关键词: 内耳畸形, 人工耳蜗植入, 颞骨计算机断层扫描

Abstract: Objective  To assess the morphological characteristics of the bony structure of the cochlea in patients with different subtypes of cochlear hypoplasia (CH) and to explore the relationship between the auditory and speech rehabilitation outcomes following cochlear implantation (CI) in patients with CH and the subtype of malformation as well as anatomical characteristics.Methods  Clinical data of CI patients diagnosed with CH at Beijing Tongren Hospital, Capital Medical University were collected and their postoperative outcomes were followed up. Temporal bone computed tomography (CT) 3D reconstruction technology was used to reconstruct 3D images of the cochlea in patients with different subtypes. Measurements and analyses were conducted on the cochlear length, cochlear width, cochlear height, cochlear volume, basal turn length, and cochlear duct length. A questionnaire was used to evaluate auditory and speech rehabilitation two years postoperatively. The study investigated the effects of different subtypes and cochlear nerve development on postoperative outcomes and explored the relationship between cochlear anatomical parameters and postoperative results.Results  Among 53 patients, a total of 102 ears were identified with CH malformations, with 9 ears having unique cochlear morphology that could not be classified into specific subtypes. Significant differences were found in the anatomical parameters among different CH subtypes (P<0.05). 54.90% of CH patients had concomitant cochlear nerve deficiency (CND). Postoperative follow-up was conducted on 38 of the patients. There were no significant differences in postoperative outcomes among different CH subtypes, but the presence of CND showed significant differences in  Categories of Auditory Performance （CAP）, the Speech Intelligibility Rating （SIR）  and  Meaningful Use of Speech Scale（MUSS） scores (P<0.01). In CH patients with normal cochlear nerve development, there was a positive correlation between postoperative outcome scores and several cochlear anatomical parameters.Conclusions  CH patients exhibit complex variations in cochlear morphology and a high probability of concurrent CND, resulting in significant individual differences in postoperative outcomes. Preoperative temporal bone CT 3D reconstruction can help in evaluating cochlear morphology, differential diagnosis of various subtypes, and identification of unique cochlear morphologies in CH patients. Patients with CND have poorer outcomes compared to those with normal cochlear nerve development. When cochlear nerve development is normal, better cochlear development correlates with better postoperative results. It is essential to perform a differential diagnosis and comprehensive evaluation of cochlear morphology and cochlear nerve development in CH patients preoperatively, to make reasonable predictions about surgical methods and postoperative outcomes.

Key words: inner ear malformations, cochlear implantation, temporal bone computed tomography