*2.1. Study Design and Patients*

This prospective, pilot study included two adult patients (females, aged 57 and 61 years) who underwent cochlear implantation in a tertiary referral center. Robot-assisted cochlear implantations were performed on 12–13 July 2022. The surgeries were preceded by surgical training on an artificial temporal bone (Figure 1). The patients had passed the typical procedure for qualifying for a cochlear implant at our center before surgery. Both patients had residual hearing in the implanted ear (Figure 2). The preoperative CT of the temporal bone (Siemens, Somatom Definition Edge, Munich, Germany) showed normal anatomy of the ear qualified for cochlear implantation in the both cases (case 1–right ear, case 2–left ear) (Figure 3). The patients provided informed, written consent for their

participation in the study and the publication of its findings. The study was approved by the local Bioethics Committee (decision number 1033/19).

**Figure 1.** Surgical training with RobOtol® on artificial temporal bone.

**Figure 2.** *Cont*.

**Figure 2.** Preoperative audiograms of the patients.

**Figure 3.** Preoperative CT of temporal bones of the patients, both cases with normal anatomy of the temporal bone.
