Cochlear implantation and hearing preservation: Results in 21 consecutively operated patients using the round window approach.
CONCLUSIONS
Prevalent hearing conservation may be achieved after round window (RW) cochlear implantation using soft and flexible electrode arrays if variations of RW anatomy, topography, and facial nerve position are considered. The most favorable electrode insertion depth remains to be established.


OBJECTIVE
We assessed the incidence of cochlear function after cochlear implant (CI) electrode insertion through the RW in our first 21 consecutively operated patients aimed at hearing conservation.


METHODS
Eleven patients had a preoperative low frequency hearing suitable for electro-acoustic stimulation. Hearing was preserved in an additional nine patients at their request with the intention to use full frequency CI stimulation. Anatomic variations of the RW were carefully considered using our temporal bone collection of micro-dissected ears. Electrode extension was assessed on X-ray by measuring the insertion angle of the first electrode and intra-cochlear length and correlated with audiometric data.


RESULTS
There was no incidence of total loss of residual hearing in any of the patients. A slight deterioration of low frequency thresholds occurred in some patients. Mean hearing loss at 125-500 Hz was 14.4 dB at 1 month following surgery and 15.6 dB after 1 year. Insertion angle (300-540°) and depth (17.5-28.5 mm) were not statistically correlated to hearing loss.
Department of Otorhinolaryngology, Uppsala University Hospital and Department of Surgical Sciences, Section of ORL Uppsala University, Uppsala, Sweden. elsa.erixon@surgsci.uu.se
Elsa
E
Erixon
Susanne
S
Köbler
Helge
H
Rask-Andersen
D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology; D002648:Child; D003051:Cochlea / Q000503:physiopathology; D019929:Cochlear Implantation / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010898:Pitch Perception / Q000502:physiology; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D017755:Prosthesis Fitting; D012086:Reoperation; D012405:Round Window, Ear / Q000601:surgery*; D013018:Sound Spectrography; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult