Body mass index of girls in health influences menarche and skeletal maturation: a leptin-sympathetic nervous system focus on the trunk with hypothalamic asymmetric dysfunction in the pathogenesis of adolescent idiopathic scoliosis?

Lower body mass index (BMI) and lower circulating leptin levels have been reported in girls with AIS. In this paper we evaluate skeletal sizes and asymmetries by higher and lower BMI subsets about the means for each of three groups of girls age 11-18 years: 1) normals, 2) school screening referrals, and 3) preoperative girls. Higher and lower BMI subsets, likely to have separated subjects with higher from those with lower circulating leptin levels, identify: 1) girls with relatively earlier and later menarche; 2) trunk width size greater in the higher than in the lower BMI subset, of all three groups; 3) abnormal upper arm length (UAL) asymmetries (right minus left) in the lower BMI subset of the preoperative girls; and 4) in thoracic AIS of screened and preoperative girls, Cobb angle and apical vertebral rotation each significantly and positively correlate with UAL asymmetry in the lower BMI subset but not in the higher BMI subset. In preoperative girls, the lower BMI subset shows the combination of relatively reduced pelvic width and abnormal UAL asymmetry, suggesting that both are linked to lower circulating leptin levels. An earlier puberty with hormonal changes provides a plausible explanation for the larger trunk width at the shoulders and pelvis especially at the younger ages in the higher BMI subsets. At the shoulders, this widening is driven by the ribcage which, in human evolution was acquired with decoupling of head and trunk movements required for efficient bipedal gait. The UAL asymmetry patterns within the groups and BMI subsets are not explained by hormonal mechanisms. It is hypothesized that 1) normal trunk widening of the thoracic cage by hormones in human adolescence is supplemented via the sympathetic nervous system under leptin-hypothalamic control influenced by energy stores (metabolic fuel); and 2) hypothalamic dysfunction with altered hypothalamic sensitivity to leptin through a SNS-driven asymmetric effect may create skeletal length asymmetries in upper arms, ribs, ilia and vertebrae, and initiate AIS. Additional mechanisms acting in the spine and trunk may be required for AIS to progress including 1) somatic nervous system dysfunction, 2) biomechanical spinal growth modulation, and 3) osteopenia.

Ultrasound femoral anteversion (FAV) relative to tibial torsion (TT) is abnormal after school screening for adolescent idiopathic scoliosis (AIS): evaluation by two methods.

In the scoliotic spine, torsion is generally evaluated in relation to axial rotation of the apical vertebra. In the lower limbs, the changes in torsion by age of femoral anteversion (FAV) relative to tibial torsion (TT) have been studied in dried bones, normal growing subjects and adults and subjects with osteoarthritis of the hip or the knee. This paper reports the application of real-time ultrasound to FAV and TT in normal children age 11-18 years and in scoliosis screening referrals with particular reference to how FAV relates to TT as 1) ratios, and 2) tibio-femoral index (TFI) of torsion, calculated as TT minus femoral FAV. The FAV/TT ratio findings show an abnormal normal relationship of FAV to TT both proximo-distally and in left-right asymmetry. These may express torsional abnormalities in femoral and/or tibial growth plates with left-right asynchrony suggesting the possibility of similar torsional abnormalities in vertebral end-plates and/or rib growth plates initiating the deformity of AIS. TFI of the right limb in the scoliosis girls is greater than in the normals that is interpreted as resulting from earlier skeletal maturation of FAV. FAV/TT ratios and TFI are unrelated to the spinal deformity (Cobb angle and apical vertebral rotation) except for boys where TFI is associated with apical vertebral rotation. FAV/TT ratios may be a more accurate method estimating the relationship of FAV to TT. than TFIs.

Leg-arm length ratios correlate with severity of apical vertebral rotation in girls after school screening for adolescent idiopathic scoliosis (AIS): a dynamic pathomechanism in the initiation of the deformity?

There is increasing support for the view that the unique human bipedalism and the erect posture are prerequisites for the pathogenesis of adolescent idiopathic scoliosis (AIS). How human bipedalism may contribute to the pathogenesis of AIS is not clear. In normal humans, axial rotations and counter-rotations of the trunk are carried out frequently and forcibly in activities that are not performed by quadrupeds. Some workers have analysed gait in AIS subjects, others have studied torsions in lower limb bones, but there are only two reports on leg-arm ratios in relation to AIS. In this paper, leg-arm ratios studied in relation to the spinal deformity in scoliosis screening referrals, reveal a highly significant correlation with the apical vertebral rotation but not the Cobb angle of the scoliosis curves. We suggest that leg-arm proportions and movements during gait involving pelvi-spinal axial rotations and thoracic counter-rotations contribute a dynamic pathomechanism to early AIS from whatever cause and involving the thoracic cage. Curve progression needs other mechanisms that may include a central nervous system failure to control structural asymmetry of vertebral axial rotation, and biomechanical spinal growth modulation.

