The lumbar spine has an intrinsic shape specific to each individual that remains a characteristic throughout flexion and extension

Abstract

Purpose We have previously shown that the lumbar spine has an intrinsic shape specific to the individual and characteristic of sitting, standing and supine postures. The purpose of this study was to test the hypothesis that this intrinsic shape is detectable throughout a range of postures from extension to full flexion in healthy adults. Methods Sagittal images of the lumbar spine were taken using a positional MRI with participants (n = 30) adopting six postures: seated extension, neutral standing, standing with 30, 45 and 60°and full flexion. Active shape modelling (ASM) was used to identify and quantify 'modes' of variation in the shape of the lumbar spine. Results ASM showed that 89.5 % of the variation in the shape of the spine could be explained by the first two modes; describing the overall curvature and the distribution of curvature of the spine. Mode scores were significantly correlated between all six postures (modes 1-9, r = 0.4-0.97, P \ 0.05), showing that an element of intrinsic shape was maintained when changing postures. The spine was most even in seated extension (P \ 0.001) and most uneven between 35 and 45°flexion (P \ 0.05). Conclusions This study shows that an individual's intrinsic lumbar spine shape is quantifiable and detectable throughout lumbar flexion and extension. These findings will enable the role of lumbar curvature in injury and low back pain to be assessed in the clinic and in the working and recreational environments.

Statistical shape modelling of hip and lumbar spine morphology and their relationship in the MRC National Survey of Health and Development

“…, ; Pavlova et al. ). Curviness describes the overall curvature from lordotic to almost straight, while evenness describes whether curvature appears uniformly along the lumbar spine or is found predominantly in the lower lumbar region.…”

“…; Pavlova et al. ). The power of SSM lies in its ability to quantify variations in morphology and it has recently shown promise as a biomarker for a number of musculoskeletal disorders.…”

“…; Pavlova et al. ). Familial correlations have been observed, indicating a genetic component to spine shape (Dryden et al.…”

“…Statistical shape modelling (SSM) is a method of image analysis employing pattern recognition statistics to describe and quantify such shapes from images, mostly in two dimensions but increasingly in 3D (Neogi et al 2013;Barr et al 2016). This method has been used to describe and quantify the variations in the shape of complex anatomical structures, such as the knee, hip and spine (Smyth et al 1999;Gregory et al 2004;Meakin et al 2008; Barr et al 2009), using a wide range of imaging modalities including radiography (Barr et al 2012;Nelson et al 2016a), dual energy X-ray absorptiometry (DXA) (Goodyear et al 2013), CT/pQCT (Bredbenner et al 2014;Varzi et al 2015) and magnetic resonance imaging (MRI; Meakin et al 2009;Neogi et al 2013;Pavlova et al 2014). The power of SSM lies in its ability to quantify variations in morphology and it has recently shown promise as a biomarker for a number of musculoskeletal disorders.…”

“…There is increasing awareness that simply describing the spine by its lordosis or kyphosis angle is not sufficient to describe the morphology accurately (Roussouly et al 2005;Been & Kalichman, 2014) and that important information relating to subtle variations in curvature can be missed (Meakin et al 2009;Ali et al 2012). SSM of the lumbar spine has shown that each individual has a characteristic shape that is maintained during different postures and has been linked to lifting techniques with implications for management and prevention of back pain (Meakin et al 2009;Pavlova et al 2014). Familial correlations have been observed, indicating a genetic component to spine shape (Dryden et al 2008).…”