Using the described techniques and materials, the risk of loss of vestibular function and the incidence of clinical vertigo can be minimized. Postoperative vertigo did not occur more often in patients with preoperative diminished vestibular function than in patients with normal findings. Therefore, preoperative vestibular function tests cannot be an indicator for the frequency of vertigo after CI. If one vestibular organ shows preoperative dysfunction, the non-affected normal vestibular organ should not be implanted.