Abstract Otology 2000 B18-1

Yukihiko Kanda MD, Kouichi Motokawa MD, Toshimitsu Kobayashi MD, PhD

Department of Otolaryngology Nagasaki Univ. School of Medicine J-Nagasaki

Tinnitus is one of the most annoying symptoms affecting patients with ear problems. To date, however, there has been no curative therapy against this symptom. Using a new method developed by the first author, Kanda, a way has been found to fade out this tinnitus. Twenty patients suffering from severe tinnitus accompanied by sensori-neural hearing loss were investigated as to the effectiveness of this method. A non-linear hearing aid or a digital hearing aid was used as a tinnitus masker. All the patients were examined as to the threshold, uncomfortable level (UCL), the most comfortable level (MCL), and pitch and loudness match scaling in the sound pressure level (SPL) audiogram. [Results] In this study, 19 of 20 (95%) patients reported that their tinnitus disappeared completely, and 1 reported as considerable decrease of the tinnitus. Background noise is said to range from about 40 dB to 50 dB even in a silent home environment. It is speculated that the patient's tinnitus faded out because this silent background noise is non-linearly amplified in the pitch match frequency with tinnitus. This new Non-Linear Masking Therapy (Kanda's Method) appears to be a useful and promising treatment for tinnitus.

Abstract Otology 2000 B18-2

David W. White MD

Eastern Oklahoma Hearing and Balance Center USA-Tulsa OK

Encephaloceles of the temporal bone can occur spontaneously, be the result of trauma or infection or be caused by iatrogenic trauma to the tegmen. A technique to repair temporal bone encephaloceles has be used with good success. The technique involves harvesting bone from the superior edge of the bone flap removed during the middle fossa craniotomy. This bone has been found to have a curved shape similar to the floor of the middle fossa. This similarity in shape facilitates the placement of the bone over the tegmen defect. The technique will be discussed. Long term follow up using high resolution CT scanning will be presented.

Abstract Otology 2000 B18-3

Antje Aschendorff MD, Nikolaos Marangos MD, Roland Laszig MD

Universitäts-HNO-Klinik D-Freiburg

Dilatation of the lateral end of the internal auditory canal with missing bony separation to the basal turn of the cochlea and atypical route of the intrameatal and tympanic part of the fallopian canal is known as X-linked deafness. This malformation is associated with progressive mixed hearing loss or deafness. Attempts of stapes surgery always result in profound CSF-gusher and complete loss of labyrinth function. In these cases cochlear implant surgery was considered as contraindicated as the electrode array may be accidentally inserted into the internal auditory meatus resulting in CSF-fistula or meningitis. We report our experience and first results in using a new custom-made CI24M with curly electrodes. The specific feature of this new device is a short precurved electrode carrier that prevents insertion into the internal auditory canal. In spite of other preformed electrodes the thickness is similar to the standard electrode of Nucleus CI24M. It can be inserted via a small cochleostomy that can be sealed by the electrode array and some tissue. This is important to minimize the risk of CSF leakage and/or meningitis. Patients with this kind of malformation now have a chance of auditory rehabilitation using the cochlear implant.

Abstract Otology 2000 B18-4

R. Behr PD Dr., Joachim Müller MD, Wafaa E. Shehata-Dieler MD, PhD, Jan Helms MD, K. Roosen Dr.med.

Department of Neurosurgery University of Wuerzburg D-Würzburg

Objective: Despite progress in diagnosis and therapy of neurofibromatosis 2, deafness is still one major complication. If the cochlear nerve is destroyed, restoration of hearing can only be achieved by direct stimulation of the cochlear nucleus. Methods: After tumor resection, in cooperation of neuro- and ENT-surgeons and stimulation of the cochlear nucleus, the ABI was implanted in 7 cases. Postoperatively, the electronic fitting of the device was accomplished. Results: There were no complications directly related to implantation. In 2 patients a CSF leak occured, one of them required a vp-shunt due to aresorptive hydrocephalus. In 2 patients minor side effects of stimulation happend. The responsible electrods were switched off. Out of 12 available electrodes 5-8 were choosen for auditory stimulation. All patients fitted so far had tonotopy, sound perception, -discrimination and speech perception. Lipreading (LR) was facilitated, in 1 patient from 19% to 57%, in an other from 43% to 71%. One patient had a 82% recognition of Freiburg Numbers (FN) without LR, an other 65% FN (no LR) and a 71% open set sentence recognition (LR + ABI). Tinnitus was markedly masked by the ABI. MRI investigations are possible with imlanted device. Conclusion: The CIS-ABI is promissing for the feasibility of hearing rehabilitation in deaf NF-2 patients. Combined with a tumor resection, the implantation is a safe procedure.

Abstract Otology 2000 B18-5

Olivier Sterkers MD, Bernard Fraysse MD, D. Bouccara MD, E. Ambert MD, Jean Marc Sterkers MD, M. Kalamarides MD

Service d'ORL, Hôpital Beaujon Faculté Xavier Bichat Université Paris 7 F-Clichy

The aim of this study is to evaluate the results of Auditory Brainstem Implantation (ABI) in 8 cases with several different conditions before implantation. Seven cases were Neurofibromatosis type 2 (NF2) patients: three cases were surgically treated for bilateral acoustic neuroma and implantation was performed several years after tumors removal; in four cases the ABI was performed during the second acoustic tumor removal, three of them being treated previously by irradiation. The last patient presented post meningitis, the placement of the 21 electrodes on the cochlear Nucleus through the lateral recess of the fourth ventricle was guided by the intraoperative monitoring of electrically evalued brainstem response. The intra operative monitoring of electrically evoked brainstem response helped to the localisation of these nucleus. Post operative activation of the electrodes permitted to use 4 to 21 electrodes without indesirable effect. Long term results show benefits in five cases, with capacity to phone in two cases. In one case the benefit which was first limited now decreases and there are no auditory response without indesirable effect. The last case is too recent to be evaluated. These results show the benefit of ABI during NF2 and even in other indications when cochlear implant seems to be hazardous.