Is
it possible to predict diffuse obliterative otosclerosis
preoperatively by audiologic examination. Int J Audiol. 2007 May;
46(5):203-7.
Patients
with diffuse obliterative otosclerosis have more extensive footplate
pathology than annular cases. As a result of this more skill is
required for diffuse otosclerosis cases, and postoperative hearing
results are usually worse than annular cases. In this retrospective
study we compared the preoperative audiological features of annular
and diffuse otosclerosis patients. The subjects were 60 patients
with conductive hearing loss who had undergone stapedectomy. Annular
and diffuse groups were comprised of 30 patients each. Annular
otosclerosis was defined as the footplate pathology involving the
annular ligament only, where the footplate of the stapes is very
thin and retains its bluish color. On the other hand diffuse,
obliterative otosclerosis was defined as the pathology involving the
whole footplate and also in some cases extending beyond the confines
of the annular ligament. In each group preoperative air- and
bone-conduction levels at 125-6000 Hz and 500-4000 Hz were noted
respectively. Average air-bone gap for the obliterative otosclerosis
group was 37.5 dB; the same value for the annular group was 23.8 dB
(p<0.05). The gap characteristics of the audiogram were different
for the two groups. The annular group had an air-bone gap which was
nearly constant for all the frequencies. In the diffuse otosclerosis
group, the air-bone gap was more prominent in the low frequencies
and it decreased at higher frequencies. No difference was noted in
bone-conduction thresholds, and Carhart notch between the two
groups. This study demonstrated that a large air-bone gap in
patients with conductive hearing loss may be a sign of diffuse
obliterative otosclerosis. This may warn the surgeon that a more
challenging surgery is possible, and the patient may have a less
favorable hearing result. Therefore, in the presence of a large
air-bone gap, it may be appropriate to inform the patient of the
strong possibility of diffuse otosclerosis.
Otosclerosis of
the incus. Otol Neurotol. 2007 Apr;28(3):301-3.
OBJECTIVE:
To report a case of a patient with otosclerosis of the incus.
PATIENTS: A 61-year-old woman with a progressive hearing loss on her
left ear and a computed tomographic scan of the temporal bone
revealing an expansible lesion of the incus. INTERVENTIONS: The
ossicle was removed by using a transtympanomastoid approach; the
ossicular chain was reconstructed using a titanium partial ossicular
replacement prosthesis. MAIN OUTCOME MEASURE: The diagnosis of the
disease was obtained by means of histopathologic examination of the
specimen. RESULTS: The patient obtained a good postoperative hearing
result. The histopathologic examination of the specimen documented
an otosclerosis of the incus. CONCLUSION: Otosclerotic involvement
of the middle ear ossicles, apart from footplate, was very rarely
mentioned. Most subjects were incidentally diagnosed postmortem by
means of examination of specimens from temporal bone collections.
The diagnosis and treatment of a patient with otosclerosis of the
incus is exceptional; however, otosclerosis should be considered in
the differential diagnosis of expansible lesions of the ossicles.
Phenotype-genotype
correlations in otosclerosis: clinical features of OTSC2.Adv
Otorhinolaryngol. 2007;65:114-8.
As part of
the GENDEAF consortium, a European multi-centre otosclerotic
database is under construction to collect the clinical data of as
many otosclerotic patients as possible. Otosclerosis represents a
heterogeneous group of heritable diseases in which different genes
may be involved regulating the bone homeostasis of the otic capsule.
The purpose of the GENDEAF otosclerosis database is to explore the
otosclerotic phenotype more in depth. Subtle phenotypic differences
otherwise not visible, may become statistically relevant in a large
number of patients. Their identification can lead towards the
discovery of new genes involved in the pathway of abnormal bone
metabolism in the human labyrinth. As soon as one of the
otosclerotic genes is identified, it would allow us to identify
genotype-phenotype correlations. From other deafness genes, it is
know that different mutations in the same gene may cause similar
phenotypes of varying severity. Also the variability in treatment
outcomes after surgery or fluoride therapy may result not only from
differences in practice or surgical skill among physicians, but also
on the nature of the underlying disorder. Screening large numbers of
patients would make it possible to undertake clinical trials
comparing different treatments. Identifying a genetic susceptibility
would allow us to dissect out possible environmental factors that
prevent the expression of clinical otosclerosis in those that carry
the mutated gene and yet retain normal hearing.
Measles virus prevalence in otosclerotic foci. Adv
Otorhinolaryngol. 2007;65:93-106.
