Modification of Brain Functional Connectivity in Adolescent Thoracic Idiopathic Scoliosis by Lower Extremities Position

Sense of verticality in girls with right thoracic adolescent idiopathic scoliosis (AIS): Evaluation of bottom up and top down mechanisms

The sacroiliac joint (SIJ) is the largest axial joint in the human body, and the SIJ vacuum phenomenon (SIJ VP) is a common finding in computed tomography studies of the abdomen, pelvis, and lumbosacral spine in adults, with the incidence increasing with age. Adolescent idiopathic scoliosis (AIS) is an abnormal spinal curvature that appears during adolescence and places abnormal stress on the SIJs. This retrospective observational study aimed to investigate the incidence of the SIJ VP in thoracic AIS (Lenke types 1 and 2). Sixty-seven patients with AIS (age: 12-19 years) and 76 controls (age: 11-19 years) were retrospectively analyzed to investigate SIJ VP, subchondral bone cysts, and SIJ degeneration (Eno classification: type 0, no degenerative change; type 1, mild degenerative changes; type 2, substantial degenerative changes; and type 3, ankylosis). SIJ degeneration was defined as type ≥ 2. The association between SIJ VP, cysts, SIJ degeneration, and sagittal/coronal spinopelvic alignment was assessed. SIJ VP (59% vs. 35.5%, P < .01), cysts (32.8% vs. 1.3%, P < .01), and SIJ degeneration (3.2% vs. 2.6%, P = .823) differed significantly between the 2 groups. There were 0 cases of SIJ ankylosis (Eno classification type 3) in both groups. The VP was not correlated with lumbar lordosis, sacral slope, or Cobb angle. All lumbar modifier type C belonged to the VP present group, whereas none to VP absent group. Our results suggest an association between AIS and SIJ VP and SIJ cysts. SIJ VP and SIJ cysts in AIS may be caused and accelerated by abnormal mechanical stress on SIJ due to spinal deformity.

To investigate the association between the tissue inhibitor of metalloproteinase-2 (TIMP-2) gene polymorphisms with the predisposition and disease severity of thoracic adolescent idiopathic scoliosis (AIS). Three hundred and fifty-four female thoracic AIS patients treated from January 2007 to March 2009 and 210 healthy female who underwent health examination during March 2005 to June 2006 as normal controls were recruited in this study. One SNP-418G/C (rs8179090) in the promoter region were selected for TIMP-2 gene. PCR- RFLP was used for genotyping. No significant differences of genotype and allele frequency distribution were found between AIS patients and normal controls (P > 0.05). In AIS patients, the frequency of C allele of the patients with the body mass index (BMI) < 17 kg/m(2) was significantly higher than those with the BMI > or = 17 kg/m(2) (P < 0.05), and the frequency of C allele of cases with the major Cobb angle > or = 40 degrees was significantly higher than that with Cobb angle < 40 degrees (P < 0.05). Among the patients who reached skeletal maturity without any interference of natural history, significantly higher average maximum Cobb angle was found in patients with GC and CC genotype compare with those with GG genotype. The SNP-418G/C (rs8179090) in the promoter region of TIMP-2 gene may be associated with abnormal growth pattern and curve progression of thoracic AIS. TIMP-2 gene is a disease-modifier gene of thoracic AIS.

Do Adolescents With Idiopathic Scoliosis Have an Erroneous Perception of the Gravitational Vertical?

There is no generally accepted scientific theory for the etiology of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The text for this EFG was written by Professor Jack Cheng and his colleagues who used whole spine magnetic resonance imaging (MRI) to re-investigate the relative anterior spinal overgrowth of progressive AIS in a cross-sectional study. The text is drawn from research carried out with his co-workers including measurement of the height of vertebral components anteriorly (vertebral body) and posteriorly (pedicles) in girls with AIS and in normal subjects. The findings confirm previous anatomical studies and support the consensus view that in patients with thoracic AIS there is relatively faster growth of anterior and slower growth of posterior elements of thoracic vertebrae. The disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves. In interpreting the findings they consider the Roth/Porter hypothesis of uncoupled neuro-osseous growth in the spine but point out that knowledge of normal vertebral growth supports the view that the scoliosis deformity in AIS is related to longitudinal vertebral body growth rather than growth of the canal. In the mechanical mechanism (pathomechanism) they implicitly adopt the concept of primary skeletal change as it affects the sagittal plane of the spine with anterior increments and posterior decrements of vertebral growth and, in the biological mechanism (pathogenesis) propose a novel histogenetic hypothesis of uncoupled endochondral-membranous bone formation. The latter is viewed as part of an 'intrinsic abnormality of skeletal growth in patients with AIS which may be genetic'. The hypothesis that AIS girls have intrinsic anomalies (not abnormalities) of skeletal growth related to curve progression and involving genetic and/or environmental factors acting in early life is not original. While the findings of Professor Cheng and his colleagues have added MRI data to the field of relative anterior spinal overgrowth in AIS their interpretation engenders controversy. Three new hypotheses are proposed to interpret their findings: (1) hypoplasia of articular processes as a risk factor for AIS; (2) selection from the normal population to AIS involves anomalous vertebral morphology and soft tissue factors--this hypothesis may also apply to certain types of secondary scoliosis; and (3) a new method to predict the natural history of AIS curves by evaluating cerebro-spinal fluid (CSF) motion at the cranio-cervical junction. What is not controversial is the need for whole spine MRI research on subjects with non-idiopathic scoliosis.

