Objective: The purpose of the study is to create a porcine scoliosis model that mimics an infantile scoliosis deformity without chest wall injuring.
Methods: Seven 1 month's old pigs (9 kilograms weight, T1-S1 length: 32 cm) were used (6 +1 control). An original offset implant was fixed posteriorly (mid thoracic spine and L1-L2 vertebrae) and connected with a cable. Spinal deformity was assess by a CT scan. A three dimension stereographic analysis of the clinical parameters was performed with two digital reconstructed radiography. Thoracic parameters were analysed with thorax rotation angle, posterior asymmetric ratio and lung volume calculation. In four pigs, the cable was sectioned after two months and their deformity followed-up for next 2 months.
Results: No post-operative complication was observed. Mean weight growth was 10 kg/months and mean spine lengthening (T1-S1) was 7cm/months. We obtained structural curves with vertebral wedging and chest wall deformity. Mean frontal and sagittal Cobb angle was 45° at 2 months. The chest wall deformity was statistically correlated with the amount of spine deformity. The cable section resulted in somewhat predictable curve regression.
Conclusion: The model create a structural scoliosis and chest wall deformity without violating spinal and chest wall elements that can be assimilated to an early onset scoliosis in term of 3D deformity. The spinal deformities were obtained quickly, and were constant in term of amount and characteristic. Useful spinal and chest informations in scoliotic process could be extracted from this model.
Introduction: Congenital scoliosis and fused ribs can create athree-dimensional deformity affecting the normal thoracic growth and function resulting in thoracic insufficiency syndrome. The objective of this study was to develop an animal model to evaluate the effect of chest deformity on pre- and post-natal lung development and volume. There is currently no animal model of chest wall deformity mimicking the thoracic insufficiency syndrome seen in humans available to study the impact of an expansion thoracoplasty.
Method: Fetal surgery was performed in 8 ewes between 65 and 70 days gestation (term:140d) under anesthesia. Following exposure through a hysterotomy, a left thoracic deformity was created in 9 fetal lambs by either tying 3 ribs together or adding resection of the 7th rib in addition to partial destruction of the vertebral body.
Results: All 9 lambs who underwent surgery were born at term through vaginal delivery and suffered from a scoliotic and thoracic deformity ranging from mild to severe (Cobb 10 – 70). They were all sacrificed at 2 months of age for necropsy except for one animal who died earlier from failure to thrive. The scoliotic and chest wall deformities were maintained during the post-natal period.
Conclusion: We have successfully created a model of congenital thoracic deformity that can be used to study the impact of the deformity on lung development and to evaluate treatment strategies. This novel approach is attractive because it could theoretically recreate a form of congenital scoliosis/thoracic insufficiency syndrome seen clinically very early in life.
Significance: Congenital human chest wall deformity represents a disease continuum that starts early during fetal life and progresses thereafter. Therefore, the detrimental impact of the thoracic deformity on lung development is established prior to birth. This animal model will allow the evaluation of thoracic growth modulation, the evaluation of lung development during normal growth and in the presence of a prenatal chest wall deformity, as well as the evaluation of the impact of different treatment strategies on the deformity as well as lung development.
Introduction: An understanding on normal pubertal growth pattern is of great importance in understanding the abnormal peripubertal growth in many diseases conditions such as adolescent idiopathic scoliosis (AIS). The timing of the onset of puberty depends on both genetic and environmental factors. Economy in China improved significantly in the past decades. The latest normal pubertal growth pattern of Chinese, however, is not available.
Objective: To update the normative data for the onset and temporal pattern of puberty in healthy Chinese children in an urban setting by a cross-sectional study.
Materials and Methods: 15204 healthy boys and 13047 healthy girls between 8–17 yrs were recruited randomly from primary and middle schools. Standard anthropometric measurements were carried out then the subjects were grouped according to their age (8.50-9.49yrs, 9.50-10.49yrs, et al) for the data analysis. Growth velocity curves were constructed using SPSS 13.0 and MATLAB7.3 software based on PB1 model with the best fit for pubertal growth spurt.
Results: The age at onset of peak of growth was 12.6 years for boys and 10.6 years for girls, and the growth velocity was 6.91 cm/yr in boys and 6.69 cm/yr in girls. (Figure 1A and 1B)
Conclusion and Significance: The current study showed earlier onset of peak growth in both Chinese boys and girls when compared with reports twenty years ago showing a clear secular change. The latest data would serve as important reference for studies on diseases related to abnormal growth and development in peripubertal period in the Chinese urban population.
