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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4455_Библиотеки_им_академика_М_И_Перельмана
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150 Disorders of the Auditory System
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If a secreting tumor is suspected, laboratory tests should include a 24-hr urine
test. This test can detect vasoactive tumor
products, such as vanillylmandelic acid
and epinephrine derivatives.
Imaging studies are vital to correct
diagnosis and management of patients
with glomus tumors. Computed tomography scans of the temporal bone and skull
base with contrast can provide evidence
of bone erosion by the tumor and additionally help to document the extent of the
compromise. Magnetic resonance imaging (MRI) with contrast provides definition of the tumor itself and delineates the
presence and degree of intracranial extension. The typical appearance of the tumor
is a “salt and pepper” pattern, which is
due to flow voids within vessels of the
tumor. Angiography is also helpful in
the diagnosis and may be combined with
treatment by embolization. This imaging
procedure is especially helpful in delineating which blood vessels are providing
the major blood flow to the tumor.
Audiologic Management
Audiologic management is dependent on
surgical outcome and degree of involvement. Patients who present with favorable postopertative outcomes resulting in
essentially no hearing loss will only need
to be monitored audiologically. However,
patients who continue to present with
peripheral involvement or who have complications following surgery may benefit
from traditional amplification.
Medical Management
Typically, glomus tympanicum tumors are
treated surgically. The removal of tumors
in Glasscock-Jackson classes I and II may
be removed through a tympanoplasty
approach. A laser is sometimes utilized
to assist with hemostasis. Surgical intervention for classes III and IV tumors may
involve a mastoidectomy. Complete excision is important in these cases as small
remnants of tumor can create a sizable
recurrence.
Glomus jugulare tumor treatment
has evolved over time. Surgical excision
of these tumors has historically been the
standard management strategy. However, other options such as observation,
a variety of radiation therapy options,
or a combination of surgery and postoperative radiation have been utilized.
Due to the slow growing nature of these
tumors, many patients may opt for observation for a period of time. Radiation
treatment of glomus jugulare tumors
has shown to be an effective treatment
for these tumors (Dobberpuhl, Maxwell,
Feddock, St. Clair, & Bush, 2016; Saringer,
Khayal, Ertl, Schoeggl, & Kitz, 2001; Sheehan, Kondziolka, Flickinger, & Lunsford,
2005). Patients with advanced disease or
advanced age may benefit from primary
radiation. One study found a difference
of 10% in treatment failures between
radiation and surgery favoring radiation (Carrasco & Rosenman, 1993). Surgery for jugular paraganglioma tumor is
often extensive in nature and carries the
potential of significant complications. The
surgical approach is based on the extension of the tumor and is quite variable.
Preoperative angiography is typically
performed. During preoperative angiography, embolization of feeding arterial
vessels can be performed and can assist
in decreasing the amount of bleeding
during surgical resection. Some basic elements present in surgical management of
Glasscock-Jackson types I and II tumors
involve identification and ligation of the
internal jugular vein in the neck. Simi-
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larly, the sigmoid sinus within the temporal bone is identified and occluded.
A mastoidectomy to access the tumor is
performed, which may involve mobilization of the facial nerve. Tumor margins
are identified, and the tumor is removed
carefully. Types III and IV tumors require
access to deeper portions of the temporal
bone, the skull base, and potentially to
the intracranial space. A defect within the
surgical site can be reconstructed using
multiple techniques. Both radiation treatment and surgical resection carry the risk
of damage to cranial nerves. Dysfunction
of previously functioning cranial nerves
occurs postoperatively in 25% to 50% of
patients (Pensak & Jackler, 1997). Vagus
nerve damage can lead to chronic aspiration and feeding tube dependence, which
can be devastating to patients of any age.
Combination of surgery and radiation may be a beneficial option. Incomplete removal of tumor is typically treated
with postoperative radiation. Patel and
colleagues reported on complication rates
in patients with combination therapy and
found that the incidence of facial and
lower cranial nerve injury was similar to
those rates from traditional infratemporal
fossa resections (Patel, Sekhar, Cass, &
Hirsch, 1994).
