Natural sagittal spino-pelvic alignment in boys and girls before, at and after the adolescent growth spurt

Assessment of age-dependent sexual dimorphism in paediatric vertebral size and density using a statistical shape and statistical appearance modelling approach

This work focuses on the growth patterns of the human fourth lumbar vertebra (L4) in a paediatric population, with specific attention to sexual dimorphism. The study aims to understand morphological and density changes in the vertebrae through age-dependent statistical shape and statistical appearance models, which can describe full three-dimensional anatomy. Results show that the main growth patterns are associated with isotropic volumetric vertebral growth, a decrease in the relative size of the vertebral foramen, and an increase in the length of the transverse processes. Moreover, significant sexual dimorphism was demonstrated during puberty. We observe significant age and sex interaction in the anterior vertebral body height (P = 0.005), where females exhibited an earlier increase in rates of vertebral height evolution. Moreover, we also observe an increase in cross-sectional area (CSA) with age (P = 0.020), where the CSA is smaller in females than in males (significant sex effect P = 0.042). Finally, although no significant increase in trabecular bone density with age is observed (P = 0.363), a trend in the statistical appearance model suggests an increase in density with age.

Current biomechanical theories on the etiopathogenesis of idiopathic scoliosis

PURPOSE

There is great controversy about the etiologic origin of adolescent idiopathic scoliosis. Multiple theories have been suggested, including metabolic aspects, endocrine dysfunction, neurological central abnormalities, genetic predisposition and epigenetic factors involved in the development of scoliosis. However, there has always been speculations based on human biomechanical behavior.

METHODS

In this article, we performed a literature review on the biomechanical traits of human posture, and the proposed theories that explain the special characteristics present in idiopathic scoliosis.

RESULTS

The current theory on the etiopathogeneis of AIS suggests that dorsally directed shear loads acting on a preexisting axial plane rotation, in a posteriorly inclined sagittal plane of a growing patient, together with disc maturation, collagen quality at this phase of development and immaturity of proprioception, is the perfect scenario to spark rotational instability and create the three-dimensional deformity that defines idiopathic scoliosis.

CONCLUSION

The unique spinal alignment of human bipedalism, gravity and muscle forces acting straight above the pelvis to preserve an upright balance, and the instability of the soft tissue in a period of growth development, is an appealing cocktail to try to explain the genesis of this condition in humans.

More Prevalent and Severe Low Bone-Mineral Density in Boys with Severe Adolescent Idiopathic Scoliosis Than Girls: A Retrospective Study of 798 Surgical Patients

INTRODUCTION

A total of 0.1-0.8% of AIS patients progress to severe stages without clear mechanisms, and AIS girls are more prone to curve progression than boys. Recent studies suggest that AIS girls have systemic and persistent low bone-mineral density (BMD), which has been shown to be a significant prognostic factor of curve progression in AIS. The present study aimed to (a) investigate the prevalence of low BMD in patients with severe AIS and (b) assess the sexual dimorphism and independent risk factors of low BMD in severe AIS patients.

MATERIALS AND METHODS

A total of 798 patients (140 boys vs. 658 girls) with AIS who reached surgical threshold (Cobb ≥ 40°) were recruited. BMD were assessed using BMD Z-scores from dual-energy X-ray absorptiometry (DXA). Demographic, clinical, and laboratory values of the subjects were collected from their medical records. Logistic regression analysis was performed to identify independent risk factors of low BMD.

RESULTS

The overall prevalence of BMD Z-score ≤ -2 and ≤ -1 were 8.1% and 37.5%, respectively. AIS boys had significantly lower BMD Z-scores (-1.2 ± 0.96 vs. -0.57 ± 0.92) and higher prevalence of low BMD (Z-score ≤ -2: 22.1% vs. 5.2%, p < 0.001; Z-score ≤ -1: 59.3% vs. 32.8%, p < 0.001) than girls. Sex, BMI, serum alkaline phosphatase, and potassium were independent factors of low BMD in the severe AIS patients.

CONCLUSIONS

The present large cohort of surgical AIS patients revealed that low BMD is more prevalent and severe in boys than in girls with severe curves. Low BMD may serve as a more valuable predictive factor for curve progression to the surgical threshold in boys than girls with AIS.

Comparison of Spinopelvic Configuration and Roussouly Alignment Types Between Pediatric and Adult Populations

STUDY DESIGN

Retrospective cross-sectional study.

OBJECTIVE

The aim was to describe spinopelvic alignment types by pelvic incidence (PI) and age to compare the Roussouly classification between pediatric and adult populations.

SUMMARY OF BACKGROUND DATA

The Roussouly classification was validated for adults. Alignment types may vary during growth.

MATERIALS AND METHODS

Radiographs of 1706 non pathologic individuals (5-49 yr) were analyzed. Individuals ≤19 years were stratified by chronological age and skeletal maturity (triradiate cartilage, Risser), and compared with adults. Global and spinopelvic alignment parameters were assessed. Roussouly Types 1, 2, 3, 3A (anteverted pelvis), and 4 were determined. The distribution of parameters was analyzed by Bayesian inference. The relationship between PI and age by Roussouly type was modeled by linear regression.

RESULTS

The Sagittal Vertical Axis C7 decreased during growth and was significantly smaller in adults (20-34 yr) (Pr>0.99). Thoracic kyphosis and lumbar lordosis increased during growth and were larger in adults (Pr<0.025). Lordosis increased mainly in the cranial arch (Pr<0.025). PI and pelvic tilt increased during growth and were larger in adults (Pr<0.025). In children and adolescents, PI<45° represented the largest proportion, significantly larger compared with adults (Pr>0.99). Proportions of Roussouly Types 1 and 2 were similar throughout ages. Types 3 and 4 were rarer during the prepubertal period (Pr<0.025). The proportion of Type 3A was significantly higher in children and adolescents (Pr>0.99). Linear regression showed that Type 4 had the largest PI increase with age, with significantly higher curve slope compared with other types (Pr>0.9999). Types 3, 3A and 2 had similar slopes and lowest PI increase with age.

CONCLUSION

Global and spinopelvic alignment changed during childhood and adolescence, leading to different kyphosis and lordosis distribution compared with adults. Growth-related PI increase influenced Roussouly types with typical predominance of Type 3A in the pediatric population and larger PI increase in Type 4.

LEVEL OF EVIDENCE

Level III.

Analysis of the prevalence of asymmetry and muscle tone disorders in the first year of life among youth with idiopathic scoliosis: A retrospective case-control study

BACKGROUND

Not much is known about developmental motor disorders in the first year of life of children diagnosed with idiopathic scoliosis (IS).

OBJECTIVE

This study aimed to compare the occurrence of asymmetry or muscle tone disorders in the first year of life in adolescents with IS and their healthy counterparts.

METHODS

The parents of adolescents with IS and without scoliosis completed a survey on the occurrence of asymmetry, abnormal muscle tone, and physiotherapy in their children in the first year of life. Pearson's chi square test and Cramer's coefficient were used.

RESULTS

The final analysis included 527 surveys completed by parents of adolescents with idiopathic scoliosis (150) and without scoliosis (377). A significantly higher frequency of asymmetry (p= 0.001) and muscle tone disorders (p= 0.001) was noted in adolescents with idiopathic scoliosis. The results also revealed a significant association between scoliosis and asymmetry (p= 0.001), as well as muscle tone (p= 0.001).

CONCLUSIONS

Developmental asymmetry or improper muscle tone in the first year of life could be considered a potential factor in the development of scoliosis; however, this hypothesis should be confirmed in future studies. Infants diagnosed with developmental disorders require systematic observation.

The Adolescent Spine

Adolescent idiopathic scoliosis (AIS) is the most characteristic disorder of the adolescent spine. It is a three-dimensional (3D) disorder that occurs from 10 years of age and comprises 90% of all idiopathic scolioses. Imaging plays a central role in the diagnosis and follow-up of patients with AIS. Modern imaging offers 3D assessment of scoliosis with less radiation exposure. Imaging helps rule out occult conditions that cause spinal deformity. Various imaging methods are also used to assess skeletal maturity in patients with AIS, thus determining the growth spurt and risk of progression of scoliosis. This article provides a brief overview of the pathophysiology, biomechanics, clinical features, and modern imaging of AIS relevant to radiologists in clinical settings.

