Radiographic analysis of cochlear nerve vascular compression.
OBJECTIVE
We analyzed whether radiographically demonstrated anterior inferior cerebellar artery (AICA) vascular compression of the cochleovestibular nerve in asymmetric hearing loss could be correlated to either the symptomatic ear or to cochlear nerve diameter.


METHODS
We undertook a retrospective case-control study in which patients were enrolled into a database if audiometry demonstrated asymmetry of 20 dB at one frequency, asymmetry of 10 dB at two frequencies, or a difference of 20% on word recognition scores. If AICA vascular contact was demonstrated on subsequent magnetic resonance imaging of the cerebellopontine angle, patients were included in the study. Patients with vestibular schwannoma or Meniere's disease were excluded. The AICA contact was graded by a blinded neuroradiologist according to criteria proposed by McDermott et al. The cross-sectional area of the cochlear nerve was measured.


RESULTS
Symptomatic ears could be correlated to a decreased cochlear nerve diameter, but not to the degree of AICA penetration into the internal auditory canal.


CONCLUSIONS
AICA vascular compression of the cochleovestibular nerve does not appear to correlate to hearing loss or to cochlear nerve diameter. The finding of decreased cochlear nerve diameter in symptomatic ears implies an alternative mechanism for asymmetric hearing loss.
Clift
Julie M
JM
Department of Otolaryngology-Head and Neck Surgery, University of South Florida, Tampa, Florida 33612, USA.
Wong
Robert D
RD
Carney
Gregory M
GM
Stavinoha
Rose C
RC
Boyev
K Paul
KP
D000328:Adult; D000368:Aged; D002531:Cerebellum / Q000098:blood supply* / Q000000981:diagnostic imaging; D003056:Cochlear Nerve / Q000000981:diagnostic imaging / Q000473:pathology; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D034381:Hearing Loss / Q000209:etiology* / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D011859:Radiography; D000159:Vestibulocochlear Nerve / Q000000981:diagnostic imaging* / Q000473:pathology; D000160:Vestibulocochlear Nerve Diseases / Q000000981:diagnostic imaging*; D055815:Young Adult