Validating Surface Topography for the Measurement of the Thoracic Kyphosis Angle in Patients With Scoliosis: A Prospective Study of Accuracy.

OBJECTIVE: The purpose of this study was to test the validity and determine the accuracy of surface topography in relation to photogrammetry for measuring the thoracic kyphosis angle in patients with scoliosis. METHODS: This was a prospective, cross-sectional study of diagnostic accuracy that followed the guidelines recommended by the Standards for Reporting Diagnostic Accuracy. We consecutively included 51 participants aged 7 to 18 years. Exclusion criteria were surgical treatment of the spine, neurological disease, lower limb discrepancy greater than 1.5 cm, and body mass index above 29 kg/m². Each participant was evaluated using both a surface topography scan and photogrammetry in random order. The measurement obtained through photogrammetry was used as a reference in this study. For statistical purposes, Pearson's correlation test, Bland-Altman graphical analysis, and the receiver operating characteristic curve (P < .05) were performed. RESULTS: The correlation between the measurements was strong and significant (r = 0.76, P < .001) with an average difference of 0.4° in the Bland-Altman analysis. The receiver operating characteristic curve area was excellent for hypokyphosis (93.4%) and good for hyperkyphosis (86.4%), both being significant (P < .005). CONCLUSION: The agreement and strong correlation between the 2 methods indicate the validity of surface topography to measure the thoracic kyphosis angle. The surface topography provides accurate measures for the thoracic kyphosis angle with cutoff points for hypo- (33.3°) and hyperkyphosis (40.8°) for individuals with scoliosis.

Radiography and photogrammetry-based methods of assessing cervical spine posture in the sagittal plane: A systematic review with meta-analysis.

BACKGROUND: There are numerous radiography and photogrammetry-based methods of assessing the cervical spine posture in the sagittal plane. The choice of instrument should be based on scientific parameters such as validity and reliability, thus avoiding restrictions to the applicability of the instrument. RESEARCH QUESTION: What radiography and photogrammetry-based methods used to assess the cervical spine posture in the sagittal plane are valid and/or reliable? METHODS: Systematic searches were conducted following Meta-analysis of Observational Studies in Epidemiology guidelines. Methodological quality was assessed according to the Brink & Louw appraisal tool. RESULTS: Twenty-one studies were included in the qualitative analysis. Twenty different methods of calculating cervical spine posture in the sagittal plane were found. Two studies included validation measures, 16 studies assessed inter-rater reliability, and 17 studies assessed intra-rater reliability. Fourteen studies were included for the quantitative analysis. The meta-analysis shows that the cervical arrow and cervical lordosis photogrammetry-based methods present very high intra-rater reliability. In radiography, the meta-analysis also showed that the Cobb method (inferior C2 - inferior C7), Cobb method (middle C1 - inferior C7), absolute rotation angle, and Gore angle (C2-C7) present very high inter-rater reliability, and the Cobb method (inferior C2 - inferior C7) and absolute rotation angle present very high intra-rater reliability. SIGNIFICANCE: This systematic review presents an overview of the methods used to assess cervical spine posture and the respective information on validity and reliability. This panorama facilitates the choice of method when conducting radiography or photogrammetry-based assessment of the cervical spine in the sagittal plane. In addition, it shows the need for new studies that investigate the accuracy and precision of these methods for their possible use in larger studies.

Validation of the Measurement of the Angle of Trunk Rotation in Photogrammetry.

