Comparative Study Of Electrode Impedance And ART Threshold Value Of Cochlear Implantation With Round Window And Extended Round Window Insertions

Objective:To study the difference of Electrode Impedance and ART threshold value of Cochlear implantation with Round Window versus Extended Round Window Insertions and to understand the impact of cochlear electrophysiology by the two ways.Methods:Consecutively collect a group of 50 prelingual cases with cochlear implantation from Otolaryngology Head and Neck Surgery of Anhui Provincial Hospital Affiliated to Anhui Medical University. All case underwent unilateral cochlear implantation with MED-EL SONATAti100. All operations performed by one doctor.Exclude 6 case of cochlear dysplasia and ART test failure, the remaining 44 patients has been divided into two group depending on the surgical approach. Group A(n=31) with round window Insertions and group B (n=13) with extended round window Insertions. Comparison of Electrode Impedance value and ART value had been made at intraoperate, first week, first months respectively.Results:All case had been done well and all electrodes were implanted completely confirmed by postoperative X-ray radiography. There were no postoperative incision and intracranial infection, there was no case of facial paralysis, and the cochlea work normally. The average time of surgery is 95 ± 13 minutes in Group A and 97 ± 12 minutes in Group B, there are no significant difference (p> 0.05). The mean electrode impedance value of Group A was 3.8±1.04kΩ,3.49±1.2 kΩ,6.71±1.51kΩ at intraoperate, first week, first months respectively; The mean electrode impedance value of Group B was4.38±1.49kΩ,4.14±1.5kΩ,7.12±1.06 kΩ respectively; There are no significant difference in electrode impedance value of both Group A and Group B at intraoperate, first week, first months. The electrode impedance value of both Group A and Group B are higher than others at first months, there are statistically significant difference (p<0.05). There are no significant difference in electrode impedance value between Group A and Group B at intraoperate, first week, first months (p> 0.05). The mean ART value of Group A was 228±11.3(μV、219±96.8μV、224±78.2μV at intraoperate, first week, first months respectively. The mean ART value of Group B was 224±15.9μV、 226±87.6μV、214±44.1μV at intraoperate, first week, first months respectively. There are no significant difference in ART value of both Group A and Group B at intraoperate, first week, first months. The ART value of 10、12 electrode are higher than 2、4、6、8 electrode in both Group A and Group B (p<0.05). There are no significant difference in ART value between Group A and Group B at intraoperate, first week, first months (p> 0.05).Conclusion:The cochlear implantation with Round Window or Extended Round Window Insertions are safe and effective surgical approach, you can select the appropriate surgical approach based on the intraoperative situation, There are no significant difference on ART threshold value and electrode impedance value in the early time, and the long-term impact on ART threshold and electrode impedance values for further follow-up observation. MED-EL SONATAti100 multi-cochlear electrode impedance variation of early ART threshold value and is consistent with other cochlear basic products.