The kyphosis–lordosis difference parameter and its utility in understanding the pathogenesis of adolescent idiopathic scoliosis

Objective

The relationship of sagittal spinal shape in the pathogenesis of adolescent idiopathic scoliosis (AIS) is recognised. What is not clear is the relationship between the sagittal shape of those without scoliosis and the potential development of AIS, including the greater prevalence in females. The use of a new parameter, the kyphosis–lordosis (KL) difference, was developed to explore this further.

Results

The KL difference was calculated for 117 males and 79 females over seven years with 831 measures made. For females, the KL difference, between the ages of 9 and 12 ½ years, decreases from 5° to nearly 0° until starting to climb again from the age of 14 years, back to 5° by the age of 16 ½ years. For males, there is a gradual decline from 9° at age 9 years to 5° at age 17 years. Both age and sex were statistically significant in the development of the parameter. When comparing to previously published data around the true, de-rotated, sagittal shape of the scoliotic spine, the KL difference has utility in explaining the female predominance in the prevalence of AIS. This adds to the weight of evidence behind understanding why AIS develops.

Sagittal Balance in Children: Reference Values of the Sacral Slope for the Roussouly Classification and of the Pelvic Incidence for a New, Age-Specific Classification

Background: The Roussouly classification, based on the functional parameter sacral slope (SS), describes the normal sagittal balance in adults and has proved useful for surgery. Reference values in children should be defined, since they are an important treatment target of conservative treatment. Moreover, during growth, there are few correlations between sagittal parameters, and we hypothesize that a new classification based on the anatomical parameter pelvic incidence (PI) could also be useful. We performed a cross-sectional study to identify the reference values for the Roussouly classification during growth and to develop a new classification based on PI in children. Methods: Correlations between sagittal parameters and age were searched in 222 healthy subjects at the first consultation (6–18 years old). A new classification, based on PI, and comprising three types, is defined and compared to the Roussouly classification. Results: With age, correlations among sagittal balance parameters increase, as well as SS and PI, but with different cut-offs. The distribution of Roussouly types do not correspond to that in adulthood; thus, we defined new reference cut-offs. We defined a PI-based classification in three types, not overlapping Roussouly’s. We found a uniform and balanced distribution of cases among the nine possible combinations. Conclusions: In children, we need to use new thresholds for the Roussouly types. The new classification based on PI is correlated with the Roussouly classification, but it is also clearly different. Future studies will determine its validity.

Radiographic study of peak velocity of pelvic incidence in adolescent idiopathic scoliosis

BACKGROUND

Pelvic incidence (PI), a parameter related to the ideal spinopelvic alignment, is a morphological parameter that is usually considered fixed, but the PI's growth during adolescence has been reported. We investigated the peak PI velocity during adolescence and describe the relationship between increasing PI and changes in the morphology of the pelvis and sacrum.

METHODS

We measured standing height (SH) and radiological anatomical parameters including pelvic height (PH), pelvic width (PW), sacral width (SW), femoral head-sacrum (FH-S), sacrum-coccyx (S-C) length, and S-C distance at each follow-up of 76 adolescent idiopathic scoliosis (AIS) patients. ΔParameter was the difference between the next measurement and the previous one. Growth velocity was ΔParameter divided by time interval. All ΔParameters were compared between different Risser stages using repeated-measures analysis of variance (ANOVA). The Pearson coefficients of correlation were calculated to assess the relationships between PI and ΔParameters.

RESULTS

PI reached peak growth with a 1.6°/year growth in females and 1.8°/year in males at Risser stage 1. PI tended to grow rapidly with Risser 0 and closed triradiate cartilage (female: 1.3°/year and male: 1.4°/year) and to slow down at Risser 2 (female: 1.2°/year and male: 1.3°/year). ΔPI strongly correlated with ΔFH-S (R>0.508, P<0.05) and also correlated with ΔSH, ΔPH, ΔPW, ΔSW, and ΔS-C length (R>0.192, P<0.05) but not correlated with ΔS-C distance and ΔS-C ratio.

CONCLUSIONS

In patients with AIS, the peak PI velocity is at Risser 1, and it is still increasing at Risser 5. Our result suggested that the growth of the PI may be associated with SH and changing pelvic morphology during skeletal growth of adolescence.

Neglected problem: Influence of school bag on lumbar segment in children

BACKGROUND AND OBJECTIVES

School bag (SB) load causes significant changes in the height and symmetry of the intervertebral discs at each level of the spine from T12-L1 to L5-S1. This study aims to determine the change in the size of the lumbar segment angle at a particularly critical point L3-L4 of the spine in relation to the load of the average weight of SB in healthy male children (students) at standing and after 2-minute gait.

METHODS

47 boys, aged 12.2 ± 0.92 years, underwent photogrammetric measurements in the sagittal plane in statics and dynamics, walking on a laboratory treadmill. Measurements were repeated with the weight of SB with a constant load of 6,251 kg, which represents 13.78% of the average body weight of our sample. The lumbar angle (LA) connecting the point of the big toe, the lumbar point L3-L4 and the processus spinosus C7 was measured. In gait, LA was measured in the phases of the middle support and the initial contact of the heel.

RESULTS

T-test of paired samples was used to estimate the change in LA at standing from 4.953° and walking phases from 6.295° to 7.332° in relation to the unloaded state, and the value of the effect size (ES) indicates that the impact of SB load is significant.

CONCLUSIONS

Cumulatively, microtraumas caused by SB load significantly affect the increase in intervertebral pressure at the L3-L4 point, which is susceptible to degenerative processes and which can be the cause of lumbar syndrome (LS). Preventive measures are needed in order to lighten SB in this population and introduce up to 10% of students' body weight into the safe zone.

Spinopelvic alignment and lumbar vertebral shape in children: associations with structural spinal abnormalities and body composition in the generation R study

PURPOSE

To investigate the spinopelvic alignment and vertebral shape in children, and associations with body composition and structural spinal abnormalities on magnetic resonance imaging (MRI).

METHODS

We performed a cross-sectional study embedded in the Generation R Study, a prospective population-based birth cohort. Pelvic incidence and vertebral concavity ratios for each lumbar level were determined on sagittal MRI images in 9-year-old children, and structural spinal abnormalities were scored semi-quantitatively. The BMI-SD score was calculated, and body composition was assessed using DXA scans. Associations of pelvic incidence and vertebral concavity ratios with structural abnormalities and body composition measures were assessed using (multilevel) regression analyses.

RESULTS

This study included 522 participants (47.7% boys), aged 9.9 years (IQR 9.7-10.0). The mean pelvic incidence was 36.6° (SD 8.0). Vertebral concavity ratios ranged from 0.87 to 0.90, with significantly lower ratios for boys compared to girls. Associations were found for a larger pelvic incidence with decreased disc height [OR 1.03 (95% CI 1.02-1.05)], and a pelvic incidence in the lowest tertile with less disc bulging [OR 0.73 (95% CI 0.56-0.95)]. Increased vertebral concavity ratio was associated with decreased disc height [OR 14.16 (95% CI 1.28-157.13)]. Finally, increased fat-free mass index was associated with a smaller pelvic incidence [adjusted OR 0.85 (95% CI 0.07-1.63)].

CONCLUSION

The mean pelvic incidence of 9-year-old children is 36.6° on supine MRI images, and a slightly concave shape of the lumbar vertebrae is seen. Spinopelvic alignment is associated with structural spinal abnormalities, and might itself be influenced by the children's body composition.

Assessment of sagittal spinopelvic alignment in asymptomatic Chinese juveniles and adolescents: a large cohort study and comparative meta-analysis

STUDY DESIGN

Retrospective study and comparative meta-analysis.

OBJECTIVE

To document the sagittal spinopelvic alignment in a large cohort study in asymptomatic Chinese juveniles and adolescents, and to explore whether these parameters were different from various regions using meta-analysis.

METHODS

Medical records of 656 asymptomatic Chinese juveniles and adolescents were reviewed, whose mean age was 13.14 ± 3.41 years old, including 254 male and 402 female volunteers. Demographic and lateral radiological parameters were evaluated. Furthermore, a systematic online search was performed to identify eligible studies. Weight mean difference (WMD) with 95% confidence interval (CI) were used to evaluate whether these sagittal parameters were different from various regions.

