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DIGISONIC® SP AUDITORY BRAINSTEM IMPLANT: EXPERIENCE IN NF2 PATIENTS
Franco Trabalzini1, Gregorio Babighian1, Renato Scienza2, Giacomo Pavesi2
1Dept. of Otosurgery, Padova, Italy/2Dept. of Neurosurgery,Padova, Italy
Between February 2004 and December 2007 7 patients with Neurofibromatosis type 2 and bilateral acoustic neuroma underwent implantation with a multichannel Auditory Brainstem Implant. Age at implantation ranged from 17 up to 52 years (mean 30 years). Mean post-operative follow-up was 9 months (ranged from 4 up to 25 months). Tumor diameter ranged from 22 to48mm. In five patients a sub-occipital approach (semi-sitting position) and in two patients a translabyrinthine approach were performed to achieve a complete acoustic neuroma removal and a proper positioning of the implant in the Luschka foramen. Measurement of the impedance, and eABR were used to validate the electrode-array positioning. No additional surgical complications were observed due to the implant. During first stimulation, 4 weeks after surgery, all patients received some auditory sensation; one patient claimed some tingling of the arm, and another disturbing vertigo. These side effects were solved reprogramming the stimulation level of some electrode. All patients but one had benefit on speech understanding with significant enhancement of lip-reading. One 18year-old patient, 3 months after removal of a very large tumor (48mm extrameatal diameter), is non-user due to absence of auditory benefit. Best score in open-set (words and sentences recognition) was surprising achieved in a 19year-old blind patient. In conclusion, 6 out of 7 patients, with Neurofibromatosis type 2 and bilateral acoustic neuroma, implanted with a multichannel auditory brainstem implant, reported enhancement in communication skills with a substantial improvement in quality of life.