Introduction: The most well accepted phenotypes of adolescent idiopathic scoliosis (AIS) are relative anterior spinal overgrowth and osteopenia which might because of abnormal endochondral ossification and bone metabolism. Previous linkage studies on familial AIS revealed several candidate chromosomal regions. Asporin (ASPN), tissue inhibitor of metalloproteinases (TIMPs) and insulin-like growth factor-1 receptor (IGF-1R) genes were located in these regions and contribute to bone growth.
Objectives: To investigate the genetic association between ASPN, TIMP-2 and IGF-1R with AIS girls.
Materials and Methods: 222 AIS girls and 210 health girls were recruited. Cobb angle, height, menarche status, curve pattern and Risser sign were recorded. Genetic DNA was extracted from peripheral blood phenol/chloroform method. PCR-RFLP was used for the genotyping.
Results: No significant differences of genotype and allele frequency distribution were found between AIS patients and normal controls in three genes. For the SNP-418G/C (rs8179090) in the promoter region of TIMP-2 gene, patients with GC and CC genotypes showed significantly larger maximal Cobb angles than those with GG genotype.
Conclusion: The SNP-418G/C (rs8179090) in the promoter region of TIMP-2 gene may be associated with curve progression of AIS and TIMP-2 gene is a disease-modifier gene of thoracic AIS. Both ASPN and IGF-1R gene are neither predisposition nor modifier gene of AIS.
Significance: The current study demonstrates that TIMP-2 is not a predisposition gene but a modifier gene of T-AIS and patients with GC and CC genotype have the risk of curve progression and should receive earlier treatment to prevent curve deterioration.
Introduction: The study of the molecular changes occurring in scoliosis animal models revealed an increased production of Osteopontin (OPN), at the mRNA and protein levels and led us to study the role of this multifunctional cytokine in idiopathic scoliosis (IS) pathomechanism.
Methods: A group of 434 consecutive patients with IS were compared with 247 healthy control subjects and 121 asymptomatic offspring, born from at least one scoliotic parent, who are considered at-risk of developing this disorder. Plasma OPN and soluble CD44 receptor (sCD44) levels were measured by enzyme-linked immunosorbent assays.
Results: Mean plasma OPN levels were significantly increased in IS patients and correlated with disease severity, with average values of 712±299 ng/ml and 914±366 ng/ml for moderate (10–44°) and severe (geq45°) spinal deformities, respectively, when compared to the healthy control group (540±244 ng/ml). Elevated plasma OPN levels were also found in the asymptomatic at-risk group (816±349 ng/ml), suggesting that these changes precede scoliosis onset. Mean plasma sCD44 levels were significantly lower only in IS patients with Cobb angle ≥45° compared to healthy control subjects. All transgenic C57Bl/6j mice devoid of OPN were protected against scoliosis, contrasting with wild-type ones.
Conclusions: Our clinical data and experiments on animals demonstrate that OPN is essential to induce scoliosis formation and curve progression through interactions with CD44 receptors, thus offering a first molecular concept to explain the pathomechanism leading to the asymmetrical growth of the spine in idiopathic scoliosis. Plasma OPN and sCD44 values could be useful markers for diagnosis of IS and prognosis of curve progression.
Introduction: Mechanical loading, which can regulate longitudinal bone growth, has clinical implications in progressive skeletal deformities. Nevertheless, the mechanisms underlying this process, occurring in growth plates with structurally distinct zones, are not well understood.
Objective: This study aims at documenting the relationship between the biochemical composition and the morphological changes following compression of growth plates in its three zones.
Method: Growth plates were dissected from ulnae of immature swine (N=13). Six of the specimens were tested under 15% compressive strain and confocal microscopy was used to image fluorescently labeled chondrocytes. Quantitative morphological analyses at both tissue (cell/matrix volume ratio) and cell levels (volume, surface area, and sphericity) were performed using IMARIS software. Seven of the samples were processed to evaluate water, collagen (Hydroxyproline assay) and GAG (Dimethylmethylene blue assay) contents within the three zones.
Result: Both deformational state and biochemical composition results showed heterogeneity among the zones. Lower volume changes were mainly found in the reserve zone where higher collagen content was measured, whereas higher volume changes were observed in the proliferative and hypertrophic zones where lower collagen content was detected. All three zones contained a similar GAG and water content.
