[Impact of transtympanic miniature endoscopy of the middle ear--a conceptual cadaver study]

Endoscopic inspections of the middle ear have already been described. So far, the low optical quality due to the small diameter is limiting this type of procedure. In this study the use of a miniature endoscope for visualization of the middle ear structures has been evaluated.

8 human cadaveric head specimens have been inspected. Following myringotomy, 2 miniature endoscopes were placed into the middle ear and the promontory, the incudostapedial joint, the round und oval window niche with stapes footplate were visualized and fotodocumentated. After endaural approach all middle ear structures were visualized microscopically and the quality of pictures was compared. Technical picture quality and anatomical visualization were evaluated by 5 ear surgeons. In addition, 2 interventional procedures were performed (control of ossicular chain mobility and intratympanic substance application).

Still, the technical picture quality was significantly better for the microscope. The anatomical visualization of the middle ear structures with the miniature endoscope was not inferior compared to the microscope. The feasibility of additional interventions, e.g. control of ossicular chain mobility or intratympanic substance application could be shown. An inspection of the correct prosthesis position after tympanoplasty could be evaluated, too.

This study showed that middle ear structures can be visualized by trans-tympanic miniature endoscopy equal or even better compared to conventional microscopy in spite of reduced technical quality.