Development and validation of the arabic version of the Spine Functional Index (SFI-AR) in patients with spinal disorders.

BackgroundThe Spine Functional Index (SFI) is a patient-reported outcome measure used to evaluate functional limitations in patients with spinal disorders. However, no validated Arabic version has been available, limiting standardized assessment in Arabic-speaking populations.MethodsThis prospective cross-sectional validation study translated and culturally adapted the SFI into Arabic (SFI-AR) following internationally accepted guidelines, including forward and back-translation, expert committee review, and pilot testing. Adults aged ≥18 years with spinal pain or dysfunction completed the SFI-AR and the Arabic Chronic Pain Grade Scale (CPGS-AR). A clinically stable subgroup repeated the SFI-AR after 5-10 days. Psychometric evaluation assessed interpretability, internal consistency, test-retest reliability, measurement error, structural validity using exploratory and confirmatory factor analyses, and convergent validity.ResultsA total of 411 patients were included, with 137 completing the retest. Internal consistency was excellent (Cronbach's α = 0.954), and test-retest reliability was outstanding (ICC(2,1) = 0.998; 95% CI: 0.997-0.998). Measurement error was low (SEM 4.27; MDC 12.56). No significant floor or ceiling effects were observed. Exploratory factor analysis supported an essentially unidimensional structure, explaining 48.29% of the variance, and confirmatory factor analysis showed acceptable fit for a single-factor model (CFI = 0.905; TLI = 0.896; RMSEA = 0.073; SRMR = 0.065). Convergent validity was confirmed by strong correlations with CPGS-AR disability (ρ = 0.915) and moderate correlations with pain intensity (ρ = 0.692; p < 0.001).ConclusionThe SFI-AR is a reliable, valid, and culturally adapted instrument for assessing spinal function in Arabic-speaking populations, supporting its use in clinical practice and research.