Abnormal pattern of growth has been reported in adolescent idiopathic scoliosis (AIS) patients. However, the sequential changes of growth in different curve types of AIS have not been properly studied. The present study aimed to investigate the body growth characteristics of girls with single thoracic idiopathic scoliosis and lumbar idiopathic scoliosis in China. 339 AIS girls and 3914 healthy girls, aged 10~17yr, were included. All AIS girls had a mean Cobb angle of 32&amp;plusmn;10&amp;deg; (range 15~63&amp;deg;). According to the locations of curves end vertebrae, AIS girls were divided into 2 subgroups: a single thoracic curve and a single lumbar curve. Body weight and standing height was measured, and body mass index (BMI) and leg length was calculated of each subject in three groups, and corrected height was computed in AIS group according to Bjure's formula. One-way ANOVA was used to determine the differences in weight, height, corrected height and BMI between AIS and healthy girls. Standing height and sitting height showed no significant difference between thoracic scoliosis and lumbar scoliosis girls. Compared to healthy girls at the same age, thoracic and lumbar AIS girls had a significantly higher corrected standing and sitting height, arm span and leg length. Thoracic AIS girls had a significantly lower body weight than healthy girls at the age of 15yr. Yet, body weight showed no significant difference between lumbar AIS and healthy girls. The standing and sitting height between thoracic and lumbar AIS girls were similar during the pubertal period. Compared to healthy girls at the same age, thoracic and lumbar AIS girls had a significantly higher corrected standing, sitting height and leg length. In addition, thoracic AIS girls are leaner than healthy girls.

Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine, with unknown origin. Some studies have noted impaired postural balance in AIS, in particular, difficulty to manage situations with sensory conflict. The motion sickness susceptibility can be secondary to a sensory conflict, for example, between visual and vestibular information. Our hypothesis is: patients with AIS have difficulty in managing situations with sensory conflict and therefore have increased motion sickness susceptibility. The purpose of this study was to evaluate in AIS subjects by evaluating their susceptibility to motion sickness, as compared to a control group. We conducted an analysis of data on motion sickness susceptibility collected prospectively from 2012, with the B score of motion sickness susceptibility questionnaire. This evaluation was completed for 65 adolescents (age 14.5 ± 1.6 year) with major right thoracic AIS (Cobb = 40.7° ± 13.1°) and 71 matched controls (14.6 ± 1.6 year). Adolescents with major right thoracic AIS were more susceptible to motion sickness (B score = 5.3 ± 5.8) than controls (B score = 3.4 ± 3.7) with significant difference (p = 0.025). We interpret our results suggesting there is difficulty for patients with AIS to manage situations with sensory conflict. Previous studies focusing on situations with sensory conflict in AIS have required sophisticated technology. They are not accessible for routine patient management. Our research shows the same result with simple, non invasive, low-cost and quick method: B score of motion sickness susceptibility questionnaire.

The aetiology of idiopathic scoliosis (IS) remains unknown, but there is growing support for the possibility of an underlying neurological disorder. Functional magnetic resonance imaging (fMRI) can characterize the abnormal activation of the sensorimotor brain network in movement disorders and could provide further insights into the neuropathogenesis of IS. Twenty subjects were included in the study; 10 adolescents with IS (mean age of 15.2, 8 girls and 2 boys) and 10 age-matched healthy controls. The average Cobb angle of the primary curve in the IS patients was 35° (range 27°-55°). All participants underwent a block-design fMRI experiment in a 1.5-Tesla MRI scanner to explore cortical activation following a simple motor task. Rest periods alternated with activation periods during which participants were required to open and close their hand at an internally paced rate of approximately 1 Hz. Data were analyzed with Statistical Parametric Mapping (SPM5) including age, sex and laterality as nuisance variables to minimise the presence of bias in the results. Compared to controls, IS patients showed significant increases in blood oxygenation level dependent (BOLD) activity in contralateral supplementary motor area when performing the motor task with either hand. No significant differences were observed when testing between groups in the functional activation in the primary motor cortex, premotor cortex and somatosensory cortex. Additionally, the IS group showed a greater interhemispheric asymmetry index than the control group (0.30 vs. 0.13, p < 0.001). This study demonstrates an abnormal pattern of brain activation in secondary motor areas during movement execution in patients with IS. These findings support the hypothesis that a sensorimotor integration disorder underlies the pathogenesis of IS.

