An unusual occurrence in cochlear implantation surgery: misplaced electrode.
OBJECTIVE
To highlight the possibility of misplacement of electrodes during cochlear implantation surgery, to stress the importance of routine neural response telemetry, and also to emphasise the value of conventional radiography in confirming electrode positioning in the immediate post-operative period.


METHODS
A two-year-old boy presented with bilateral, profound, sensorineural hearing loss and underwent conventional cochlear implantation surgery. During insertion of the implant, there was doubt regarding the direction of passage of the electrode array. Instead of the usual smooth passage of the electrode, some resistance was felt. Neural response telemetry, performed at the end of the procedure, showed absent responses. A confirmatory X-ray in Stenver's view confirmed the extra-cochlear positioning of the electrodes in the superior semicircular canal. The wound was reopened, the electrode array removed and the cochleostomy was positioned a little more antero-inferiorly on the promontory with respect to the round window. Correct insertion of the electrode was then performed without difficulty.


CONCLUSIONS
The misplacement of electrodes during cochlear implantation surgery is rare but can occur. Neural response telemetry and conventional radiography are invaluable in assessing the placement of the electrode intra-operatively. Conventional radiographs are very cost-effective and aid in confirming the position of the electrode array.
Ramalingam
R
R
Head and Neck Department of the KKR, ENT Hospital and Research Institute, Chennai, India.
Ramalingam
K K
KK
Padmaja
H S
HS
D002675:Child, Preschool; D019929:Cochlear Implantation / Q000295:instrumentation* / Q000379:methods; D004567:Electrodes, Implanted; D006319:Hearing Loss, Sensorineural / Q000601:surgery; D006801:Humans; D008297:Male; D019300:Medical Errors; D012086:Reoperation / Q000379:methods