International Journal of Otolaryngology and Head & Neck Surgery, 2013, 2, 245-247
Published Online November 2013 (http://www.scirp.org/journal/ijohns)
http://dx.doi.org/10.4236/ijohns.2013.26051
Open Access IJOHNS
Vascular Loops and Neuro-Otologic Symptoms :
Is Ther e Any Correlation?
Amaya Roldán-Fidalgo*, Antonio Rodríguez-Valiente, Francisco Martín González, Mayte Pinilla,
Almudena Trinidad, Beatriz Brea Álvarez
Department of Otorhinolaryngology and Neuroradiology, Puerta de Hierro University Hospital, Madrid, Spain
Email: *amayarf@gmail.com, arova777@gmail.com, madrigal111@gmail.com, pinillamayte@gmail.com, atrinid@yahoo.es,
beatrizbreaalvarez@yahoo.es
Received September 25, 2013; revised October 20, 2013; accepted November 2, 2013
Copyright © 2013 Amaya Roldán-Fidalgo et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Objective: To determine the relationship between vascular loops in the internal auditory canal and otologic symptoms.
Methods: We performed a retrospective study, with a systematic review of the literature and analyzed the magnetic
resonances imaging (MRI) of 91 patients attended in the ENT department since April to June 2013, in order to correlate
radiological findings with otologic symptoms. Results: Vascular loops were seen in the internal auditory canal of pa-
tients without clinical symptoms; however an association was found between the presence of vascular compression of
the eighth nerve displayed on MRI and the presence of sensorineural hearing loss and tinnitus. No association was
found between vertigo and vascular loops. Conclusion: The presence of vascular loops in the internal auditory canal
may be an incidental finding in MRIs of patients without clinical symptoms. However, in patients with tinnitus or sen-
sorineural hearing loss that is unexplained by other clinical pathologies, these may be correlated with the existence of
vascular loops which compress the eighth cranial nerve or contact the bone wall of the internal auditory canal. Further
studies involving a larger number of patients are required to accurately evaluate the association between these symp-
toms and vascular loops.
Keywords: Vascular Loop; Arterial Loop; Internal Auditory Canal; Tinnitus; Deafness; Vertigo
1. Introduction
The presence of vascular loops in the internal auditory
canal (IAC), formed by the anterior inferior cerebellar
artery (AICA), is a common finding in the systematic
study of MRIs [1,2]. Controversial results have been re-
ported in the literature about the relationship between
vascular compression of the vestibular nerve trunks and
neuro-otologic symptoms, and some authors have sug-
gested that compression of the nerve might be the origin
of otherwise unexplained as hearing loss, tinnitus, neu-
rological symptoms and vertigo [3-10].
In order to determinate the relationship between vas-
cular loops and otologic symptoms, we performed a ret-
rospective study in patients attended in the ENT depart-
ment.
2. Materials and Methods
We performed a retrospective study with a systematic
review of the literature and we studied the MRIs of 91
patients attended in our ENT department over a three
months period (April to June 2013), looking for the
presence of vascular loops in the internal auditory canal.
In patients with vascular loops in the MRI we collected
data related to neuro-otologic symptoms (hearing loss,
tinnitus, vertigo and hemifacial spasm) from their medi-
cal history. All patients had been performed a complete
otoneurological examination with otoscopy, audiometry
and videonystagmography.
3. Results
A total of 91 MRIs of patients attended in our ENT de-
partment were analyzed, 20 MRIs displayed vascular
loops in the IAC.
We collected data from the medical history of the 20
patients with vascular loop in the MRI, related to neuro-
otologic symtoms. We found 12 patients with otologic
symptoms, three patients with IAC vascular loops in the
*Corresponding author.
A. ROLDÁN-FIDALGO ET AL.
246
asymptomatic ear, and five patients without clinical
symptoms.
Out of 12 patients with otologic symptoms, a vascular
compression of the eighth cranial nerve on MRI (Figure
1(a)) was presented in six patients, four patient reported
sensorineural hearing loss, and two patients continuous
tinnitus. A vascular loop in con tact with the bone wall of
the internal auditory canal (Figure 1(b)) was presented
in six patients; all of th em reported the presence of tinni-
tus resistant to standard medical treatment (Table 1).
None of the patients had vertigo or hemifacial spasm.
