Minimally invasive ossiculoplasty via an endoscopic transtympanic approach

Abstract

IntroductionThe aim of this study was to evaluate the feasibility of ossiculoplasty via a minimally invasive endoscopic transtympanic approach (ETTA). Case seriesWe investigated the exposure of target structures (incus and stapes) on 4 human temporal bones by placing an endoscope into the middle ear cleft through the 4 tympanic quadrants. Then, on 3 additional specimens, we performed an incudostapedial disjunction and repaired it with a drop of hydroxyapatite cement via ETTA. We measured the size of tympanic perforation, and the acoustic transfer function of the middle ear (125–8000Hz) before and after repair by placing an insert in the external auditory canal and recording the acoustic signal in the utricle by a microphone. The acoustic signal gain was estimated in dB μV. Exposure was similar in all four quadrants but ergonomics was better with a posteroinferior myringotomy. Ossicular chain repair was conducted successfully in all cases and the acoustic transfer function of the middle ear was significantly improved. Residual tympanic perforation (n=3) was 2±0.3mm in diameter. ConclusionETTA to reconstruct incudostapedial joint with bone cement was feasible and effective. It opens perspectives for robot-based procedures guided by augmented reality.