Conclusion: Growth plate compressive behaviour was related to its collagen content. The reserve zone might play a more significant role of mechanical support relative to the proliferative and hypertrophic zones, which have an anabolic role in the growth process.
Significance: Study of growth plate mechanobiology is essential to establish a scientific basis to improve treatment approaches of progressive skeletal deformities.
Introduction: Combinations of angulation (A), compression (C) and angulation and compression (B) reduced mobility (I) have been shown to induce intervertebral disc narrowing and increased bending stiffness in tails of growing rats (IRSSD 2008). Reduced mobility was probably present in all interventions, and in adjacent discs.
Objective: To determine in vivo mechanisms responsible for these changes.
Methods: Disc tissue from discs subjected to each of the above interventions for 5 weeks provide measurements of matrix protein content (DMMB assay for GAG and hydroxyproline assay), synthesis (via incorporation of radiolabelled proline and sulphate tracers) and gene expression of matrix proteins, their degradative enzymes and inhibitors (via real-time RT-PCR). In addition, tracer incorporation and gene expression were measured in animals euthanized after 5 days. Values were compared between groups, and against within-animal controls.
Results: Tissue composition (water content, and cellularity via DNA Hoechst assay) was not significantly altered at any of the intervention discs. Compression resulted in increased GAG content, but angulation did not result in asymmetrical content. Synthesis rates (tracer incorporation) were higher at 5 days than 5 weeks. After 5 days, compression was associated with greater incorporation of both proline and sulphate. Gene expression studies showed matrix degradation indicative or degeneration and/or remodeling at 5 days in all groups. After 5 weeks, gene expression and tracer incorporation measurements indicated declining levels of tissue remodeling.
Conclusion and Significance: Measurements of disc composition and metabolism indicated relatively small changes relative to large reduction in disc space and mechanical flexibility, but compression was associated with increased GAG synthesis, and increased turnover of collagen. Changes associated with reduced mobility were not evident in measurements of disc metabolism. Disc wedging and structural changes in human scoliosis may result from asymmetrical compression, as well as reduced mobility.
Introduction: The effects of dynamic loading on growth are presently poorly understood. Studies investigating static/dynamic loadings do not use matched and normalized loading parameters.
Objectives: This study aimed at characterizing the effects of static/dynamic loading of growth plate explants, matched in terms of average strain, on the histomorphometry.
Methods: Growth plate explants were extracted from distal ulnae of 4-week-old swine. Four groups were implemented: normal, culture control, static loading, matched dynamic loading. Normal samples were immediately fixed. The static samples underwent 10% strain. The dynamic samples underwent equivalent cyclic strain at 0.1 Hz. Matched control samples were kept in identical conditions. Sections were made from methymetacrylate embedded samples and stained with Toluidine Blue. The total growth plate thickness and the combined thickness of the hypertrophic/proliferative zones were measured.
Results: The chondrocytes columnar arrangement from the dynamic samples was disorganized, especially in the hypertrophic/proliferative zones, when compared to the other groups. A decrease was observed in all parameters when comparing the static/dynamic groups to the control group. These reductions were statistically significant for the static group only.
Conclusion: Explants responded differently to static/dynamic loading. The loss of columnar arrangement was more severe in the dynamically loaded explants, but decreases in all histological parameters were more significant following static loading. Complementary mechanobiological data is required to fully interpret these results.
Significance: The exact response of the physis to static/dynamic stresses will help improve current treatment approaches and develop new approaches for the treatment of pediatric musculoskeletal deformities, such as scoliosis.
Introduction: Leptin, adipocyte hormone and energy sufficiency signal to the hypothalamus, has many regulatory functions including bone growth controlled through the sympathetic nervous system (SNS) and peripherally. In AIS girls, we attribute several skeletal asymmetries associated with lower BMI to asymmetric SNS function created by hypothalamic dysfunction (upregulation) resulting from hormesis as an abnormality of a putative normal leptin-hypothalamic-SNSdriven mechanism. Hormesis is a bimodal dose response of cells, or organisms, to an exogenous (eg drug or toxin), or intrinsic factor (eg hormone), in which the factor induces stimulatory or beneficial effects at low doses and inhibitory or adverse effects at high doses.