RESULTS

The mean value of sagittal spinopelvic alignment in this study was calculated and analyzed respectively. Significant differences of PI (34.20 ± 4.00 vs. 43.18 ± 7.12, P < 0.001) and PT (3.99 ± 6.04 vs. 8.42 ± 7.08, P < 0.001) were found between juveniles and adolescents. A total of 17 studies were recruited for meta-analysis. For juvenile populations, TK, PI and SS of Caucasians were significantly larger than those of our study (all P < 0.001). As for adolescent populations, PI (P = 0.017), TK (P = 0.017) and SS (P < 0.001) of Caucasians was found to be greater when compared with that of our study. All in all, TK, PI and SS in Chinese pre-adult populations were significantly smaller than those populations in Caucasian regions (all P < 0.001).

CONCLUSION

Our study was the first large-scale study that reported the mean values of sagittal parameters in asymptomatic Chinese juveniles and adolescents. There were significant differences in TK, PI and SS between our study and other previous reported populations, which reminded us for using specific mean values in different populations when restoring a relatively normal sagittal spinopelvic balance in spinal deformity.

The role of sagittal pelvic morphology in the development of adult degenerative scoliosis

PURPOSE

Pelvic morphology dictates the alignment and biomechanics of the spine. Recent observations in different types of adolescent idiopathic scoliosis indicate that individual pelvic morphology is related to the spinal levels in which scoliosis develops: primary lumbar adolescent scoliosis is associated with a higher pelvic incidence (PI) than thoracic scoliosis and non-scoliotic controls. We hypothesize that adult degenerative scoliosis (ADS) of the lumbar spine follows the same mechanical principles and is associated with a high PI.

METHODS

This study used an existing CT-scan database, 101 ADS patients were sex and age matched to 101 controls. The PI was measured by two observers with multi-planar reconstruction, perpendicular to the hip-axis according to a previously validated technique.

RESULTS

The PI was 54.1° ± 10.8° in ADS patients and 47.7° ± 10.8° in non-scoliotic controls (p < 0.001). The median ADS curve apex was the disc L2-3 and median curve length was 4 vertebral levels. The mean supine Cobb angle was 21° ± 8° (ranged 10°-47°). There was no significant correlation between PI and the apex level (p = 0.883), the curve length (p = 0.418) or the Cobb angle (p = 0.518).

CONCLUSIONS

ADS normally develops de novo in the lumbar spine of patients with a higher PI than controls, similar to primary lumbar adolescent idiopathic scoliosis. This suggests a shared mechanical basis of both deformities. Pelvic morphology dictates spinal sagittal alignment, which determines the segments of the spine that are prone to develop scoliosis.

Computed tomography study of the relationship between pelvic incidence and bony contribution to lumbar lordosis in children

There is little data regarding the relationship in children and how it may change with aging. The aim of this radiographic study was to define the relationship between pelvic incidence (PI) and segmental vertebral body lordosis through childhood. In 150 children, CT scans of the lumbar spine and pelvis were analyzed measuring PI, sacral table angle (STA), sacral kyphosis (SK), and segmental lordosis (SL) individually L1-L5. Children were grouped by age: (1) 0-60 months; (2) 61-120 months; (3) 121-185 months. Mean PI for the entire cohort was 40.4, mean SL for L1-0.6, L2 0.0, L3 1.8, L4, 4.7, and L5 11.4. There were 40 children in Group 1, 63 in Group 2 and 37 in Group 3. SL differed between age groups at all levels except at L2. L1 and L2 became more kyphotic with increasing age; L3, L4, and L5 became more lordotic with increasing age. The correlation between PI and SL at each level became stronger with increasing age. Similarly, the correlation between PI and STA and between PI and SK also became stronger with increasing age. As children mature, the relationship between PI and segmental lordosis at each level of the lumbar spine becomes stronger-the relationship between PI and lordosis trends toward that seen in the adult. Future work should aim to define when the adult PI-LL relationship is realized.

Sagittal standing spinal alignment and back pain in 8 to 12-year-old children from the Region of Murcia, Spain: The ISQUIOS Program

BACKGROUND

The child's spine shows changes in posture and balance of its curvatures during growth and musculoskeletal spinal conditions are likely to develop, such as back pain (BP).

OBJECTIVE

The purposes of this study were (a) to describe the sagittal spinal alignment in a relaxed standing position and (b) to analyze its association with BP among 8 to 12-year-old children.

METHODS

This was a cross-sectional study. A total of 731 elementary schoolchildren (379 girls and 352 boys), from 16 Spanish schools, participated. An unilevel inclinometer was used to quantify the sagittal spinal curvatures (thoracic and lumbar) in a relaxed standing position. Sagittal spinal morphotype was analyzed by sex, age, weight, height, and BMI. Children's parents or legal guardians filled in a questionnaire according to the children's responses about the BP suffered in the previous week and the preceding year.

RESULTS

The mean angular value of thoracic kyphosis was 36.08 ± 8.99∘ and significantly higher in males than in females (p= 0.036). In contrast, the mean value of lumbar lordosis was 32.11 ± 7.46∘, being higher in females than in men (p< 0.01). The thoracic curve tends to increase by age (p= 0.003). Children who had low back pain (LBP) in the previous week had a significantly greater lumbar curve (35.88 ± 8.20∘) than those who did not have LBP in the preceding week (32.24 ± 7.30∘). The angle for lumbar curvature was a small predictor of LBP occurrence in the assessed children (OR = 1.082 [small]; 95% CI = 1.009-1.160, p= 0.028).

CONCLUSIONS

To conclude, almost 3/4 of the students were classified with normal thoracic kyphosis; however, 27.36% of the students had thoracic hyperkyphosis. Lumbar hyperlordosis was identified in 9.05% of the students, and was 2.5 times more frequent in girls. The lumbar curvature was a small predictor of LBP occurrence in the assessed children and the angle of lumbar curvature that most accurately identified individuals at risk of developing LBP was determined to be 33∘. The results of this study indicate the need to assess sagittal spinal curvatures at school during development ages.

Influence of Chêneau-Brace Therapy on Lumbar and Thoracic Spine and Its Interdependency with Cervical Spine Alignment in Patients with Adolescent Idiopathic Scoliosis (AIS)

Chêneau-brace is an effective therapy tool for treatment in adolescent idiopathic scoliosis (AIS). Data on potential interdependent changes of the sagittal profile including the cervical spine are still sparse. The purpose of this study was to evaluate in-brace changes of the thoracic and lumbar spine and their influence on the pelvis and the cervical spine and apical vertebral rotation was reported. Ninety-three patients with AIS undergoing Chêneau-bracing were included. Patients were stratified by lumbar, thoracic and global spine alignment into normolordotic vs. hyperlordotic or normokyphotic vs. hypokyphotic or anteriorly aligned vs. posteriorly aligned groups. The coronal Cobb angle was significantly decreased in all groups indicating good correction while in-brace therapy. Sagittally, in-brace treatment led to significant flattening of lumbar lordosis (LL) in all stratified groups. Thoracic kyphosis (TK) was significantly flattened in the normokyphotic group, but no TK changes were noticed in the hypokyphotic group. Pelvic tilt (PT) stayed unchanged during the in-brace therapy. Chêneau-brace showed marginal changes in the lower cervical spine but had no influence on the upper cervical spine. The apical vertebral axis in primary and secondary curves was unchanged during the first radiological follow-up. Results from this study contribute to better understanding of initial spine behavior in sagittal and axial plane in the context of bracing.

A reduced-order model of the spine to study pediatric scoliosis

The S-shaped curvature of the spine has been hypothesized as the underlying mechanical cause of adolescent idiopathic scoliosis. In earlier work, we proposed a reduced-order model in which the spine was viewed as an S-shaped elastic rod under torsion and bending. Here, we simulate the deformation of S-shaped rods of a wide range of curvatures and inflection points under a fixed mechanical loading. Our analysis determines three distinct axial projection patterns of these S-shaped rods: two loop (in opposite directions) patterns and one Lemniscate pattern. We further identify the curve characteristics associated with each deformation pattern, showing that for rods deforming in a Loop1 shape the position of the inflection point is the highest and the curvature of the rod is smaller compared to the other two types. For rods deforming in the Loop2 shape, the position of the inflection point is the lowest (closer to the fixed base) and the curvatures are higher than the other two types. These patterns matched the common clinically observed scoliotic curves-Lenke 1 and Lenke 5. Our S-shaped elastic rod model generates deformations that are similar to those of a pediatric spine with the same sagittal curvature characteristics and it can differentiate between the clinically observed deformation patterns.

