Evaluation of spinal mobility by pocket goniometer (Inclimed) in patients with ankylosing spondylitis: preliminary data.

Background: Ankylosing spondylitis (AS) is a chronic inflammatory disease affecting sacroiliac joints and whole the spine. The clinical instrument of functional evaluation of spine in AS is mainly based on BASMI score. Objectives: The aim of our study was to verify the usefulness of new gravity-dependent and compass-needle pocket goniometer (IncliMed R, University of Padua) for AS spinal mobility measurement. Methods: Forty one consecutive out-patients with AS (New York modified criteria) entered the study; 33 males and 8 females, age 46.5±12.3 years (range 21-73). Their active range of motion (AROM) of whole spine were evaluated by the same metrologist (B.L.) throughout the IncliMed R. The results of angular measures in 3 plane (frontal, coronal and sagittal) of cervical, thoracic and lumbo-sacral spine were expressed in grades and then summarized. At the same visit the classical BASMI evaluation was performed and VAS (last week), BASDAI and BASFI were applied. The simple linear regression were performed for BASDAI, BASFI and VAS in the function of AROM and BASMI. The results were expressed as a coefficient of determination (r2) and the level of significance of p<0.05. The data were elaborated by SPSS 12.0. Results: The AROM was 395±136.4° and BASMI was 3.9±2.3. The Pearson correlation between these tests were r=-0.78 (p<0.000). BASDAI, BASFI and VAS were respectively 41.3±26.2 mm, 30.5±23.7 mm and 27.1±23.2 mm. BASDAI, BASFI and VAS were more correlated with AROM, (respectively r2=0.30, p<0.000; r2=0.39, p<0.000; r2=0.14, p<0.05) than with BASMI (respectively r2=0.09, p=ns; r2=0.24, p<0.01; r2=0.06, p=ns). Conclusion: AROM was significantly correlated with BASMI. The self-assessed questionnaires were better correlated with AROM than with BASMI. Probably BASMI as a simplify score reflects incompletely the disease activity and functional impairment of AS. We propose that the AROM by IncliMed R may be utilised as an objective method for the evaluation of AS, useful for the research and for clinical trials.