[Classification and surgical outcomes of congenital middle ear malformations with concomitant facial nerve anomalies]

Objective: To investigate the clinical classification and surgical outcomes of congenital middle ear malformations accompanied by facial nerve anomalies. Methods: A retrospective cohort study was conducted to analyze clinical data of patients with congenital middle ear malformations and concomitant facial nerve anomalies who received treatment in the Department of Otolaryngology, Zhujiang Hospital, Southern Medical University, between January 2021 and December 2024. Facial nerve anomalies were categorized into four distinct types: partial obstruction of the oval window, complete obstruction of the oval window, aberrant course over the promontory, and branching anomalies. Ossicular chain malformations were classified in accordance with the Teunissen classification system. Individualized hearing reconstruction strategies were implemented based on the specific anatomical characteristics of the anomalies. All patients were followed up for 3 to 24 months. Postoperative therapeutic efficacy was evaluated by comparing preoperative and postoperative mean air conduction thresholds and air-bone gaps (ABG), while monitoring surgical complications. Results: Thirteen patients (17 ears) aged [M (Q₁, Q₃)] 15.0 (11.5, 21.0) years were included, with eight males and five females. Facial nerve anomalies were categorized as follows: partial obstruction of the oval window in six ears (three cases of Type Ⅰ, three cases of Type Ⅲ), complete obstruction of the oval window in three ears (one case of Type Ⅰ, two cases of Type Ⅲ), aberrant course over the promontory in six ears (all Type Ⅳ), and branching anomalies in two ears (both Type Ⅳ). Hearing reconstruction modalities employed included: incus-stapedial piston placement following vestibular fenestration in nine ears, malleus-stapedial piston placement following vestibular fenestration in two ears, partial ossicular replacement prosthesis (PORP) implantation in three ears, total ossicular replacement prosthesis (TORP) implantation in one ear, stapes mobilization in one ear, and laser-assisted ossicular chain release in one ear.Statistical analysis revealed that postoperative mean air conduction thresholds [(33.8±15.2) dB HL vs (60.1±13.8) dB HL, P<0.001] and mean ABG [(14.6±6.9) dB vs (37.2±9.2) dB, P<0.001] were significantly reduced compared with preoperative values. Postoperative ABG≤20 dB was achieved in 15 ears (88.2%). Postoperative complications were limited to transient vertigo in five cases and taste disturbance in two cases. No cases of facial paralysis, sensorineural hearing loss, tympanic membrane perforation, or tinnitus were observed. The median follow-up duration was 6.0 (5.5, 20.0) months. Conclusion: Individualized hearing reconstruction strategies based on the classification of facial nerve and ossicular chain anomalies can effectively protect the facial nerve and achieve significant hearing improvement, demonstrating favorable clinical outcomes.