Is the SRS-22 Instrument Responsive to Change (Surgical Treatment) in Adult Scoliosis Patients Having Primary Spinal Deformity Surgery?

Introduction: A number of efforts have been directed at validation of the SRS-22 instrument in the setting of adult spinal deformity. However, no study has extensively analyzed the ability of the instrument to detect change (i.e., surgical treatment) in treated adult scoliosis patients. The purpose of this study is to prospectively analyze responsiveness of SRS-22 to change (surgical treatment) at 1 and 2 years following surgery.

Methods: A multicenter prospective series of adult scoliosis patients (all primary/no revisions) were administered SRS-22, ODI and SF-12 questionnaires preop and 1 and 2 years postop. 102 patients had 1-year follow-up, 39 had 2-year follow-up.

Demographics: 90% of patients were female, 10% male. 30% were 20-39, 48% were 40 to 60 and 22% were >=61 years of age. The average preop Cobb was 59.5 and 29 at ultimate follow-up.

Results: The greatest changes from preop to 2-year follow-up were SRS appearance domain followed by SRS total, SRS pain and ODI scores. These comparisons were the same at 1- and 2-year follow-up. The proportion of patients meeting minimally clinically important difference (MCID) threshold at 1- and 2-year postop, respectively, were SRS appearance (71%,76%), ODI (59%,73%), SRS pain (56%,63%), SF-12 physical (47%,56%) and SRS activity (40%,42%). All outcome measures, except SF-12 mental health, showed statistically significant improvement from baseline to 2-year follow-up. Strong correlation (Pearson's correlation coefficients above r=0.8) was noted for SRS pain, activity and appearance with total score and SRS activity and total score with ODI.

Conclusion: Based on these 3 outcome tools, the greatest responsiveness to change was demonstrated by SRS appearance domain followed by SRS total, then SRS pain, then ODI. This suggests the SRS tool is more responsive than ODI, which is more responsive than SF-12 to change brought on by primary surgical treatment of adult scoliosis patients.