2.2. Surgical procedure
The surgical site was visualised with the VITOM® 3D exoscopic system (Karl Storz GmbH, Tuttlingen, Germany). The system consisted of a 3D high-resolution (4K) camera, a joystick, a processing module (Image 1S+ D3-LINK), and a 3D monitor (HD or 4K). The camera allowed 8 – 30x magnification at a focal distance of 20 – 50 cm. Polarised glasses were used to enable 3D vision.
The arrangement of the equipment relative to the operation table and the staff is shown in Figures 1-2. The 3D monitor was placed at the eye level of the chief surgeon and the scrub nurse. The audience consisting of residents followed the procedure on the same screen, while the assistant used the 2D monitor. The 3D camera was placed 30 – 35 cm away from the surgical site (recommended minimum distance is 20 cm). The joystick was nearby, within reach of the chief surgeon. Between surgeries, the camera and the joystick arms were stowed safely by moving them away from the operation table to the level of the tripod mount.
Prior to the surgeries, all staff members were instructed by an expert technician on how to use the VITOM® 3D system. The technician also provided support during the first surgeries. The first author was the chief surgeon during all surgeries. Standard cochlear implantation procedure was implemented. The initial external steps of the intervention (skin and soft tissue incision, mastoidectomy, preparation of an implant bone bed) were performed under conventional surgical lighting, without any magnification. Posterior tympanotomy, electrode insertion, and the stapedius reflex check were performed using the 3D monitor of the VITOM® 3D system with appropriate (8 – 30x) magnification. A ready-to-use microscope was also available. Patients were implanted with the Nucleus system from Cochlear Limited (n = 18), SONATA from MED-EL (n = 7), and HiRes90K from Advanced Bionics (n = 3).