Towards quantitative diagnosis of ossicular fixation: Measurement of stapes fixations using magnetically driven ossicles in human temporal bones

CONCLUSION

Information on the degree of stapes fixation can be found by measuring the ratio of stapes to umbo and stapes to incus velocity.

OBJECTIVES

To evaluate a method of quantifying ossicular fixation in an ear with elevated tympanic membrane.

METHOD

Measurements were made on four fresh-frozen human temporal bones. After elevating the tympanic membrane, a small magnet was attached to the manubrium and an electromagnetic excitation coil was used to vibrate the ossicles. The vibration response of the umbo, the tip of the incus long process, and the posterior crus of the stapes were measured before and after partially fixing the footplate with luting cement.

RESULTS

The velocities at the different measurement points were unequally affected by the fixation. The difference in the velocity ratio between different points provides an indication of the degree of footplate fixation.

Cochlear otospongiosis etiology, diagnosis and therapeutic implications

First, the authors discuss the most valuable way to correlate specific morphological changes encountered in cochlear otospongiosis with sensorineural hearing loss. They think that biochemical factors may be responsible for this association of cochlear otospongiosis and histopathologic changes, and they explain their enzymatic concept resulting from experimental findings and cyto-clinical relationship. Second, the authors analyze clinical, audiometric and X-Rays investigations enabling the diagnosis of cochlear otospongiosis, in its pure pereceptive form as well as in the perceptive component added to the conductive loss in far-advanced mixed audiometric types in surgical otospongiosis. They present two typical cases of cochlear otospongiosis: one combines clinical history, audiometric test and post mortem investigations;-the other shows the passage from a pure cochlear otospongiosis to a secondary stapedial fixation, ten years later, thus confirming by audiometric data and by stapedectomy the otospongiotic etiology of this previous pure sensorineural loss. Finally, they insist upon the great interest of establishing an early diagnosis in cochlear otospongiosis on account of its therapeutic implication, particularly from the enzymatic point of view.

CHD7 deficiency in "Looper", a new mouse model of CHARGE syndrome, results in ossicle malformation, otosclerosis and hearing impairment

CHARGE syndrome is a rare human disorder caused by mutations in the gene encoding chromodomain helicase DNA binding protein 7 (CHD7). Characteristics of CHARGE are varied and include developmental ear and hearing anomalies. Here we report a novel mouse model of CHD7 dysfunction, termed Looper. The Looper strain harbours a nonsense mutation (c.5690C>A, p.S1897X) within the Chd7 gene. Looper mice exhibit many of the clinical features of the human syndrome, consistent with previously reported CHARGE models, including growth retardation, facial asymmetry, vestibular defects, eye anomalies, hyperactivity, ossicle malformation, hearing loss and vestibular dysfunction. Looper mice display an otosclerosis-like fusion of the stapes footplate to the cochlear oval window and blepharoconjunctivitis but not coloboma. Looper mice are hyperactive and have vestibular dysfunction but do not display motor impairment.

[Stapedoplasty in a HIV-infected patient]

This paper reports an observation illustrating the possibility of the successful surgical treatment of otosclerosis in a HIV-infected patient presenting with acquired immunodeficiency syndrome (AIDS) and positive response in the test for hepatitis C. The authors used the results of multispiral computed tomography (MSCT) of the temporal bones as a basis for the prediction of the outcome of the surgical intervention taking into consideration specific primary manifestations of HIV infection as well as immunological and virlogical responses to anti-retroviral therapy.

On the biology of the bony otic capsule and the pathogenesis of otosclerosis

In human otosclerosis, focal pathological bone remodeling occurs in significant amounts inside the normally anti-resorptive perilabyrinthine domain of the bony otic capsule. Otosclerosis causes hearing loss in 0.2-0.5% of the population by ankylosis of the footplate. The disease cannot be predicted, avoided or medically reversed as the pathogenesis remains unknown. Previously genetic research has failed to identify a specific otosclerosis-gene and earlier theories of virus infections, autoimmunity or association to generalized bone diseases have been unable to explain why otosclerosis only occurs in the bony otic capsule while the rest of the skeleton remains completely normal. Studies from the otopathological laboratory (RH) have revealed how the bone turnover rates increase centrifugally from a sub-normal 0.1% adjacent to the inner ear space towards a normal 10% per year at the capsular periphery. This graded restriction of bone remodeling is most likely caused by the anti-resorptive action of the cytokine osteoprotegerin (OPG), which is expressed in high levels (1000 x normal bone levels) by inner ear structures to inhibit perilabyrinthine osteoclast formation and function. OPG knockout mice develop excessive, irregular bone remodeling, stapes fixation and progressive hearing loss. The lacuno-canalicular porosity is the candidate anatomical routes for the transmission of OPG-derived signals to the surrounding bone. This extracellular signaling pathway depends crucially on the viability of individual osteocytes. When bone remodeling is low, the average age of the bone matrix and osteocytes increases. We detected a high fetal density of labyrinthine osteocytes, which may secure a life-long anatomical route for inner ear OPG despite accumulation of non-viable osteocytes. Moreover, 3-D reconstructions and vector-based stereology revealed a co-existence between non-viable osteocytes and otosclerosis. We suggest that bone remodeling may commence when the effect of anti-resorptive OPG fails locally within regions of non-viable osteocytes. A sustained OPG signal from surrounding osteocyte survivors might distort the process and account for the otosclerotic morphology.

