Age- and gender-related normative value of whole-body sagittal alignment based on 584 asymptomatic Chinese adult population from age 20 to 89.

To establish the age- and sex-related normative values of sagittal alignment in asymptomatic Chinese adults, and to investigate the changes and possible associated compensation mechanisms across age groups. 584 asymptomatic Chinese adults aged 20-89 years were recruited. Subjects were grouped according to age and gender. Whole-body standing radiographs were acquired for evaluating sagittal alignment from spine to lower limb. Sagittal parameters between gender in different age groups were compared via independent t test. Pearson correlation analysis was used to demonstrate relationships between parameters. Thoracic kyphosis (TK) increased steadily while lumbar lordosis decreased gradually in both genders. Pelvic tilt (PT) in male is greater than in female across all age groups with age related gradual increase. There were significant differences between male and female from 20s to 60s in terms of knee flexion angle (KA) and ankle dorsiflexion angle (AA), but the differences were not significant after 60s. T1 pelvic angle (TPA) was significantly correlated with spinal, pelvic and lower-limb alignment. The older group (≥50 years) had a stronger correlation of TPA with PT and KA, whereas the younger (<50 years) had stronger correlation with TK. This study comprehensively presented the normative sagittal alignment based on a large asymptomatic population, which could serve as an age- and gender-specific reference value for spine surgeons when planning for correction surgery. Age can influence the recruitment of compensation mechanism that involve more pelvic and lower limb mechanisms for elderly people.

Morphological changes of intervertebral disc in relation with curve severity of patients with Adolescent Idiopathic Scoliosis - a T2-weighted MRI study.

The purpose of this study was to evaluate the morphological changes of intervertebral discs (IVD) and vertebral bodies (VB) in AIS girls according to the subgroups with different curve severity by magnetic resonance imaging (MRI). This study included 33 age-matched female controls and 76 AIS girls with a right-sided thoracic curvature. Wedge angle, height ratio and distance ratio of VB and IVD were measured on the best midline coronal and sagittal planes from reformatted MRI spine. Volumes of VB, IVD and nucleus pulposus (NP) were evaluated on volumetric images. One-way ANOVA with Bonferroni correction was used. There was significant difference in wedge angle and height ratio of VB and IVD between AIS and controls. In severe-AIS, the position of NP was significantly shifted to the convexity when compared with non-severe AIS and controls. Whereas, the volume of IVD and NP in severe-AIS was found to be significantly smaller. On top of coronal wedging of VB and IVD, there was significantly reduced volume of IVD and NP in severe-AIS patients, despite T2 signal of IVD was preserved. The current findings indicate that early mechanical effects on the discs and vertebrae in adolescent scoliotic spine is evident on quantitative imaging. Importantly, these patients may be vulnerable to disc degeneration if no operative treatment is prescribed.

Is ultrasound accurate for radiation-free quantitative assessment of spinal curvatures in patients with idiopathic scoliosis - a systematic review and meta-analysis.

Despite application of ultrasound for quantitative measurement of spinal curvatures has been reported with various studies, a systematic review for such is lacking. This systematic review aimed to evaluate (1) reliability of ultrasound; (2) validity of ultrasound using radiographic measurement as gold standard in idiopathic scoliosis patients; and (3) the use of various anatomical landmarks for measurement of spinal curvatures. MEDLINE, EMBASE, CINAHL, and CENTRAL databases were searched. QUADAS-2 quality assessment tool was adopted. Reliability of ultrasound in terms of intra-class correlation coefficient was recorded. Pearson correlation coefficients between ultrasound and radiographic measurements were extracted for meta-analysis. Subgroup analyses based on ultrasound measurement protocols of spinous process (SP), transverse processes (TP) and center of lamina (COL) were conducted. Eleven articles reporting 18 correlation analyses on 766 subjects were eligible for meta-analysis. The mean inter-rater reliability of ultrasound measurement was 0.87±0.07. Pooled correlation for all studies was 0.918 (95% CI: 0.868-0.949), exhibiting substantial heterogeneity (I2=90.50%, p<0.001). Subgroup analyses showed that pooled correlations were 0.887 for COL method (comprising 356 subjects); 0.924 for SP method (255 subjects); and 0.941 for TP method (117 subjects); all with notable heterogeneity (I2>90%, p<0.001). The overall risk of bias was rated moderate; yet publication bias was noted. Evidences showed that ultrasound was a promising non-invasive method with satisfactory validity and reliability for measuring coronal curvatures utilizing the SP, TP or COL methods. Further development of three-dimensional ultrasound towards scoliosis assessment will facilitate its translational application for managing scoliosis.

Using ultrasound for screening scoliosis to reduce unnecessary radiographic radiation - a prospective diagnostic accuracy study on 442 schoolchildren.

Scoliosis screening is important for timely initiation of brace treatment to mitigate curve progression in skeletally immature children. Scoliosis screening programs frequently include the protocol of referring children screened positive with Scoliometer and Moiré Topography for confirmatory standard radiography. Despite being highly sensitive (88%) for detecting those who require specialist referral, the screening program was found to have more than 50% false positive rate that leads to unnecessary radiation exposure. Radiation-free ultrasound has been reported to be reliable for quantitative assessment of scoliosis curves. The aim of this prospective diagnostic accuracy study was to determine the accuracy of ultrasound in determining the referral status for children initially screened positive for scoliosis. 442 schoolchildren with a mean Cobb angle of 14.0 ± 6.6° were recruited. Using x-ray as the gold standard, the sensitivity and specificity of ultrasound in predicting the correct referral status were 92.3% and 51.6% respectively. ROC curve analysis revealed an area under curve of 0.735 for ultrasound alone and 0.832 for ultrasound plus scoliometer measurement. The finding provided strong evidences on the accuracy of ultrasound in determining the referral status that could result in more than 50% reduction of unnecessary radiation exposure for children undergoing scoliosis screening.