Differentiation of back pain patients using a pain questionnaire.

A specially designed pain questionnaire was administered to 52 consecutive out-patients referred to an orthopaedic clinic of a general hospital over a two week period because of pain in the lower back. A clinical evaluation, based on the patients' markings on 'pain drawings', and on the degree of compatibility between their reported pain symptoms and the results of physical examinations, led to the classification of 21 cases (40%) as psychogenic. The answers of these patients to the questionnaire differed in several aspects from those of the remaining 60%. Pain was more severe, multiform and enduring, and had a more pervasive influence on their life situation; they included a higher frequency of family problems, changes of employment, stress experienced at work, sleeping problems, and 'specialist shopping'. Without being aware of which patients were classified as psychogenic cases, the orthopaedic surgeons made less auspicious prognoses for these patients and also found the questionnaire more helpful in evaluating them. When asked to rate the intensity of the patients' pain, the surgeons, unlike the patients, avoided extreme ratings. Comparing the two scales used (a six-step verbal scale and a 10 cm graphic rating scale (GRS) for rating pain intensity, patients found the GRS to be more meaningful. The words occupied different relative positions on the verbal scale and the GRS, and their position on the GRS fluctuated according to whether they denoted general pain or pain during attacks. The findings suggest that the questionnaire is a useful screening tool for identifying patients requiring further psychological evaluation.