The spinal appearance questionnaire - Results of reliability, validity, and responsiveness testing in patients with idiopathic scoliosis

Study Design. Prospective, sequential enrollment. Objective. We report the development and testing of the Spinal Appearance Questionnaire (SAQ) for reliability, validity, and responsiveness in patients with idiopathic scoliosis. Summary of Background Data. The SAQ was designed to measure patients' and their parents' perception of their spinal deformity's appearance using standardized drawings and questions. This study was designed to test the instrument's psychometric properties. Methods. The SAQ was administered as a test-retest to idiopathic scoliosis patients and parents for reliability and initial validity assessment ( Group I). It was then administered to patients before surgery and 1 year after surgery ( Group II) for responsiveness and further validity testing. Finally, both the SAQ and SRS instruments were administered to adolescent idiopathic patients before surgery and 1 year after surgery ( Group III) for comparison of the 2 instruments. Results. Group I: The individual scale items had good to excellent reliability ( Spearman's rho, 0.57-0.99) and high internal scale consistency (Cronbach's alpha > 0.7). The mean scale scores differentiated between curves greater than 30 and lesser curves ( P < 0.01). Surgery improved scores compared with those with "surgery recommended." Group II: The domains correlated with clinical and radiographic aspects of the deformity before surgery. All of the domains showed significant difference after surgery ( P < 0.0001) and large effect size for all domains except for the patient chest domain. Group III: Both the SAQ and the SRS instruments had significant improvement in all of their domains except for the SRS Activity scale. The relative efficiency of the SAQ domains to the SRS appearance domain ( the most responsive SRS domain) was greater for 5 SAQ domains. Conclusion. The SAQ is reliable, responsive to curve improvement, and shows strong evidence of validity. It provides more detail than the SRS in the appearance domain, and provides explanation of spinal deformity's concerns and improvements.