Fixation der temporär entfernten hinteren Gehörgangswand mit Plattenosteosynthese: Eine neue Technik

Abstract

Temporary removal of the posterior external ear canal wall allows excellent exposure of the middle ear and epitympanum without the negative sequelae of a cavity as can occur after canal-wall down procedures. Safe fixation of the bony canal wall, however, has not always been possible with a risk for prolonged healing and bone necrosis. A new technique permits rigid internal fixation of the posterior canal wall. A titanium miniplate of 10 holes length commonly used for orbital rim surgery is adapted to the cortical surface of the mastoid just posterior to the external ear canal. Six holes for 1.3 mm screws are drilled into the cortical bone: two screws behind the ear canal, two screws on the temporal line, and two on the mastoid tip. All fixation material is then removed and a mastoidectomy is carried out with preservation of the cortical bone for the screws. The external ear canal skin, which has been incised previously near the fibrous annulus with lateral extensions, is mobilized laterally using a newly designed retroflected microraspatory. This creates a vital skin flap that might be essential to avoid bone necrosis. No other skin incisions are needed in the canal. The posterior bony canal wall is cut using an oscillating saw Osseoscalpel, secured by facial nerve monitoring. After middle ear surgery and tympanoplasty have been completed, the canal wall is repositioned and fastened precisely in its place with rigid internal fixation allowing a secure stabilization. This new technique has proven to be safe and reliable on the first five patients. There has been no bone necrosis within an observation period of 18 months. Rigid internal fixation is an alternative technique to safely readapt the posterior auditory canal wall.