Association of Total Cochlear Volume and Initial Hearing Preservation With a Straight Electrode Array

OBJECTIVE: To evaluate total cochlear volume and its association with low-frequency hearing preservation for CI recipients receiving a straight electrode array. STUDY DESIGN: A retrospective clinical capsule report. SETTING: Tertiary academic referral center. PATIENTS: Adult CI recipients implanted with a 23 mm straight array between 2019 and 2023 with preoperative computed tomography (CT) imaging and an unaided low-frequency hearing threshold ≤45 dB HL at 250 Hz. MAIN OUTCOME MEASURE: Assess the relationship between total cochlear volume as estimated from the preoperative CT image and hearing preservation (at CI activation and 6 months postactivation). The shift in the low-frequency pure tone average (LFPTA; 125, 250, and 500 Hz) relative to the preoperative visit was calculated for the activation and 6-month visits. RESULTS: Fourteen patients met the inclusion criteria and had sufficient imaging to estimate total cochlear volume. There were significant correlations between total cochlear volume and LFPTA shifts at activation (r=0.28, P=0.05; mean shift: 21 dB HL) and at 6 months postactivation (r=0.29, P=0.048; mean shift: 22 dB HL). CONCLUSIONS: For CI recipients of a 23 mm straight array, a larger total cochlea volume is associated with better low-frequency hearing preservation. These data support review of an individual's cochlear anatomy to assist in stratifying individual patient risk for loss of residual hearing as well as for assisting in device selection.