Mannion, A FA FMannionElfering, Achim HeikoAchim HeikoElferingFekete, T FT FFeketeHarding, I JI JHardingMonticone, MMMonticoneObid, PPObidNiemeyer, TTNiemeyerLiljenqvist, UULiljenqvistBoss, AndreasAndreasBossZimmermann, LLZimmermannVila-Casademunt, AAVila-CasademuntSánchez Pérez-Grueso, F JF JSánchez Pérez-GruesoPizones, JJPizonesPellisé, FFPelliséRichner-Wunderlin, SSRichner-WunderlinKleinstück, F SF SKleinstückObeid, IIObeidBoissiere, LLBoissiereAlanay, AAAlanayBagó, JJBagó2024-10-092024-10-092022-09https://boris-portal.unibe.ch/handle/20.500.12422/70417PURPOSE In patients with adult spinal deformity, it was previously shown that 16 of the non-management items of the SRS-instrument showed a better fit to the theoretical four-factor model (pain, function, self-image, mental health) than did all 20 items. Whether the same phenomenon is observed in data from younger (< 20y) patients, for whom the questionnaire was originally designed, is not currently known. METHODS Confirmatory factor analysis was used to evaluate the factor structure of the 20 non-management items of the SRS-instrument completed by 3618 young patients with spinal deformity (75.5% female; mean age, 15.0 ± 2.0 years) and of its equivalence across language versions (2713 English-speaking, 270 Spanish, 264 German, 223 Italian, and 148 French). The root mean square error of approximation (RMSEA) and comparative fit index (CFI) indicated model fit. RESULTS Compared with the 20-item version, the 16-item solution significantly increased the fit (p < 0.001) across all language versions, to achieve good model fit (CFI = 0.96, RMSEA = 0.06). For both 16-item and 20-item models, equivalence across languages was not reached, with some items showing weaker item-loading for some languages, in particular German and French. CONCLUSION In patients with adolescent idiopathic scoliosis, the shorter 16-item version showed a better fit to the intended 4-factor structure of the SRS-instrument. The wording of some of the items, and/or their equivalence across language versions, may need to be addressed. Questionnaire completion can be a burden for patients; if a shorter, more structurally valid version is available, its use should be encouraged.enAIS Factor analysis Language versions Patient-reported outcome SRS-22600 - Technology::610 - Medicine & health300 - Social sciences, sociology & anthropology::360 - Social problems & social services100 - Philosophy::150 - Psychology300 - Social sciences, sociology & anthropologyarticle10.48350/1695773547632110.1007/s43390-022-00509-5