2.3. Outcome measures
Intra- and post-operative complications were recorded. The 3D image quality was assessed in terms of the spatial orientation and visibility of the middle ear anatomy. More specifically, we looked at three parameters: stereoscopy, lighting, and focusing during posterior tympanotomy and electrode insertion. Surgeon comfort was assessed in terms of physical discomfort and eye strain. Staff comfort was assessed in terms of equipment ergonomics and eye strain. All parameters were rated on a 5-point Likert scale, where 5 meant “very good”, 4 – “good”, 3 – “neutral”, 2 – “bad”, and 1 – “very bad”. The assessment was performed by the chief surgeon immediately after each surgery. The mode of the answers by the scrub nurse, circulating nurse, and three residents was used as a measure of staff comfort. The percentage of surgeries falling under each Likert category was calculated.