Audiology
Audiologic test results demonstrated
normal peripheral hearing sensitivity
and excellent word recognition bilaterally (Figure 4–7). Tympanometry revealed
normal pressure, volume, and compliance
for the right ear. For the left ear, the tympanogram was of unusual shape, showing
high compliance with normal middle ear
pressure and volume measures.
Medical Examination
The patient presented with a normal
appearing mastoid, pinna, external auditory canal, and tympanic membrane on
the right side. The left ear canal presented
with erythematous changes of the posterior canal wall with a bulging erythematous pulsatile mass posteriorly-inferiorly
and within the posterior portion of the
tympanic membrane. Results from the CT
evaluation demonstrated a very large vascular lesion (2.4 cm) with expansion into
and erosion of the skull base.
Impression
Large left-sided jugular paraganglioma
tumor.
Case 4–7: Paraganglioma
Tumor
History
This 44-year-old female presented with
a persistent left-sided pulsatile tinnitus.
She indicated that the tinnitus was initially faint, mild, and intermittent, but
that over the past 2 years it had become
very noticeable and constant. No other
significant audiologic or otologic history
was reported.
Audiologic Recommendations
and Management
Reevaluation following medical intervention.
Medical Recommendations
and Management
A CT scan was recommended to evaluate the middle ear structures. In addition,
surgical excision of the tumor was recommended. The patient underwent the recommended surgery where a transmastoid
and transcervical approach was utilized.
152 Disorders of the Auditory System
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A
Figure 4–7. Pure-tone air- and bone-conduction results, speech audiometry, and tympanometry
results for a 44–year-old female with a glomus tumor on the left side (Case 4–7). Results are shown
for both preoperative testing (A) and postoperative testing (B). continues
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B
Figure 4–7. continued
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Additional Comments
After surgery, there was a decrease in
pure-tone hearing in the left ear (see Figure 4–7B). However, speech recognition
remained excellent bilaterally. Although
the patient did well following surgery,
she has had significant recurrence of the
tumor and has undergone multiple surgeries for continued removal of the lesion.
Interestingly, she has had little additional
loss of hearing in light of the extensive
tumor involvement (see Figure 4–7).
otoscleRosis
Introduction
In 1704, Valsalva first identified a fixed
stapes during a cadaveric dissection (see
Canalis, 1990). Subsequently, Toynbee
studied many cases of stapes fixation and
found the fixation to exist around the margins of the oval window (Toynbee, 1841).
Some 50 years later, Politzer (1894) performed the first histologic evaluation of
otosclerosis and identified the presence
of abnormal bone in the otic capsule. Otosclerosis is a metabolic bone-remodeling
disease of the temporal bone. It primarily
affects the otic capsule and the ossicles.
A
change in the character and composi-
tion of the bone results in hearing loss.
Symptoms
The hallmark symptom of otosclerosis is
conductive hearing loss. Typically, the loss
is unilateral initially, but often becomes
bilateral with time. Tinnitus may also be
present; however, vertigo or dizziness is
uncommon. If the disease is progressive,
sensorineural hearing loss or deafness
may develop. A family history is usually
positive for this disease process and a history of chronic otitis media is typically
absent.
Incidence and Prevalence
This disease is the most common cause
of adult conductive hearing loss. It is
more common in Caucasian patients and
an otosclerotic focus of disease is present
in 10% of this population, but approximately 1% of the overall population is
affected by the disease (Levin, Fabian, &
Stahle, 1988). Women are more commonly
affected by the disease than men (Cawthorne, 1955), and the disease typically
presents between the 2nd and 4th decades
of life, but it may present at any age. Pregnancy seems to accelerate the presentation
of the disease; thus, this may be a reason
for the higher prevalence in women. The
disease has a multigenic autosomal dominant transmission pattern with incomplete penetrance.
Etiology and Pathology
In otosclerosis, the endochondral bone
of the otic capsule can become affected.
If and when this happens, the affected
area(s) becomes highly vascularized and
the bone is resorbed. Immature bone is
then laid down in this area and eventually becomes mineralized. This happens
in discrete areas throughout the otic capsule leaving a mosaic pattern. When this
occurs around the oval window, the stapes footplate becomes fixed and fails to
conduct sound into the cochlea efficiently.