The
etiology of otosclerosis is still unknown. Persistent measles virus
infection of the otic capsule is supposed to be one of the etiologic
factors in otosclerosis. The presence of measles virus was shown in
otosclerotic patients by RT-PCR amplification of the viral RNA,
detecting the viral proteins by immunohistochemistry and antimeasles
immunoglobulin G in the perilymph samples. Nucleic acid (mRNA, vRNA,
DNA) was extracted from pulverized, frozen stapes footplate samples
of otosclerotic patients. Measles virus RNA was amplified by RT-PCR:
reverse transcription and the first-round PCR amplification were
performed by heat-stable recombinant Thermus thermophilus polymerase,
while in the nested round PCR Taq polymerase was employed.
Oligonucleotide primers specific to measles virus nucleoprotein and
matrix protein RNA were used in these reactions. Edmonston- and
Schwartze-type measles viruses served as positive controls and
cortical bone fragments, stapes superstructures, cadaver stapes,
incus and malleolar samples served as negative controls. Among 102
otosclerotic patients, 62 stapes footplate samples contained measles
virus RNA. Measles virus RNA was not detected in other bone
specimens of the patients. The etiologic role of measles virus in
the pathogenesis of otosclerosis should be considered. The 40
negative samples may be genetically determined otosclerotic cases or
stapes fixations due to other causes.
Measles virus and otosclerosis. Adv
Otorhinolaryngol.2007;65:86-92.
Measles
virus (MeV) might play an important role as an environmental
stimulus in the etiopathogenesis of otosclerosis. Chronic
inflammation was shown in morphologic investigations of otosclerotic
foci and MeV N, P, and F proteins were detected within cells of the
otosclerotic focus by immunohistochemical investigations. MeV RNA
was extracted from fresh-frozen otosclerotic tissue by the use of in
vitro RT-PCR. This result was validated through amplification of MeV
genome sequences by RT-PCR from celloidin-embedded sections with
morphologically ascertained otosclerotic foci. In searching for an
immune response of the inner ear immune system against MeV proteins,
elevated anti-MeV IgG levels were detected in the perilymph of
patients with otosclerosis in comparison with the serum levels. In
situ RT-PCR allowed the localization of MeV sequences in osteoclasts,
osteoblasts, chondrocytes, macrophages, and epithelial cells in
middle ear mucosa of otosclerotic tissue. Further evidence for MeV
persistence has recently been given. Genotyping of MeV in
otosclerotic foci demonstrated the presence of MeV genotype A, which
circulated in Europe around 1960. All the above results confirm a
strong association between MeV and otosclerosis.
Dynamic bone studies of the labyrinthine capsule in relation to
otosclerosis. Adv Otorhinolaryngol. 2007;65:53-8.
The
pathological perilabyrinthine bone remodelling of otosclerosis is
associated with a genetic predisposition and triggered by mechanisms
so far unknown. A proposed viral aetiology of otosclerosis
originates from a similar concept of Paget's disease. However, at
present, it is not clear why a virus should cause otosclerosis,
confined to the bony otic capsule with no effects on the general
skeleton in some patients, and systemic Paget's disease with only
occasional involvement of the bony otic capsule in others. Moreover,
the extent and distribution of pathological bone remodelling is
different in Paget's disease of the temporal bone and in
otosclerosis. Bone resorption and consequently bone remodelling
which turns over the general skeleton at a rate of 10% per year is
normally highly restricted in perilabyrinthine bone to a minimum of
0.13% per year except in otosclerosis, and systemic remodelling
rates are normal even in otosclerotic patients. This suggests the
existence of a local inner ear mechanism in control of capsular
remodelling activity, which is either overruled, bypassed or most
likely defective in otosclerosis, no matter what may have triggered
the disease process. We present experimental data related to this
mechanism, which may offer a truly local pathogenetic factor in
otosclerosis.
Otosclerosis associated with Ménière's disease: a histological
study. Adv Otorhinolaryngol.2007;65:50-2.
A
histological study of a pair of temporal bones was performed in a
case of Menière's disease. A severe endolymphatic hydrops and
extensive capsular otosclerosis bilaterally was found. Severe
endolympathic hydrops results from otosclerotic endolympahtic duct
occlusion. Our unique histopathological findings show that a causal
association exists between these two entities.
Expression of collagens in the otosclerotic bone.Adv
Otorhinolaryngol. 2007;65:45-9.
The
etiopathogenesis of otosclerosis is still controversially discussed.
The major hypotheses discussed are a viral infection on a genetic
background and an (autoimmune) collagen disease. The aim of our
study was to investigate by immunohistochemistry the expression
pattern of collagens within the otosclerotic focus. Stapes
footplates from 30 patients with clinical otosclerosis undergoing
stapedectomy were formalin fixed, decalcified and paraffin embedded.
