Peripheral Vestibular Dysfunction and Postural Control Impairments in Adolescents with Idiopathic Scoliosis: A Multimodal Clinical and Instrumental Analysis

Background and Objectives: Idiopathic scoliosis (IS) has been conceptualized as a structural spinal deformity; emerging evidence suggests that postural control and vestibular mechanisms may contribute to curve development and functional severity. This study investigated the relationship between radiological parameters, postural stability, and vestibular dysfunction in adolescents with IS. Materials and Methods: A retrospective cohort of 177 patients aged 8–22 years was analyzed between 2022 and 2024. Standard radiography was performed on 135 participants to evaluate the major curve as established by the Cobb method, Nash–Moe classification, and Risser stage. Peripheral vestibular syndrome (PVS) was investigated using the Fukuda (FST), video-nystagmography (VNG), and instrumental Romberg tests on a stable and unstable platform. Associations between vestibular variables and radiographic parameters were explored using Mann–Whitney U and Kruskal–Wallis tests, supported by non-parametric correlations. Results: Female participants (63%) exhibited significantly higher initial major curve angle value compared with males (median 14° vs. 10.5°, p = 0.004). Positive FTS findings and the presence of peripheral vestibular syndrome were strongly associated with higher baseline and final major curve angles (both p < 0.001). Romberg performance showed significant correlations with major curve angle across stable and unstable conditions (r = 0.298–0.396, all p < 0.001). VNG identified multi-canal vestibular involvement, particularly anterior–horizontal combinations on the right ear, as being associated with substantially greater curve magnitude; left-ear impairment demonstrated similar non-significant trends. Curve localization did not differ by vestibular involvement. Conclusions: Patients with idiopathic scoliosis (IS) display consistent associations between vestibular dysfunction, impaired postural control, and greater curve severity. These findings support the clinical relevance of vestibular assessment in scoliosis evaluation and suggest a potential role for sensorimotor rehabilitation strategies. Integrating vestibular screening into standard care may enhance risk stratification and inform the clinician on individualized conservative management.