Spinal appearance questionnaire: factor analysis, scoring, reliability, and validity testing.

Area of Science:

• Orthopedics
• Psychometrics
• Spinal Surgery

Background:

• The Spinal Appearance Questionnaire (SAQ) is used in adolescent idiopathic scoliosis (AIS) but requires further psychometric evaluation.
• Previous studies have administered the SAQ to surgically treated AIS patients, but a comprehensive analysis of its properties is lacking.

Purpose of the Study:

• To conduct a factor analysis of the SAQ to determine its underlying structure.
• To evaluate the psychometric properties, including reliability and validity, of the SAQ in a large cohort of AIS patients.
• To assess the SAQ's ability to correlate with clinical measures and differentiate patient groups.

Main Methods:

• A cross-sectional study involving 1802 adolescent idiopathic scoliosis (AIS) patients.
• Patients completed the Spinal Appearance Questionnaire (SAQ) and the Scoliosis Research Society-22 (SRS-22).
• Demographic data and radiographic measures, including Lenke type and curve magnitude, were collected.

Main Results:

• Factor analysis identified two factors for the SAQ: Appearance (10 items) and Expectations (4 items).
• The SAQ demonstrated good reliability (Cronbach's α = 0.88) and test-retest reliability (0.81-0.91).
• SAQ scores correlated more strongly with curve magnitude than SRS-22 scores and differentiated patients needing surgery.

Conclusions:

• The SAQ is a valid and reliable instrument for assessing self-image in AIS patients.
• The SAQ's Appearance and Expectations factors provide valuable insights into patient self-perception.
• The SAQ is a useful tool for correlating with spinal deformity severity and guiding treatment decisions.