How I do it: implantation of Osia® 2 system under local anesthesia

To ensure continuous monitoring of the patient, a pulse oximeter and a three-wire lead electrocardiogram were attached to the patient. A supplementary oxygen source was administered through either a nasal cannula or a facial mask (Fig. 1A).

The Osia template was used to accurately determine the precise location for creating the incision and placing of OSI200 and BI300. The optimal placement of the transducer is approximately 1–1.5 cm above the midline of the ear canal, similar to the method described by Deep et al., where the flat surface of the bone allows for improved alignment without the need for additional bone removal and provides less protrusion and consequent tension on the sutures [2]. Additionally, the OSI200 implant was tilted anteriorly by approximately 20–25° around its axis in order to get the optimal position for the sound processor. The local infiltration procedure involved using a solution containing 10 ml of lidocaine (20 mg/ml), 0.2 ml of adrenaline (1 mg/ml), and 10 ml of saline. The solution infiltrated the predetermined region, and directly on the top of the bone, acting as a hydrodissector to facilitate the lifting of the periosteum (Fig. 1C). After 5 min, an approximately 5–6 cm arc-shaped incision was performed 1.5 cm from the lower posterior edge of the transducer (Fig. 1D-E). A direct and precise separation of the soft tissue flap was carried out using a scissors and raspatory instrument to establish a space for the OSI200 (Fig. 1F). As a mandatory step, soft tissue was also raised on the other side of the incision line to aid the manipulation with the Langenbeck retractor and later minimize the tension on the suture line. This incision type, together with the extended elevation of the temporal flap, allowed enough space to work comfortably with the Osscora™ Surgical Set to drill the bone bed (Fig. 2A-B). The BI300 fixed, and the OSI200 implant mounted on it (Fig. 2C-D). In one case, where soft tissue reduction was necessary at the level of the coil, a tunnel was created between the temporal and the temporoparietal fascia, and the coil part was inserted between these layers without the necessity of removing subcutaneous fat, while the implant body remained under the periosteum pocket. The musculo-periosteal layer was sutured with hand-tied 2–0 vicryl sutures due to the requirement for sutures capable of withstanding higher stress in this tightly layered area (Fig. 2E). Subsequently, the profound dermal layer and skin were closed in the customary manner. A mastoid dressing was placed on implant area.