DIGITAL IMAGING - A VALUABLE TECHNIQUE FOR THE POSTOPERATIVE ASSESSMENT OF COCHLEAR IMPLANTATION

Cochlear implantation with a multi-channel electrode array which provi des stimulation via the auditory nerve has become a standard treatment for profound deafness. Postoperative radiography demonstrates electro de position and enables confirmation of satisfactory intra-cochlear el ectrode placement. The number of active electrodes which have been ins erted can be determined and possible complications such as electrode k inking or slippage can be assessed, We evaluated digital radiography w ith confirmation of electrode position by intermittent fluoroscopy and assessed the relative radiation dose of the digital technique, conven tional radiography and CT scanning. Radiation dose for this method usu ally ranges between 40,mu Gy and 440 mu Gy compared With a single expo sure on the skull stand which produces a dose to the region of the coc hlea of 470 mu Gy and a CT exposure of 950 mu Gy. The digital techniqu e is comfortable for the patient, easily reproducible and provides ima ges of high diagnostic quality enabling each electrode to be identifie d, which is especially valuable in association with postoperative elec trode mapping. It also involves a lower radiation dose than convention al radiography. We now use digital radiography for all postoperative c ochlear implant assessment.