Identification of optimized rod shapes to guide anatomical spinal reconstruction for adolescent thoracic idiopathic scoliosis

To prospectively evaluate the strategy of surgery and choice of the fusion segments in thoracic adolescent idiopathic scoliosis (AIS) treatment. Selective posterior fusion was used on 72 AIS patients, 13 male and 59 female, aged 14.3 (12 - 18), 50 being of Lenke-type IA, 8 Lenke-type IB, and 14 Lenke-type IC. In principle the upper neutral vertebrae were selected as upper instrumented vertebrae. The lower neutral vertebrae, the vertebrae 1 level proximal to the neutral vertebrae, or stable vertebrae were chosen as the lower instrumented vertebrae based on the analysis of the correlation among the lower end vertebrae, neutral vertebrae and stable vertebrae's locations. Standing anteroposterior and lateral and side-bending radiographs were taken preoperatively, postoperatively and during the follow-up. The coronal and sagittal Cobb angle, translation and rotation of apical vertebrae, and trunk translation were evaluated to observe the curve correction and trunk balance. The patients underwent spinal fusion of 7.3 segments (4 - 10 segments) on average. Follow-up was conducted for 15.9 months (12 - 39 months). The thoracic curves' coronal Cobb angle before the operation was 56.7 degrees +/- 14.5 degrees (40 degrees - 98 degrees), and was 18.5 degrees +/- 8.3 degrees (3 degrees - 40 degrees) after the operation. The lumbar curves' coronal Cobb angle before operation was 33.9 degrees +/- 10.4 degrees (25 degrees - 69 degrees), and was 11.1 degrees +/- 6.4 degrees (0 degrees - 30 degrees ) after operation. The spontaneous correction rate was 66.9% +/- 16% (44% - 100%). The trunk translation before operation was 16.1 +/- 10.2 mm (4 - 43 mm), and was 8.2 +/- 6.1 mm (0 - 25 mm) after operation. Two patients were found with slight trunk decompensation postoperatively, but with no progression during a 2-year follow-up. Determination of the fusion levels based on the analysis of the correlation among the end vertebrae, neutral vertebrae and stale vertebrae's location helps obtain the satisfying curative effect in the management of single thoracic curve AIS.

Does an Internal Thoracoplasty Correct and Prevent a Reassertion of the Rib Cage Deformity After Spine Surgery for an Adolescent Idiopathic Thoracic Scoliosis Greater Than 70 Degrees

In adolescent idiopathic scoliosis (AIS), lung function impairment is not necessarily related to the coronal spinal deformity. Recently, right-sided bronchial narrowing has been reported in thoracic AIS. The aim of this study was to describe the relation of chest and spinal deformity parameters, bronchial narrowing, and lung volumes with pulmonary function in preoperative AIS. Spinal radiographs, low-dose computed tomographic (CT) scans of the spine including the chest, and pulmonary function tests were retrospectively collected for 85 preoperative patients with thoracic AIS in 2 centers and were compared with 14 matched controls. Three-dimensional lung and airway reconstructions were acquired. Correlation analysis was performed in which radiographic spinal parameters, CT-based thoracic deformity parameters (rib-hump index [RHi], spinal penetration index, endothoracic hump ratio, hemithoracic-width ratio), lung volume asymmetry, and bronchial cross-sectional area were compared with percent-of-predicted spirometry results. Forty-one patients (48%) had a percent-of-predicted forced expiratory volume in 1 second (FEV1%) or percent-of-predicted forced vital capacity (FVC%) of <65%, and 17 patients (20%) had obstructive lung disease. All thoracic deformity parameters correlated significantly with FEV1% and FVC%; RHi was found to be the best correlate (rs = -0.52 for FEV1% and -0.54 for FVC%). Patients with AIS with impaired pulmonary function had hypokyphosis, a larger rib hump, increased spinal and thoracic rotation, a narrower right hemithorax, and increased intrusion of the spine into the chest. Spinal intrusion correlated with right-sided bronchial narrowing, relative right lung volume loss, and decreased FEV1% and FVC%. Multivariate regression including spinal and thoracic deformity parameters, lung volume asymmetry, and airway parameters could explain 57% of the variance in FEV1% and 54% of the variance in FVC%. Chest intrusion by the endothoracic hump is related to right-sided bronchial narrowing and lung function loss in preoperative AIS. The findings support the theory that ventilatory dysfunction in thoracic AIS is not only restrictive but frequently has an obstructive component, especially in patients with hypokyphosis. RHi is the most predictive chest parameter for lung function loss. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BackgroundThe uniqueness of spinal sagittal alignment in thoracic adolescent idiopathic scoliosis (AIS), for example, the drastically smaller thoracic kyphosis seen in some patients, has been recognized but not yet fully understood. The purpose of this study was to clarify the characteristics of sagittal alignment of thoracic AIS and to determine the contributing factors.MethodsWhole spine radiographs of 83 thoracic AIS patients (73 females) were analyzed. The measured radiographic parameters were the Cobb angle of thoracic scoliosis, thoracic kyphosis (TK), lumbar lordosis (LL), C7 sagittal vertical axis (C7 SVA), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Additionally, max-LL, which was defined as the maximum lordosis angle from the S1 endplate, the inflection point between thoracic kyphosis and lumbar lordosis, and the SVA of the inflection point (IP SVA) were measured. The factors significantly related to a decrease in TK were assessed by stepwise logistic regression analysis. In addition, cluster analysis was performed to classify the global sagittal alignment.ResultsThe significant factors for a decrease in TK were an increase in SS (p = 0.0003, [OR]: 1.16) and a decrease in max-LL (p = 0.0005, [OR]: 0.89). According to the cluster analysis, the global sagittal alignment was categorized into the following three types: Type 1 (low SS, low max-LL, n = 28); Type 2 (high SS, low max-LL, n = 22); and Type 3 (high SS, high max-LL, n = 33).ConclusionsIn thoracic AIS, a decreased TK corresponded to an increased SS or a decreased max-LL. The sagittal alignment of thoracic AIS patients could be classified into three types based on SS and max-LL. One of these three types includes the unique sagittal profile of very small TK.

