Construct validity and reliability of tests for sacroiliac dysfunction: standing flexion test (STFT) and sitting flexion test (SIFT).

CONTEXT: Sacroiliac dysfunction is characterized by a hypomobility of the range of motion of the joint, followed by a positional change regarding the relationship between the sacrum and the iliac. In general, the clinical tests that evaluate the sacroiliac joint (SIJ) and its dysfunctions lack validity and reliability values. OBJECTIVES: This article aims to evaluate the construct validity and intra- and inter-rater reliability of the standing flexion test (STFT) and sitting flexion test (SIFT). METHODS: In this prospective study, the sample consisted of 30 individuals of both sexes, and the evaluation team was composed of five researchers. The evaluations took place on two different days: first day, inter-rater reliability and construct validity; and second day, intra-rater reliability. The reference standard for the construct validity was 3-dimensional measurements obtained utilizing the BTS SMART-DX system. For statistical analysis, the percentage (%) agreement and the kappa statistic (K) were utilized. RESULTS: The construct validity was determined for STFT (70% agreement; K=0.49; p<0.01) and SIFT (56.7% agreement; K=0.29; p<0.05). The intra-rater reliability was determined for STFT (66.3% agreement; K=0.43; p<0.01) and SIFT (56.7% agreement; K=0.38; p<0.01). The inter-rater reliability was determined for STFT (10% agreement; K=-0.02; p=0.825) and SIFT (13.3% agreement; K=0.01; p=0.836). CONCLUSIONS: The STFT confirmed the construct validity and was reliable when applied by the same rater to healthy people, even if the rater had no experience. It was not possible to achieve minimum scores using the SIFT either for construct validity or reliability. We suggest that further studies be conducted to investigate the measurement properties of palpatory clinical tests for SIJ mobility, especially in symptomatic patients.

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.

Validity and Reliability of Palpatory Clinical Tests of Sacroiliac Joint Mobility: A Systematic Review and Meta-analysis.

OBJECTIVE: The primary objective of this review was to investigate the reliability and validity of palpatory clinical tests of sacroiliac mobility. The secondary objective was to investigate which palpatory clinical tests of sacroiliac mobility exist in the literature. METHODS: PubMed, Embase, Scopus, Medline, and the Physiotherapy Evidence Database were searched. There was no restriction on the study design or participants. The data extracted from each study were sample size, study deign, and clinical test used. If there was information on reliability values, number of examiners, concurrent validity values, gold standard used, or inferential statistical test used, that was also extracted. For intraexaminer reliability, the data were expressed as κ values that were meta-analyzed using random effects. RESULTS: Fifteen palpatory clinical tests of sacroiliac mobility were identified from 28 studies; 14 studies performed inferential statistical analysis, all including analysis of interexaminer reliability, with κ values ranging from -0.05 to 0.77. Analysis of intraexaminer reliability was performed in 8 studies, with κ values ranging from 0.08 to 0.73. No study included in this systematic review verified the concurrent validity of the tests. Our meta-analysis of intraexaminer reliability showed moderate to good agreement results for the Gillet test (κ = 0.46), the standing flexion test (κ = 0.61), and the sitting flexion test (κ = 0.68). CONCLUSION: We found 15 palpatory clinical tests of sacroiliac mobility in this systematic review. According to our meta-analysis, only the sitting flexion test obtained a good and statistically significant intraexaminer agreement. Further studies are necessary to evaluate the reliability and validity of these tests.

Validity and Reliability of Smartphones in Assessing Spinal Kinematics: A Systematic Review and Meta-analysis.

