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Histopathology of the inner ear in unoperated acoustic neuroma.Ann
Otol Rhinol Laryngol. 2003
Nov;112(11):979-86.
Although
hearing loss is the most common presenting symptom in patients with
acoustic neuroma, the pathophysiology of hearing loss associated
with acoustic neuroma is unknown. Although primary dysfunction of
the auditory nerve is intuitively logical, available histopathologic
and clinical data suggest that although neural degeneration is
common, it alone does not adequately account for hearing loss in
many cases. The purpose of this study was to evaluate 11 cases of
unoperated unilateral acoustic neuromas. Temporal bones were
identified by means of a search mechanism provided by the National
Temporal Bone, Hearing, and Balance Pathology Resource Registry and
were prepared for light microscopy by standard techniques.
Quantification of spiral ganglion cells, hair cells, stria
vascularis, and spiral ligament was accomplished for each specimen.
In addition, the maximum diameter and volume of each tumor were
calculated from histopathologic sections. Increasing tumor size did
predict a reduced spiral ganglion count. However, although there was
a tendency for decreasing spiral ganglion cell count and for
increasing tumor size to predict a higher pure tone average and
lower speech discrimination score, these correlations did not reach
statistical significance. In tumor ears in which the speech
discrimination score was 50% or less, there was always significant
degeneration of other structures of the inner ear in addition to
neurons, including hair cells, the stria vascularis, and the spiral
ligament. Endolymphatic hydrops and eosinophilic precipitate in the
perilymphatic spaces were found in 2 of 3 such cases. It is
concluded that acoustic neuromas appear to cause hearing loss, not
only by causing degeneration of the auditory nerve, but also by
inducing degenerative changes in the inner ear. It is hypothesized
that the proteinaceous material seen histologically may represent
the products of up-regulated genes in acoustic neuroma, some of
which may interfere with normal cochlear function.
Clinical
tumoral size dissociation in acoustic neuroma: reality or measure
distortion?
Acta
Otorrinolaringol Esp. 2006 Oct;57(8):345-9.
INTRODUCTION: In this study we have analyzed (i) the audiometric
frequencies more often affected in acoustic neuroma (AN), (ii) the
percentage of patients presenting normal hearing and those with
sudden hearing loss, (iii) if there is a correlation between tumor
size and hearing loss, and (iv) the relationship between clinical
and radiological parameters and audiological data. METHODS AND
MATERIAL: Retrospective study of 81 patients undergoing surgical
removal of a sporadic AN. RESULTS: The highest threshold in the
tumor's ear was found at 8000 Hz, and the highest interaural
difference at 4000 Hz. The percentage of patients presenting normal
hearing and sudden hearing loss was 2.5% and 9%, respectively. No
significant association was found between tumor size and hearing
loss, preoperative facial palsy or Vth cranial nerve deficit. There
was a significant association between the degree of hearing loss and
Vth cranial nerve deficit, and between hearing loss and preoperative
facial palsy. CONCLUSIONS: The association between hearing loss and
Vth cranial nerve deficit, and between hearing loss and preoperative
facial palsy is independent the size of the tumour.
Translabyrinthine surgery for disabling vertigo in vestibular
schwannoma patients.Clin
Otolaryngol. 2007 Jun;32(3):167-72.
OBJECTIVE:
To determine the impact of translabyrinthine surgery on the quality
of life in vestibular schwannoma patients with rotatory vertigo.
STUDY DESIGN: Prospective study in 18 vestibular schwannoma
patients. SETTING: The study was conducted in a multispecialty
tertiary care clinic. PARTICIPANTS: All 18 patients had a unilateral
intracanalicular vestibular schwannoma, without serviceable hearing
in the affected ear and severely handicapped by attacks of rotatory
vertigo and constant dizziness. Despite an initial conservative
treatment, extensive vestibular rehabilitation exercises,
translabyrinthine surgery was performed because of the disabling
character of the vertigo, which considerably continued to affect the
patients' quality of life. MAIN OUTCOME MEASURES: Preoperative and
postoperative quality of life using the Short Form 36 Health Survey
(Short Form-36) scores and Dizziness Handicap Inventory (DHI)
scores. RESULTS: A total of 17 patients (94%) completed the
questionnaire preoperatively and 3 and 12 months postoperatively.
All Short Form-36 scales of the studied patients scored
significantly lower when compared with the healthy Dutch control
sample (P < 0.05). There was a significant improvement of DHI total
scores and Short Form-36 scales on physical and social functioning,
role-physical functioning, role-emotional functioning, mental health
and general health at 12 months after surgery when compared with
preoperative scores (P < 0.05). CONCLUSIONS: Vestibular schwannoma
patients with disabling vertigo, experience significant reduced
quality of life when compared with a healthy Dutch population.
Translabyrinthine tumour removal significantly improved the
patients' quality of life. Surgical treatment should be considered
in patients with small- or medium-sized tumours and persisting
disabling vertigo resulting in a poor quality of life.
Cochlear
origin of early hearing loss in vestibular schwannoma.Laryngoscope.