The development of scoliosis in animal models after inducing asymmetric rib growth suggests the possible role of asymmetric rib growth in the etiopathogenesis of adolescent idiopathic scoliosis (AIS). Asymmetric rib length is well recognized in idiopathic scoliosis; however, whether this rib asymmetry is primary or secondary has not been clearly documented. The objectives of this study were to investigate any rib length asymmetry in patients with AIS and compare those with scoliosis with syringomyelia (SS) with the intention of elucidating any relationship between rib growth and pathogenesis of AIS. Forty-eight AIS and 29 SS with apical vertebrae located between T7 and T9 were recruited. The average age was 13.5 ± 2.3 versus 12.5 ± 3.4 years, and the average Cobb angle of thoracic curve was 43.3° ± 16.4° versus 45.6° ± 22.6° in patients with AIS or SS, respectively. The length of all ribs was measured from the tip of costal head to the end of the same rib by built-in software on spiral computed tomography. At the levels of the apical vertebrae, the vertebrae above and below the apex, the mean discrepancy in rib length (concave minus convex rib) was 7, 4 and 7 mm, respectively, in AIS group (p < 0.01), and 6, 5 and 7 mm in SS group, respectively (p < 0.01). The rib length discrepancy between concave and convex sides was significantly correlated with the magnitude of the Cobb angle of thoracic curve in both AIS and SS groups (p < 0.01). Similar findings of the asymmetry of rib length in both AIS and SS patients pointed strongly to the fact that the rib length asymmetry in apical region is most likely secondary to the scoliosis deformity rather than playing a primary role in the etiopathogenesis.

The factors contributing to reduced work capacity (disability) in adolescent idiopathic thoracic scoliosis are poorly understood. We performed a cross-sectional study using multivariate analysis to identify the individual and additive influence of spinal deformity, pulmonary impairment, and muscular function on work capacity in 79 subjects with idiopathic scoliosis (angle of scoliosis 45 +/- 18.5 degrees, SD). Work capacity was measured using an incremental cycle test, and the cardiorespiratory response to exercise was compared with that of normal subjects. Work capacity was reduced (% Wcap, 86%; 95% CI 81.9 to 89.7), indicating significant disability. The % Wcap was unrelated to the nature and extent of spinal deformity (p > 0.05). Leg muscularity and pulmonary impairment had an additive influence on work capacity, the relationship with muscularity being the stronger of the two. Independently of muscularity and pulmonary impairment, a high heart rate response at submaximal work rates was also associated with a reduced work capacity. Ventilation was normal for metabolic demands. During exercise, the tidal volumes of scoliotic subjects were reduced in proportion to the vital capacity. We conclude that disability occurs with mild to moderate idiopathic scoliosis and appears to be related to a combination of reduced ventilatory capacity, reduced muscularity, and cardiovascular deconditioning. These findings suggest that physical activity should be encouraged in subjects with idiopathic scoliosis to maintain peripheral muscle and cardiovascular conditioning, thereby minimizing disability.