Score Distribution of the Scoliosis Research Society-22 Questionnaire in Subgroups of Patients of All Ages With Idiopathic Scoliosis

Abstract

Cross-sectional measurement study. To analyze the score distribution of the Scoliosis Research Society (SRS)-22 questionnaire domains and items for patients with idiopathic scoliosis (IS) of all ages. Scoliosis-related quality-of-life questionnaires have demonstrated high ceiling effects in younger patients. However, the score distribution has not been examined thoroughly in other clinically relevant IS subgroups. The SRS-22 was completed by 173 females with IS. The proportions of ceiling effects, floor effects, of patients scoring greater than or equal to 4 out of 5 and the box plots of the score distribution for each domain and item were compared between subgroups. Subgroups were formed based on age (k = 4), management (k = 6), curve severity (k = 3), and curve type (k = 4). Domain ceiling effects varied between 0% and 23.1%. Domain floor effects were observed only for Self-image (<7%) and Satisfaction (<12%). Only Pain and Satisfaction showed moderate (>20%) ceiling effects. Ceiling effects for Pain and Mental Health decreased with increasing age (P < 0.05). Pain ceiling effects decreased and Satisfaction ceiling effects increased from least to most invasive management (P < 0.05), but no differences were found among Cobb severity or curve types subgroups. Of the 22 items, 9 had major (>or=50%) ceiling effects and 11 had moderate ceiling effects. Most subgroups (14/16) had 4 to 6 items with major ceiling effects. The following items had major ceiling effects in the majority of subgroups: Function, 9 and 15; Pain, 11 and 17; and Self-image, 14. Most SRS-22 domains had acceptable levels of ceiling effects (<20%) in the majority of the subgroups examined. However, more sensitive measurements may be needed to supplement the SRS-22 in assessing Pain in patients below 18 years or Satisfaction after surgery.