Specific sagittal alignment patterns are already present in mild adolescent idiopathic scoliosis

PURPOSE

The complex three-dimensional spinal deformity in AIS consists of rotated, lordotic apical areas and neutral junctional zones that modify the spine's sagittal profile. Recently, three specific patterns of thoracic sagittal 'malalignment' were described for severe AIS. The aim of this study is to define whether specific patterns of pathological sagittal alignment are already present in mild AIS.

METHODS

Lateral spinal radiographs of 192 mild (10°-20°) and 253 severe (> 45°) AIS patients and 156 controls were derived from an international consortium. Kyphosis characteristics (T4-T12 thoracic kyphosis, T10-L2 angle, C7 slope, location of the apex of kyphosis and of the inflection point) and sagittal curve types according to Abelin-Genevois were systematically compared between the three cohorts.

RESULTS

Even in mild thoracic AIS, already 49% of the curves presented sagittal malalignment, mostly thoracic hypokyphosis, whereas only 13% of the (thoraco) lumbar curves and 6% of the nonscoliosis adolescents were hypokyphotic. In severe AIS, 63% had a sagittal malalignment. Hypokyphosis + thoracolumbar kyphosis occurred more frequently in high-PI and primary lumbar curves, whereas cervicothoracic kyphosis occurred more in double thoracic curves.

CONCLUSIONS

Pathological sagittal patterns are often already present in curves 10°-20°, whereas those are rare in non-scoliotic adolescents. This suggests that sagittal 'malalignment' patterns are an integral part of the early pathogenesis of AIS.

Staying ahead of the curve: the use of spinopelvic parameters to predict curve progression and bracing success in adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To investigate radiographic sagittal and spinopelvic parameters of patients with adolescent idiopathic scoliosis (AIS) treated with bracing and assess differences among those treated successfully and unsuccessfully. AIS is a three-dimensional deformity of the spine, sharing an intricate relationship with pelvic morphology. However, the most relevant predictors of curve progression have historically been coronal parameters and skeletal maturity. Sagittal and spinopelvic parameters have not been thoroughly investigated as predictors of curve progression and brace treatment success.

METHODS

Retrospective review of AIS patients who underwent brace treatment. Coronal Cobb angles (CC), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), thoracic kyphosis (TK), lumbar lordosis (LL), and thoracic spinopelvic angles (T1SP, T9SP) were measured prior to initiation of bracing. The sagittal and spinopelvic parameters of patients requiring surgical treatment due to curve progression were compared to those treated successfully with bracing.

RESULTS

No significant differences were found for age, race, gender, Risser category (0/1 vs 2/3), initial CC, TK, LL, T1SP, or T9SP between cohorts. The cohort requiring surgery had significantly lower PI (p  <  0.001, 42.0 v. 54.6), SS (p  <  0.001, 37.0 v. 44.5), and PT (p  =  0.003, 5.0 v. 10.2) compared to those successfully treated with bracing. Multivariable models controlling for Risser stage and Initial CC revealed the odds for successful brace treatment increases with an increase in PI (OR  =  1.47, CI 1.18-1.83, p  <  0.001), SS (OR  =  1.26, CI 1.07-1.48, p  =  0.006), and PT (OR  =  1.43, CI 1.09-1.86, p  =  0.006) (Table 3). The odds of successful brace treatment is given per one-unit increase for each radiographic measure after adjusting for Initial CC and Risser sign which were forced into each multivariable model.

CONCLUSIONS

Spinopelvic parameters may indicate potential spine adaptability and skeletal maturity. For these reasons, we proposed that spinopelvic parameters may be a potential predictor of curve progression and brace treatment success. Our results demonstrated a higher risk of curve progression with lower PI, PT, or SS which support this hypothesis, however, given the small sample size and high variability, the magnitude of this effect should be viewed with caution and should serve as an impetus to further, larger scale studies to investigate the value spinopelvic parameters in curve progression and bracing efficacy.

LEVEL OF EVIDENCE

IV.

Idiopathic Scoliosis as a Rotatory Decompensation of the Spine

Many years of dedicated research into the etiology of idiopathic scoliosis have not led to one unified theory. We propose that scoliosis is a mechanical, rotatory decompensation of the human spine that starts in the transverse, or horizontal, plane. The human spine is prone to this type of decompensation because of its unique and individually different, fully upright sagittal shape with some preexistent transverse plane rotation. Spinal stability depends on the integrity of a delicate system of stabilizers, in which intervertebral disc stiffness is crucial. There are two phases in life when important changes occur in the precarious balance between spinal loading and the disc's stabilizing properties: (i) during puberty, when loads and moment arms increase rapidly, while the disc's "anchor," the ring apophysis, matures from purely cartilaginous to mineralized to ultimately fused to the vertebral body, and (ii) in older age, when the torsional stiffness of the spinal segments decreases, due to disc degeneration and subsequent laxity of the fibers of the annulus fibrosus. During these crucial periods, transverse plane vertebral rotation can increase during a relatively brief window in time, either as adolescent idiopathic or degenerative de novo scoliosis. Much more is known of the biomechanical changes that occur during disc aging and degeneration than of the changing properties of the disc during maturation. © 2020 American Society for Bone and Mineral Research (ASBMR).

Current concepts in the diagnosis and management of adolescent idiopathic scoliosis

BACKGROUND

Adolescent Idiopathic Scoliosis (AIS) is a complex 3D structural disorder of the spine that has a significant impact on a person's physical and emotionalstatus. Thus, efforts have been made to identify the cause of the curvature and improve management outcomes.

AIM

This comprehensive review looks at the relevant literature surrounding the possible aetio-pathogenesis of AIS, its clinical features, investigations, surgicalmanagement options, and reported surgical outcomes in anterior spinal fusion, posterior spinal fusion or combined approach in the treatment of AIS.

Classification System of the Sagittal Integral Morphotype in Children from the ISQUIOS Programme (Spain)

The sagittal spinal morphology presents 4 physiological curvatures that increase endurance to axial compression forces and allow adequate postural balance. These curves must remain within normal ranges to achieve a static and dynamic balance, a correct functioning of the muscles and an adequate distribution of the loads, and thus minimize the injury risk. The purpose of this study was to categorize the sagittal spinal alignment according to the different morphotypes obtained for each curve in standing, slump sitting, and trunk forward bending positions in schoolchildren. It was a cross-sectional study. Sagittal spinal curvatures were assessed in 731 students from 16 elementary schools. In the sagittal standing position assessment, 70.45% and 89.06% of schoolchildren presented a “normal” morphotype for both dorsal and lumbar curves, respectively. After the application of the “Sagittal Integral Morphotype” protocol according to the morphotypes obtained in the three positions assessment (standing, slump sitting, and trunk forward bending), it was observed how the frequency of normal morphotypes for the dorsal and lumbar curve decreased considerably (only 32% and 6.6% of children obtained a “normal sagittal integral morphotype” for the thoracic and lumbar curvatures, respectively). These results show how it is necessary to include the slump sitting and trunk forward bending assessment as part of the protocol to define the “integral” sagittal alignment of the spine and establish a correct diagnosis. The use of the diagnostic classification presented in this study will allow early detection of misalignment not identified with the assessment of standing position.

Spinal Coronal and Sagittal Balance in 584 Healthy Individuals During Growth: Normal Plumb Line Values and Their Correlation With Radiographic Measurements

BACKGROUND

Plumb line distances (PDs) are widely used in conservative clinical practice to evaluate the sagittal shape of the spine.

OBJECTIVE

The objective was to assess the normative values of PDs in a large, healthy population in an age range representative of the adolescent population with spinal deformities, and to correlate it with x-ray measurements.

DESIGN

This was a cross-sectional study.

