Reproducibility of sagittal radiographic parameters in adolescent idiopathic scoliosis—a guide to reference values using serial imaging

Hey, Hwee Weng Dennis; Wong, Gordon Chengyuan; Chan, Chloe Xiaoyun; Lau, Leok-Lim; Kumar, Naresh; Thambiah, Joseph; Ruiz, John Nathaniel; Liu, Ka-Po Gabriel; Wong, Hee‐Kit

doi:10.1016/j.spinee.2017.01.001

Cited by 11 publications

(4 citation statements)

References 46 publications

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“…Barrey et al showed that young subjects with a flat back had a higher occurrence of disc herniation compared to those with marked lumbar lordosis [34]. Many authors have commented that vertical sacrum and less lumbar lordosis statistically have a higher risk to cause chronic low back pain [4,35,36]. When lumbar lordosis is relatively hypolordotic (type 4), this anatomical structure allowed for a larger range of motion of the spine, and had larger IDPs and matrix and fiber stresses at the L5-S1 segment in extension.…”

Section: Discussionmentioning

confidence: 99%

Biomechanical responses of human lumbar spine and pelvis according to the Roussouly classification

et al. 2022

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Background Few studies have analyzed the different biomechanical properties of the lumbar with various morphological parameters, which play an important role in injury and degeneration. This study aims to preliminarily investigate biomechanical characteristics of the spine with different sagittal alignment morphotypes by using finite element (FE) simulation and in-vitro testing. Methods According to the lumbar-pelvic radiographic parameters of the Chinese population, the parametric FE models (L1-S1-pelvis) of Roussouly’s type (1–4) were validated and developed based on the in-vitro biomechanical testing. A pure moment of 7.5 Nm was applied in the three anatomical planes to simulate the physiological activities of flexion, extension, left-right lateral bending and left-right axial rotation. Results The sagittal configuration of four Roussouly’s type models had a strong effect on the biomechanical responses in flexion and extension. The apex of the lumbar lordosis is a critical position where the segment has the lowest range of motion among all the models. In flexion-extension, type 3 and 4 models with a good lordosis shape had a more uniform rotation distribution at each motor function segment, however, type 1 and 2 models with a straighter spine had a larger proportion of rotation at the L5-S1 level. In addition, type 1 and 2 models had higher intradiscal pressures (IDPs) at the L4-5 segment in flexion, while type 4 model had larger matrix and fiber stresses at the L5-S1 segment in extension. Conclusion The well-marched lordotic type 3 lumbar had greater stability, however, a straighter spine (type 1 and 2) had poor balance and load-bearing capacity. The hypolordotic type 4 model showed larger annulus fiber stress. Therefore, the sagittal alignment of Roussouly’s type models had different kinetic and biomechanical responses under various loading conditions, leading to different clinical manifestations of the lumbar disease.

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Section: Discussionmentioning

confidence: 99%

Biomechanical responses of human lumbar spine and pelvis according to the Roussouly classification

et al. 2022

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“…13,27,28 Among the parameters that have been shown to correlate with good PROS, many of them are based on parameters that vary with posture 28,29 which may be inconsistent and not accurately reproducible. Hey et al 30,31 demonstrated that spinal parameters can vary even when patients are given the same instructions, and expected to stand in the same posture during the imaging process. Therefore, the use of these parameters may be highly unreliable.…”

Section: Discussionmentioning

confidence: 99%

The Impact of Radiographic Lower Limb-Spinal Length Proportion on Whole-Body Sagittal Alignment

