title: The validity of the SRS-22 instrument in an adult spinal deformity population compared with the Oswestry and SF-12: a study of response distribution, concurrent validity, internal consistency, and reliability.
abstract: METHODS
  Prospective analysis of a consecutive cohort of adult spinal deformity patients queried over a 12-month period.
  
  
  OBJECTIVE
  To assess the SRS-22 instrument compared with the SF-12 and Oswestry.
  
  
  BACKGROUND
  Very few reports in the literature have applied the SRS-22 to adult spinal deformity patients.
  
  
  METHODS
  Consecutive adult spinal deformity patients were applied the SRS-22, SF-12, and Oswestry. Four analyses were done: 1) floor/ceiling effect; 2) Pearson's correlation coefficients between the SRS-22, SF-12, and Oswestry; 3) Cronbach's alpha analysis for internal consistency within the SRS-22; and 4) test/retest.
  
  
  RESULTS
  Floor/ceiling range for the SRS-22 compared favorably with the SF-12 and Oswestry. The Pearson's coefficients correlating the two questionnaires relative to the SRS-22 were > 0.7. The Cronbach's alpha within each domain for the SRS-22 were > 0.7, except for pain (0.67). Test/retest correlation coefficients ranged from 0.84 to 0.95 for the subscales.
  
  
  CONCLUSIONS
  The SRS-22 is a disease-specific instrument with the capacity to demonstrate change in health status more effectively than the SF-12 and in more domains than the Oswestry. The SRS-22 showed high criterion validity with the SF-12 and Oswestry based on Pearson's coefficients. High Cronbach's alpha scores suggested a high internal consistency within each domain of the SRS-22, except for pain (0.67). Test/retest reliability was excellent.
authors.affiliation: Adult Spinal Deformity Study Group, Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA. bridwellk@wustl.edu
authors.forename: Keith H
authors.initials: KH
authors.lastname: Bridwell
authors.forename: William
authors.initials: W
authors.lastname: Cats-Baril
authors.forename: John
authors.initials: J
authors.lastname: Harrast
authors.forename: Sigurd
authors.initials: S
authors.lastname: Berven
authors.forename: Steven
authors.initials: S
authors.lastname: Glassman
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Farcy
authors.forename: William C
authors.initials: WC
authors.lastname: Horton
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lenke
authors.forename: Christine
authors.initials: C
authors.lastname: Baldus
authors.forename: Terri
authors.initials: T
authors.lastname: Radake
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000013:Congenital Abnormalities; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods* / Q000592:standards*; D011446:Prospective Studies; D015203:Reproducibility of Results; D013116:Spinal Cord / Q000002:abnormalities* / Q000473:pathology