Age-gender matched comparison of SRS instrument scores between adult deformity and normal adults - Are all SRS domains disease specific?

Study Design. Prospective, observational study. Objective. To further validate the Scoliosis Research Society (SRS) instrument by comparing scores of adult deformity patients with no prior history of spine surgery to the scores of normal adult volunteers in age-gender matched groups. Summary of Background Data. Efforts have been made to validate the SRS questionnaire in adolescent and adult deformity patients. An important psychometric attribute of any quality of life tool is its ability to discriminate between subjects with and without the condition of interest. Discriminate validity of the SRS questionnaire has not been established in the primary (no prior surgical treatment) adult deformity population. Methods. The SRS questionnaire was issued prospectively to 935 primary adult deformity patients with a diagnosis of idiopathic or de novo scoliosis and minimum Cobb angle of 30 degrees (average Cobb angle: 54 degrees; range: 30 degrees-132). Five hundred forty-three patients were treated nonsurgically while 392 patients underwent surgical intervention. Baseline SRS scores of the deformity population were compared to 1222 volunteers with no history of spine disease randomly sampled from the US population. Analysis between the 2 populations was broken down into 6 age-gender groups: male/female; 20-40, 41-60, 61-80 years of age. Results. SRS domain scores of the deformity subgroups demonstrated significant statistical differences from their corresponding age-gender matched normative group. The only exceptions were the mental health domain in the older males, 61-80 years of age. The average SRS subscore for each age-gender subgroup was less than the tenth percentile in the corresponding normative population, indicating substantial limitations in these patients. Conclusion. Our findings confirm the SRS instrument has excellent discriminate validity in the adult population. It appears to be disease-specific in the domains of pain, appearance and activity in adult spinal deformity patients who have not had prior surgery.