METHODS

Participants were 584 healthy individuals (341 females) with x-rays showing no spine deformities. The whole sample (OVERALL) was divided into 5 groups: 6 to 9 years old (n = 106); >10 years, Risser 0 with triradiate cartilage open (n = 129) or closed (n = 104); Risser 1 to 2 (n = 126); and Risser 3 to 5 (n = 119).PDs were taken by maintaining a tangent to the thoracic kyphosis apex at C7, T12, L3, and S2. Sagittal index (C7 + L3), and sagittal and coronal balances (C7 related to S2) were calculated.

RESULTS

In OVERALL, PDs at C7, T12, L3, and S2 were 39.9 ± 16.7, 21.4 ± 15.3, 39.9 ± 15, 20.6 ± 17.0 mm, respectively. Sagittal index was 79.8 ± 26.8, sagittal balance was 19.3 ± 17 mm anterior to S2 plumb line; 13.5% had a coronal imbalance of 11.4 ± 5.4 mm to the right and 24.7% of 13.2 ± 6.0 mm to the left. C7 and L3 PDs, sagittal index, and sagittal balance were significantly lower in ages 6 to 9 compared to older patients in Risser 1 to 2 group. C7 and S2 PDs and sagittal index were significantly larger in males. Sagittal index correlated with thoracic kyphosis Cobb degrees (r = 0.47).

LIMITATIONS

The participants were not randomly chosen from the general population; and they had an x-ray because of spine pathology suspicion.

CONCLUSIONS

This study shows normative data to be used in clinical practice. Sagittal spinopelvic alignment has gained more and more importance in the last decades because of its high correlation to Health-Related Quality of Life scores in adults. 1.

Using the Scoliometer and a Surface Topography Apparatus to Check if Back Trunk Asymmetry Changes in Children and Adolescents in the Forward Flexion and Standing Erect Positions

Background

The purpose of this study is to evaluate the effects of the forward bending (FB) test versus the standing erect (SE) position on back trunk asymmetry (TA). The Scoliometer in the FB position and the 4D Formetric (4DF; Diers International, Schlangenbad, Germany) readings in the SE position were assessed.

Method

The angle of trunk inclination (ATI) was measured at the midthoracic, thoracolumbar, and lumbar levels using the Scoliometer in the FB position and the 4DF in the SE position.

A total of 134 subjects attending the scoliosis clinic (86 girls and 48 boys), age ranging from seven to 18 years, were assessed. The children and adolescents were divided into three groups according to the severity of TA, symmetric group 1 (0-2 degrees), asymmetry group 2 (2 to 6 degrees), and group 3 having asymmetry of seven or more degrees. Children with leg length discrepancy were excluded from the study.

The IBM SPSS v.20 package (IBM Corp., Armonk, NY) was used for analysis.

Results

At the midthoracic level comparing the Scoliometer to 4DF readings in males in group 1, the Wilcoxon signed ranks test was p=0.451 while for the Spearman’s Rho, it was -0.138; in group 2, p=0.184 and Rho=0.204; and in group 3, p=0.109 and Rho=0.500. For females in group 1, p=0.000 while Rho=0.003; in group 2, p=0.008 and Rho=0.000, and in group 3, p=0.003 while Rho=0.642.

At the thoracolumbar level in males for group 1, p=0.004 and Rho=-0.517; in group 2, p=0.006 and Rho=0.000; and in group 3, p=0.043 while Spearman’s Rho=0.053. For females in group 1, p=0.000 and Rho=-0.095; in group 2, p=0.000 and Rho=-0.171; in group 3, p=0.001 while Rho= -0.081. At the lumbar level for males in group 1 p=0.000 while Rho=0.149; in group 2, p=0.003 and Rho=0.373; while in group 3, p=0.109 and Rho= (-). For females in group 1, p=0.000 while Rho=-0.072; in group 2, p=0.001 and Rho=0.168; and in group 3, p=0.068 while Rho=0.500.

Conclusion

The results of this study show that the back TA in children and adolescents is not similar in the FB and SE positions. This phenomenon probably is attributed to the complicated trunkal (spinal, thoracic, and pelvic) anatomy, and the results of this study may be used as a useful foundation for further understanding of torso dynamics.

3D Deformation Patterns of S Shaped Elastic Rods as a Pathogenesis Model for Spinal Deformity in Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) deformity of the spinal column in pediatric population. The primary cause of scoliosis remains unknown. The lack of such understanding has hampered development of effective preventive methods for management of this disease. A long-held assumption in pathogenesis of AIS is that the upright spine in human plays an important role in induction of scoliosis. Here, the variations in the sagittal curve of the scoliotic and non-scoliotic pediatric spines were used to study whether specific sagittal curves, under physiological loadings, are prone to 3D deformation leading to scoliosis. To this end, finite element models of the S shaped elastic rods, which their curves were derived from the radiographs of 129 sagittal spinal curves of adolescents with and without scoliosis, were generated. Using the mechanics of deformation in elastic rods, this study showed that the 3D deformation patterns of the two-dimensional S shaped slender elastic rods mimics the 3D patterns of the spinal deformity in AIS patients with the same S shaped sagittal spinal curve. On the other hand, the rods representing the non-scoliotic sagittal spinal curves, under the same mechanical loading, did not twist thus did not lead to a 3D deformation. This study provided strong evidence that the shape of the sagittal profile in individuals can be a leading cause of the 3D spinal deformity as is observed in the AIS population.

Evaluation of balance in young adults with idiopathic scoliosis

Objectives

This study aims to evaluate the relation of scoliosis with coronal and sagittal balance parameters and the effect of postural balancing in young adults with idiopathic scoliosis.

Patients and methods

Between April 2017 and June 2017, a total of 24 patients (7 males, 24 females; mean age 20.3±2 years; range 17 to 24) who were diagnosed with scoliosis and 65 age- and sex-matched healthy controls (20 males, 45 females; mean age 20.3±1.6 years; range 19 to 25) were included in the study. The Cobb angle, sagittal balance, coronal balance, and truncal shift were measured with radiographs in the patient group. The Biodex Balance System (BBS) was used to assess the general stability index, anterior- posterior and medial-lateral stability index, and fall risk.

Results

All balance parameters were significantly worse in the patient group than in the control group (p<0.05). The static balance was mostly associated with sagittal balance, followed by coronal balance. In the patients with left scoliosis, sagittal balance was 93% negative and 67% of the patients gave their weight to the back. Coronal balance was negative in 60% of the patients and 93.3% of the patients were weighted to the right side. In 89% of the patients with right scoliosis, sagittal balance was negative and 89% of the patients gave their weight to the back. Coronal balance was 44% neutral and 78% of the patients gave their weight to the right side.

Conclusion

In patients with scoliosis, the static balance is worse than healthy individuals. Static balance is mostly related to sagittal balance and also to coronal balance. While the coronal balance tends to be in the direction of the curve, both right and left scoliosis give more weight to the right.

Sagittal spinal parameters after en bloc resection of mobile spine tumors

BACKGROUND CONTEXT

En bloc resection and reconstruction (EBR) in patients with spinal malignancy aims to achieve local disease control. This is an invasive procedure with significant alterations of the physiological anatomy and subsequently, the spino-pelvic alignment. Sagittal spinal parameters are useful measurements to objectively identify disproportionate alignment on a radiograph. In the field of spinal deformities, there is increasing evidence for a relationship between sagittal alignment and patient reported outcomes.

PURPOSE

To determine sagittal spino-pelvic alignment after EBR in patients with spinal malignancies and the effect of these parameters on surgical and patient reported outcomes.

STUDY DESIGN

A retrospective case series.

METHODS

We included 35 patients who underwent EBR for spinal malignancies between 2000 and 2018. Radiographic measurements were performed using semi-automatic software; the parameters included were pelvic incidence (PI), sacral slope, pelvic tilt (PT), global tilt and lumbar lordosis. We calculated PI-based Global Alignment and Proportion (GAP) scores and prospective patient reported outcome scores Patient-Reported Outcome Measurement Information System-Physical Function (PROMIS-PF) were used.

RESULTS

Twenty-one (60%) patients filled out the PROMIS-PF score at a median of 16 months (Interquartile Range (IQR) 4-108) after surgery with a median score of 39 (IQR 32-42), the median GAP score was 7 (IQR 5-9). Bivariate analysis showed no statistically significant relationship between GAP score and instrumentation failure or need for revision surgery. Multivariable analysis of GAP score and PROMIS-PF score corrected for local disease recurrence showed a statistically significant correlation coefficient of -1.721 (p=.026; 95%CI=-3.216, -0.226).