Objectives: Dr EJ Calabrese recommended testing for hormetic effect in AIS girls using BMI as a surrogate measure for leptin as the “dose”, and evaluating skeletal growth asymmetries of AIS as the adverse effect.
Materials and Methods: Data from girls with right thoracic (n=110) and lower spine scoliosis (thoracolumbar and lumbar, n=64) are evaluated for skeletal asymmetries in relation to BMI – Cobb angle (CA), apical vertebral (AVR), upper arm length asymmetry (UALA) and iliac height asymmetry (IHA)(Spearman's rho, ñ).
Results: RT scoliosis. AVR (p=0.007, ñ=0.257), but not CA or UALA correlates significantly with BMI, Lower spine scoliosis. AVR (p=0.012, ñ=0.311) and IHA (p=0.046, ñ=0.250) but not CA correlate significantly with BMI.
Conclusion: These left-right skeletal asymmetries increase with increase of BMI, and possibly with increase in circulating leptin levels (dose).
Significance: The findings are consistent with leptin having a hormetic effect in AIS girls.
Introduction: Automatization of 3D reconstruction of the spine from frontal and sagittal radiographs is extremely challenging. For example, the overlying features of soft tissues and air cavities may interfere with image processing algorithms.
Method: To overcome these problems, the proposed method efficiently combines the partial information contained in two images from a patient with a statistical 3D spine model generated from a database of scoliotic patients. The algorithm operates through two simultaneous iterating processes. The first process generates a personalized vertebra model using 2D/3D registration with bone boundaries extracted from radiographs, while the other process infers the position and the shape of less visible vertebrae from the estimation of the well registered vertebrae using a statistical 3D model.
Results: The method is applied to 8 patients of the Erasme Hospital (Belgium) to obtain some results on shape accuracy based on 20 lumbar vertebrae (L1 to L4). The in-vivo experiments, which consist in comparing the 3D reconstructions (only the regions of the vertebral body and pedicles) obtained from the low-dose radiographic system EOS (biospacemed) to 3D surface models of the vertebral shapes reconstructed from CT-scan, show an average and a standard deviation error of less than 1.0 mm for the 20 vertebral shapes reconstructed by two users.
Conclusion: Experimental evaluations confirm that the proposed method gives viable 3D reconstructions and is an accurate and reliable alternative to competitive state-of-the-art methods. The proposed method requires only 3 minutes to complete, allowing an acceptable and fast enough 3D reconstruction for a routine clinical use.
Preoperative 3D models used in surgical navigation bring complementary information on structures of interest during surgery. Such models can be reconstructed pre-operatively using different imaging modalities (CT, MRI, radiographs) that differ from that available intra-operatively (radiographs or video). Registration of pre-operative 3D models with 2D intra-operative images is challenging due to the spine shape variation of different patient positioning between the image acquisitions. As a first attempt to address this technological problem, the objective is to propose a 2D/3D registration technique based on a 3D MRI model and only one per-operative calibrated radiograph.
The registration was performed using an optimization technique, which minimized the retroprojection errors of 14 landmarks on each vertebra. Additional constraints were incorporated based on rigid intervertebral transformations. The technique was tested on 3 scoliotic cases with their pre-operative 3D models from supine MRI and their pre-operative standing 2D posteroanterior radiographs. A mean 3D difference of 3.8mm was found between the positions of the landmarks for all vertebrae of the 3 cases. Part of the difference could be explained by the elapsed time between the image acquisitions up to 1 year and the manual identification of landmarks. The preliminary results show the potential of the technique to update the pre-operative MRI model using only one radiograph to compensate the difference in posture between the two acquisitions. Further work is under way to improve the precision by minimizing landmarks error identification avoiding manual identification by using semi-automatic detection of vertebral contours.
Introduction: Previous statistical morphometric analysis of the brain MRI in Adolescent Idiopathic Scoliosis (AIS) patients and normal controls suggested there were statistically significant regional differences in the white matter.
Objectives: The aim of this study was to qualitatively and quantitatively identify the differentiation of the cortical thickness between the right-curve AIS patients and the age-matched normal controls.
Materials and Methods: The comparative study involved T1W MRI data acquired using FFE sequence on 20 right-curve AIS subjects and 20 age-matched normal controls. The white matter and pial surfaces were automatically segmented, from which the cortical thickness values were calculated. The Freesurfer software was applied to perform the cortical parcellation, cortical thickness calculation, and statistical analysis.