OBJECTIVE: Advances in mobile technology have led to the development of smartphones, whose applications present numerous utilities, such as the analysis of human movement based on inertial sensors. The purpose of this review was to investigate validity and reliability of smartphones in assessing the kinematics of the human spine. METHODS: A systematic search was performed on MEDLINE, Embase, Scopus, and LILACS databases, as well as manual searches. The included studies evaluated psychometric properties of smartphones in assessing kinematic variables of the spine (range of motion [ROM], speed, and acceleration). Two independent reviewers performed the selection, reading, data extraction, and risk of bias assessment of the studies. RESULTS: Of the 2651 articles initially found, 9 were included and had their results for ROM analyzed. The meta-analyses for validity showed very high correlation coefficients in the evaluation of cervical flexion, extension, and lateral flexion; high ones in the evaluation of cervical rotation; and also high ones for intrarater and interrater reproducibility of all cervical movements. The meta-analyses for interrater reproducibility showed high correlation coefficients in the evaluation of lumbar flexion and very high ones for intrarater reproducibility. CONCLUSION: The use of smartphones for assessing the ROM of cervical flexion, extension, and lateral flexion and lumbar flexion is feasible. Their use for assessing thoracic rotation is potentially viable, but further validation studies are still needed to ensure a safe use. There is a lack of validation studies that evaluate the applicability of this device in assessing other kinematic characteristics, such as speed and acceleration.

Concurrent Validity of Digital Image-based Postural Assessment as a Method for Measuring Thoracic Kyphosis: A Cross-Sectional Study of Healthy Adults.

OBJECTIVE: To analyze the concurrent validity of the Digital Image-based Postural Assessment (DIPA) method for identifying the magnitude and classification of thoracic kyphosis in adults. METHODOLOGY: On the same day and in the same place, thoracic kyphosis was assessed in 68 adults using 2 methods: the DIPA software protocol and radiography. The DIPA software provided angular values of thoracic kyphosis based on trigonometric relations, while with the radiograph, the curvature was calculated using the Cobb method. The following tests were applied in the statistical analysis: Pearson's correlation, Bland-Altman's graphic representation, root mean square error, and receiver operating characteristic (ROC) curve; α = 0.05. The reference angular values for the standard thoracic posture used in DIPA were determined with the ROC curve based on the Cobb angles. RESULTS: The correlation between the angles obtained for thoracic kyphosis using the DIPA and Cobb methods was found to be high (r = 0.813, P < .001), and the accuracy was ±4°. According to Bland-Altman's representation, the magnitudes provided by the DIPA software were in agreement with those of the Cobb method. In reference values for determining the standard posture of the thoracic spine, the ROC curve indicated good accuracy in diagnosing a decrease in thoracic kyphosis (with a value of 33.9°) and excellent accuracy in diagnosing thoracic hyperkyphosis (with a value 39.9°) when using DIPA. CONCLUSION: The DIPA postural assessment method is valid in the sagittal plane for identifying the magnitude of thoracic kyphosis in adults. Furthermore, it is accurate in diagnosing alterations in thoracic kyphosis.

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.

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.

The Validity and Reproducibility of the Flexicurve in the Evaluation of Cervical Spine Lordosis.

OBJECTIVE: The purpose of this study was to measure the validity and reliability of flexicurve measurements of cervical curvature in the sagittal plane in adults. METHODS: One hundred thirteen adults were assessed in the seated position with flexicurve radiographs. Two groups were measured: (1) the validity group (n = 55), and (2) the reliability group (n = 58). Both groups were subdivided into 3 subgroups according to body mass index: underweight, normal weight, and overweight. Radiographs were simultaneously taken with flexicurve molded on the cervical spine. Pearson's correlation and the root mean square error were used for the concurrent validity. The reliability of the flexicurve was assessed by 3 raters using the intraclass correlation coefficient (ICC), the standard error of the measurement (SEM), and minimal detectable change (MDC). RESULTS: For the concurrent validity, a high correlation (r = 0.570, P < .001, root mean square error = 9.8°), and excellent results were obtained for intra-rater (ICC = 0.771, P < .001, SEM = 4.4°, MDC = 8.6°) and inter-rater (ICC = 0.775, P < .001, SEM = 4.3°, MDC = 8.5°) reliability. The subgroups had different results, whereas the underweight subgroup consistently had the best results. CONCLUSION: These findings suggest that the flexicurve can be a valid instrument for evaluating the curvature of the cervical spine in the sagittal plane in adults classified according to the body mass index as underweight and normal weight. Reliable measurements were provided for its use whether by the same or different raters. The flexicurve can be recommended for use both in clinical practice and in research settings as long as the suggested protocol is followed.