OBJECTIVE: The purpose of this study was to validate the photogrammetric measurement of the angle of trunk rotation in relation to the scoliometer instrument. METHODS: Fifty-eight prominences from individuals with ages between 7 and 18 and with suspicion of spinal asymmetry (SA) were evaluated through the scoliometer and photogrammetry. The photographs were analyzed in the Digital Image-based Postural Assessment software. For statistical purposes, we used Pearson's correlation test (r), root mean square error, Bland-Altman graphical analysis, and receiver operating characteristic curve. The level of significance was P ≤ .05. RESULTS: Excellent correlation for the angle of trunk rotation was obtained between the scoliometer and photogrammetry, with a root mean square error of 3°. The Bland-Altman graphical analysis showed equally dispersed data with no participants outside the limits of agreement. The receiver operating characteristic curve evidenced that (1) the cutoff point for the identification of the presence of spinal asymmetry is 4°; (2) mild to moderate SA is between 4° and 7°; (3) moderate to severe SA is above 8°; and (4) sensitivity and specificity were above 83% and 78%, respectively, with an area under the curve ≥ 90%. CONCLUSION: Photogrammetry is validated for measuring the angle of trunk rotation, being an accurate and accessible tool for the evaluation of patients with spinal asymmetries.

Anatomical reference marks, evaluation parameters and reproducibility of surface topography for evaluating the adolescent idiopathic scoliosis: a systematic review with meta-analysis.

BACKGROUND: Surface topography is a radiation-free examination that provides relevant information for the evaluation of patients with Adolescent Idiopathic Scoliosis (AIS). However, its usage is not standardized, which restricts the applicability of this instrument. RESEARCH QUESTIONS: (a) To identify the anatomical reference markers used on surface topography; (b) to identify the parameters used on surface topography; and (c) to pool correlation and reproducibility results. METHODS: Systematic searches were conducted following MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. The methodological quality was assessed according to Brink & Louw appraisal tool. RESULTS: Twenty-three studies were included for the qualitative synthesis. The most commonly used anatomical reference markers were: the prominent vertebra (C7 or T1), the posterior superior iliac spines (PSISs) and the sacrum (S1). The parameters for the evaluation of the AIS by surface topography are: spinal inclination angle (analogous to Cobb), gibbosity, thoracic kyphosis angle, lumbar lordosis angle, pelvic obliquity, spine length, apex of the curve, C7-S1 distance (frontal plane), and C7-S1 displacement (sagittal plane). Data from eleven studies were metanalyzed and evidenced the correlation of the surface topography with X-ray exams and the reproducibility of the surface topography in the sagittal and frontal planes. SIGNIFICANCE: The findings of this study recommend the use of a protocol for the application of the equipment. The analyzed studies predict the use of only four markers for anatomical reference. The evaluation of the AIS can be carried out observing nine parameters. Surface topography correlates with radiography when the spinal inclination angle (Cobb angle), thoracic kyphosis angle and lumbar lordosis angle are compared. Also, surface topography presents inter and intra-rater reproducibility in the sagittal plane and intra-rater reproducibility in the frontal plane.

Validation of a Mathematical Procedure for the Cobb Angle Assessment Based on Photogrammetry.

OBJECTIVE: This prospective study aimed to assess the concurrent validity and diagnostic accuracy of a mathematical procedure for measurement of the spinal inclination angle, analogous to the Cobb angle, by means of photogrammetry. METHODS: Sixty-one subjects (aged 7 to 18 years), male and female, underwent radiographic (Cobb angle) and photogrammetric (DIPA [Digital Image-based Postural Assessment] angle) evaluations. The measurement of spinal inclination angle obtained through photogrammetry followed the Digital Image-Based Postural Assessment software protocol. Concurrent validity was appraised using Spearman rank correlation, the coefficient of determination, the root-mean-square error, Bland-Altman plot analysis, and receiver operating characteristic analysis, adopting P ≤ .05. RESULTS: The analyses were divided according to the topography of the scoliotic curve (thoracic, lumbar, or thoracolumbar). The correlations were excellent (from 0.72 to 0.81) and significant for all the regions of the spine, and the coefficients of determination ranged between 0.75 and 0.88. The root-mean-square error was between 5° and 11°, and the mean difference was very close to 0. The area under the curve was excellent and significant, ranging between 95% and 99%. CONCLUSION: The mathematical procedure presented is valid to evaluate the spinal inclination angle in photogrammetry, analogous to the Cobb angle in radiography.

