Cochlear implantation ; Temporal bone growth ; Electrode extrusion
Abstract
It is now clear that young profound to totally deafened children can receive considerable benefit from a multiple-channel cochlear implant. However postnatal growth of temporal bone can displace the electrode. So we observed the postnatal temporal bone growth with computed tomogram. The temporal bone computed tomogram from 65 children without anomaly were selected. The age distribution was 1 to 16 years-old. After scanning the tomogram several parameters were measured with computed measuring program, Pi view CD archiving system (Mediface co.). The parameters were interpromontory distance (IP), mastoid index (MI), cochlear index (CoI), temporal bone thickness (TT). IP was increased about 1.5 cm after 2 years-old and TT was not changed. MI increased 1.6 cm and CoI increased 1.06 cm. So fixations of the electrode with 1.5 cm or more redundancy can prevent electrode extrusion.