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.

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.