A comparison of direct eighth nerve monitoring and auditory brainstem response in hearing preservation surgery for vestibular schwannoma.
OBJECTIVE
The objective of this study was to compare the effectiveness of direct eighth nerve monitoring (DENM) and auditory brainstem response (ABR) in facilitating hearing preservation during vestibular schwannoma resection.


METHODS
This was a retrospective study.


METHODS
: Tertiary referral center.


METHODS
We conducted a retrospective clinical study of the use of ABR and DENM during vestibular schwannoma removal. Tumors were removed through a retrosigmoid craniotomy. The rate of hearing preservation between the two monitoring modalities was compared. The additional outcome measures of facial nerve function and cerebral spinal fluid leak rate were also evaluated.


RESULTS
Hearing preservation was attempted in 77 patients with vestibular schwannomas. Tumor sizes ranged from 0.5 cm to 2.5 cm. Hearing was preserved in 71% of patients with tumors 1 cm or less and in 32% of patients with tumors between 1 and 2.5 cm when direct eighth nerve monitoring was used. Hearing preservation rates with ABR for tumors 1 cm or less were 41% and 10% in patients with tumors between 1 and 2.5 cm (p=0.03) Facial nerve preservations rates were 94% (House-Brackmann 1-2) for tumors less than 2 cm.


CONCLUSIONS
DENM provides significantly higher rates of hearing preservation during vestibular schwannoma resection when compared with ABR.
Danner
Christopher
C
Department of Otolaryngology-Head and Neck Surgery, University of California-San Diego, California 92120, USA.
Mastrodimos
Bill
B
Cueva
Roberto A
RA
D003056:Cochlear Nerve / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem; D006319:Hearing Loss, Sensorineural / Q000517:prevention & control*; D006801:Humans; D016343:Monitoring, Intraoperative / Q000379:methods; D009464:Neuroma, Acoustic / Q000601:surgery*; D011183:Postoperative Complications / Q000517:prevention & control*; D012189:Retrospective Studies; D016896:Treatment Outcome