Revisiting thoracic kyphosis: a normative description of the thoracic sagittal curve in an asymptomatic population

Sebaaly, Amer; Silvestre, Clément; Rizkallah, Maroun; Grobost, Pierre; Chevillotte, Thomas; Kharrat, Khalil; Roussouly, Pierre

doi:10.1007/s00586-020-06670-7

Cited by 17 publications

(24 citation statements)

References 21 publications

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“…7,14-16 Stagnara and Park, Roussouly, Yamato, Harrinson, Vavari Vacari.This variation in the location of the inflection point highlights the importance of individualized analysis of spinal curves and sagittal balance.The spectrum of inflection point variability (T7-L4) explains why it is not reasonable for us to consider fixed anatomical references for all individuals, 12,14 and the influence of other parameters like age, sex, weight, and race must also be taken into account. 14,17 Despite the small size of the sample used in our study, it was possible to observe the differences between the points of inflection defined by anatomical and dynamic segmentation 12,14,17 (Vaz, Stagnara, Berthonnaud).The inflection pointhas beenused to classify the different types of spinal sagittal alignment (Roussouly), and the influence of age (Boyle) and pelvic incidence has also been observed. 1,6,14 Thoracic kyphosis has been measured using different anatomical references and use of the inflection point has increased with the contemporary concept of vertebral segmentation.…”

Section: Discussionmentioning

confidence: 92%

“…1,6,14 Thoracic kyphosis has been measured using different anatomical references and use of the inflection point has increased with the contemporary concept of vertebral segmentation. 17,18 There were statistical differences both between the thoracic kyphosis measurements using the different anatomical references (T1-T12, T4-T12, and T5-T12) and those using the inflection point.Similarresults have been reportedand emphasizethe kyphosis measured between T1 and T12 as representing real thoracic kyphosis. 11 These findings reinforce the need for individual evaluation of the sagittal parameters and observation of the references usedfor that evaluation.…”

Section: Discussionmentioning

confidence: 93%

“…19 However, the measurements based on these references were statistically different from the other thoracic kyphosis measurements, whichshould be used with caution considering the current concepts about the measurement and interpretation of spinal sagittal parameters. [16][17][18] Currently there is consensus around the anatomical references for measuring lumbar lordosis and L1-S1 has been used, replacing L1-L5, which was previously used. 1,6 Different geometric measurementmethods (circular arc, elliptical quadrant, etc.)…”

Section: Discussionmentioning

confidence: 99%

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Anatomic and Functional Analysis of Thoracic Kyphosis and Lumbar Lordosis

et al. 2022

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Objective: Rate and compare radiographic measurements of thoracic kyphosis and lumbar lordosis using anatomical and dynamic parameters. Methods: Measurements were performed on lateral radiographs of 10 adults of both sexes without spinal disease or deformity. Thoracic kyphosis and lumbar lordosis were measured using anatomical parameters (T1-T12, T4-T12, T5-T12 and L1-S1) or dynamic parameters (cervicothoracic or thoracolumbar inflection point). Results: Thoracic kyphosis and lumbar lordosis were different in 30% of subjects. Differences in thoracic kyphosis values were observed according to the anatomical reference used for measurement. Lumbar lordosis wasn`t statistical difference considering the anatomical or dynamic reference, but in 30% of the individuals the inflection point was different from the anatomical reference. Conclusions: Thoracic kyphosis and lumbar lordosis values differ according to anatomical and dynamic references. The reference used must be considered in the measurement and interpretation of values. Level of evidence IV; Case series.

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

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Anatomic and Functional Analysis of Thoracic Kyphosis and Lumbar Lordosis

et al. 2022

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“…Hence, the magnitude of TK across individuals is largely determined by the difference in ULL. This needs to be noted during ASD surgery because overcorrected ULL requires a large TK to match with it, which may lead to the occurrence of PJK ( 18 , 21 ).…”

Section: Discussionmentioning

confidence: 99%

Predicting the ideal apex of lumbar lordosis based on individual pelvic incidence and inflection point in asymptomatic adults

Wang

Zhang²,

Liu³

et al. 2022

Front. Surg.

