か牛ろう孔 中耳根本手術後のめまいの一因

Abstract

Labyrinthine fistula is a common complication of cholesteatoma, but cochlear fistula is very rare. We report three cases of cochlear fistula found in ears which had previously been treated with radical tympanomastoidectomy, one male and two females, who had developed dizziness 10 to 28 years after the last middle ear surgery. Two patients had no hearing in the affected ear and 80 dB mixed type hearing loss was noted in one patient. At surgery, cochlear fistulas of various sizes were found in the promontory between the oval and round windows. One patient also had a fistula opening into the lateral semicircular canal. In two patients the cochlear fistula was covered with fascia and bone fragments and then firmly sealed with fibrin glue. One patient had obvious infection in the cochlea, so labyrinthectomy was performed. Surgery relieved the fistula symptoms caused by manipulation of the ear. The patient with residual hearing became deaf after surgery.Cochlear fistula is hard to detect by regular otoscopy. When a patient complains of dizziness upon manipulation of the middle ear, the site where the dizzy sensation is most severe should be recorded as a possible fistula site. CT scan of the bony cochlear wall should be examined carefully to confirm the diagnosis. In addition to fistulas of the semicircular canals, cochlear fistula must be included in the differential diagnosis of dizziness in patients who have had radical tympanomastoidectomy type middle ear surgery.