Influência da posição do marcador maleolar sobre os parâmetros posturais no plano sagital / Influencia de la posición del marcador maleolar en los parámetros posturales del plano sagital / Influence of the malleolar marker position on postural parameters in the sagittal plane

RESUMO Fotogrametria é um método de avaliação postural que fornece informações baseadas no referencial de marcadores anatômicos. No plano sagital, uma das principais avaliações está relacionada ao fio de prumo, apresentando divergências a respeito da colocação do marcador de referência maleolar na bibliografia. Alguns defendem que seja feita exatamente sobre o centro do maléolo lateral, enquanto outros defendem a colocação um pouco à frente do maléolo lateral. O objetivo deste estudo foi identificar se a modificação da posição do marcador maleolar influencia os resultados do procedimento. Trata-se de um estudo observacional analítico transversal, com delineamento comparativo intrassujeitos. Foram avaliados 44 indivíduos saudáveis (25 mulheres e 19 homens; 27±6 anos; 170±11cm; 71±15Kg) utilizando o protocolo e software DIPA© para investigação das variáveis (teste do fio de prumo e pulsão da pelve) no plano sagital, com o marcador maleolar em duas posições: (1) no centro do maléolo lateral e (2) à frente do maléolo lateral. A análise realizada segundo os métodos estatístico, descritivo (distribuição de frequências, média e desvio padrão) e inferencial (testes de Shapiro Wilk, t de Student dependente e Wilcoxon, α=0,05). Para ambas as variáveis, a posição do marcador maleolar exerceu influência estatisticamente significativa (p<0,05) apenas no valor escalar, não afetando significativamente (p>0,05) a classificação postural. Os resultados sugerem que o ponto de referência vertical para a fotogrametria, baseado no marcador maleolar pode ser de escolha do avaliador.

RESUMEN La fotogrametría es un método de evaluación postural que proporciona información basada en los referenciales de los marcadores anatómicos. En el plano sagital, una de las principales evaluaciones se relaciona con la plomada, y demuestra divergencias en cuanto a la colocación del marcador de referencia maleolar en la bibliografía. Algunos autores argumentan que se lo hace exactamente en el centro del maléolo lateral, mientras que otros lo defienden colocando un poco delante del maléolo lateral. El estudio propone identificar si la modificación de la posición del marcador maleolar influye en los resultados del procedimiento. Se trata de un estudio observacional analítico transversal, de concepción comparativa intraindividual. Se evaluaron a 44 individuos sanos (25 mujeres y 19 hombres; 27±6 años; 170±11 cm, 71±15 kg) por medio del protocolo y el software DIPA© para analizar las variables (prueba de la plomada y pulsión de la pelvis) en el plano sagital, con el marcador maleolar en dos posiciones: (1) en el centro del maléolo lateral y (2) delante del maléolo lateral. Se realizó el análisis conforme los métodos estadístico, descriptivo (distribución de frecuencias, media y desviación estándar) y estadística inferencial (prueba de Shapiro-Wilk, prueba t de Student dependiente y de Wilcoxon, α=0,05). En ambas variables, la posición del marcador maleolar tuvo una influencia estadísticamente significativa (p<0,05) en el valor escalar, pero no afectó significativamente (p>0,05) a la clasificación postural. Los resultados revelaron que el punto de referencia vertical a la fotogrametría desde el marcador maleolar puede ser elegido por el evaluador.

