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
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 ( ). Correlations were strong and significant for the thoracic ( , ) and lumbar ( , ) 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. 1. Introduction Traditionally, physiotherapy has been considered a good option for both the treatment and prevention of spinal alterations. Postural evaluation is used to identify such alterations or follow the evolution of treatment at the different healthcare levels [1]. Both quantitative and qualitative postural evaluation methods are available to physiotherapists. Without doubt, of the qualitative methods, the most widely used is the plumb line method, which consists in a subjective visual evaluation of parts of the body in relation to its position in space. This method depends on the experience of each evaluator in diagnosing postural deviation and, due to its subjective nature it is difficult to compare diagnoses among physiotherapists [2]. The subjective nature of this traditional method of postural evaluation has encouraged the search for quantitative methods, capable of providing numerical measures of spinal curvature deviation. Since the 1930’s, the gold standard method of measuring spinal kyphosis and lordosis has been the X-ray examination [3, 4]. Traditionally, the angles of the spinal curvatures are obtained using the two or four-line Cobb method [4–7]. Despite its confirmed validity, some issues can be raised regarding the use of X-ray examination. First, the patient is exposed to radiation and this therefore is not recommended for
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