title: Reliability and validity of the adapted Dutch version of the revised Scoliosis Research Society 22-item questionnaire.
abstract: BACKGROUND
  As in other fields of medicine, there is an increasing interest among orthopedic surgeons to measure health-related quality of life in adolescent idiopathic scoliosis patients and to evaluate the burden of disease and the effectiveness of different treatment strategies. The development of the revised Scoliosis Research Society 22-item patient questionnaire (SRS-22r) enabled a comprehensive evaluation of health-related quality of life of these patients. Over the years, the SRS-22r gained wide acceptance and has been used in several different countries, languages, and cultures. The SRS-22r has not been translated into Dutch to date.
  
  
  OBJECTIVE
  To translate the SRS-22r into Dutch and adapt it cross-culturally as outlined by international guidelines and to test its psychometric properties to measure health-related quality of life of adolescent idiopathic scoliosis patients in the Netherlands.
  
  
  METHODS
  A cross-sectional, multicenter validation study.
  
  
  METHODS
  A total of 135 adolescent idiopathic scoliosis patients (mean age 15.1 years old) of three major scoliosis centers in the Netherlands were enrolled in this study. Ninety-two (68%) subjects completed the Dutch SRS-22r, Child Health Questionnaire (CHQ)-CF87 (golden standard for adolescents), and Short Form (SF)-36 (golden standard for adults). Two weeks later, 73 (79%) of 92 respondents returned a second SRS-22r. Demographics, curve type, Risser stage, and treatment status were documented.
  
  
  METHODS
  Floor and ceiling effects, internal consistency, reproducibility, concurrent validity, and discriminative ability of the Dutch version of the SRS-22r questionnaire.
  
  
  METHODS
  For content analysis, SRS-22r domain scores (function, pain, self-image, mental health, and satisfaction with management) were explored and floor and ceiling effects were determined. Cronbach's α was calculated for internal consistency of each domain of the questionnaires and reproducibility was assessed by test-retest reliability analysis. Using Pearson's correlation coefficient, comparison of the domains of the Dutch SRS-22r with the domains of the SF-36 and Child Health Questionnaire-CF87 assessed the concurrent validity. Differences in SRS-22r domain scores between untreated patients with different curve severity determined the discriminative ability of the questionnaire.
  
  
  RESULTS
  The SRS-22r domains as well as the SF-36 and CHQ-CF87 domains demonstrated no floor effects, but the function, pain, and satisfaction with management domains had ceiling effects, indicating the proportion of subjects with the maximum score between 19.6% and 33.0%. Internal consistency was very satisfactory for all SRS-22r domains: Cronbach's α was between 0.718 and 0.852. By omitting question 15, the internal consistency of the function domain increased from 0.746 to 0.827. Test-retest reliability was ≥0.799 for all SRS-22r domains. The function, pain, mental health, and self-image domains correlated under the 0.001 significance level with the corresponding CHQ-CF87 and SF-36 domains. The satisfaction with management domain did not correlate with the other questionnaires. The SRS-22r had the ability to detect differences between groups with different curve severity; patients with a severe scoliotic curvature had significantly lower pain and self-image domain scores than patients with relatively mild scoliosis.
  
  
  CONCLUSIONS
  The Dutch SRS-22r had the properties needed for the measurement of patient perceived health-related quality of life of adolescent idiopathic scoliosis patients in the Netherlands. The Dutch SRS-22r could be used for the longitudinal follow-up of adolescent idiopathic scoliosis patients from adolescence to adulthood and for establishing the effects of conservative or invasive surgical treatment.
authors.affiliation: Department of Orthopaedic Surgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
authors.forename: Tom P C
authors.initials: TP
authors.lastname: Schlösser
authors.affiliation: Department of Orthopaedic Surgery, Vrije Universiteit medical center, De Boelelaan 117, 1081 HZ, Amsterdam, The Netherlands.
authors.forename: Agnita
authors.initials: A
authors.lastname: Stadhouder
authors.affiliation: Research Department, Sint Maartenskliniek, Hengstdal 3, 6574 NA, Ubbergen, The Netherlands.
authors.forename: Janneke J P
authors.initials: JJ
authors.lastname: Schimmel
authors.affiliation: Department of Orthopaedic Surgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
authors.forename: A Mechteld
authors.initials: AM
authors.lastname: Lehr
authors.affiliation: Department Social Dentistry, Academic Center for Dentistry Amsterdam, VU Amsterdam University and University of Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands; Department of Epidemiology, Division Julius Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
authors.forename: Geert J M G
authors.initials: GJ
authors.lastname: van der Heijden
authors.affiliation: Department of Orthopaedic Surgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. Electronic address: R.M.Castelein@umcutrecht.nl.
authors.forename: René M
authors.initials: RM
authors.lastname: Castelein
mesh_terms: D000293:Adolescent; D002648:Child; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D003469:Culture; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D012600:Scoliosis / Q000175:diagnosis* / Q000601:surgery; D011795:Surveys and Questionnaires
keywords: Adolescent idiopathic scoliosis; Concurrent validity; Content analysis; Cross-cultural adaptation; Discriminantive ability; Health-related quality of life; Reliability; Scoliosis Research Society 22 revised questionnaire