, Vincent Y. W. Lin2 and Joseph M. Chen2
(1)
Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
(2)
Department of Otolaryngology Head & Neck Surgery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada
Finding a patent cochlea may be very challenging in postmeningitic patients with labyrinthis ossificans. A myriad of cochlear drill out procedures including access to the scala vestibuli and mid/apical cochleostomies have been described.
Scala Vestibuli Approach
Due to pathophysiological mechanisms that are not fully understood, the process of postmeningitic ossification of the inner ear often starts in the lateral semicircular canal, then reaches the scala tympani and finally affects both scalae in a basal to apical progress pattern. Whereas the status of the lateral SCC serves as an important marker for early detection of ossification by MRI, the fact that the scala vestibuli is often spared from ossification initially renders it an important alternative route for electrode insertion.
After the scala tympani is drilled open for a few millimeters and no lumen can be found, a scala vestibuli approach is performed: The incus and stapes suprastructure are removed. The footplate of the stapes is left in place.
The cochleostomy of the scala vestibuli is performed in the anterior niche of the oval window, lateral to the spiral ligament (Figs. 6.1 and 6.2).1
