Nasal Septal Deviation Classifications, Including the Mladina System, and Their Craniofacial Correlates: A Scoping Review

Background/Objectives: Nasal septal deviation (NSD) is a common anatomical condition that may influence nasal airflow and has been proposed as a potential factor associated with craniofacial growth and morphology. However, available studies use heterogeneous classifications and measurement methods, including the Mladina classification, angular parameters, volumetric assessment, CT, CBCT, and cephalometric analyses. This scoping review aimed to map and synthesize the available evidence on the relationship between NSD classifications, including the Mladina system, and craniofacial morphological correlates. Methods: This scoping review was conducted according to Joanna Briggs Institute methodology for scoping reviews and reported in accordance with the PRISMA-ScR checklist. The protocol was prospectively registered in the Open Science Framework. A broad literature search was performed in PubMed, Embase, Cochrane Library, BASE, and Google Scholar, without restrictions on publication date or language. Eligible studies included clinical or academic investigations assessing NSD using a defined classification or quantitative parameters and relating it to craniofacial, maxillary, mandibular, dentofacial, or asymmetry-related outcomes. Results: From 715 identified records, 387 remained after deduplication, and 6 studies met the inclusion criteria. The included studies varied substantially in sample size, imaging modality, NSD assessment method, and outcome domains. The most consistent findings suggested associations between NSD and localized or transverse nasomaxillary changes, particularly involving the palate, maxilla, nasal floor, and dentoalveolar region. Evidence regarding global facial asymmetry, basic maxillomandibular dimensions, and malocclusion was limited and inconsistent. Studies using the Mladina classification did not provide uniform conclusions across outcome domains. Conclusions: Current evidence does not support NSD as a uniform marker of global craniofacial morphology abnormalities. NSD appears more plausibly associated with selected local and transverse nasomaxillary features than with overall facial asymmetry. Future studies should combine standardized NSD classifications, especially the Mladina system, with precise three-dimensional craniofacial assessment in homogeneous populations.