Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on Otologic and Audiologic Screening for Patients With Vestibular Schwannomas

Abstract

QUESTION 1
What is the expected diagnostic yield for vestibular schwannomas when using a magnetic resonance imaging (MRI) to evaluate patients with previously published definitions of asymmetric sensorineural hearing loss?

TARGET POPULATION
These recommendations apply to adults with an asymmetric sensorineural hearing loss on audiometric testing.

RECOMMENDATION
Level 3: On the basis of an audiogram, it is recommended that MRI screening on patients with ≥10 decibels (dB) of interaural difference at 2 or more contiguous frequencies or ≥15 dB at 1 frequency be pursued to minimize the incidence of undiagnosed vestibular schwannomas. However, selectively screening patients with ≥15 dB of interaural difference at 3000 Hz alone may minimize the incidence of MRIs performed that do not diagnose a vestibular schwannoma.

QUESTION 2
What is the expected diagnostic yield for vestibular schwannomas when using an MRI to evaluate patients with asymmetric tinnitus, as defined as either purely unilateral tinnitus or bilateral tinnitus with subjective asymmetry?

TARGET POPULATION
These recommendations apply to adults with subjective complaints of asymmetric tinnitus.

RECOMMENDATION
Level 3: It is recommended that MRI be used to evaluate patients with asymmetric tinnitus. However, this practice is low yielding in terms of vestibular schwannoma diagnosis (<1%).

QUESTION 3
What is the expected diagnostic yield for vestibular schwannomas when using an MRI to evaluate patients with a sudden sensorineural hearing loss?

TARGET POPULATION
These recommendations apply to adults with a verified sudden sensorineural hearing loss on an audiogram.

RECOMMENDATION
Level 3: It is recommended that MRI be used to evaluate patients with a sudden sensorineural hearing loss. However, this practice is low yielding in terms of vestibular schwannoma diagnosis (<3%).
The full guideline can be found at: https://www.cns.org/guidelines/guidelines-management-patients-vestibular-schwannoma/chapter_2.

