The Ear, Nose and Throat  Department of the” Trakia” hospital in Bulgaria’s Stara Zagora has performed the first in this country surgery of the middle ear in the treatment Cholesteatoma using a specialized navigation system. Cholesteatoma is aggressive disease of the middle ear, which causes bone destruction. The operation was carried out in early August and has very good early postoperative results. The assistance of the endoscopic system allows the circumvention of healthy bone structures that obscure the field and which need to be removed when working with a microscope. The surgical navigation system could be usefully applied in the treatment of tumors in the middle ear and the base of the skull, experts from hospital say.