2007 Apr;117(4):680-3.
OBJECTIVE: To
test whether early hearing loss (HL) is cochlear in origin in
patients with vestibular schwannoma (VS). STUDY DESIGN:
Retrospective case review in an academic tertiary referral center.
METHODS: A group of 19 VS patients with normal/symmetrical hearing
and a group of 20 VS patients with mild HL (threshold at any tested
frequency better than 45 dB HL) on the tumor ear side. Differences
of the amplitudes of the distortion products of otoacoustic
emissions (DPOAEs) between the tumor ear and the nontumor ear were
studied at frequencies of 1, 1.4, 2, 2.8, and 4 kHz. The Wilcoxon
test was used to compare the ears for both groups and to test for
possible differences in tumor size between groups. RESULTS: DPOAE
amplitudes do not differ strongly between the ears in VS patients
with normal/symmetrical hearing (two-sided P values: .050 at 1 kHz,
.182 at 1.4 kHz, .378 at 2 kHz, .293 at 2.8 kHz, and .238 at 4 kHz)
but are decreased compared with the nontumor ear at frequencies 1,
1.4, 2, and 2.8 kHz in VS patients with even mild HL (two-sided P
values: .013 at 1 kHz, .007 at 1.4 kHz, .033 at 2 kHz, .010 at 2.8
kHz, and .156 at 4 kHz). Tumor size did not differ significantly
between the two groups (P = .436). CONCLUSION: Amplitudes of DPOAEs
begin to decrease even at the early stages of HL in VS patients,
which suggests a cochlear origin of early HL in these patients.
DPOAEs may be used in a clinical setting to monitor progression of
cochlear damage at the early stages of hearing impairment in VS
patients.
Surgical approaches and complications in the
removal of vestibular schwannomas.
Otolaryngol Clin North Am.
2007 Jun;40(3):589-609.
Vestibular
schwannomas are benign tumors that usually originate from the
balance portion of cranial nerve VIII. The treatment options
currently available for vestibular schwannomas include observation
with serial imaging, stereotactic radiation, and microsurgical
removal. Although the ultimate goal in treatment of vestibular
schwannomas is preservation of life, the best option for each
patient depends on symptoms, tumor size, tumor location, and the
patient's general health and age. Surgical exposure of the
cerebellopontine angle for removal of vestibular schwannomas can be
performed safely via a translabyrinthine, retrosigmoid, and middle
fossa approach. Each approach has its advantages and disadvantages.
The goal of surgery is complete eradication of tumor with
preservation of hearing and facial nerve function when possible.
Cystic
vestibular schwannomas.Neurochirurgie.
2004 Jun;50(2-3 Pt 2):401-6.
RATIONALE:
Patients with cystic vestibular schwannomas (VS) are a
radiologically well-defined subgroup of patients who classically
have poor outcome after microsurgical resection. Since Pendl's
report of a high rate of failures, they are also considered as poor
candidates for radiosurgery. MATERIAL AND METHOD: Among the 1000
consecutive patients who underwent Gamma Knife surgery in
Marseilles, France between July 1992 and January 2002, we have
collected and studied 54 patients with cystic VS at the time of
treatment. RESULTS: The median follow-up of this group was 26 Months
(mean: 33, range: 6-90). Failure (6.4%) led to microsurgical removal
in 2 patients and a radiosurgery in 1 patient with a delay of 2
Years for 2 of them and 3 Years for the third. No facial palsy has
been reported. Two patients developed transient hypesthesia. Among
the 32 patients with functional hearing at the time of treatment,
53% preserved their hearing function at 3 Years. CONCLUSIONS: We
found an increased risk of failure in this group compared to
patients with no cyst at time of radiosurgery (93.6% instead of
98%). But this is also a group were we observe most dramatic
shrinkage. Prudent radiosurgical treatment of cystic vestibular
schwannomas remains mandatory: strict follow-up is specially
important.
Inner ear
extension of vestibular schwannomas.Laryngoscope.
2003 Sep;113(9):1605-8.
OBJECTIVE:
Inner ear extension of vestibular schwannomas (VSs) is a rare
finding but has important clinical implications. This report reviews
the treatment options and presents the experience of the Gruppo
Otologico, Piacenza, Italy, in this field. STUDY DESIGN: Case report
and literature review. METHODS: Five cases of VSs with inner ear
extension were surgically removed. In all of them, the cochlea was
partially or completely invaded by the lesion. RESULTS: In 4 cases,
the inner ear extension was preoperatively identified on magnetic
resonance imaging, and the surgical removal was planned through a
transotic approach. In the last case, the cochlear invasion was not
detected preoperatively, and the lesion was removed during a second
surgery performed to seal a cerebrospinal fluid fistula.
CONCLUSIONS: VSs with inner ear extension should be distinguished
from pure intralabyrinthine schwannomas because of differences in
clinical significance. Cochlear involvement is more frequent than
vestibular involvement and is often accompanied by a dead ear. Dead
ear caused by small VSs should alert the surgeon to the possibility
of a cochlear extension. The presence of an intracochlear
involvement requires the adoption of an approach that allows control
of the cochlear turns, and we found the transotic approach to be the
most suitable. Undetected cochlear extensions that are left in place
may grow with time.
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