Full text

VESTIBULAR SCHWANNOMA GUIDELINES
Congress of Neurological Surgeons Systematic
Review and Evidence-Based Guidelines on Otologic
and Audiologic Screening for Patients With
Vestibular Schwannomas
Alex D. Sweeney, MD∗‡
Matthew L. Carlson, MD§¶
Neil T. Shepard, PhD§
D. Jay McCracken, MD||
Esther X. Vivas, MD#
Brian A. Ne, MD§¶
Jerey J. Olson, MD||
∗Bobby R. Alford Department of Oto-
laryngology—Head and Neck Surgery,
Baylor College of Medicine, Houston,
Tex as ; ‡Department of Neurosurgery,
Baylor College of Medicine, Houston,
Tex as ; §Department of Otorhinolaryn-
gology, Mayo Clinic School of Medicine,
Rochester, Minnesota; ¶Department of
Neurosurgery, Mayo Clinic School of
Medicine, Rochester, Minnesota; ||De-
partment of Neurosurgery, Emory Uni-
versity School of Medicine, Atlanta,
Georgia; #Department of Otolaryngo-
logy—Head and Neck Surgery, Emory
University School of Medicine, Atlanta,
Georgia
Sponsored by: Congress of Neurological
Surgeons (CNS) and the Section on
Tumors.
Endorsed by: Joint Guidelines Committee
of the American Association of
Neurological Surgeons (AANS) and the
Congress of Neurological Surgeons
(CNS).
No part of this manuscript has been
published or submitted for publication
elsewhere.
Correspondence:
Alex D. Sweeney, MD,
Bobby R. Alford Department of
Otolaryngology—Head and Neck
Surgery,
Department of Neurosurgery,
Baylor College of Medicine,
1 Baylor Plaza,
Mail Stop—NA102,
Houston, TX 77030.
E-mail: alex.sweeney@bcm.edu
Received, August 10, 2017.
Accepted, October 2, 2017.
Copyright C
2017 by the
Congress of Neurological Surgeons
QUESTION 1: What is the expected diagnostic yield for vestibular schwannomas when
using a magnetic resonance imaging (MRI) to evaluate patients with previously published
denitions of asymmetric sensorineural hearing loss?
TARGET POPULATION: These recommendations apply to adults with an asymmetric
sensorineural hearing loss on audiometric testing.
RECOMMENDATION: Level3:Onthebasisofanaudiogram,itisrecommendedthat
MRI screening on patients with ≥10 decibels (dB) of interaural dierence at 2 or more
contiguous frequencies or ≥15 dB at 1 frequency be pursued to minimize the incidence
of undiagnosed vestibular schwannomas. However, selectively screening patients with
≥15 dB of interaural dierence at 3000 Hz alone may minimize the incidence of MRIs
performed that do not diagnose a vestibular schwannoma.
QUESTION 2: What is the expected diagnostic yield for vestibular schwannomas when
using an MRI to evaluate patients with asymmetric tinnitus, as dened as either purely
unilateral tinnitus or bilateral tinnitus with subjective asymmetry?
TARGET POPULATION: Theserecommendationsapplytoadultswithsubjective
complaints of asymmetric tinnitus.
RECOMMENDATION: Level 3: It is recommended that MRI be used to evaluate patients
with asymmetric tinnitus. However, this practice is low yielding in terms of vestibular
schwannoma diagnosis (<1%).
QUESTION 3: What is the expected diagnostic yield for vestibular schwannomas when
using an MRI to evaluate patients with a sudden sensorineural hearing loss?
TARGET POPULATION: Theserecommendationsapplytoadultswithaveriedsudden
sensorineural hearing loss on an audiogram.
RECOMMENDATION: Level 3: It is recommended that MRI be used to evaluate patients
with a sudden sensorineural hearing loss. However, this practice is low yielding in terms of
vestibular schwannoma diagnosis (<3%).
The full guideline can be found at: https://www.cns.org/guidelines/guidelines-
management-patients-vestibular-schwannoma/chapter_2.
KEY WORDS: Acoustic neuroma, Audiologic screening, Otologic screening, Vestibular schwannoma, Skull base
surgery
Neurosurgery 82:E29–E31, 2018 DOI:10.1093/neuros/nyx509 www.neurosurgery-online.com
ABBREVIATIONS: ASNHL, asymmetric sensorineu-
ral hearing loss; dB, decibels; JGC, Joint Guide-
lines Committee; MRI, magnetic resonance imaging;
SSNHL, sudden sensorineural hearing loss; VS,
vestibular schwannoma
Despite considerable evolution in the
methods of vestibular schwannoma (VS)
management over the past century, the
optimal screening strategy for patients suspected
of having a tumor remains unclear. The sensi-
tivity of contrast-enhanced high-resolution
magnetic resonance imaging (MRI) to detect
retrocochlear pathology and the wide availability
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SWEENEY ET AL
of this modality in the present day have led to it becoming the
standard for VS identification.1However, knowing when an MRI
is indicated can be challenging in the absence of clear neuro-
logical deficits. Additionally, rising healthcare costs have inspired
analysis of resource utilization in a variety of different settings
where screening tests are traditionally employed.2-4Undoubtedly,
indiscriminate screening for VSs would have unfavorable financial
ramifications given the rarity of these tumors, yet, a widely
accepted, symptom-based screen to identify patients “at risk” for
VS diagnosis continues to be elusive.
METHODS
Details of the systematic literature review are provided in the
full text of this guideline (https://www.cns.org/guidelines/guidelines-
management-patients-vestibular-schwannoma/chapter_2) and in the
methodology (https://www.cns.org/guidelines/guidelines-management-
patients-vestibular-schwannoma/chapter_1) article of this guideline
series. The authors collaborated with a medical librarian to search for
articles published from January 1, 1990 to December 31, 2014. Three
electronic databases, PubMed, EMBASE, and Web of Science, were
searched. A total of 806 citations were manually reviewed by the task
force. The authors supplemented searches of electronic databases with
manual screening of the bibliographies of all retrieved publications. The
authors went to great lengths to obtain a complete set of relevant articles
to ensure that the guideline is not based on a biased subset of articles.
The selected studies were classified according to criteria for evidence
on diagnosis as detailed in the Joint Guidelines Committee (JGC)
guideline development methodology (https://www.cns.org/guidelines/
guideline-procedures-policies/guideline-development-methodology).
RESULTS
A total of 806 studies were screened and assessed for eligibility
per the previous criteria, and 17 publications were included in
the final review.5-21 Using these studies, this guideline sought
to evaluate audiometric definitions of interaural asymmetry in
pure tone audiometry, the utility of asymmetric tinnitus as a
screening tool by analyzing both the association of asymmetric
tinnitus in the general population with the diagnosis of a VS
and the frequency with which tumor patients retrospectively
reported asymmetric tinnitus at the time of their presentation,
and the utility of sudden sensorineural hearing loss (SSNHL) as a
screening tool for VS by analyzing both the likelihood of patient