CONCLUSION

In this cohort, all patients had a moderate or severe disproportioned spinal alignment after EBR and reconstruction surgery. The degree of sagittal spino-pelvic misalignment after EBR for spinal malignancies seems to be associated with patient reported health status in terms of PROMIS-PF scores. Further research with a larger patient cohort and standardized imaging and follow-up protocols is necessary in order to accurately use sagittal alignment as a predictive value for instrumentation failure and revision surgery.

Sagittal standing posture and relationships with anthropometrics and body composition during childhood

BACKGROUND

Anthropometry and body composition are plausible influences on pediatric sagittal standing posture. Despite that, the relationship of anthropometrics since birth and body composition with individual postural parameters in children has never been assessed.

RESEARCH QUESTION

To assess the associations between anthropometrics since birth and body composition parameters, and angles of sagittal standing posture in children.

METHODS

The sample included 1021 girls and 1096 boys, evaluated in the population-based birth cohort Generation XXI, Portugal. Weight and height were obtained at birth, 4 and 7 years of age. At age 7, total body less head fat/fat-free mass and bone properties were estimated from whole body dual energy X-ray absorptiometry scans and posture was assessed through right-side photographs during habitual standing with retro-reflective markers placed on body landmarks.

RESULTS

Girls showed increased values of lumbar angle, head and neck flexion, and craniocervical angle with the largest mean (standard deviation) difference in lumbar angle [281.7° (7.4) vs. 276.8° (7.1) in boys, p < 0.001]. In both genders, weight and body mass index were weakly associated with lumbar angle: 0.24 ≥ r ≤ 0.31 in girls and 0.16 ≥ r ≤ 0.26 in boys, all p < 0.001. Fat and fat-free mass and bone mineral density were weakly associated with lumbar angle in both genders.

SIGNIFICANCE

Our study showed clear postural heterogeneity between girls and boys in early ages. Lumbar angle is likely to be the single most relevant proxy of overall posture based on the associations with the exposures reported in this study.

Development of Pelvic Incidence and Lumbar Lordosis in Children and Adolescents

Pelvic incidence (PI) is a measure of the sagittal orientation of the sacrum relative to the acetabula and is not dependent on posture. In asymptomatic adults, PI correlates with lumbar lordosis. Lumbar lordosis is shown to increase with age following the onset of unassisted bipedal locomotion in children, but to what extent PI changes in relation to lumbar lordosis during skeletal maturation is unclear. The purpose of this study is to understand how PI, lumbar lordosis, and age are related in children and adolescents. PI, supine lumbar lordosis (SLL), and individual wedging angles of the lumbar vertebral bodies were measured on mid-sagittal reformatted images from 144 abdominal computed tomographic scans of individuals aged 2-20 years old, divided into three separate age categories representing pre-growth spurt (ages 2-9), growth spurt (10-15), and post-growth spurt (16-20). Our results showed that, while SLL significantly increased with age during development, PI did not. Despite the fact that PI hardly changed with age, the difference between PI and SLL decreased nonlinearly with age. SLL did not correlate with PI in the youngest age category, but positively correlated with PI in the middle and oldest age categories. The relationship between lumbar lordosis and PI, which is correlated in adults, was significant in our older age categories and not in our youngest age category. Our results indicate that PI in children and adolescents may have some predictive value for adult lumbar lordosis. Anat Rec, 302:2132-2139, 2019. © 2019 American Association for Anatomy.

Preoperative Sagittal Spinal Profile of Adolescent Idiopathic Scoliosis Lenke Types and Non-Scoliotic Adolescents: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

This study aims to determine the differences in sagittal spinopelvic parameters between adolescent idiopathic scoliosis (AIS) Lenke types and non-scoliotic controls through a systematic review and meta-analysis of the available literature.

SUMMARY OF BACKGROUND DATA

AIS classification mainly focuses on frontal curve differences; however, the variations in the sagittal spinopelvic alignment in the current classification system is not fully established.

METHODS

Following preferred reporting items for systematic reviews and meta-analyses guidelines, searches were performed for sagittal spinal and pelvic parameters of Lenke types and non-scoliotic controls in PubMed, Scopus, EMBASE, and Cochrane databases. Selection criteria were: (1) age range 10 to 21 years; (2) Lenke types 1-6 (for AIS group) or non-scoliotic adolescents (for the control group); (3) preoperative data for T5-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and sagittal vertical axis (SVA). (4) Written in English language. PI-LL mismatch was calculated from the weighted average of PI and LL. Publication bias between studies and within studies quality were assessed. A meta-regression compared each measured variable between groups. Thoracic (Lenke1 and 2) and thoracolumbar/lumbar (Lenke 5 and 6) scoliosis were combined and statistically compared with the control group.

RESULTS

Meta-analysis, including 81 AIS and 18 control studies, showed no significant differences in sagittal parameters between Lenke types and controls for LL, PI, PI-LL mismatch, SS, and SVA (P > 0.05). Publication bias was significant in Lenke 1 TK, Control LL, and Lenke 1, and 5 SVA. Stratification based on deformity region (thoracic vs. thoracolumbar/lumbar) showed no significant differences in sagittal spinopelvic parameters (P > 0.05).

CONCLUSION

No definitive difference was found between non-scoliotic adolescents and Lenke types in sagittal spinal and pelvic parameters. Future studies on developing a sagittal classification specific to AIS patients with a goal to improve surgical planning and outcome prediction are highly encouraged.

LEVEL OF EVIDENCE

4.

Sagittal Spinopelvic Alignment After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

The aim of this study was to determine the differences in the sagittal spinopelvic parameters between the nonscoliotic controls, preoperative, and different time points postoperative in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The postoperative changes in the sagittal profile of Lenke 1 and 5 AIS at varying time points after posterior spinal fusion (PSF) has not been rigorously demonstrated; studies performed have had conflicting results.

METHODS

Sagittal spinal and pelvic parameters, T5-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and sagittal vertical axis (SVA), for Lenke 1 and 5 preoperatively, at immediate, less than 2-year, and more than 2-year postoperatively, and for nonscoliotic adolescents were searched. Differences in the sagittal spinopelvic parameters between preoperative and the follow-ups and between the nonscoliotic and pre- and postoperative AIS subtypes were calculated through meta-analysis.

RESULTS

A total of 22 studies on Lenke1 (1229 patients), 13 studies on Lenke5 (437 patients), and 18 studies on controls (1636 patients) were reviewed. Among all the measured variables, only PI in Lenke1 was significantly different between the final follow-up and controls, P < 0.05. In Lenke 1, SVA was significantly more anterior at the immediate postoperative than preoperative, but continued moving posteriorly up to 2-year postoperative resulting in no significant difference in the SVA position between the final follow-up and preoperative, P > 0.05. In Lenke 5, SVA was significantly more posterior at the immediate postoperative and more anterior at the final follow-up than the preoperative measurements, p < 0.05.

CONCLUSIONS

Continuous changes in the sagittal spinal parameters should be expected after PSF. Normalization of the sagittal spinal parameters appears to be the rule after PSF, and watchful waiting appears to be appropriate in this population when viewing the lateral X-ray postoperatively.

LEVEL OF EVIDENCE

4.

The Development of Kyphosis and Lordosis in the Growing Spine

STUDY DESIGN

A longitudinal cohort study.

OBJECTIVE

The aim of this study was to do the analysis of the development of kyphosis and lordosis in the growing spine.

SUMMARY OF BACKGROUND DATA

Previous studies have measured kyphosis and lordosis in different ways with differing techniques. None of the previous literature has a truly longitudinal design and there is disagreement as to whether there exists a difference between the development of kyphosis and lordosis between males and females.

METHODS

Repeated measures using Integrated Shape Imaging System Integrated Shape Imaging System 2 surface topography over 5 years of a group of children aged 5 to 16 years without spinal deformity. Longitudinal analysis was performed using linear mixed effects modeling.