This sequence of events typically results
in a conductive hearing loss. However, if
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the cochlea also becomes involved, a sensorineural component to the hearing can
also occur, resulting in a mixed hearing
loss (Doherty & Linthicum, 2004).
Site of Lesion
The most common site of otosclerotic
bone is an area just anterior to the stapes
footplate, referred to as the fissula ante
fenestrum. This is the site that can fix the
footplate in position causing a conductive
hearing loss. Another focus of otosclerosis can be the round window, which can
be completely obliterated by the disease.
Recent research indicates that cochlear
otosclerosis involves damage to the spiral
ligament, thus leading to progressive sensorineural hearing loss (Doherty & Linthicum, 2004).
Audiology
Careful audiologic evaluation is a key
component to the diagnosis and management of otosclerosis. Comprehensive
audiometry should include pure-tone
air- and bone-conduction threshold tests,
as well as speech threshold and speech
recognition testing. The hallmark audiologic finding in patients with otosclerosis
is a conductive hearing loss. The amount
of conductive involvement often correlates with the degree of stapes fixation.
One cannot discuss audiologic patterns
of otosclerosis without mentioning the
Carhart notch. First described by Carhart in 1950, the Carhart notch has been
observed in otosclerotic patients. This
notch is the result of a reduction in boneconduction thresholds, particularly at
2000 Hz; however, it may be observed at
other frequencies. This notch in the bone-
conduction thresholds is attributed to
abnormal mechanical effects on the middle ear system secondary to stapes fixation. Often, the pure-tone air-conduction
audiogram shows an ascending audiometric configuration. This is likely related
to the increased stiffness of the middle ear
system and is termed the “stiffness tilt”
(Hannley, 1993).
Speech recognition is typically excellent in patients who present with purely
conductive involvement; however, patients who have comorbid sensorineural involvement may show diminished
speech recognition abilities correlated to
the degree of pathology. Tympanometry
results in these patients will often be normal or demonstrate reduced compliance
(Jacobson & Mahoney, 1977; Sutherland &
Campbell, 1990). However, in many of the
cases with normal compliance, the width
of the tympanogram shape is reduced
(Ivy, 1975). Acoustic reflex testing typically yields elevated or absent acoustic
reflexes (Probst, 2007). A general exception
to this rule is for patients early in the clinical course of the disease. Though these
individuals can present with reflexes at
normal or near-normal levels, an unusual
negative deflection often is observed in
their tracings at both the onset and the
offset of the eliciting stimulus (Rane, Yut,
& Berger, 1978).
Audiologic findings are particularly
important in cases where surgical intervention is being considered. Successful surgery will often result in partial or complete
closure of the presurgical air-bone gap.
Medical Examination
Examination of the otosclerotic ear reveals a
normal tympanic membrane with normal
mobility. In active forms of the disease,
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which are characterized by hypervascularity and bone resorption, the promontory may have a reddish hue that can
be visualized on otoscopic exam. This is
known as Schwartze’s sign (House, 1997).
A tuning fork exam provides an approximation of conductive hearing loss and is
a necessary part of the physical exam. The
use of 512-Hz tuning fork has the greatest
utility in confirming surgical candidacy
and a negative Rinne with a 512-Hz fork
approximates a conductive hearing loss of
20 dB to 25 dB. Some have recommended
the use of CT imaging in conductive hearing loss evaluation; however, this is not
commonly used unless other conditions
such as cochlear otosclerosis or superior
semicircular canal dehiscence syndrome
are suspected.
Audiologic Management
Audiologic management depends on three
factors: (1) medical management, (2) presurgical peripheral involvement, and
(3) postsurgical outcome measures. Some
patients may not be surgical candidates
for a variety reasons; for those patients,
traditional amplification may be an appropriate intervention strategy to assist with
hearing difficulties. As most patients with
otosclerosis have good to excellent word
recognition, they typically do well with
amplification if there are medical contraindications to surgery or if they do not want
to undergo a surgical procedure. In some
instances, patients undergoing surgery
may present with preexisting, comorbid
sensorineural involvement. In these cases,
patients will routinely require amplification following medical intervention even
if the air-bone gap is closed. Appropriate
presurgical counseling is critical in these
circumstances.
Medical Management
Historically, surgical management of this
disease has been a source of controversy.
