Learning Objectives:

Introduction: Endoscopes can facilitate surgery within the facial recess, sinus tympani, and deep part of the round window niche, which are not fully visualized under an operating microscope. We investigated whether using endoscope-assisted dissection of cholesteatoma gave a lower incidence of cholesteatoma recurrence than using microscopic dissection only.

Methods: Four patients with middle ear cholesteatoma were operated on by using intact canal-wall techniques, canal-wall reconstruction techniques, or transcanal approaches assisted by endoscope-guided dissection. Eleven patients were operated on by using the same techniques but under an operating microscope alone. Comparison of group (A) microscopic surgery assisted by endoscope-guided dissection, with group (B) microscopic surgery only.

Main Outcome Measures: Rates of cholesteatoma recurrence, controlling for the site of the initial cholesteatoma and whether the tumor was detected by second-stage surgery or by non-echo-planar-imaging diffusion-weighted MRI.

Results: Five patients in group B (5/11, 45%) had cholesteatoma recurrences in a follow up of 1 year that needed to be surgically removed. No group A patients (0/4, 0%) developed cholesteatoma recurrences in that period.

Conclusions: In those techniques with canal-wall techniques, canal-wall reconstruction techniques, or transcanal approaches, most surgical failures occur within the tympanic cavity and its hard-to-reach extensions, rather than within the mastoid. Using an endoscope enables us to see inside the facial recess, sinus tympani, and deep part of the round window niche, which are not fully visible under an operating microscope, thus leading to lower rates of cholesteatoma recurrence. These areas are minimally accessible even with extensive postauricular mastoidectomy. Microscopic surgery assisted by endoscope-guided dissection is therefore useful in such cases.