The Development of Kyphosis and Lordosis in the Growing Spine

Analysis of sagittal spinal alignment at the adolescent age: for furniture design

Knowledge of the parameters of the human spine is essential in designing ergonomic furniture. The purpose of this study was to evaluate spinal alignment in adolescents of various ages. The lengths, curvatures, and concave-convex spacings of the spine were investigated in 268 participants aged 9-18 years. Ten ages were classified, and the rate of increase of parameters was calculated for each age and age group. The results showed that spinal parameters, except for cervical lordosis, increased with age. Adolescents were classified as 9-10, 11-12, 13-15, and 16-18 years old. A rapid increment of lengths and concave-convex spacings occurred at ages 13-15, while that of curvatures occurred at ages 16-18. Spinal parameters differed significantly among the age groups (p < 0.05). Concave-convex spacings reflected differences in the spine more clearly than the other parameters. This study suggests the necessity of designing spine-related furniture based on spinal parameters, thus providing adaptive support for the adolescent spine, particularly the lumbar spine. Practitioner summary: This study examined spinal lengths, curvatures, and concave-convex spacings in adolescents aged 9-8 years and then divided them into four age groups. Concave-convex spacings effectively reflected spinal differences between age groups, particularly the lumbar spine. These results can inform the ergonomic design of spine-related furniture.HIGHLIGHTSSpinal parameters increased progressively between 9 and 18 years. Regression analysis showed good linear correlations between TK, LL, SK, TS, and LS with age.Age classification of adolescents was Group I (9-10 years), Group II (11-12 years), Group III (13-15 years), and Group IV (16-18 years). The rapid increment of lengths and concave-convex spacings were in Group III while that of curvatures were in Group IV.Concave-convex spacings were vital parameters to evaluate the global balance of the spine.The lumbar spine is an essential segment for characterizing spinal alignment.

The relationship between minor coronal asymmetry of the spine and measures of spinal sagittal shape in adolescents without visible scoliosis

The purpose of this work is to identify what features of overall spinal sagittal shape are associated with coronal asymmetry in those without scoliosis. Using a longitudinal analysis of Integrated Shape Imaging System 2 (ISIS2) surface topography images of those without scoliosis, measures of coronal asymmetry, along with measures of spinal sagittal shape (kyphosis, lordosis and sagittal imbalance, which is a measure of the position of the top of the thoracic spine relative to the sacrum) were analysed using linear mixed effect models (LMEM), which is a method of analysing the components of a complex model (such as that describing overall spinal shape), to ascertain the relative relationships between the parameters. Data was also analysed when subdivided for the anatomical level of coronal asymmetry (thoracic or thoracolumbar/lumbar pattern). There were 784 measures from 196 children. Kyphosis had little effect on coronal asymmetry for males and females, lordosis increased with coronal asymmetry in females only and sagittal imbalance increased with coronal asymmetry in males only. The results of the LMEM modelling were that the parameters related to coronal asymmetry were lordosis and sagittal imbalance. In thoracic coronal asymmetry, whilst lordosis was predominant, kyphosis played more of a role. In thoracolumbar/lumbar coronal asymmetry, lordosis and sagittal imbalance were the larger coefficients. Coronal asymmetry of the spine in those without scoliosis is related to features of spinal sagittal shape, particularly lordosis and sagittal imbalance. This knowledge adds to the understanding of the aetiology of adolescent idiopathic scoliosis.

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.

Relationship between lumbar lordosis and the ratio of the spinous process height to the anterior spinal column height

Purpose Global sagittal imbalance with lumbar hypo-lordosis leads to various problems in elderly populations and is often treated with long-segment fusion and osteotomy. These highly invasive procedures result in a wide range of rigid spines with a high rate of complications. Although some reports have mentioned the primary aetiology of hypo-lordosis, there is limited evidence. Thus, understanding the exact underlying mechanism is required for developing minimally invasive procedures. This study aimed to investigate the factors related to lumbar lordosis (LL) in elderly people. Methods A total of ninety consecutive patients aged ≥ sixty years at a single spine centre were included. We measured LL, the anterior spinal column height consisting of vertebral bodies and intervertebral discs from L1 to L5 (ASC-5) and the sum of the spinous process heights from L1 to L5 (SP-5) with computed tomography in a supine position. The relationship between LL and the SP-5/ASC-5 ratio, SP-5, and ASC-5 was analysed. Results The Pearson correlation coefficients between LL and the SP-5/ASC-5 ratio, SP-5, and ASC-5 were −0.80 (p < 0.001), −0.43 (p < 0.001) and 0.36 (p < 0.001), respectively. Conclusion LL was significantly related to the SP-5/ASC-5 ratio of the lumbar spine in elderly people. In addition to shortening of the ASC, elongation of the SP-5 also contributed to a loss of LL.