Radiological insight into aberrant intracranial course of the facial nerve and its association with inner ear malformations: a retrospective case series
摘要
The purpose of this study was to characterize the imaging features of an aberrant intracranial course of the facial nerve (AIFN) in patients with congenital sensorineural hearing loss and to assess its association with cochlear nerve deficiency and inner ear abnormalities.
MethodsThis retrospective descriptive case series study included patients with congenital sensorineural hearing loss who underwent high-resolution MRI of the cerebellopontine angle. Facial nerve trajectory, relationship to trigeminal nerve, angle of emergence from the brainstem, cochlear nerve status, internal auditory canal morphology, and associated inner ear anomalies were systematically evaluated. Imaging findings were analyzed on a per-ear basis.
ResultsSeven patients (5 females, 2 males; median age 8.5 years, range 2–59 years) with a total of 12 affected ears were identified. Five patients (71%) demonstrated bilateral involvement. In all affected ears, the facial nerve followed an aberrant intracranial course characterized by anterior and/or medial deviation toward the prepontine cistern and Meckel’s cave, with absence along its expected cisternal trajectory toward the internal auditory canal. Cochlear nerve deficiency was present in all ears. Associated internal auditory canal abnormalities and inner ear malformations were frequently observed. Facial nerve function was preserved in all patients.
ConclusionAn aberrant intracranial course of the facial nerve is consistently associated with cochlear nerve deficiency and internal auditory canal anomalies in patients with congenital sensorineural hearing loss. Recognition of this imaging pattern may aid in differentiating this entity from trigeminal nerve variants and has important implications for preoperative assessment and selection of appropriate auditory rehabilitation strategies.