Otosclerosis: a perilabyrinthine threshold phenomenon

This paper is a review of our most recent findings concerning the osteo-dynamics of the bony otic capsule and pathogenesis of otosclerosis. By exploring the spatial relationship between normal perilabyrinthine bone remodeling, the viability and spatial distribution of labyrinthine osteocytes, and the location of otosclerosis, a unique spatial pattern emerged. Bone remodeling is highly inhibited around the inner ear space. Most likely, inner ear anti-resorptive signals enter the bony otic capsule through the lacuno-canalicular porosity. The patency of this signaling pathway depends on the viability of individual osteocytes. In the young otic capsule the density of viable osteocytes is high and centripetally distributed. This arrangement may sustain a life-long osseus pathway for anti-resorptive signals even within a bone where a considerable loss of viable osteocytes must be expected, as demonstrated by a centripetal accumulation of dead osteocytes with age. The spatial distribution of dead osteocytes follows the same general pattern as otosclerosis. We suggest that clustering of dead osteocytes may impede the transmission of anti-resorptive signals locally, leaving such ghost regions susceptible to focal bone remodeling as in human otosclerosis. The preserved network of viable osteocytes around the depleted ghost regions may contain the process and distort the structure of bone remodeling into an abnormal otosclerotic pattern.

[Otosclerosis- <<the mysterious sphinx>> or the loss of the natural variant of inertness (<<bradytrophicity>> of the labyrinth capsule)]

The author suggests an original hypothesis of otosclerosis based on the analyses of the literature publications for many years and his personal clinical observations. The normal labyrinth capsule is considered to be bradytrophic, i.e. inert and showing an extremely low level of metabolic processes. The disturbance of bradytrophicity under the action of individual factors and/or especially their combination make it involved in the maintenance of calcium homeostasis in the body. The validity of this conjecture is confirmed by the results of histological investigations, viz. the appearance of diquide or xplasma-like, bone in the labyrinth of the patients suffering otosclerosis. Such bone resorption is known to occur in other parts of the bony skeletontoo and should be regarded as a normal physiological process contributing to the replenishment of blood calcium deficiency.The subsequent reorganization (remodeling) of any part of the bony skeleton is physiologically neutral. In the labyrinth capsule,with its small size and delicate structure, such reorganization induces the otosclerotic process responsible for dysfunction of the membranaceous labyrinth. The surgical treatment of the patients presenting with otosclerosis should be supplemented by conservative treatment intended to slow down the otosclerotic reorganization and to restore bradytrophicity of the labyrinth capsule.

Origin and growth of otosclerosis

CONCLUSION

The external layer of the otic capsule arises from periosteal osteoblasts, which produce large numbers of Volkmann's canals as well as lamellar bone. The main plaque of otosclerosis is a histologic replica of the external layer and seems to arise from similar cells in the periosteum and to follow a defined invasive course into the footplate of the stapes, the basal coil of the cochlea and the saccule.

OBJECTIVES

To determine by histologic study of the developing otic capsule and temporal bones with otosclerosis the site, tissue of origin, and pathways of growth of the disease.

METHODS

Step sections of 60 celloidin-embedded temporal bones from fetuses and 24 from patients aged between 1 and 52 years were examined in the study of the development of the otic capsule. Step sections of 65 temporal bones each with 2 or more deposits of otosclerosis were surveyed to obtain data on the site, tissue of origin, and pathways of its growth.

RESULTS

The otic capsule differs from other bones in that the formation of the ultimate lamellar bone tissue is accompanied by very numerous intercommunicating channels. In the middle (cartilage origin) layer these are chondro-osseous canals and Volkmann's canals (like Haversian canals, but multidirectional). In the external (periosteal origin) layer these are Volkmann's canals only. In all, 63 of the 65 temporal bones with otosclerosis that were studied showed a prominent posterior otic capsule plaque. Evidence that this is derived from the periosteum of the external canal is as follows. (a) The otosclerotic tissue of the plaque--like all otosclerotic tissue--is composed of Volkmann's canals and lamellar bone only, as does external layer tissue. (b) All posterior plaques have an edge at the periosteum bordering the processus cochleariformis and tensor tympani muscle. The presumed invasive edge of the plaque on the opposite (cochlear) side shows a variable level of its front. (c) The tissue on the cochlear side of the plaque has a darkly stained appearance with large numbers of osteoblasts and poorly differentiated Volkmann's canals, suggesting that this is an invasive front. The otosclerosis becomes progressively better differentiated away from the darkly stained zone, indicating increasing maturation, which is greatest in the suggested origin of the plaque at the processus/tensor tympani muscle region because this would be the oldest region of the plaque. The pathway of the growth indicated by this study suggests a possible time sequence in the symptomatology of otosclerosis as it moves first to stapes footplate and then through the spiral ligament of cochlea to the saccule. An anterior plaque was seen in 42 of the 65 temporal bones with multiple sites of otosclerosis examined. These showed features similar to those listed above for the posterior plaque, with a base on the periosteum bordering the canal for the internal carotid artery, dark zonation at the invasive front near the cochlea, and increasing differentiation towards the base.