Results: Compared to normal controls, significantly increased thickness was detected in cortical surface of the right-thoracic AIS subjects around their middle parts of the superior frontal lobe in the left hemisphere (P<0.001).
Conclusion and Significance: The detected result implies the faster development in the superior frontal lobe in AIS subjects, which might be caused by their excessive attention and planning in their body movements. Moreover, it might also be associated with their emotional responses for not being socially acceptable as norms.
Introduction: Spine diseases such as scoliosis or spondylolisthesis affect the structure and composition of the intervertebral disc (IVD). These modifications can be assessed by MRI imaging.
Objectives: We hypothetise that the distribution of the MRI signal intensity within the IVD depends on the pathology and its severity.
Materials and methods: A 3D retrospective study was realized on 12 scoliotic cases of different severities (Cobb: 11°-50°) and 14 spondylolisthesis cases (Meyerding's grade I to V) using T2 weighted MRI (TR/TE = 3200/124). The IVD at the apex of the scoliotic curve or the L4-L5 disc for spondylolisthesis was selected. A pixel by pixel histogram of the normalised intensity (soft tissues /bone tissues) was achieved and analyzed using a two-way ANOVA. The considered factors were the pathology (Scoliosis/Spondylolisthesis) and its severity (Level I (Cobb≤20° or Spondylolisthesis grades I & II), level II (20°<Cobb≤40° or grade III) and level III (40°<Cobb or grades IV & V)).
Results: Significant differences were found in the signal intensity due to the severity of the pathology (p = 0,017-0,018) and to a linked interaction of pathology and severity (p = 0,021).
Conclusion: Inclusion of more patients will allow to conclude of the isolated effect of the pathology.
Significance: These results are suggesting that this new parameters describing the intensity distribution could be predictive factors of the potential progression of the disease. These factors should be investigated by contingency tables and validated by follow-up studies.
Introduction: Standing radiograph Cobb measurement is the standard for clinical assessment of coronal spinal deformity. Angle of trunk inclination (ATI) is an accepted clinical measurement of transverse plane trunk deformity, and has variable reported correlations with Cobb angles. Transverse plane spine deformity is most accurately measured using axial computed tomography (RAsag). To our knowledge no study has correlated ATI with RAsag.
Objectives: To determine the relationship, or lack thereof, between commonly used measures of trunk and spine deformity.
Materials and Methods: Sixteen females that underwent preoperative apical vertebra(e) CT scans were retrospectively studied. Thoracic and thoracolumbar RAsag measurements were date-matched to clinically obtained ATI and Cobb measurements. Two-tailed Pearson correlations were calculated; α<0.01.
Results: Patient age was 14.9 years (11.2−19.0); BMI 19.4 (16.0−25.5). Curve patterns: Lenke 1:5; 2:5; 3:1; 4:1; 5:2: 6:2. Twenty-six curves (15T; 11TL) with complete, date-matched data points were analyzed (Table 1). Relative to RAsag, thoracolumbar ATI is smaller than thoracic. In thoracic curves, ATI correlated with Cobb (r=0.711, P<0.004), Cobb flexibility (r=−0.647, P<0.01), and RAsag (r=0.730, P<0.003). In thoracolumbar curves, ATI correlated with Cobb (r=0.789, P<0.005) and RAsag (r=0.771, P<0.006) but not with Cobb flexibility (r=−0.452, P=0.190).
Conclusions: Trunk and spine thoracic and thoracolumbar transverse plane deformity are correlated, as are trunk transverse plane and spine coronal plane deformity. Increasing trunk deformity limits thoracic, but not thoracolumbar spine flexibility.
Significance: In the un-operated AIS patient, clinically measured ATI accurately reflects the magnitude of transverse plane spine deformity.
Finite Element Models can be a helpful tool to investigate new, motion preserving means of treatment of spinal deformities. However, an effective validation is even more challenging than for a healthy spine, as in-vitro experiments are very hard to perform due to the limited availability of human cadaver specimens. Measuring the stiffness of scoliotic motion segments intra-operatively offers the possibility to acquire data in an in-vivo situation and at the pathology of interest. We developed a measurement setup to determine the lateral bending stiffness of motion segments after the opening of the back and before the corrective surgery of Adolescent Idiopathic Scoliosis. The apparatus includes a distraction forceps modified to measure force and displacement and an optelectronic camera to track motion. The combination of geometric computer models (vertebral models derived from MRI or CT), motion tracking and forceps data enables the determination of moment and angular displacement measurements for each distraction. The feasibility of this method was validated in a cadaver study using lumbar ovine spines. Measurements were performed with the distraction forceps and compared to equivalent experiments on a spinal loading simulator, as we consider this to be the gold standard for the determination of spinal stiffness. The stiffness computed with the proposed concept was within a range of 15% compared to data obtained with the spinal loading simulator under applied loads of less than 3 Nm. First, intraoperative trials have been performed. The preliminary results confirm the observation that the coupling is such that the anterior portion of the vertebra always rotates into the convexity of the curve when exposed to a left lateral bending.
