Preoperative magnetic strength imaging in adult cochlear implant restorations
23 April 2019 (online)
It is well known that the necessary magnetic strength of the coil of the cochlear implant is dependent on the skin thickness. The wrong magnetic strength may sometimes lead to skin irritation or skin necrosis underneath the coil. The aim of the presented study is to assess whether the intraoperative skin thickness measurement as well as the skin thickness determined in the preoperative temporal bone CT predicts the individual magnetic strength.
Postlingual deaf adults were measured intraoperatively before CI implantation using a needle to measure skin thickness. The retroauricular skin was punctured at a standardized location with a sterile needle. Subsequently, the skin thickness was measured on the basis of the puncture depth of the needle. The data was correlated with the skin thickness of the preoperatively performed CT scan and with the magnet strength of the coil.
Preliminary data shows that there is a correlation between the magnetic strength and the radiologically and intraoperatively determined skin thickness.
A preoperative assessment of skin thickness on temporal bone scans allows a more individual determination of the magnetic strength