Hey

Tan

Lau

et al. 2021

Spine

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Study Design. A radiographic comparative study. Objective. To investigate the influence of radiographic lower limb-spinal length proportion on sagittal radiographic parameters. Summary of Background Data. Although lordotic realignment of the lumbar spine is a well-established surgical strategy, its ideal target has not been fully understood. The widely used pelvic incidence-lumbar lordosis discrepancy (PI-LL) method to guide lordotic restoration of the lumber spine in the standing posture, may be further refined using the novel, radiographic lower limb-spinal length proportion parameter in selected subjects. Methods. A 100 healthy subjects were imaged in the standing posture using EOS imaging to obtain whole-body lateral radiographs for the measurement of sagittal radiographic parameters. Univariate analyses were performed to compare radiographic parameters between groups with different radiographic lower limb-spinal length proportion. Multivariate analyses were performed to identify the associations between lower limb-spinal length proportions and other radiographic parameters. Results. Regardless of lower limb-spinal length proportion (mean = 1.4), global lumbar angle (GLA) differed from spinal lordosis (SL), with the absolute means of SL and GLA larger and smaller than pelvic incidence (PI) respectively. Univariate analysis showed that patients with proportionately larger lower limb-spinal length proportion are more likely to have larger mean T1-slope, global thoracic angle (GTA), spinal kyphosis (SK), GLA, and SL. Multivariate analysis showed that a larger lower limb length-spinal length proportion is predictive of larger GLA is less than –47.69° (Odds Ratio (OR) 2.660, P = 0.026), and larger T1-slope of more than 18.84° (OR 3.695, P = 0.012). Conclusion. Larger radiographic lower limb-spinal length proportion results in naturally accentuated spinal curves. These patients balance with a larger lumbar lordosis that is closer to the PI and a higher T1-slope which should be considered for spinal realignment. SL differs from GLA and should be separately assessed. Level of Evidence: 3

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“…The spine is made up of functional units and has a multi-segment structure. Over the last 15 years, epidemiological and clinical studies have shown that the sagittal S-shaped curvature of the human spine eliminates energy expenditure of the back muscles while preserving balance and stability [ 8 – 11 ]. The sagittal alignment of the spine is a recently developed concept to understand the mechanical equilibrium process and develop therapeutic strategies for a variety of spinal diseases [ 11 – 13 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of dynamic and rigid implantation on biomechanical characteristics of different sagittal alignment lumbar after single- or double-level spinal fixations: a finite-element modeling study

Wang,

Kong,

Pan

et al. 2023

Eur J Med Res

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Background Although it is critical to understand the accelerated degeneration of adjacent segments after fusion, the biomechanical properties of the spine have not been thoroughly studied after various fusion techniques. This study investigates whether four Roussouly’s sagittal alignment morphotypes have different biomechanical characteristics after different single- or double-level spinal fixations. Methods The parametric finite element (FE) models of Roussouly’s type (1–4) were developed based on the radiological data of 625 Chinese community population. The four Roussouly's type models were reassembled into four fusion models: single-level L4–5 Coflex fixation model, single-level L4–5 Fusion (pedicle screw fixation) model, double-level Coflex (L4–5) + Fusion (L5–S1) model, and double-level Fusion (L4–5) + Fusion (L4–5) model. A pure moment of 7.5 Nm was applied to simulate the physiological activities of flexion, extension, lateral bending and axial rotation. Results Both single-level and double-level spinal fixation had the greatest effect on lumbar range of motion, disc pressure, and annulus fibrosis stress in flexion, followed by lateral bending, extension, and axial rotation. In all models, the upper adjacent segment was the most influenced by the implantation and bore the most compensation from the fixed segment. For Type 2 lumbar, the L4–L5 Coflex effectively reduced the disc pressure and annulus fibrosis stress in adjacent segments compared to the L4–L5 Fusion. Similarly, the L4–L5 Coflex offered considerable advantages in preserving the biomechanical properties of adjacent segments for Type 1 lumbar. For Type 4 lumbar, the L4–L5 Coflex did not have superiority over the L4–L5 Fusion, resulting in a greater increase in range of motion at adjacent segments in flexion and extension. The difference between the two fixations was not apparent in Type 3 lumbar. Compared to the single-level Fusion, the changes in motion and mechanics of the lumbar increased after both the double-level Coflex + Fusion and Fusion + Fusion fixations, while the differences between two double-level fixation methods on adjacent segments of the four lumbar models were similar to that of the single-level fixation. Conclusion Type 3 and Type 4 lumbar have good compensatory ability and therefore allow for a wider range of surgical options, whereas surgical options for small lordotic Type 1 and Type 2 lumbar are more limited and severe.

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Reproducibility of sagittal radiographic parameters in adolescent idiopathic scoliosis—a guide to reference values using serial imaging

Cited by 11 publications

References 46 publications

Biomechanical responses of human lumbar spine and pelvis according to the Roussouly classification

Biomechanical responses of human lumbar spine and pelvis according to the Roussouly classification

The Impact of Radiographic Lower Limb-Spinal Length Proportion on Whole-Body Sagittal Alignment

Effects of dynamic and rigid implantation on biomechanical characteristics of different sagittal alignment lumbar after single- or double-level spinal fixations: a finite-element modeling study

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