[Clinical review of cochlear implant in 533 cases]

To summarize and analyze the etiology, surgical indications, operation methods and outcomes of cochlear implantation.

533 cases (534 ears) with severe and profound hearing loss received cochlear implant, 489 were pre-lingual deafness and 38 cases were post-lingual deafness. Their ages at implant, 1 to approximately 3 were 167, approximately 5 were 77, approximately 7 were 73, approximately 14 were 136, approximately 17 were 28, >17 were 52. 76 cases (14. 3%) were found the middle and inner ear malformations. That included Mondini 26 in cases, Common cavity in 10 cases and Large vestibule aqueduct syndrome in 20 cases. The average pure tone threshold were 105.5 dB HL, ABR threshold were >95 dB nHL and 40 Hz threshold in 500 Hz were 101.7 dB. The devices they used were Nucleus 22M in 27 ears, 24M in 308 ears, 24R Contour in 131 ears and 24R ST in 21 ears; Med El C40+ in 44 ears; Clarion CI in 3 ears. Facial recess approach was performed in normal cases, and in Common cavity cases horizontal semicircular canal approach was used. Preoperative hearing and speech evaluations were done in most cases.

In 26 Mondini case, gusher were happened in 20 cases. The insertion depth in normal cases: Nucleus were 30 bands, Med El were 31 mm. In Mondini cases, Nucleus were 28 bands. In Common cavity cases, Nucleus were 26 bands. Of 533 cases, The average of open set sentences discrimination of post-lingual deafness was 70%, the satisfaction rate of questionnaire for pre-lingual deafness under 17 years old was 94.7%.

Cochlear implant is a useful method to restore the hearing of the patients with severe and profound hearing loss. It is important for the outcomes with proper preoperative assessment, surgery and postoperative speech and hearing evaluations.