Ultrasound femoral anteversion (FAV) and tibial torsion (TT) after school screening for adolescent idiopathic scoliosis (AIS).

Torsion and counter-torsion in the spine are features of the three-dimensional deformity of adolescent idiopathic scoliosis, Vertebral axial rotation has recently been found in the normal adult thoracic spine. Torsion in the lower limbs, femora and tibiae is a feature of normal human skeletal postnatal development. In recent years, femoral anteversion (FAV) and tibial torsion (TT) have been studied in normal children by imaging techniques, especially ultrasound. This paper reports summaries of the application of real-time ultrasound to FAV and TT of normal children and scoliosis school screening referrals. In the scoliosis girls and boys, the FAV decrease and FAV asymmetry compared with normals may result from abnormally increased femoral detorsion maturationally earlier with left-right asynchrony which, if repeated as a growth plate anomaly in the trunk (spine and/or periapical ribs), might initiate the AIS deformity, given other requirements. In scoliosis boys relative to girls, the TT decrease without asymmetry may result from sexually dimorphic maturation at knee tibial growth plates ? maturationally delayed TT with left-right synchrony.

The posterior skeletal thorax: rib-vertebral angle and axial vertebral rotation asymmetries in adolescent idiopathic scoliosis.

The deformity of the ribcage in thoracic adolescent idiopathic scoliosis (AIS) is viewed by most as being secondary to the spinal deformity, though a few consider it primary or involved in curve aggravation. Those who consider it primary ascribe pathogenetic significance to rib-vertebra angle asymmetry. In thoracic AIS, supra-apical rib-vertebra angle differences (RVADs) are reported to be associated with the severity of the Cobb angle. In this paper we attempt to evaluate rib and spinal pathomechanisms in thoracic and thnoracolumbar AIS using spinal radiographs and real-time ultrasound. On the radiographs by costo-vertebral angle asymmetries (rib-vertebral angle differences RVADs, and rib-spinal angle differences RSADs), apical vertebral rotation (AV) and apical vertebral translation (AVT) were measured; and by ultrasound, spine-rib rotation differences (SRRDs) were estimated. RVADs are largest at two and three vertebral levels above the apex where they correlate significantly and positively with Cobb angle and AVT but not AVR. In right thoracic AIS, the cause(s) of the RVA asymmetries is unknown: it may result from trunk muscle imbalance, or from ribs adjusting passively within the constraint of the fourth column of the spine to increasing spinal curvature from whatever cause. Several possible mechanisms may drive axial vertebral rotation including, biplanar spinal asymmetry, relative anterior spinal overgrowth, dorsal shear forces in the presence of normal vertebral axial rotation, asymmetry of rib linear growth, trunk muscle imbalance causing rib-vertebra angle asymmetry weakening the spinal rotation-defending system of bipedal gait, and CNS mechanisms.

An evaluation of lycra garments in the lower limb using 3-D gait analysis and functional assessment (PEDI).

Whole body lycra garments were assessed in eight children using gait analysis, the paediatric evaluation of disability index (PEDI), and a questionnaire of parental acceptance. Seven of the children had cerebral palsy and one Duchennes muscular dystrophy. After initial assessment and fitting of the garment, there was a 2-week introduction period followed by 6 weeks of wearing the garment for at least 6 h everyday, following which they were re-assessed. The root mean square error (RMSE) was used as a measure of variability over three separate passes through the gait laboratory and was a reference figure for gait stability. Proximal stability around the pelvis improved for five children and distal stability improved for three. Five children improved in at least one aspect of the PEDI scale. Although the parents and children detected these improvements, they did not outweigh the disadvantages of wearing the suit and as a consequence only one out of eight families considered continuing with the lycra garment.

Segmental evaluation of the surface and radiological deformity after Cotrel-Dubousset (CD) instrumentation for King type II and III. adolescent idiopathic scoliosis (AIS): surgical and etiological implications.

In this paper we report the segmental effects of CD in each of the three planes of deformity (frontal, transverse and sagittal) in 35 children with AIS (King types II and III) treated by Cotrel-Dubousset instrumentation. Patients were examined preoperatively and in follow-up at 8 weeks and one year, and 15 patients were also examined at two years. Back shape was appraised segmentally as angle of trunk inclination (ATI) at each of ten levels by ISIS and the Scoliometer. The radiographs were measured nonsegmentally for Cobb angle, apical vertebral rotation and spinal balance, and segmentally for both vertebral rotation and tilt (frontal and sagittal plane), and in the rib cage for rib-vertebra angles (RVAs).