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.

Accuracy of a Radiological Evaluation Method for Thoracic and Lumbar Spinal Curvatures Using Spinous Processes.

OBJECTIVE: The purpose of this study was to assess a radiographic method for spinal curvature evaluation in children, based on spinous processes, and identify its normality limits. METHODS: The sample consisted of 90 radiographic examinations of the spines of children in the sagittal plane. Thoracic and lumbar curvatures were evaluated using angular (apex angle [AA]) and linear (sagittal arrow [SA]) measurements based on the spinous processes. The same curvatures were also evaluated using the Cobb angle (CA) method, which is considered the gold standard. For concurrent validity (AA vs CA), Pearson's product-moment correlation coefficient, root-mean-square error, Pitman- Morgan test, and Bland-Altman analysis were used. For reproducibility (AA, SA, and CA), the intraclass correlation coefficient, standard error of measurement, and minimal detectable change measurements were used. RESULTS: A significant correlation was found between CA and AA measurements, as was a low root-mean-square error. The mean difference between the measurements was 0° for thoracic and lumbar curvatures, and the mean standard deviations of the differences were ±5.9° and 6.9°, respectively. The intraclass correlation coefficients of AA and SA were similar to or higher than the gold standard (CA). The standard error of measurement and minimal detectable change of the AA were always lower than the CA. CONCLUSION: This study determined the concurrent validity, as well as intra- and interrater reproducibility, of the radiographic measurements of kyphosis and lordosis in children.

Test-retest, inter- and intra-rater reliability of the flexicurve for evaluation of the spine in children

Introduction: The early evaluation of the spine in children is desirable because it is at this stage of development that the greatest changes in the body structures occur. Objective: To determine the test-retest, intra- and inter-rater reliability of the Flexicurve instrument for the evaluation of spinal curvatures in children. Method: Forty children ranging from 5 to 15 years of age were evaluated by two independent evaluators using the Flexicurve to model the spine. The agreement was evaluated using Intraclass Correlation Coefficients (ICC), Standard Error of the Measurement (SEM), and Minimal Detectable Change (MDC). Results: In relation to thoracic kyphosis, the Flexicurve was shown to have excellent correlation in terms of test-retest reliability (ICC2,2=0.87) and moderate correlation in terms of intra-(ICC2,2=0.68) and inter-rater reliability (ICC2,2=0.72). In relation to lumbar lordosis, it was shown to have moderate correlation in terms of test-retest reliability (ICC2,2=0.66) and intra- (ICC2,2=0.50) and inter-rater reliability (ICC=0.56). Conclusion: This evaluation of the reliability of the Flexicurve allows its use in school screening. However, to monitor spinal curvatures in the sagittal plane in children, complementary clinical measures are necessary. Further studies are required to investigate the concurrent validity of the instrument in order to identify its diagnostic capacity.

Test-retest, inter- and intra-rater reliability of the flexicurve for evaluation of the spine in children.

INTRODUCTION: The early evaluation of the spine in children is desirable because it is at this stage of development that the greatest changes in the body structures occur. OBJECTIVE: To determine the test-retest, intra- and inter-rater reliability of the Flexicurve instrument for the evaluation of spinal curvatures in children. METHOD: Forty children ranging from 5 to 15 years of age were evaluated by two independent evaluators using the Flexicurve to model the spine. The agreement was evaluated using Intraclass Correlation Coefficients (ICC), Standard Error of the Measurement (SEM), and Minimal Detectable Change (MDC). RESULTS: In relation to thoracic kyphosis, the Flexicurve was shown to have excellent correlation in terms of test-retest reliability (ICC2,2=0.87) and moderate correlation in terms of intra-(ICC2,2=0.68) and inter-rater reliability (ICC2,2=0.72). In relation to lumbar lordosis, it was shown to have moderate correlation in terms of test-retest reliability (ICC2,2=0.66) and intra- (ICC2,2=0.50) and inter-rater reliability (ICC=0.56). CONCLUSION: This evaluation of the reliability of the Flexicurve allows its use in school screening. However, to monitor spinal curvatures in the sagittal plane in children, complementary clinical measures are necessary. Further studies are required to investigate the concurrent validity of the instrument in order to identify its diagnostic capacity.