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ObjectiveThe main aim of this study was to comprehensively explore the relationship among pelvic incidence (PI), inflection point (IP), and apex of lumbar lordosis (LLA), and establish a predictive formula for LLA based on individual PI and IP in asymptomatic Chinese adults.MethodsA total of 385 asymptomatic adults with average age 38.3 ± 11.9 years (range 20–73 years) were recruited between November 2020 and October 2021. Full-spine, standing x-rays were then obtained from each participant. Next, the following sagittal parameters were measured: PI, IP, LLA, the horizontal offset between the plumb line of the lumbar apex and that of the posterosuperior corner of S1 (LASO), the upper lumbar lordosis (ULL) and lower lumbar lordosis (LLL), lumbar lordosis (LL), and thoracic kyphosis (TK). Moreover, the association among PI, IP, and the other sagittal parameters was evaluated, followed by linear regression analyses. A P-value of <0.05 was considered statistically significant.ResultsPI showed statistically significant correlations with LLA (rs = −0.629; P < 0.01), LASO (rs = 0.537; P < 0.01), LLL (rs = 0.788; P < 0.01), and LL (rs = 0.663; P < 0.01). On the other hand, IP also showed statistically significant correlations with LLA (rs = 0.671; P < 0.01), LASO (rs = −0.493; P < 0.01), LLL (rs = −0.402; P < 0.01), and LL (rs = −0.283; P < 0.01). The corresponding predictive formulae were displayed as follows: LLA = −0.03 * PI + 0.23 * IP + 14.45 (R2 = 0.669); LASO = 0.38 * PI−2.09 * IP + 53.62 (R2 = 0.460); and LLL = 0.58 * PI−0.88 * IP + 18.86 (R2 = 0.659).ConclusionThe specific lumbar shape should be modulated by pelvic morphology and IP level. In addition, we established predictive formulae for ideal sagittal lumbar profile based on individual PI and IP, with the overarching goal of helping surgeons to better comprehend the regulatory mechanisms of the individual sagittal lumbar alignment, and design a precise and personalized corrective plan.

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“…17 Other than posture, factors such as body mass, muscle morphology, and spine curvature may considerably vary between individuals and may have a strong effect on the model outputs. [18][19][20][21] Many studies 22,23 have proposed alternate methods to estimate subject-specific muscle geometry data by predictive algorithms, 22 linear regression, 24,25 and polynomial regression analysis 23 based on sex, BMI, etc. For example, Chaffin et al 26 indicated that the size of erector spinae mass may not correlate with body weight because the size of the muscles depends more on the physical requirements of the muscle during routine manual activities than on simple total body weight.…”

Section: Introductionmentioning

confidence: 99%

Estimation and assessment of sagittal spinal curvature and thoracic muscle morphometry in different postures

Zhang

Ashjaee

et al. 2021

Proc Inst Mech Eng H

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Spine models are typically developed from supine clinical imaging data, and hence clearly do not fully reflect postures that replicate subjects’ clinical symptoms. Our objectives were to develop a method to: (i) estimate the subject-specific sagittal curvature of the whole spine in different postures from limited imaging data, (ii) obtain muscle lines-of-action in different postures and analyze the effect of posture on muscle fascicle length, and (iii) correct for cosine between the magnetic resonance imaging (MRI) scan plane and dominant fiber line-of-action for muscle parameters (cross-sectional area (CSA) and position). The thoracic spines of six healthy volunteers were scanned in four postures (supine, standing, flexion, and sitting) in an upright MRI. Geometry of the sagittal spine was approximated with a circular spline. A pipeline was developed to estimate spine geometry in different postures and was validated. The lines-of-action for two muscles, erector spinae (ES) and transversospinalis (TS) were obtained for every posture and hence muscle fascicle lengths were computed. A correction factor based on published literature was then computed and applied to the muscle parameters. The maximum registration error between the estimated spine geometry and MRI data was small (average RMSE∼1.2%). The muscle fascicle length increased (up to 20%) in flexion when compared to erect postures. The correction factor reduced muscle parameters (∼5% for ES and ∼25% for TS) when compared to raw MRI data. The proposed pipeline is a preliminary step in subject-specific modeling. Direction cosines of muscles could be used while improving the inputs of spine models.

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Revisiting thoracic kyphosis: a normative description of the thoracic sagittal curve in an asymptomatic population

Cited by 17 publications

References 21 publications

Anatomic and Functional Analysis of Thoracic Kyphosis and Lumbar Lordosis

Anatomic and Functional Analysis of Thoracic Kyphosis and Lumbar Lordosis

Predicting the ideal apex of lumbar lordosis based on individual pelvic incidence and inflection point in asymptomatic adults

Estimation and assessment of sagittal spinal curvature and thoracic muscle morphometry in different postures

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