RESULTS

There were 638 measures in 194 children. Both kyphosis and lordosis increased with age in both males and females (P < 0.001 for kyphosis and P = 0.002 for lordosis). There was no statistical difference in the development of kyphosis between males and females (P = 0.149). However, there was a significant difference in lordosis between males and females (P < 0.001) with female lordosis larger than that seen in males. Kyphosis and lordosis increased in a nonlinear fashion with age.

CONCLUSION

Kyphosis and lordosis increase as children age. Between males and females there is no difference in the increase in the size of kyphosis, but there is difference in the size of lordosis with females having greater lordosis versus males at the same age.

LEVEL OF EVIDENCE

2.

2016 SOSORT guidelines: orthopaedic and rehabilitation treatment of idiopathic scoliosis during growth

BACKGROUND

The International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) produced its first guidelines in 2005 and renewed them in 2011. Recently published high-quality clinical trials on the effect of conservative treatment approaches (braces and exercises) for idiopathic scoliosis prompted us to update the last guidelines' version. The objective was to align the guidelines with the new scientific evidence to assure faster knowledge transfer into clinical practice of conservative treatment for idiopathic scoliosis (CTIS).

METHODS

Physicians, researchers and allied health practitioners working in the area of CTIS were involved in the development of the 2016 guidelines. Multiple literature reviews reviewing the evidence on CTIS (assessment, bracing, physiotherapy, physiotherapeutic scoliosis-specific exercises (PSSE) and other CTIS) were conducted. Documents, recommendations and practical approach flow charts were developed using a Delphi procedure. The process was completed with the Consensus Session held during the first combined SOSORT/IRSSD Meeting held in Banff, Canada, in May 2016.

RESULTS

The contents of the new 2016 guidelines include the following: background on idiopathic scoliosis, description of CTIS approaches for various populations with flow-charts for clinical practice, as well as literature reviews and recommendations on assessment, bracing, PSSE and other CTIS. The present guidelines include a total of 68 recommendations divided into following topics: bracing (n = 25), PSSE to prevent scoliosis progression during growth (n = 12), PSSE during brace treatment and surgical therapy (n = 6), other conservative treatments (n = 2), respiratory function and exercises (n = 3), general sport activities (n = 6); and assessment (n = 14). According to the agreed strength and level of evidence rating scale, there were 2 recommendations on bracing and 1 recommendation on PSSE that reached level of recommendation "I" and level of evidence "II". Three recommendations reached strength of recommendation A based on the level of evidence I (2 for bracing and one for assessment); 39 recommendations reached strength of recommendation B (20 for bracing, 13 for PSSE, and 6 for assessment).The number of paper for each level of evidence for each treatment is shown in Table 8.

CONCLUSION

The 2016 SOSORT guidelines were developed based on the current evidence on CTIS. Over the last 5 years, high-quality evidence has started to emerge, particularly in the areas of efficacy of bracing (one large multicentre trial) and PSSE (three single-centre randomized controlled trials). Several grade A recommendations were presented. Despite the growing high-quality evidence, the heterogeneity of the study protocols limits generalizability of the recommendations. There is a need for standardization of research methods of conservative treatment effectiveness, as recognized by SOSORT and the Scoliosis Research Society (SRS) non-operative management Committee.

Associations of anthropometry since birth with sagittal posture at age 7 in a prospective birth cohort: the Generation XXI Study

OBJECTIVES

Adult sagittal posture is established during childhood and adolescence. A flattened or hypercurved spine is associated with poorer musculoskeletal health in adulthood. Although anthropometry from birth onwards is expected to be a key influence on sagittal posture design, this has never been assessed during childhood. Our aim was to estimate the association between body size throughout childhood with sagittal postural patterns at age 7.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

A subsample of 1029 girls and 1101 boys taking part in the 7-year-old follow-up of the birth cohort Generation XXI (Porto, Portugal) was included. We assessed the associations between anthropometric measurements (weight, height and body mass index) at birth, 4 and 7 years of age and postural patterns at age 7. Postural patterns were defined using latent profile analysis, a probabilistic model-based technique which allows for simultaneously including anthropometrics as predictors of latent profiles by means of logistic regression.

RESULTS

Postural patterns identified were sway, flat and "neutral to hyperlordotic"in girls, and "sway to neutral", flat and hyperlordotic in boys; with flat and hyperlordotic postures representing a straightened and a rounded spine, respectively. In both girls and boys, higher weight was associated with lower odds of a flat pattern compared with a sway/"sway to neutral"pattern, with stronger associations at older ages: for example, ORs were 0.68 (95% CI 0.53 to 0.88) per SD increase in birth weight and 0.36 (95% CI 0.19 to 0.68) per SD increase in weight at age 7 in girls, with similar findings in boys. Boys with higher ponderal index at birth were more frequently assigned to the hyperlordotic pattern (OR=1.44 per SD; p=0.043).

CONCLUSIONS

Our findings support a prospective sculpting role of body size and therefore of load on musculoskeletal spinopelvic structures, with stronger associations as children get older.

The weight of pupils' schoolbags in early school age and its influence on body posture

BACKGROUND

Postural development progresses through a series of stages (growth spurts, development of balance and coordination, postural stability) which occur when children are at school age. The reduction in the level of physical activity, increased body weight, overloaded school bags, asymmetry of the backpack straps, the method of putting on and taking off the backpacks and increased usage of electronic devices have negative side effects such as bad body posture habits.

METHODS

A prospective cohort study in the group of 155 pupils at early school age 7-9 years old has been conducted. Examinations have been conducted twice: first, at the beginning of the school year (initial examination) and second - after 10-11 months (final examination). Age, gender, BMI, weight of school bag carried to school and the length of straps have been assessed. Body posture measurement (using Adams' test), the evaluation of the plumb line deflection from the gluteal cleft, the angle values of kyphosis and lordosis (according to Dobosiewicz methodology) and the pelvis and shoulder blades position (using a ruler and pediscoliometer) have been also measured.

RESULTS

The mean weight of a school bag in the initial study was 6.3 ± 0.8 (range between 4,7 and 9 kg). A tendency to carry slightly heavier school bags was noted in boys (6.7 vs. 5.9 kg; p = 0,00001). This tendency has linearly changed with age (R = 0.68; p < 0,001). In 3.2% of all school bags of children, weights exceeded norms with regard to the weight of the pupil. The increase of torso rotation exceeding norms was observed in 35.3% of girls (mean 2.7 ± 1.2) and in 60.9% of boys (mean 2.3 ± 1.3). The increase of kyphosis angle was noted in 48.5% of girls and in 36.8% of boys. The difference of straps length had a significant influence on the increase of rotation in upper thoracic spine, thoracolumbar junction and it also had influence on the decrease of lumbar lordosis in the group of girls.

CONCLUSIONS

Differences in the weight of school bags after one school year have influenced changes in body posture abnormalities, especially in rotation parameters. Backpack straps asymmetry was noticeably stronger in the group of girls and the difference between braces may have an impact on some posturometric parameters. Lack of proper backpack lifting skills tends to create programs and training systems in this regard.

Defining Patterns of Sagittal Standing Posture in Girls and Boys of School Age

Background

Sagittal postural patterns are associated with back pain in adolescents and adults. However, whether postural patterns are already observable during childhood is unknown. Such a finding would confirm childhood as a key period for posture differentiation and thus for chronic pain etiology.

Objective

The aims of this study were to identify and describe postural patterns in girls and boys of school age.

Design

This was a cross-sectional study.

Methods

Eligible children were evaluated at age 7 in the population-based birth cohort Generation XXI in Portugal. Posture was assessed through right-side photographs during habitual standing with retroreflective markers placed on body landmarks. Postural patterns were defined from trunk, lumbar, and sway angles with model-based clusters, and associations with anthropometric measures were assessed by multinomial logistic regression.

Results

Posture was evaluated in 1,147 girls and 1,266 boys. Three postural patterns were identified: sway (26.9%), flat (20.9%), and neutral to hyperlordotic (52.1%) in girls and sway to neutral (58.8%), flat (36.3%), and hyperlordotic (4.9%) in boys. In girls, a higher body mass index was associated with a sway pattern (versus a flat pattern: odds ratio = 1.21; 95% CI = 1.12, 1.29), whereas in boys, a higher body mass index was associated with a hyperlordotic pattern (versus a flat pattern: odds ratio = 1.30; 95% CI = 1.17, 1.44).

