Noninvasive Measurement of Lumbar Sagittal Mobility: An Assessment of the Flexicurve Technique

K. Malcolm Tillotson, A. Kim Burton

Research output: Contribution to journalArticle

56 Citations (Scopus)


The use of flexicurves to measure lumbar sagittal mobility was subjected to a series of reliability and validation experiments. Appropriate statistical methods were described and used to quantify intraobserver and intrasubject variability and to determine limits of agreement with measurements from radiographs. It was shown that the traditional use of correlation coefficients can produce misleading or inadequate information. The flexicurve technique had an intraobserver variability of 3-4° of movement, was not significantly influenced by intrasubject variability, and provided measurements typically within 6° of radiographic measurements. The data suggest that the flexicurve technique is less biased than the inclinometric method. These results demonstrate the use of suitable statistical methods to assess the clinical usefulness, or level of interchangeability, of spinal measurement instruments.

Original languageEnglish
Pages (from-to)29-33
Number of pages5
Issue number1
Publication statusPublished - 1 Jan 1991


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