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Skull Base 2008; 18(4): 281-287
DOI: 10.1055/s-2008-1043753
CASE REPORT

© Thieme Medical Publishers

CNAP To Predict Functional Cochlear Nerve Preservation in NF-2: Cochlear Implant or Auditory Brainstem Implant

Enrico Piccirillo1 , Maurizio Guida1 , Sean Flanagan2 , Lorenzo Lauda1 , Paolo Fois1 , Mario Sanna1
  • 1Gruppo Otologico, Otology and Skull Base Quaternary Referral Center, Piacenza-Rome, Italy
  • 2Department of Otology/Neuro-Otology, St. Vincent's Hospital, Sydney, Australia
Further Information

Publication History

Publication Date:
19 February 2008 (online)

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ABSTRACT

The ideal management of bilateral vestibular schwannomas (VSs) involves complete tumor resection with preservation of hearing in at least one ear. While auditory brainstem implants (ABIs) have represented a significant advance in the management of neurofibromatosis type 2 (NF-2) patients, hearing rehabilitation is far from ideal. More recently, cochlear implantation has been used in selected cases of NF-2, following tumor removal, where the patient is left with bilateral profound hearing loss but with anatomical continuity of the cochlear nerve. In selected cases, cochlear implant (CI) has given superior results to ABI. The Gruppo Otologico experience in managing NF-2 patients consists of 29 patients treated between December 1996 and December 2007 out of a total of 1723 VSs. Thirty-nine tumors have been removed, with 10 patients having had bilateral tumor removed. Ten ABIs have been implanted and 5 CIs placed. We present a case that illustrates some of the difficulties encountered in the management of NF-2 VS and provides a basis for discussion of a technique to assist intraoperative decision-making to achieve optimal hearing rehabilitation. In the setting of a negative fast auditory brainstem response (ABR), but preserved cochlear nerve action potential (CNAP), the option of a CI can be considered. However, where the fast ABR and the morphology and amplitude of the CNAP are significantly degraded at the brainstem, the placement of an ABI should be strongly considered at the time of tumor removal. This technique must be further evaluated, but it represents an adjunct in this difficult area for the neurotologist. To this end we propose that a multicenter trial be undertaken to further elucidate the role of intraoperative monitoring to determine the functional preservation of the cochlear nerve.

KEYWORDS

Intraoperative monitoring - NF-2 - fast ABR - CNAP - hearing rehabilitation

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Enrico PiccirilloM.D. 

Via Emmanueli 42

Piacenza 2900, Italy

Email: enricopiccirillo@libero.it