Clinical portrait of cochlear implantation in patients with incomplete partition type-III malformation

To investigate the clinical characteristics and postoperative speech development in children with incomplete partition type III (IPIII) cochlear malformation.

A retrospective analysis was conducted on 6 patients (12 ears) diagnosed with IPIII cochlear malformation, all patients underwent preoperative high-resolution CT (HRCT), middle ear and cranial MRI, and audiological evaluations. Intraoperative cochlear imaging was performed to confirm electrode placement, there was also 1 types of comparison: IP III patients with matched CI patients without inner ear malformations, questionnaires were used to evaluate auditory and speech perception.

All 6 patients were male, with 3 undergoing bilateral cochlear implantation and 3 undergoing unilateral implantation (1 left, 2 right). The surgical age ranged from 8 months to 12 years, with a median age of 17 months. HRCT findings in all 12 ears (100%) showed a grossly normal cochlear shape with bony cochlear partitions present but an absent modiolus. Ten ears (10/12; 83.3%) exhibited enlarged internal auditory canals (6.13 ± 0.395 mm), 9 ears (9/12; 75%) had profound sensorineural hearing loss, 4 ears (4/12; 33.3%) showed significant vestibular dilation with a cystic appearance, and 4 ears (4/12; 33.3%) had enlarged vestibular aqueducts. All patients had normal auditory nerve development (100%). intraoperative neural response telemetry (NRT) responses were successfully elicited in all cases, and all patients experienced gusher phenomenon (6/6; 100%). Intraoperative cochlear imaging preliminarily confirmed electrode placement. Follow-up ranged from 3 months to 1 year, with preoperative CAP scores 0.83 ± 0.41 and postoperative CAP scores 6 ± 1.55, p<0.05. In Speech Intelligibility Rating (SIR) questionnaires, CI patients without inner ear malformations outperformed IP III patients, while there was no significant difference in other questionnaires.

IPIII cochlear malformation is more common in male patients and is often associated with profound to severe sensorineural hearing loss. Cochlear implantation for IP-III malformation leads to significant auditory-speech improvement in early stage and can result in varying degrees of oral competence.