We previously reported that subjects who underwent modified cochlear implantation with combined electric and acoustic stimulation (EAS), have acquired a greater benefit in their hearing and speech understanding. However, the precondition for obtaining access to this result is that the residual hearing should be preserved during and post surgery. So far, there are some decisive points for preserving residual hearing. Among them, what surgical tools to be chosen and how to use them to open inner ear, is the first step.