PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 29 no. 2 July – december 2014

PhiliPPine Journal of otolaryngology-head and neck Surgery 37

FROM THE VIEWBOX

This middle-aged gentleman with no previous medical history presented to the local
ENT outpatient clinic complaining of right-sided hearing loss. No history of trauma or
previous head and neck surgery was elicited.

Following clinical and auditory assessment a right sensorineural hearing loss was
confirmed. A right-sided facial palsy was additionally identified on examination.

A MRI of the internal auditory meati was performed (Figure 1A & 1B). Following
radiologist review, MRI and MRA of the brain was undertaken.

Sensorineural Hearing Loss: What Lies Beneath?
Neurovascular Conflict Secondary to a Dural

Arteriovenous Malformation

Correspondence: Dr. Ian C. Bickle
Consultant Radiologist
Department of Radiology
RIPAS Hospital
Bandar Seri Begawan BA1710
Brunei Darussalam
Phone: + 00 673 8 612182
Fax: + 00 673 224 2690
Email: firbeckkona@gmail.com
Reprints will not be available from the author.

The author declared that this represents original material
that is not being considered for publication or has not been
published or accepted for publication elsewhere, in full or in
part, in print or electronic media; that the manuscript has been
read and approved by the author, that the requirements for
authorship have been met by the author, and that the author
believes that the manuscript represents honest work.

Disclosures: The author signed disclosures that there are no
financial or other (including personal) relationships, intellectual
passion, political or religious beliefs, and institutional affiliations
that might lead to a conflict of interest. Philipp J Otolaryngol Head Neck Surg 2014; 29 (2): 37-38 c Philippine Society of Otolaryngology – Head and Neck Surgery, Inc.

Ian C. Bickle, MB, BCh, BAO, FRCR

Department of Radiology
RIPAS Hospital,
Bandar Seri Begawan
Brunei Darussalam

Figures 1A & B. Axial and Coronal T2 sequences of the IAMS

A B

DISCUSSION
Auditory impairment is a condition with a legion of potential causes. One of the

routine aspects of the assessment process for those with sensorineural hearing loss is
MR imaging (MRI) of the internal auditory meati (IAMS).

The vast majority of MRI studies are normal, however one of the more commonly
identified pathologies are cerebrovascular abnormalities. The most-well recognised is
neurovascular conflict of the vestibulocochlear nerve by a vascular loop at the root entry
zone (REZ), however a broader range of potential responsible structural abnormalities

PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 29 no. 2 July – december 2014

FROM THE VIEWBOX

38 PhiliPPine Journal of otolaryngology-head and neck Surgery

are known. A wide range of processes for auditory dysfunction
have been outlined.1 These include: cerebral ischemia events,
subarachnoid hemorrhage, cerebrovascular malformations and
rarely dural arteriovenous fistulas (dAVFs).

Dural AVF’s are abnormal vascular communications between
the dural venous sinuses and an arter(ies) - most frequently
branches of the external carotid artery. Sensorineural hearing
impairment is one of the rarer presenting symptoms. The
mechanism for hearing impairment is believed to result from
either direct vascular compression on the vestibulocochlear
nerve from an enlarged aberrant draining vein or from a vascular
steal phenomenon (Figures 2A & 2B). An engorged draining vein
from the dAVF causing mechanical compression on the nerve is
the most well recognized.2 A single prior case has been reported
of compression from an intraossesous dAVF of the skull base.3

REFERENCES
1. Tabuchi,S. Auditory dysfunction in patients with cerebrovascular disease. The world

scientific journal. 2014, ID 261824. Doi/10.1155/2014/261824.
2. Lasjaunias, P, Chiu, M, ter Brugge, K et al. Neurological manifestations of intracranial

dural arteriovenous malformations. J Neurosurg 1986; 64: 724-30.
3. Kim MS, Oh CW, Han DH, Kwon OK, Jung HW, Han MH. Intraosseous dural arteriovenous

fistula of the skull base associated with hearing loss. J Neurosurg. 2002; 96(5):952-5.

The arteriovenous fistula may be directly identified (Figure 3)
along with the associated signs of enlarged cerebral cortical
veins and white matter change of venous hypertension (Figure 4).

Figures 2A & B. Axial and Coronal T2 sequences of the IAMS. A: engorged aberrant veins crowding the
right IAM (white arrows). B: Engorged veins compressing the intracanalicular right vestibulocochlear
nerve (thin white arrow). Normal left side for comparison (thick white arrow)

Figure 3. Axial MRA Brain raw data set: A direct communication (arrow) between a distal external
carotid artery branch (triangle) and the sigmoid-tranverse sinus junction (star) in keeping with a dural
AV fistula

Figure 4. Axial MRI FLAIR Brain: Extensive periventricular high signal (black arrows) due to cerebral
venous hypertension. Distended cerebral cortical veins are also present (white arrow)