Background: For the functional outcome after cochlear implant surgery, the electrode position is of essential importance. Therefore, radiological techniques to localize the electrode within the cochlea are becoming increasingly important. In our study, we used multi-slice computed tomography (CT) to find radiological criteria to allocate the electrode within the cochlea.
Methods: Ten Nucleus 24 RCA electrodes were implanted into isolated human temporal bones using an extended cochleostomy and the Advance Off-Stylet technique. Five electrodes were implanted into the scala tympani and five into the scala vestibuli. After implantation, the temporal bones were blinded to the radiologist, and 64-slice CT scans were performed and analysed.
Results and conclusions: In all 10 cases, the surgical positioning of the electrode was equal to the radiological analysis of the CT scans. Radiological criteria were found that permit correct identification of the electrode within the cochlea. We think that this technique is sufficient for most questions concerning quality control and is widely available.