Abstract: CONCLUSIONS: The patient’s residual hearing is still well preserved after applying long electrodes all over the cochlea so that the long electrodes are inserted to the residual hearing region of the cochlea. Purpose: New electrode designs with noninvasive concepts and noninvasive surgical techniques have made it possible to preserve residual hearing in cochlear implant recipients, and EAS (combined acoustic and electrical stimulation) and residual hearing protection have become the new trend in cochlear implantation for patients with residual hearing at low frequencies. However, full implantation of long or medium-length electrodes for residual hearing preservation is still a challenging area that needs to be debated. Methods: In this study, a circular window approach, a noninvasive design of electrodes, and dexamethasone treatment were used. The noninvasive nature of total electrode implantation (preservation of residual hearing, protection of vestibular function) was evaluated. Results: The postoperative evaluation after electrode total implantation showed that residual hearing in the low-frequency region was well preserved in all five patients. Postoperative imaging and reference tonal topography determined the full implantation of the electrodes and showed the frequencies corresponding to the depth of electrode implantation. Based on the analysis of the available cases in this study, the key to the noninvasiveness of the round window approach is its minimal drilling and grinding time and the protection of vestibular function.