As controls, 30 autoptic temporal bone specimens were employed. We
investigated the expression of collagens I-V with
immunohistochemistry. The expression of collagen I showed a diffuse
homogeneous distribution with increased staining of the otosclerotic
focus. Collagen II was exclusively expressed in chondrocytes
including the globuli interossei. The pattern of collagen III in the
otosclerotic bone was web-like in contrast to a lamellar pattern in
the control bone. The mucoperiosteal layer and connective tissue
such as the vessels of the resorption lacunae expressed collagen IV.
An increased expression of collagen V around osteocytes was observed
in the otosclerotic focus. In conclusion, in the otosclerotic
tissue, in comparison with the control bone, a high expression of
collagen IV occurred. The immunohistochemical analysis of collagen
II, which has been suggested to be implicated in the
etiopathogenesis of otosclerosis, revealed no differences between
control and otosclerotic bones. The intense staining of the
otosclerotic focus with collagen I is in good agreement with an
inflammatory process but in contrast with lesions like those in
osteogenesis imperfecta.
Histologic
otosclerosis is associated with the presence of measles virus in the
stapes footplate. Otol Neurol. 2005 Nov;26(6):1128-33.
HYPOTHESIS:
Persistent measles virus infection of the otic capsule is presumed
to be one of the etiologic factors in otosclerosis. The viral
pathogenesis of otosclerosis could be established only by
correlative analysis: histologic examination of the stapes
footplates and reverse-transcriptase polymerase chain reaction
amplification of the viral RNA. At present, histologic analysis of
the removed stapes footplates is the only appropriate method of
distinguishing otosclerotic and nonotosclerotic stapes fixations.
BACKGROUND: The presence of measles virus was shown in otosclerotic
patients by reverse-transcriptase polymerase chain reaction
amplification of the viral RNA and detecting the viral proteins by
immunohistochemistry. METHODS: Nucleic acids (mRNA, vRNA, and DNA)
were extracted from ankylotic stapes footplates of stapes fixation
patients (n = 44). Measles virus genomic nucleoprotein RNA was
amplified by seminested reverse-transcriptase polymerase chain
reaction. Amplification results were correlated to postoperative
histologic findings. RESULTS: Measles virus RNA was detectable only
in histologically otosclerotic stapes footplates (n = 32). Histology
for virus-negative footplates (n = 12) excluded otosclerosis.
Virus-negative stapes footplates showed annular calcification (n =
8), bone resorption with increased numbers of hemosiderophages (n =
2), and mononuclear cell infiltration with osteolysis (n = 2).
CONCLUSION: Stapes ankylosis is a heterogenous disease causing
conductive hearing loss with different causes. Nonotosclerotic
stapes fixations may belong to degenerative disorders with variable
histopathology. Otosclerosis is an inflammatory disease resulting
from persisting measles virus infection of the otic capsule.
Two
subgroups of stapes fixation: otosclerosis and pseudo-otosclerosis.Laryngoscope.2005
Nov;115(11):1968-73.
HYPOTHESIS:
Stapes ankylosis is a disease with variable histopathology and can
be caused by otosclerosis or pseudo-otosclerosis. Viral pathogenesis
of otosclerosis could be established only by correlative analysis:
histologic examination of the stapes footplate and reverse-transcriptase
polymerase chain reaction (RT-PCR) amplification of the viral RNA.
BACKGROUND: Presence of the RNA genome of measles virus was
demonstrated in the footplates of clinically otosclerotic patients
by RT-PCR, and also viral proteins were detected by
immunohistochemistry. METHODS: Nucleic acids were extracted from
ankylotic stapes footplates of clinically stapes fixation patients
(n = 104). Measles virus genomic nucleoprotein (NP) RNA was
amplified by seminested RT-PCR. Amplification results were
correlated to postoperative histologic and audiologic findings.
RESULTS: Measles virus RNA was detectable only in histologically
otosclerotic stapes footplates (n = 67). Histology for virus
negative footplates (n = 37) excluded otosclerosis. Virus negative
stapes footplates showed nonotosclerotic, degenerative disorders.
CONCLUSIONS: Stapes ankylosis is a heterogeneous disease causing
conductive hearing loss with different etiologies. Nonotosclerotic
stapes fixations could be established as pseudo-otosclerosis and may
belong to nonspecific, degenerative disorders with variable and
noncharacteristic histopathology. Otosclerosis is an inflammatory
disease caused by persisting measles virus infection of the otic
capsule.
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