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, 2012, 186156

Validity and Reproducibility of the Measurements Obtained Using the Flexicurve Instrument to Evaluate the Angles of Thoracic and Lumbar Curvatures of the Spine in the Sagittal Plane

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Validity and Reproducibility of the Measurements Obtained Using the Flexicurve Instrument to Evaluate the Angles of Thoracic and Lumbar Curvatures of the Spine in the Sagittal Plane

Tatiana Scheeren de Oliveira et al. Rehabil Res Pract.

Abstract

Objective. to verify the validity and reproducibility of using the flexicurve to measure the angles of the thoracic and lumbar curvatures. Method. 47 subjects were evaluated by: (1) palpation and marking of the spinous processes using lead markers, (2) using X-rays in the sagittal plane to measure the Cobb angles, (3) molding the flexicurve to the spine, and (4) drawing the contour of the flexicurve onto graph paper. The angle of curvature was determined with the flexicurve based on a 3rd order polynomial. Results. No differences were found between the Cobb angles and the angles obtained using the flexicurve in thoracic and lumbar curvatures (P > 0.05). Correlations were strong and significant for the thoracic (r = 0.72, P < 0.01) and lumbar (r = 0.60, P < 0.01) curvatures. Excellent and significant correlations were found for both the intraevaluator and interevaluator measurements. Conclusion. The results show that there is no significant difference between the values obtained using the flexicurve and those obtained using the X-ray procedure and that there is a strong correlation between the two methods. This, together with the excellent level of inter- and intraevaluator reproducibility justifies its recommendation for use in clinical practice.

Figures

Figure 1
Figure 1
(a) Position of the subjects during both evaluation procedures; (b) X-ray image of the spine.
Figure 2
Figure 2
(a) Flexicurve; (b) molding the flexicurve to the spine, lateral view; (c) molding the flexicurve to the spine, posterior view.
Figure 3
Figure 3
(a) Tracing the internal contour of the flexicurve; (b) representation of the thoracic and lumbar curvatures on graph paper showing the position of the spinous processes.
Figure 4
Figure 4
(a) Outline on graph paper of the spine and points representing the shape of the lumbar and thoracic curvatures; (b) drawing of the curvatures obtained using two 3rd polynomial; (c) drawing the tangents on the limit points of the curvatures (T1/T12 for thoracic, L1/L5 for lumbar); (d) drawing the straight lines perpendicular to the tangents and establishing the thoracic (θ) and lumbar (α) angles.
Figure 5
Figure 5
The distribution of the flexicurve angle in relation to the Cobb angle. The vertical and horizontal dotted lines represent the distribution of a normal curvature [31] and divide the figure in 9 zones. The same results are obtained with both techniques in the “A” zones, false positives should appear in “B” zones; false negatives (⊙) are shown in the “C” zones.
Figure 6
Figure 6
The distribution of the flexicurve angle in relation to the Cobb angle. The vertical and horizontal dotted lines represent the distribution of a normal curvature [31] and divide the figure in 9 zones. The same results are obtained with both techniques in the “A” zones, false positives should appear in “B” zones; false negatives should appear in the “C” zones.
Figure 7
Figure 7
Graphic representation of the degree of agreement in relation to the difference between the CAT and FAT in function of the pooled mean (CAT and FAT). The thoracic curvature mean of differences (md) = 0.8°, the Standard Deviation of difference (SDd) = 8.0°, and the limits of agreement are from −15.3 to +17.0°.
Figure 8
Figure 8
Graphical representation of the degree of agreement in relation to the difference between CAL and FAL in function of the pooled mean (CAL and FAL). The lumbar curvature mean of differences (md) = 0.5°, the Standard Deviation of difference (SDd) = 8.3°, and the limits of agreement are from −16.0 to +17.0°.

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