sagittal T2-weighted MR images of the spine, can be detected from specific indices describing the distribution of the MR signal intensity. Moreover, these indices are able to discriminate between scoliosis and spondylolisthesis and their severities, and provide essential information on the composition and structure of the discs whatever the pathology considered. The AMRSID method may have the potential to complement the current diagnostic tools available in clinics to improve the diagnostic with earlier biomarkers, the prognosis of evolution and the treatment options of scoliosis and spondylolisthesis.
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Affiliation(s)
- Julien Gervais
- Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Canada.
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Swider P, Pédrono A, Ambard D, Accadbled F, Sales de Gauzy J. Substructuring and poroelastic modelling of the intervertebral disc. J Biomech 2010; 43:1287-91. [DOI: 10.1016/j.jbiomech.2010.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 11/01/2009] [Accepted: 01/27/2010] [Indexed: 10/19/2022]
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Abstract
STUDY DESIGN Longitudinal radiographic study of patients with progressive idiopathic scoliosis. OBJECTIVE To determine the relative contributions of vertebral and disc wedging to the increase in Cobb angle during 3 phases of adolescent skeletal growth and maturation. SUMMARY OF BACKGROUND DATA Both disc wedging and vertebral body wedging are found in progressive scoliosis, but their relative contribution to curve progression over time is unknown. Which occurs first is important for understanding how scoliosis progresses and for developing methods to halt progression. Previous studies have not properly identified maturity, and provide conflicting results. METHODS Eighteen girls were followed through their adolescent growth spurt with serial spine and hand skeletal age radiographs. Each Cobb angle was divided into disc wedge angles and vertebral wedge angles. The corresponding hand radiographs provided a measure of maturity level, the Digital Skeletal Age (DSA). The disc versus bone contributions to the Cobb angle were then compared during 3 growth phases: before the growth spurt, during the growth spurt and after the growth spurt. Significance of relative changes was assessed with the Wilcoxon 2-sided mean rank test. RESULTS Before the growth spurt, there was no difference in relative contributions of the disc and the bone (3 degrees vs. 0 degrees, P = 0.38) to curve progression. During the growth spurt, the mean disc component progressed significantly more than that of the vertebrae (15 degrees vs. 0 degrees, P = 0.0002). This reversed following the growth spurt with the vertebral component progressing more than the disc (10 degrees vs. 0 degrees, P = 0.01). CONCLUSION Adolescent idiopathic scoliosis initially increases through disc wedging during the rapid growth spurt with progressive vertebral wedging occurring later.
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Adam CJ, Askin GN. Lateral bone density variations in the scoliotic spine. Bone 2009; 45:799-807. [PMID: 19563925 DOI: 10.1016/j.bone.2009.06.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 05/17/2009] [Accepted: 06/22/2009] [Indexed: 11/26/2022]
Abstract
Adolescent Idiopathic Scoliosis (AIS) is the most common deformity of the spine, affecting 2-4% of the population. Previous studies have shown that the vertebrae in scoliotic spines undergo abnormal shape changes, however there has been little exploration of how scoliosis affects bone density distribution within the vertebrae. In this study, existing CT scans of 53 female idiopathic scoliosis patients with right-sided main thoracic curves were used to measure the lateral (right to left) bone density profile at mid-height through each vertebral body. Five key bone density profile measures were identified from each normalized bone density distribution, and multiple regression analysis was performed to explore the relationship between bone density distribution and patient demographics (age, height, weight, body mass index (BMI), skeletal maturity, time since Menarche, vertebral level, and scoliosis curve severity). Results showed a marked convex/concave asymmetry in bone density for vertebral levels at or near the apex of the scoliotic curve. At the apical vertebra, mean bone density at the left side (concave) cortical shell was 23.5% higher than for the right (convex) cortical shell, and cancellous bone density along the central 60% of the lateral path from convex to concave increased by 13.8%. The centre of mass of the bone density profile at the thoracic curve apex was located 53.8% of the distance along the lateral path, indicating a shift of nearly 4% toward the concavity of the deformity. These lateral bone density gradients tapered off when moving away from the apical vertebra. Multi-linear regressions showed that the right cortical shell peak bone density is significantly correlated with skeletal maturity, with each Risser increment corresponding to an increase in mineral equivalent bone density of 4-5%. There were also statistically significant relationships between patient height, weight and BMI, and the gradient of cancellous bone density along the central 60% of the lateral path. Bone density gradient is positively correlated with weight, and negatively correlated with height and BMI, such that at the apical vertebra, a unit decrease in BMI corresponds to an almost 100% increase in bone density gradient.