Introduction: Scoliosis progresses within a biomechanical process involving asymmetrical vertebral loading and growth modulation. There is a growing interest in fusionless technique of vertebral stapling for the correction of scoliosis, as it presents less surgical risks and complications than the traditional fusion surgery.
Objectives: This study aims at characterizing the effects of vertebral stapling on vertebral growth rate and growth plate histomorphometry.
Materials and Methods: Twelve female Yorkshire-Landrace pigs aged three months were divided into three groups: loaded (6), sham (3) and control (3). Loaded animals had five staples implanted at levels T6 to T11 for two months. For all animals, postoperative radiographic follow-up included imaging of the spine every two weeks. Growth rate was evaluated using calceine labelling, injected 8 and 2 days prior to sacrifice. Vertebrae were then extracted, fixed and embedded in methymetacrylate. Thin sections of vertebra-disc-vertebra complexes were imaged for growth rate measurements and histomorphometrical analyses.
Results: A scoliotic curve was developed in two loaded animals. Mean growth rates evaluated at the T8-disc-T9 complex reached 15,0, 21,4 and 19,8 for the loaded, sham and control groups respectively.
Conclusion: Vertebral stapling induces spinal curvatures and decreases vertebral growth rate. Staple positioning is critical in the performance to modulate vertebral growth. Complementary histomorphometrical analyses will provide insight on the growth plate response to stapling.
Significance: In vivo mechanobiological studies on the technique of vertebral stapling are required to better characterize the outcome of these fusionless approaches for the correction of scoliosis.
Introduction: Little has been done to quantify the differences in spinal range of motion (ROM) between adolescents with severe idiopathic scoliosis (prior to spinal instrumentation and fusion) and typically developing individuals. This data may be useful to the debate involving levels of spinal instrumentation and loss of ROM in adolescents with idiopathic scoliosis.
Methods: This is a prospective study consisting of 26 pre-operative patients (18 F, 8M, mean age 14.5±2.2y) with severe (curve over 50 degrees) adolescent idiopathic scoliosis (“Scoliosis Group”). Trunk ROM was assessed with a 3-Dimensional Motion Capture system (VICON; Oxford, UK). While standing the subjects were instructed to move their trunk maximally in all three planes (transverse, coronal and sagittal). The max values were statistically compared within the Scoliosis Group (side to side) and to a “Control Group” of age matched typically developing adolescents with significance set at p<0.05.
Results: Within the Scoliosis Group there was significantly greater rotation and side-bending to the left versus the right. When compared to the Control Group the Scoliosis Group had significantly less trunk rotation and side-bending to the right along with less forward bending flexibility (Table 1).
Conclusion: Adolescents with idiopathic scoliosis demonstrate trunk ROM asymmetry with limited motion in all three planes of motion compared to Controls.
Significance: These results could provide a good baseline comparison for spinal motion prior to surgical instrumentation and fusion and also activity limitations.
Introduction: Vision, proprioception and vestibule are involved in adolescent idiopathic scoliosis (AIS). The aim of this study was to determine if some posturographic parameters could predict the progression of AIS just at the first screening when the spine deformation is very mild.
Materials and Methods: 82 subjects with AIS were followed during a 5-year period of time. At the first screening, just at the diagnosis time, clinical and radiological examination and posturographic tests were performed. These last tests included static tests with and without sensory conflicts, dynamic and dynamised tests. The population was followed establishing 2 groups: Group P included 26 subjects with progressive AIS (Cobb angle increased greater than 5° during a 6 month-period of time), Group NP included non progressive AIS at skeletal maturity (31 subjects). Comparison of posturographic parameters at the first screening was performed to seek some significant differences between P and NP Groups.
