Learning Objectives: To present indications, surgery and results of cochlear implantation via middle fossa approach.

Introduction: Classic approach to the cochlea through the mastoid and facial recess may not be suitable for patients after middle ear surgery for cholesteatoma. In 1998 Colletti presented a technique to bypass the middle ear, and insert the electrode through the middle cranial fossa approach.

Material and methods: In our department cochlear implant program started in 1994 and till now 1266 cochlear implantations were performed. In 4 patients middle fossa approach was used. Indications, surgical technique and results in this group were analyzed. Results: Initially 6 deaf patients after middle ear operation for cholesteatoma were qualified to cochlear implantation via middle fossa approach. A middle cranial fossa craniectomy was performed. Then a careful dissection of the dura was carried out to expose the arcuate eminence and the greater petrosal nerve. In two cases surgery was stopped because of strong adhesions and bleeding from the dura during preparation. In the rest 4 cases the basal turn of the cochlea was discovered, the cochleostomy was done and successful implantation was performed. The time of surgery was nearly two times longer than during standard implantation. In 3 cases there were no complications and in one case hematoma occurred 2 days after surgery and the patient was reoperated. Postoperative CT showed correct intracochlear position of the electrode in all cases. All 4 patients use their implants and have good hearing thresholds in sound free field, but they can't fully communicate using hearing only and require lip reading.

Conclusions: Middle fossa approach enables cochlear implantation in deaf patients after middle ear surgery where implantation through standard approach (antromastoidectomy and posterior tympanotomy) is not possible.