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Affiliation(s)
- Clayton J Adam
- Paediatric Spine Research Group, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
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Driscoll M, Aubin CE, Moreau A, Villemure I, Parent S. The role of spinal concave-convex biases in the progression of idiopathic scoliosis. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2009; 18:180-7. [PMID: 19130096 DOI: 10.1007/s00586-008-0862-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 10/01/2008] [Accepted: 12/14/2008] [Indexed: 11/26/2022]
Abstract
Inadequate understanding of risk factors involved in the progression of idiopathic scoliosis restrains initial treatment to observation until the deformity shows signs of significant aggravation. The purpose of this analysis is to explore whether the concave-convex biases associated with scoliosis (local degeneration of the intervertebral discs, nucleus migration, and local increase in trabecular bone-mineral density of vertebral bodies) may be identified as progressive risk factors. Finite element models of a 26 degrees right thoracic scoliotic spine were constructed based on experimental and clinical observations that included growth dynamics governed by mechanical stimulus. Stress distribution over the vertebral growth plates, progression of Cobb angles, and vertebral wedging were explored in models with and without the biases of concave-convex properties. The inclusion of the bias of concave-convex properties within the model both augmented the asymmetrical loading of the vertebral growth plates by up to 37% and further amplified the progression of Cobb angles and vertebral wedging by as much as 5.9 degrees and 0.8 degrees, respectively. Concave-convex biases are factors that influence the progression of scoliotic curves. Quantifying these parameters in a patient with scoliosis may further provide a better clinical assessment of the risk of progression.
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Affiliation(s)
- Mark Driscoll
- Ecole Polytechnique de Montréal, Biomedical Engineering Institute, P.O. Box 6079, Station Centre Ville, Montreal, QC H3C 3A7, Canada
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Violas P, Estivalezes E, Briot J, Sales de Gauzy J, Swider P. Quantification of intervertebral disc volume properties below spine fusion, using magnetic resonance imaging, in adolescent idiopathic scoliosis surgery. Spine (Phila Pa 1976) 2007; 32:E405-12. [PMID: 17621196 DOI: 10.1097/brs.0b013e318074d69f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Prospective clinical study. A quantification of volume and hydration variation of the intervertebral discs, using magnetic resonance imaging (MRI), in the lumbar spine before and after surgery performed in adolescent idiopathic scoliosis (AIS). OBJECTIVES To evaluate an objective quantification of volume and hydration of intervertebral discs below spine fusion in scoliosis surgery. SUMMARY AND BACKGROUND DATA Repercussion of long spine fusion on the free lower lumbar spine is one of the major concerns of scoliosis surgery. However, the evolution of lumbar intervertebral disc below thoracolumbar fusions remains unknown. METHODS MRI performed in the clinical protocol, concerned 28 patients having an idiopathic scoliosis. They underwent posterior instrumentations. MRI was obtained before surgery, after surgery at 3 months and for 15 patients at 1 year. MRI data were posttreated using a custom-made image processing software to semiautomatically derive volume properties of disc, anulus fibrosus, and nucleus pulposus. The nucleus-disc volume ratio was also an indicator of the hydration level. RESULTS The reliability of the three-dimensional reconstruction process was initially verified using an intraoperator reproducibility test. Original preoperative data on disc volume properties were then derived. Postoperative volume variations were quantified in discs below spine fusion taking into account the level of the arthrodesis and the disc location. It showed that the postoperative volume criteria increased significantly for nucleus, disc, and nucleus-disc volume ratio and some magnitude modulation could be conditioned by the location of surgical instrumentation. Some stabilization or reduction depending on disc level and arthrodesis size between 3 months and 1 year is observed in the follow-up. It tended to prove that the recovery of balance physiologic positioning and inherent biomechanical loads could induce a restored hydration of disc, which should favor the remodeling of free segments. CONCLUSIONS This work was the first report dealing with consequences of scoliosis surgery on subjacent disc in term of volume and hydration properties.
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Affiliation(s)
- Philippe Violas
- Department of Pediatric Surgery, Pontchaillou University Hospital, Rennes, France.
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Violas P, Estivalezes E, Briot J, Sales de Gauzy J, Swider P. Objective quantification of intervertebral disc volume properties using MRI in idiopathic scoliosis surgery. Magn Reson Imaging 2007; 25:386-91. [PMID: 17371729 DOI: 10.1016/j.mri.2006.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Accepted: 09/22/2006] [Indexed: 10/23/2022]
Abstract
The aim of this study was to quantify from magnetic resonance imaging (MRI) the volume and hydration variation of the intervertebral disc in the lumbar spine before and after surgery in severe idiopathic scoliosis cases. MRI data were posttreated using a custom-made image processing software to semiautomatically derive volume properties of disc, annulus fibrosus and nucleus pulposus. The nucleus-disc volume ratio was also an indicator of the hydration level. The MRI that was performed in the clinical protocol concerned 28 patients with severe idiopathic scoliosis; four types of surgical instrumentations were used. The reliability of the three-dimensional reconstruction process was initially verified using an intraoperator reproducibility test. Original preoperative data on disc volume properties were then derived. Postoperative volume variations were quantified in discs below spine fusion, taking into account the level of arthrodesis and the disc location. It showed that the postoperative volume criteria increased significantly for nucleus, disc and nucleus-disc volume ratio and that some magnitude modulation could be conditioned by the location of surgical instrumentation. It tended to prove that the recovery of balanced physiological positioning and inherent biomechanical loads could induce a restored hydration of disc, which should favor the remodeling of free segments. This work was the first report to deal with the consequences of scoliosis surgery on subjacent disc in terms of volume and hydration properties. The clinical outcome will follow based on the patient cohort follow-up at 1 year after surgery.
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Affiliation(s)
- Philippe Violas
- Department of Pediatric Surgery, Pontchaillou University Hospital, 35033 Rennes, France
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