presentation with an SSNHL and the frequency with which
patients ultimately diagnosed with a tumor reported an SSNHL at
the time of their presentation. Regarding the audiometric defini-
tions of interaural asymmetry in pure tone audiometry, evidence
suggests that for the diagnosis of a VS, the most sensitive, current
audiometric definition of asymmetric sensorineural hearing loss
(ASNHL) is ≥10 dB at 2 or more contiguous frequencies; or
≥15 dB at any single frequency. However, the criterion with the
highest positive predictive value defines asymmetry as ≥15 dB
interaural asymmetry at 3000 Hz. Regarding the use of
asymmetric tinnitus as a screening tool, there were 720 patients
subjected to MRI screening on the basis of asymmetric tinnitus
in the absence of asymmetric hearing loss. The prevalence of
asymmetric tinnitus as an initial presenting symptom among
patients with a VS was <1%. However, many patients with
a VS diagnosis reported asymmetric tinnitus, irrespective of
other symptoms. Out of 584 tumors from studies that met
inclusion criteria, 319 patients (54.6%) experienced asymmetric
tinnitus. When considering these findings, it would appear that
asymmetric tinnitus may correlate more with asymmetric hearing
loss, in general, rather than the presence of a tumor. Based on
available data, the presence of asymmetric tinnitus is a relatively
unreliable screening tool for VS. Regarding the use of SSNHL as
a screening tool for VS diagnosis, 54 tumors were found out of
1007 patients screened, suggesting that SSNHL is a presenting
sign for a VS in approximately 5.4% of cases. When consid-
ering VS patients who have a documented history of SSNHL,
133 patients out of 1680 were identified, suggesting that 7.9%
of tumor patients experienced SSNHL prior to their diagnosis.
Based on available studies, SSNHL is a more reliable indicator of
the presence of a VS than asymmetric tinnitus in the absence of
an associated ASNHL.
DISCUSSION AND CONCLUSION
Although a variety of different studies have evaluated the
optimal screening methods for VS, no perfect method exists.
The existing literature on the expected VS patient symptom
profiles suggests that as long as objective audiometric criteria
are the basis of any screening protocol for VS, a portion of
tumors will always go undiagnosed. Clearly, the most sensitive
screening paradigm based on interaural audiometric threshold
asymmetry, asymmetric tinnitus, and ASNHL would incorporate
the least stringent of all of these criteria. In other words, MRI
screening would be offered to any patient presenting with subjec-
tively asymmetric tinnitus and/or a measurable SSNHL and/or
an interaural asymmetry of ≥10 dB at 2 or more frequencies; or
≥15 dB at any single frequency, and it would be expected that
this method would have the highest likelihood of diagnosing the
greatest number of VSs while also providing the lowest likelihood
of missing an opportunity for VS diagnosis. Yet, considering only
the conflict example presented in the first recommendation, this
increase in sensitivity would come at the expense of specificity,
leading to a large number of negative MRI scans, and thus, a
less efficient utilization of resources. Although the scope of this
guideline was limited to audiometric screening and subjective
tinnitus, it stands to reason that the most comprehensive criteria
for VS screening would involve multiple features, both in terms
of a patient’s symptoms, audiologic testing, and their audiologic
history (eg, noise exposure). Research directed towards the devel-
opment of a weighted “score” for VS diagnosis will be a welcome
addition to this body of literature.
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OTOLOGIC AND AUDIOLOGIC SCREENING FOR PATIENTS WITH VESTIBULAR SCHWANNOMAS
Disclosure
These evidence-based clinical practice guidelines were funded exclusively by
the Congress of Neurological Surgeons, the Tumor Section of the Congress of
Neurological Surgeons, and the American Association of Neurological Surgeons,
which received no funding from outside commercial sources to support the devel-
opment of this document.
Conict of Interest
The Vestibular Schwannoma Guidelines Task Force members were required
to report all possible COIs prior to beginning work on the guideline, using the
COI disclosure form of the AANS/CNS Joint Guidelines Committee, including
potential COIs that are unrelated to the topic of the guideline. The CNS Guide-
lines Committee and Guideline Task Force Chair reviewed the disclosures and
either approved or disapproved the nomination. The CNS Guidelines Committee
and Guideline Task Force Chair are given latitude to approve nominations of
Task Force members with possible conflicts and address this by restricting the
writing and reviewing privileges of that person to topics unrelated to the possible
COIs. The conflict of interest findings are provided in detail in the full-text intro-
duction and methods manuscript (https://www.cns.org/guidelines/guidelines-
management-patients-vestibular-schwannoma/chapter_1).
Disclaimer of Liability
This clinical systematic review and evidence-based guideline was developed
by a multidisciplinary physician volunteer task force and serves as an educational
tool designed to provide an accurate review of the subject matter covered. These
guidelines are disseminated with the understanding that the recommendations
by the authors and consultants who have collaborated in their development are
not meant to replace the individualized care and treatment advice from a patient’s
physician(s). If medical advice or assistance is required, the services of a competent
physician should be sought. The proposals contained in these guidelines may not
be suitable for use in all circumstances. The choice to implement any particular
recommendation contained in these guidelines must be made by a managing
physician in light of the situation in each particular patient and on the basis of
existing resources.
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Acknowledgments
The authors acknowledge the Congress of Neurological Surgeons Guidelines
Committee for its contributions throughout the development of the guideline
and the American Association of Neurological Surgeons/Congress of Neurological
Surgeons JGC for its review, comments, and suggestions throughout the peer
review, as well as Trish Rehring, CNS Guidelines Senior Manager, and Mary
Bodach, MLIS, for their assistance. Throughout the review process, the reviewers
and authors were blinded from one another. At this time, the guidelines task
force would like to acknowledge the following individual peer reviewers for their
contributions: Sepideh Amin-Hanjani, MD, D. Ryan Ormond, MD, Andrew
P. Carlson, MD, Kimon Bekelis, MD, Stacey Quintero Wolfe, MD, Chad W.
Washington, MD, Cheerag Dipakkumar Upadhyaya, MD, and Mateo Ziu, MD.
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