Limitations

Photogrammetry as a noninvasive method for posture assessment may have introduced some postural misclassifications.

Conclusions

Postural patterns in 7-year-old children were consistent with those previously found in adults, suggesting that childhood is a sensitive period for posture differentiation. Sagittal morphology differed between girls and boys, emphasizing sex-specific biomechanical loads during a habitual upright position even in prepubertal ages.

The Spinopelvic Geometry in Different Lenke Curve Types of Adolescent Idiopathic Scoliosis

BACKGROUND

The Lenke classification is well established in differentiation of curve types in adolescent idiopathic scoliosis (AIS) and guides selection of fusion levels. However, to date, it has neglected the spinopelvic parameters that have been associated with compensatory mechanisms in balancing the human erect posture and adjacent segment problems after spinal fusion. The aim of this study was to investigate spinopelvic parameters in different types of AIS curves.

MATERIAL AND METHODS

Preoperative whole-spine radiographs from 100 patients with AIS were reviewed and the curves were classified according to Lenke. In addition, sagittal spinopelvic parameters (pelvic incidence, sacral slope, pelvic tilt) were measured and compared between different curve types and to normal population values.

RESULTS

The spinopelvic balance was not statistically distinguishable in different Lenke curve types. Slight differences of the spinopelvic balance, compared with normal population values, were found in AIS Lenke Type 5 and 6 curves (major curve at the lumbar/thoracolumbar region) with a pelvic incidence of 44° ± 8° (norm 49°), sacral slope of 34° ± 7° (norm 41°), and pelvic tilt of 10° ± 7° (norm 8°).

CONCLUSION

Overall, the variances of spinopelvic parameters in different AIS curve types do not seem statistically large enough for a potential clinical relevance. However, the sacrum is more verticalized in AIS curves with major curves located in the lumbar/thoracolumbar region. It remains to be investigated whether such a verticalized sacrum might be a compensatory mechanism to keep the whole spine balanced and if it reverses with correction of the scoliosis.

The Development of Thoracic Vertebral Sagittal Morphology During Childhood

STUDY DESIGN

This is a cross-sectional descriptive study objectives to describe normal development of thoracic vertebrae during childhood and document contribution of individual vertebral shape to the sagittal alignment.

SUMMARY OF BACKGROUND DATA

Sagittal spinal alignment changes during growth. The changes in sagittal alignment during adolescent growth spurt as well as the individual shapes of thoracic vertebrae have been implicated as factors for the development of adolescent idiopathic scoliosis (AIS). The contribution of individual vertebral shape to the sagittal alignment and the changes in the vertebral shape with growth is not known.

METHODS

Sagittal computed tomographic (CT) scans of thoracic vertebrae were examined in children without any evidence of spinal deformity. Vertical distances between the endplates at the most anterior and most posterior sides of vertebral body were measured as anterior vertebral height (aVH) and posterior vertebral height (pVH), respectively.

RESULTS

There were a total of 133 CT scans done on 71 male and 62 female children. The children were grouped as follows: Group I (0-2 years of age), Group II (3-6 years of age), Group III (7-9 years of age), Group IV (10-12 years of age), and Group V (13-16 years of age). A-P ratios of vertebral heights were grouped as T1-T5, T6-T8, and T9-T12. Measurements demonstrated that the anterior and posterior heights in each vertebra grew longitudinally and consistently with increasing age. The aVH/pVH ratio of each individual vertebra showed no significant difference according to age. Measurements of thoracic vertebrae on sagittal spinal CT images did not show any differences in the relative growth and heights of the anterior versus posterior walls of the vertebral bodies in any of the segments in any age or age group.

CONCLUSIONS

The sagittal alignment changes during growth are likely related to maintenance of sagittal balance rather than the shapes of individual vertebrae.

LEVEL OF EVIDENCE

Level II.

Adolescent idiopathic scoliosis (AIS): a multifactorial cascade concept for pathogenesis and embryonic origin

This paper formulates a novel multifactorial Cascade Concept for the pathogenesis of adolescent idiopathic scoliosis (AIS). This Concept stems from the longitudinal findings of Clark et al. (J Bone Miner Res 29(8):1729-36, 2014) who identified leptin body composition factors at 10 years of age associated with a scoliosis deformity found at 15 years. We interpret these findings in the light of some concepts for AIS pathogenesis. In particular, we speculate that the leptin body composition effect is linked to central nervous system development and the initiation of the asynchronous neuro-osseous growth mechanism that involves the creation of a neuraxis tether of relative anterior vertebral overgrowth. The latter mechanism in combination with age and gender-related anatomical variants of vertebral backward tilt (dorsal shear concept), human upright posture, adolescent growth factors, Hueter-Volkmann effect in vertebrae and vertebral bone mass abnormalities, lead to AIS, possibly both initiation and progression of scoliosis curvatures. Being multifactorial, while the Cascade Concept cannot be tested for all its components, some components should be testable by the method of numerical simulation.

Clark et al. (J Bone Miner Res 29(8):1729-36, 2014) also suggested the origin of scoliosis was in the embryonic stages of life from cell types, including adipocytes and osteoblasts, derived from the same progenitor cells, and myoblasts from mesodermal somites. The involvement of cell types from different developmental origins suggests a process acting in embryonic life at a similar time, probably environmental, as previously proposed from anthropometric studies. As a Complex disease, AIS will involve genetic, environmental and life style factors operating in development and growth; this possibility needs evaluating in epidemiological studies.

Thoracic sagittal plane variations between patients with thoracic adolescent idiopathic scoliosis and healthy adolescents

PURPOSE

To analyze the sagittal thoracic parameters of different types of progressive thoracic adolescent idiopathic scoliosis (AIS) patients and compare them with healthy adolescents.

METHODS

115 AIS patients with main thoracic curves (Cobb: 59.4 ± 12.7) were prospectively compared with 116 healthy adolescents. The AIS and control (C) groups were homogeneous in terms of age and gender. Standing sagittal radiographs were analyzed for differences in T5-T12 kyphosis, T5-T8 and T9-T12 segmental kyphosis, the change between these two angles, and the double rib contour sign. Statistical analyses were performed using the χ ², one-way ANOVA, Mann-Whitney U and Student's t tests.

RESULTS

The sagittal parameters of Lenke 1 curves did not differ from healthy adolescents (T5-T8: 17.1 ± 10 vs C: 16 ± 7; T9-T12: 6.3 ± 7 vs C: 7.9 ± 5; T5-T12: 23.9 ± 14 vs C: 23.9 ± 8). Compared with the controls, Lenke type 3 curves were globally more hypokyphotic (T5-T12: 18.9 ± 12 vs C: 23.9 ± 8, P = 0.027) due to a "lordosis" of the lower thoracic segment (T9-T12: 0.9 ± 10 vs C: 7.9 ± 5, P = 0.001). Type 2 curves tended to exhibit more pronounced upper thoracic kyphosis (T5-T8: 20.7 ± 12 vs C: 16 ± 7). Both types 2 and 3 require a marked TK changes in the transition between the upper and lower thoracic segments to compensate for global (T5-T12) kyphosis.

CONCLUSIONS

In this 2D analysis of moderate AIS, Lenke 1 curves exhibited normal thoracic sagittal parameters, which brings into question the effect of lordosis on the development of single thoracic curves. Lenke 3 curves exhibited lower thoracic segmental hypokyphosis, and the type 2 showed upper segmental hyperkyphosis. These results should be considered when planning a surgical strategy.

Adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is the most common form of structural spinal deformities that have a radiological lateral Cobb angle - a measure of spinal curvature - of ≥10(°). AIS affects between 1% and 4% of adolescents in the early stages of puberty and is more common in young women than in young men. The condition occurs in otherwise healthy individuals and currently has no recognizable cause. In the past few decades, considerable progress has been made towards understanding the clinical patterns and the three-dimensional pathoanatomy of AIS. Advances in biomechanics and technology and their clinical application, supported by limited evidence-based research, have led to improvements in the safety and outcomes of surgical and non-surgical treatments. However, the definite aetiology and aetiopathogenetic mechanisms that underlie AIS are still unclear. Thus, at present, both the prevention of AIS and the treatment of its direct underlying cause are not possible.