Fig.4

a The red arrow indicates the exposed facial nerve canal and the red star indicates the stapedial base. The granulation or cholesteatoma epithelium on the surface of the exposed facial nerve is removed without damaging the facial nerve sheath, and the granulation tissue that cannot be removed from the stapes base is cauterized with 10W bipolar cautery to prevent recurrence of cholesteatoma. b The red triangle indicates the exposed sigmoid sinus vein wall, and the cholesteatoma epithelium on the vein wall is removed, preserving the cholesteatoma basilar membrane. c The auditory chain is reconstructed through the cartilage piece of the ear cavity and a connection to the vestibular window is established