Results: At the first screening, no significant differences were highlighted between the 2 groups in regard of age, gender, height, weight, body mass index, skeletal maturity, scoliosis type, and Cobb angle. We showed significant differences in static tests in eyes-opened condition, in slow dynamic test in eyes-opened condition and in sensory organization tests.
Conclusion: Situations soliciting proprioceptive and vestibular cues, especially in conflict, showed significant differences between the 2 groups P and NP. Complex posturographic tasks are more discriminant.
Significance: If predictive thresholds could be found further, these posturographic tests could predict the AIS progression and could allow to treat evolutive AIS very early.
Introduction: Adolescent idiopathic scoliosis is characterized by a threedimensional deviation of the vertebral column and its etiopathogenesis is unknown. Various factors cause idiopathic scoliosis, and among these a prominent role has been attributed to the vestibular system. Various studies have proposed that alteration of the vestibular or reticular formation must be implied in the generation of spine curvature (e.g., Manzoni & Miele, 2002).
Objectives: The aim of this study is to determine whether asymmetrical activity of the vestibulospinal or the reticulospinal tracts is associated to idiopathic scoliosis and its severity.
Methods: In order to quantify the response of the vestibulospinal and reticulospinal tracts, we will employ the galvanic vestibular stimulation (GVS) technique (Lund & Broberg, 1983; Britton et al., 1993). In a standing position, galvanic vestibular stimulation elicits muscles responses by stimulating only the vestibular afferences. For instance, during GVS, Ardic et al. (2000) have observed modulation in the responses of the paraspinal muscles.
Expected Results: If our hypotheses are validated the idiopathic scoliosis patients with severe curvature will demonstrate asymmetrical vestibulomotor responses. For example, we expect to observe a smaller left paraspinal muscle inhibition and greater right paraspinal activation during galvanic vestibular stimulation with the anode on the left mastoid process compared with the anode on the right mastoid process (or vice versa).
Conclusion: These results would provide evidence that asymmetrical vestibulomotor responses can increase the likelihood of developing severe curvature.
Significance: Results could help in the decision-making process and identify the mechanisms related to curve progression.
Aims: The ethiopathogenesis of idiopathic scoliosis (IS) deformity has not yet been established. There is evidence suggesting that an abnormality in central nervous system (CNS) development may play a role. Our previous work has demonstrated functional anomalies of spinal innervation by axons of the corticospinal tract (CST) in some subjects with IS. This led us to predict that hand/finger dexterity would be lower in subjects with IS, because the monosynaptic projections of CST axons to cervical motoneurons are crucial for the control of dexterous finger and hand movements.
Results: In adult subjects, there was no significant difference in scores between groups, perhaps reflecting the large variability in scores both between and within groups. However, the probability of a single score being > 1 standard deviation below the mean of control subject scores was relatively high for IS subjects. Our sample of children with IS is too small at this time to make any statements about performance.
Conclusion: Our findings indicate that despite clinically-normal arm and hand function, overall dexterity was diminished in the IS adult population tested. Future analysis of a larger group of subjects with IS – with particular emphasis on children – is necessary to see if this trend stands up to more rigorous statistical testing.
Introduction: Studies on adolescent idiopathic scoliosis (AIS) have documented the gender differences in natural history and treatments outcome. However, there are few studies comparing the difference of curve patterns between male and female patients.
Objectives: To investigate the gender difference of curve patterns in AIS patients with a small curve (Cobb angle 10° to 40°)
Materials and Methods: 213 female and 61 male AIS patients were enrolled in this study after excluding scoliosis of other causes with MRI of spine and physical examination. The mean age was 15.3 years for females and 15.7 years for males. All patients took the standing long-cassette antero posterior and lateral radiographs of the entire spine at the time of initial visit. Atypical curve patterns such as left thoracic curve, long curve et al. were defined according to the previous reported definition.
Results: The prevalence of atypical curve patterns was 16.4% %in boys and %6.6% in girls, the difference was statistically significant (Table 1). In thoracic curves, the prevalence of left-sided curves was 4.9%, which was significantly higher in boys (10.7%) compared with girls (1.7%). As for typical curve patterns, no significant gender difference was observed in the curve type in patients with typical curve pattern.
Conclusion: In AIS without neurological abnormality, the prevalence of atypical curve patterns in boys is obviously higher than that observed in girls.
Significance: Atypical curve without neurological abnormality was more common in male AIS. Whether they would have different natural history needs longitudinal follow-up.