[Psychometric properties of the pain drawing and the Ransford technique in patients with chronic low back pain].

Background: The aim of our study was the analysis of the psychometric properties of the Ransford technique which is a qualitative scoring method of the pain drawing. It has been suggested that this method could be used as a brief screening technique for psychological involvement in pain complaints.
Methods: 109 patients with chronic back pain filled in the pain drawing which was rated according to the technique described by Ransford and colleagues in 1976. As external criterium of validity we chose a differentiated expert rating of psychological interference.
Results: The Ransford technique showed moderate to good coefficients of reliability (re-test, inter and intra-rater). On the other hand, the Ransford technique demonstrated very low indices of validity in order to give a prognosis about psychological interference. Sensitivity and specificity of the Ransford technique demonstrated inadequate values, which furthermore were independent from cut-off points.
Conclusion: The pain drawing and the Ransford technique are not sufficiently sensitive and therefore allow no screening for psychological interference in complaints of back pain.