Can the adapted arcometer be used to assess the vertebral column in children?

BACKGROUND: The adapted arcometer has been validated for use in adults. However, its suitability for use in children can be questioned given the structural differences present in these populations. OBJECTIVE: To verify the concurrent validity, repeatability, and intra- and inter-reproducibility of the adapted arcometer for the measurement of the angles of thoracic kyphosis and lumbar lordosis in children. METHOD: Forty children were evaluated using both sagittal radiography of the spine and the adapted arcometer. The evaluations using the arcometer were carried out by two trained evaluators on two different days. In the statistical treatment, the intraclass correlation coefficient (ICC), Pearson's product moment correlation, Spearman's rho, the paired t test, and Wilcoxon's test were used (α=.05). RESULTS: A moderate and significant correlation was found between the x-ray and the adapted arcometer regarding thoracic kyphosis, but no correlation was found regarding lumbar lordosis. Repeatability and intra-evaluator reproducibility of the thoracic kyphosis and lumbar lordosis were confirmed, which was not the case of inter-evaluator reproducibility. CONCLUSION: The adapted arcometer can be used to accompany postural alterations in children made by the same evaluator, while its use for diagnostic purposes and continued evaluation by different evaluators cannot be recommended. Further studies with the aim of adapting this instrument for use in children are recommended. .

Can the adapted arcometer be used to assess the vertebral column in children?

BACKGROUND: The adapted arcometer has been validated for use in adults. However, its suitability for use in children can be questioned given the structural differences present in these populations. OBJECTIVE: To verify the concurrent validity, repeatability, and intra- and inter-reproducibility of the adapted arcometer for the measurement of the angles of thoracic kyphosis and lumbar lordosis in children. METHOD: Forty children were evaluated using both sagittal radiography of the spine and the adapted arcometer. The evaluations using the arcometer were carried out by two trained evaluators on two different days. In the statistical treatment, the intraclass correlation coefficient (ICC), Pearson's product moment correlation, Spearman's rho, the paired t test, and Wilcoxon's test were used (α=.05). RESULTS: A moderate and significant correlation was found between the x-ray and the adapted arcometer regarding thoracic kyphosis, but no correlation was found regarding lumbar lordosis. Repeatability and intra-evaluator reproducibility of the thoracic kyphosis and lumbar lordosis were confirmed, which was not the case of inter-evaluator reproducibility. CONCLUSION: The adapted arcometer can be used to accompany postural alterations in children made by the same evaluator, while its use for diagnostic purposes and continued evaluation by different evaluators cannot be recommended. Further studies with the aim of adapting this instrument for use in children are recommended.

Validation, repeatability and reproducibility of a noninvasive instrument for measuring thoracic and lumbar curvature of the spine in the sagittal plane / Validade, repetibilidade e reprodutibilidade de um instrumento não-invasivo para medição das curvaturas torácica e lombar da coluna vertebral no plano sagital

