Cochleostomy versus round window insertions: Influence on functional outcomes in electric-acoustic stimulation of the auditory system

OBJECTIVE: To assess the potential influence of 2 different surgical access routes to scala tympani for hearing preservation cochlear implantation on outcomes. STUDY DESIGN: Retrospective review. SETTING: Tertiary care academic center. PATIENTS: Twenty adult subjects participating in a prospective clinical trial on electric-acoustic stimulation. Subjects underwent cochlear implantation with attempted hearing preservation and subsequent ipsilateral electric-acoustic stimulation of the auditory system. INTERVENTIONS: Eight subjects (40%) were implanted using a round window-related cochleostomy and 12 subjects (60%) via a round window approach. MAIN OUTCOME MEASURES: Postoperative acoustic hearing preservation and speech perception measures were obtained at defined intervals and compared for both groups with and without the use of the external speech processor. RESULTS: The data demonstrate no statistically significant differences in postoperative outcomes for both preservation of residual hearing and unaided and aided speech perception between the cochleostomy and round window groups. CONCLUSION: The results of this investigation suggest that hearing preservation cochlear implantation can be performed either via a round window-related cochleostomy as well as via the round window membrane itself with similar outcomes in terms of both hearing preservation rates as well as speech perception measures.