ABSTRACT Photogrammetry is a postural evaluation method that provides information based on the reference of anatomical markers. In the sagittal plane, one of the main evaluations is related to the plumb line; however, the literature shows divergences regarding the placement of the malleolar reference marker. Some argue that it must be placed exactly on the center of the lateral malleolus, while others defend placing it slightly in front of the lateral malleolus. This study aimed to identify whether the modification of the position of the malleolar marker affects the results of the procedure. This is a cross-sectional analytical observational study, with comparative intrasubject design. Forty-four healthy subjects (25 women and 19 men; 27±6 years old; 170±11 cm; 71±15 kg) were evaluated using protocol and software DIPA© for investigation of the variables (plumb line test and pelvic version) in the sagittal plane, with the malleolar marker in two positions: (1) in the center of the lateral malleolus and (2) in front of the lateral malleolus. The analysis was carried out according to descriptive (frequency distribution, mean and standard deviation) and inferential (Shapiro-Wilk test, dependent Student's t-test, and Wilcoxon test, α=0.05) statistical methods. For both variables, the malleolar marker position presented statistically significant difference (p<0.05) only on the scalar value, not significantly affecting the posture classification. The results suggest that the vertical reference point for photogrammetry, based on the malleolar marker, can be chosen by the evaluator.

Development and Validation of Prediction Equations for Spinal Curve Angles Based on Skin Surface Measurements.

OBJECTIVE: The purpose of this study was to develop, assess the reliability of, and validate prediction equations that estimate the sagittal curves of the spine from the skin surface. METHODS: Forty digital panoramic radiographs were used to develop the prediction equation, and 59 radiographs were used to assess reliability and validate the equations. For evaluation of the thoracic and lumbar curves, anatomical reference points were marked on the vertebral body, spinous process, and skin surface at the C6, C7, T2, T4, T6, T8, T10, T12, L2, L4, and S2 vertebrae. Three third-degree polynomials were obtained, estimated with the least squares method: inner curves from the centroid of the vertebral bodies and from the apex of the spinous processes and external curve from the skin surface. The magnitude of the curves of each region was estimated based on the angle between tangent lines at several vertebral levels. Prediction equations were obtained (simple linear regression) for the vertebral levels that had the best correlation between the inner and surface curves. The validation of the prediction equations was confirmed using Pearson's correlation (r), Student t test, and root mean square error. The reliability of the method was confirmed using the intraclass correlation coefficient, standard error of measurement, and minimal detectable change (α = 0.05). RESULTS: The best correlations were obtained between the T4-T12 (thoracic) and T10-S2 (lumbar) levels (r > 0.85). For the intrarater and interrater reliability, the correlation was higher than 0.965 and higher than 0.896, respectively. There was a significant and strong correlation between estimated and actual values for the thoracic and lumbar curves, which was confirmed by the t-test results and by the root mean square error inferior to 1°. CONCLUSION: Prediction equations can precisely and accurately estimate the angles of the internal sagittal curves of the spine from the skin surface.

Mixed lineage kinase phosphorylates transcription factor E47 and inhibits TrkB expression to link neuronal death and survival pathways.

E47 is a basic helix-loop-helix transcription factor involved in neuronal differentiation and survival. We had previously shown that the basic helix-loop-helix protein E47 binds to E-box sequences within the promoter of the TrkB gene and activates its transcription. Proper expression of the TrkB receptor plays a key role in development and function of the vertebrate nervous system, and altered levels of TrkB have been associated with important human diseases. Here we show that E47 interacts with MLK2, a mixed lineage kinase (MLK) involved in JNK-mediated activation of programmed cell death. MLK2 enhances phosphorylation of the AD2 activation domain of E47 in vivo in a JNK-independent manner and phosphorylates in vitro defined serine and threonine residues within a loop-helix structure of AD2 that also contains a putative MLK docking site. Although these residues are essential for MLK2-mediated inactivation of E47, inhibition of MLKs by CEP11004 causes up-regulation of TrkB at a transcriptional level in cerebellar granule neurons and differentiating neuroblastoma cells. These findings allow us to propose a novel mechanism by which MLK regulates TrkB expression through phosphorylation of an activation domain of E47. This molecular link would explain why MLK inhibitors not only prevent activation of cell death processes but also enhance cell survival signaling as a key aspect of their neuroprotective potential.