BACKGROUND: The need for early identification of postural abnormalities without exposing patients to constant radiation has stimulated the development of instruments aiming to measure the spinal curvatures. OBJECTIVE: To verify the validity, repeatability and reproducibility of angular measures of sagittal curvatures of the spine obtained using an adapted arcometer, by comparing them with Cobb angles of the respective curvatures obtained by using X-rays. METHODS: 52 participants were submitted to two procedures designed to evaluate the thoracic and lumbar curvatures: (1) X-ray examination from which the Cobb angles (CA) of both curvatures were obtained, and (2) measuring the angles with the arcometer (AA). Two evaluators collected the data using the arcometer, with the rods placed at T1, T12, L1 and L5 spinous processes levels in a way as to permit linear measurements which, with aid of trigonometry, supplied the AA. RESULTS: There was a very strong and significant correlation between AA and CA (r=0.94; p<0.01), with no-significant difference (p=0.32), for the thoracic curvature. There was a strong and significant correlation for the lumbar curvature (r=0.71; p<0.01) between AA and CA, with no-significant difference (p=0.30). There is a very strong correlation between intra-evaluator and inter-evaluator AA. CONCLUSION: It was possible to quantify reliably the thoracic and lumbar curvatures with the arcometer and it can thus be considered valid and reliable and for use in evaluating spinal curvatures in the sagittal plane.

CONTEXTUALIZAÇÃO: A necessidade de identificação precoce de alterações posturais, sem expor as pessoas à radiação constante, tem estimulado a construção de instrumentos para medir as curvaturas da coluna vertebral. OBJETIVO: Verificar a validade, repetibilidade e reprodutibilidade dos ângulos das curvaturas sagitais da coluna vertebral, obtidos por meio de um arcômetro adaptado, comparando-os com os ângulos de Cobb (AC) das respectivas curvaturas, obtidos por meio de exames radiográficos. MÉTODOS: Cinquenta e dois indivíduos foram submetidos a dois procedimentos destinados a avaliar as curvaturas torácica e lombar: (1) exame de raios-X, a partir do qual os AC de ambas as curvaturas foram obtidos e (2) medição dos ângulos das curvaturas com o arcômetro (AA). Dois avaliadores coletaram os dados usando o arcômetro com as hastes sobre os processos espinhosos T1, T12, L1 e L5, de modo a permitir medidas que, com auxílio de trigonometria, forneceram os AA. RESULTADOS: Encontrou-se correlação muito forte e significativa entre AA e AC (r=0,94, p<0,01), sem diferença significativa (p=0,32) para a curvatura torácica, enquanto, para a curvatura lombar, encontrou-se uma forte e significativa correlação (r=0,71, p<0,01) entre AA e AC, sem diferença significativa (p=0,30). Existe uma correlação muito forte intra-avaliador e inter-avaliador nos AA. CONCLUSÃO: O arcômetro permitiu quantificar as curvaturas torácica e lombar, podendo-se considerar as medições válidas, fidedignas e objetivas para uso na avaliação de curvaturas da coluna vertebral no plano sagital.

Validation, repeatability and reproducibility of a noninvasive instrument for measuring thoracic and lumbar curvature of the spine in the sagittal plane.

BACKGROUND: The need for early identification of postural abnormalities without exposing patients to constant radiation has stimulated the development of instruments aiming to measure the spinal curvatures. OBJECTIVE: To verify the validity, repeatability and reproducibility of angular measures of sagittal curvatures of the spine obtained using an adapted arcometer, by comparing them with Cobb angles of the respective curvatures obtained by using X-rays. METHODS: 52 participants were submitted to two procedures designed to evaluate the thoracic and lumbar curvatures: (1) X-ray examination from which the Cobb angles (CA) of both curvatures were obtained, and (2) measuring the angles with the arcometer (AA). Two evaluators collected the data using the arcometer, with the rods placed at T1, T12, L1 and L5 spinous processes levels in a way as to permit linear measurements which, with aid of trigonometry, supplied the AA. RESULTS: There was a very strong and significant correlation between AA and CA (r=0.94; p<0.01), with no-significant difference (p=0.32), for the thoracic curvature. There was a strong and significant correlation for the lumbar curvature (r=0.71; p<0.01) between AA and CA, with no-significant difference (p=0.30). There is a very strong correlation between intra-evaluator and inter-evaluator AA. CONCLUSION: It was possible to quantify reliably the thoracic and lumbar curvatures with the arcometer and it can thus be considered valid and reliable and for use in evaluating spinal curvatures in the sagittal plane.