Cochlear implantation for cochlear hypoplasia type I: Surgical considerations and auditory outcomes in a case series.

BACKGROUND

Cochlear hypoplasia type I (CH-I) is a severe inner ear malformation often deemed a relative contraindication for cochlear implantation (CI), posing unique challenges for patients.

OBJECTIVES

This study aimed to evaluate surgical techniques, challenges, and postoperative auditory outcomes in CH-I patients undergoing CI, identifying key prognostic factors.

MATERIAL AND

METHODS

A retrospective analysis of six CH-I patients (11-222 months old) who underwent CI between 2012 and 2023 was conducted. Five patients used the transmastoid facial nerve recess approach (TFNRA) with a short straight electrode, while one employed the transmastoid slot labyrinthotomy approach (TSLA) with a customized electrode. Outcomes were assessed via Categories of Auditory Performance (CAP), Speech Intelligibility Rating (SIR), and both closed-set and open-set speech tests, including the Mandarin Lexical Neighborhood Test (MLNT).

RESULTS

Five patients achieved useable auditory function, with three demonstrating good open-set speech recognition. No significant differences were observed between unilateral and bilateral implantation.

CONCLUSIONS AND SIGNIFICANCE: CI is viable for CH-I patients when TFNRA are combined with systematic auditory training. Preoperative cochlear morphology assessment and short straight electrodes are crucial for optimizing outcomes, emphasizing the need for long-term rehabilitation.