Abstract
Purpose of the study: The principal aim of this prospective multicentric observational study was to validate an self-administered questionnaire for evaluation of functional outcome after surgical treatment of lumbar stenosis. The questionnaire was associated with an index of neurological impairment in order to account for objective neurological injury and an index exploring patient satisfaction after treatment for lumbalgia, radiculalgia and gait disorders.
Material and methods: The structure of the questionnaire was examined to determine whether the three dimensions of the evaluation scale were pertinent, to establish reproducibility (intra-observer variability), to study sensitivity to change, and finally to examine the items in the questionnaire and their capacity for effective measurement using the Cronbach alpha coefficient and principal components analysis. Reproducibility was tested on 49 patients who filled out the self-administered questionnaire twice, 15 days apart. The intra-class coefficients of correlation were calculated. Sensitivity was tested by correlating the variations of the scores obtained pre- and postoperatively with the index of satisfaction and by calculating mean standardised responses. The questionnaire items were validated by correlating the scores obtained using the questionnaire with scores obtained with three other self-administered questionnaires: SF36, EIFFEL2 and GHQ28.
Results: One hundred four patients were included in this study, 96 were seen at follow-up visits six and twelve months after surgery. Principal component analysis demonstrated the pertinence of the three dimensions in the evaluation scale. The overall Cronback alpha was 0.86. The overall intra-class coefficient of correlation was 0.95, varying from 0.86 to 0.97 for the dimensions studied. There was a good correlation (0.82) between the scores obtained and index of satisfaction. All mean standardised responses were greater than A1, indicating good sensitivity to change. There was a good correlation between the evaluated score and the EIFFEL2 self-administered questionnaire and the following dimensions of the SF36: physical activity, physical pain, vitality and limitation due to physical pain.
Discussion and conclusion: Using a simple self-administered questionnaire (eight questions), an index of satisfaction (four questions) and an objective score of neurological disorders allowed reliable, sensitive and reproducible assessment of the changes in the functional impairment caused by lumbar stenosis before and after surgical treatment.
The abstracts were prepared by Pr. Jean-Pierre Courpied (General Secretary). Correspondence should be addressed to him at SOFCOT, 56 rue Boissonade, 75014 Paris, France
