Development and Psychometric Validation of the OMFS-QoL-18: A Multidimensional Patient-Reported Outcome Measure for Postoperative Oral and Maxillofacial Surgery

Background: Quality-of-life (QoL) assessment has become an essential component of outcome evaluation in oral and maxillofacial surgery (OMFS), particularly in interventions with functional implications for breathing, sleep, and oro-facial performance. Existing instruments often lack specificity for the postoperative OMFS population. This study aimed to develop and psychometrically validate the OMFS-QoL-18 questionnaire, a condition-oriented patient-reported outcome measure designed for postoperative assessment. Methods: A cross-sectional validation study was conducted on 226 adult patients evaluated 6–12 months after orthognathic or function-oriented OMFS procedures. Internal consistency was assessed using Cronbach’s alpha, and reproducibility using the intraclass correlation coefficient (ICC) based on a two-way random-effects model with absolute agreement. The internal structure of the instrument was explored through an exploratory dimensionality analysis using Principal Component Analysis (PCA), including Kaiser–Meyer–Olkin (KMO) testing and Bartlett’s test of sphericity. Descriptive statistics were calculated for item and domain scores. Results: The OMFS-QoL-18 demonstrated good internal consistency (Cronbach’s α = 0.789; standardized α = 0.783) and satisfactory reproducibility (ICC = 0.81; 95% CI: 0.74–0.87). The exploratory dimensionality analysis suggested a multidimensional structure, with five components explaining 67.1% of the total variance. Item clustering was broadly consistent with the predefined conceptual domains, including respiratory comfort, sleep quality, daytime function, oro-maxillofacial function, and global satisfaction. Given the use of PCA as a component-based method, these findings are interpreted as preliminary evidence of dimensional organization rather than confirmation of latent constructs. Conclusions: The OMFS-QoL-18 demonstrated good internal consistency and preliminary evidence of a coherent factor structure. These findings support its use as a promising condition-specific instrument, pending further validation studies. Further multicenter and longitudinal validation studies are warranted to confirm structural stability and responsiveness over time.