4. Discussion
There is an apparent discrepancy between the frequent
finding of vascular loops penetrating the internal auditory
canal in anatomic studies (12% by post-mortem dissec-
tions [2], 7% by computed tomography cisternography
[11], 14% - 34% by magnetic resonance imaging (MRI)
[12,13] in the normal population), and the infrequency of
ear symptoms associated with the presence of the loops.
Some explanations of this discrepancy include the de-
velopment of symptoms when the artery elongates (con-
genital or acquired), hardens (arteriosclerosis), or be-
comes fixed to the nerve (arachnoid adhesions) and com-
presses it [14]. The space available for the facial, vesti-
bulocochlear nerve and AICA loop in the internal audi-
tory meatus is minimum [15], creating an anatomic sus-
ceptibility of the n erve to vascular compression dysfu nc-
tion.
Auditory symptoms may be due to a complex interac-
tion between the seventh or eighth cranial nerve and the
vascular loop, in which the loop compresses the nerve
and the nerve compromises circulation to the inner ear.
The findings of a cochlear type of hearing loss, excellent
speech discrimination and normal caloric test results
should raise the suspicion of a vascular loop [16]. A loop
in contact with the vascular wall might cause pulsatile
tinnitus by direct transmission of pulsations to the coch-
lea via the internal auditory canal (bone conduction
mechanism) [17-21]. The compression of facial nerve is
frequently, and cause hemifacial spasm [22]. The com-
pression of the auditory and vestibular nerve trunks by
vascular loops might cause sensorineural hearing loss,
tinnitus and vertigo [2 -4].
In the present study none of the 91 patients with vas-
cular loop in the IAC presented vertigo or hemifacial
spasm.
The presence of pulsatile tinnitus (50%) and sen-
sorineural hearing loss (33%) were the conditions most
frequently encountered among the patient group studied
(Table 1).
De Riddet et al. [18] and Nowe et al. [23] found that
subjects with pulsatile tinnitus were 80 times more lik ely
to have a contacting vascular loop than patients with non-
(a) (b)
Figure 1. (a) Vascular loop adjacent to the eighth cranial
nerve, in a patient with sensorineural hearing loss in the
right ear; (b) MRI with a vascular loop in contact with the
internal auditory canal in a patient with pulsatile synchro-
nous tinnitus.
Table 1. Distribution of otologic symptoms in the patients
with vascular loop in the magnetic resonance imaging.
SYMPTOMS
VASCULAR LOOP IN
THE INTERNAL
AUDITORY CANALSensorineural
hearing loss Continuous
tinnitus Pulsatile
tinnitus
Compression of the eight
nerve 4 2 -
Contact the bone wall- - 6
pulsatile tinnitus.
Chadha and Weiner [1] suggested that the presence of
unilateral hearing loss were twice more likely to have
vascular loops in the symptomatic ear than in the as-
ymptomatic ear.
In selected cases, when a vascular loop is found to be
in contact with the affected cranial nerve, and no other
cause is identified, it would seem reasonable to consider
invasive neurosurgical micro-vascular decompression
with mixed results [1,24-26]. Shredded Teflon is place in
the internal auditory canal between the cochlea and the
intrameatal vascular loop [1]. The objective is to create a
sound barrier between the walls of the internal auditory
canal an d th e lo op , an d b e tw een the lo op and th e co ch le a,
without causing too much compression on the cochlear
nerve. None patients attended in our ENT department
required neurosurgical micro-vascular decompression
due to medical control of symptoms.
5. Conclusions
In patients without associated with neuro-otologic symp-
toms, the presence of vascular loops in the internal audi-
tory canal may be an incidental finding in MRIs, how-
ever, in patients with pulsatile or continuous tinnitus, or
sensorineural hearing loss, vertigo, which is unexplained
by other clinical pathologies, it may be correlated with
the existence of vascular loops which compress the eigh th
Open Access IJOHNS
A. ROLDÁN-FIDALGO ET AL.
Open Access IJOHNS
247
cranial nerve, or facial nerve in case of hemifacial spasm,
or contact the bone wall of the internal auditory canal.
As a result of the limited number of cases and small
amount of literature found, further multicentre studies
involving a larger number of patients would be advisable
to correlate otologic symptoms with the presence of vas-
cular loops in the internal auditory canal and thereby
accurately evaluate the association between these symp-
toms and vascular loops.
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