Kessel first treated otosclerosis with stapes mobilization in 1878 (Kessel, 1878);
however, stapes operations fell out of
favor during the late 19th century in the
majority of the medical community. The
early 20th century saw many advances
in techniques for treating this disease
process. Lempert introduced a one-stage
fenestration of the horizontal semicircular
canal that became widely popular (Lempert, 1938). Shea permanently changed
the treatment of otosclerosis by describing an operation involving removal of the
stapes and placement of a wire prosthesis
from the incus to the oval window grafted
with a vein graft (Shea, 1958).
The primary indication for surgical
intervention of otosclerosis is the presence of a conductive hearing loss of more
than 25 dB HL and the presence of a negative 512-Hz Rinne test without evidence
of otitis media (McKenna & de Venecia,
2007). Contraindications include surgery
in an only hearing ear or in ears with
active Ménière’s disease, otitis media,
otitis externa, and/or tympanic membrane perforations. Surgical intervention
involves exploration of the middle ear,
typically approached through the ear
canal, to confirm the presence of a fixed
footplate. Once this is confirmed, the fixed
footplate can be addressed by two main
techniques. A stapedectomy involves the
removal of a portion of or the entire stapes footplate, grafting the open oval window, and placement of a prosthesis from
the long process of the incus to the graft.
An alternative approach is a stapedotomy.
This approach involves removal of the
stapes’ superstructure, creating a hole in
the fixed footplate with a drill or a laser,
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and placing a prosthesis from the incus
to the stapedotomy site. This procedure
can be done under general anesthesia or
under local anesthesia with intravenous
sedation. Immediate postoperative complications for these procedures include
facial nerve damage, disarticulation of
the incus, failure to correct the hearing
loss, chorda tympani injury, cerebral spinal fluid (CSF) leak, vertigo, and granuloma formation. The complication of most
concern is sensorineural hearing loss,
which can be complete, and is the result
of trauma to the vestibule during the surgical procedure. Profound sensorineural
hearing loss occurs in less than 1% of
patients undergoing surgery for otosclerosis (House, 1997). Conductive hearing
loss can occur in a delayed fashion due
to the prosthesis moving from the correct position. However, if done correctly,
stapes surgery is highly restorative and
rewarding.
revealed normal pressure, volume, and
compliance for both ears and word recognition was excellent bilaterally.
Medical Examination
A medical exam revealed normal appearing mastoids, pinnae, ear canals, and
tympanic membranes without fluid, perforation, or retraction. Given the patient’s
history, the audiometric findings (i.e., an
air-bone gap greater than 20 dB), and the
fact that the patient had a negative Rinne
512-Hz tuning fork examination (bone
conduction louder than air conduction),
otosclerosis was highly suspected.
Impression
Bilateral otosclerosis.
Audiologic Recommendations
and Management
Case 4–8: Otosclerosis
History
This 42-year-old female reported a history
of progressive hearing loss bilaterally,
with the hearing sensitivity in the right
ear perceived to be poorer than in the
left ear. The patient also reported unilateral tinnitus in the right ear with no other
audiologic or otologic history reported.
Audiology
The patient presented with a moderate,
rising to mild mixed hearing loss in the
right ear and a mild to moderate, rising to a mild mixed hearing loss in the
left ear with an asymmetry between the
ears noted (Figure 4–8A). Tympanometry
It was recommended that the patient follow up with an otolaryngologist. Depending on the outcome of her medical evaluation and medical interventions (if any
are recommended and accepted), bilateral amplification should be considered
if hearing concerns persist. The patient
took this recommendation under consideration, but elected not to proceed with
hearing aids postoperatively.
Medical Recommendations
and Management
The patient was given the options of
either using hearing aids or undergoing
surgery to close the air-bone gap in the
right ear. The patient elected to have the
surgery. A stapedectomy for correction of
the conductive hearing loss in the right
ear was performed.
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A
Figure 4–8. Pure-tone air- and bone-conduction thresholds, speech audiometry, and tympanom-
etry results for a 42-year-old female with otosclerosis (Case 4–8). Results are shown for both preoperative testing (A) and postoperative testing (B). Note: otosclerosis was confirmed for the right ear
and diagnosed as probable for the left ear. continues
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B
Figure 4–8. continued
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