Cochlear implantation trough the middle cranial fossa: A novel approach to access the basal turn of the cochlea

Abstract

The classic approach for cochlear implant surgery includes mastoidectomy and posterior tympanotomy. The middle cranial fossa approach is a proven alternative, but it has been used only sporadically and inconsistently in cochlear implantation. Objective: To describe a new approach to expose the basal turn of the cochlea in cochlear implant surgery through the middle cranial fossa. Method: Fifty temporal bones were dissected in this anatomic study of the temporal bone. Cochleostomies were performed through the middle cranial fossa approach in the most superficial portion of the basal turn of the cochlea, using the meatal plane and the superior petrous sinus as landmarks. The lateral wall of the internal acoustic canal was dissected after the petrous apex had been drilled and stripped. The dissected wall of the inner acoustic canal was followed longitudinally to the cochleostomy. Results: Only the superficial portion of the basal turn of the cochlea was opened in the fifty temporal bones included in this study. The exposure of the basal turn of the cochlea allowed the visualization of the scala tympani and the scala vestibuli, which enabled the array to be easily inserted through the scala tympani. Conclusion: The proposed approach is simple to use and provides sufficient exposure of the basal turn of the cochlea.