Otosclerosis

Otosclerosis is one of the more common forms of adult-onset hearing loss with a prevalence of 0.3-0.4% in Caucasians. It is typically characterized by a conductive hearing loss due to labyrinthine endochondral sclerosis that upon stapedio-vestibular joint invasion results in loss of free motion of the stapes. Its etiology remains poorly understood with both environmental factors and genetic causes implicated in its development. Several environmental influences have been studied and numerous genomic loci have been mapped in families segregating autosomal-dominant otosclerosis. Population-based studies have also identified associations with several genes. These advances are improving our understanding of this complex disease.

Otosclerosis associated with type B-1 inner ear malformation

Malformations of bony inner ear are rare anomalies occurring in approximately 20% of patients with congenital sensorineural hearing loss. Conductive hearing loss is usually associated with abnormalities of the external and middle ear. Recent reports of patients with lateral semicircular canal malformations indicate inner ear malformations to be associated with sensorineural or conductive hearing loss. Differential diagnosis of conductive hearing loss should include otosclerosis, isolated ossicular deformities, inner ear anomalies or a combination of these. In this report, a case is described with right vestibule-lateral semicircular canal dysplasia presenting at our centre with bilateral otosclerosis.

[Clinical analysis of 118 patients with tympanosclerosis]

OBJECTIVE

To study the incidence of tympanosclerosis (TS) and the major risk factors of hearing loss.

METHODS

A total of 118 TS patients (137 ears) were compared with 265 patients with chronic otitis media (COM) (311 ears) for gender, age and course of disease. The disease regions and hearing loss of the TS patients were analyzed.

RESULTS

TS showed higher prevalence in women of older ages. Sclerosis was seen most frequently in the tympanic membrane, followed by the malleus, incus, incudomalleolar joint, other regions, ariticulus incudostapedius and stapes. The patients with sclerosis or deterioration in the ossicular chain had worse hearing loss than the other patients. Carhart notch occurred in 45 ears (32.85%), an incidence similar to that of inverted "V"-shaped curve of air-conduction audiometry near 2 kHz (47 ears, 34.31%). The factors contributing to the hearing loss, listed in the order of their importance, included pathologies in the incus, malleus, incudomalleolar joint, ariticulus incudostapedius, stapes, other regions, tympanic membrane, and gender.

CONCLUSIONS

Female patients may had increased risk of TS. The presence of Carhart notch and inverted "V"-shaped curve in air-conduction audiograph may indicate myringosclerosis or ossicular chain sclerosis. Abnormal ossicular chain is the leading factor contributing to hearing loss.

Otosclerosis 1: the aetiopathogenesis of otosclerosis

Otosclerosis is a bone dystrophy localised to the inner ear and the stapes footplate. Otosclerosis is a frequent cause of deafness in adults. The patient with otosclerosis typically presents with a history of slowly progressive conductive or mixed hearing loss that is usually bilateral and often asymmetric, usually between the ages of 15 and 45 years. The disease is characterised by alternating phases of bone resorption and formation. The majority of studies on families with otosclerosis suggest an autosomal dominant mode of inheritance with incomplete penetrance.

Otosclerosis: an organ-specific inflammatory disease with sensorineural hearing loss

Otosclerosis is an inflammatory disease associated with persistent measles virus (MV) infection of the otic capsule. The nature of sensorineural hearing loss (SNHL) related to otosclerosis can be due to the chronic TNF-alpha release from the foci. TNF-alpha enters the inner ear fluid spaces in histologically active stages of otosclerosis and may cause outer hair cell functional disorder and subsequent SNHL without morphological changes of the organ of Corti. On the contrary, non-otosclerotic stapes ankylosis being a non-inflammatory disease is not harmful for hair cells. Theoretically, SNHL should not associate to this type of stapes fixation. Stapes footplates (N = 248) were examined by hematoxylin-eosin staining and corresponding MV-, OPG- and TNF-alpha-specific RT-PCR. Anti-measles IgG levels of serum specimens were measured by ELISA. Preoperative audiological results were correlated with otosclerotic and non-otosclerotic histopathologies. Among patients with stapes fixation, we found 93 active and 67 inactive otosclerosis, and 88 non-otosclerotic stapes ankylosis. MV could only be detected in otosclerotic stapes footplates. Audiometry revealed bone conduction threshold elevation toward the high frequencies in otosclerotic patients, which was associated to the duration of hearing loss. OPG mRNA expression was significantly lower in the TNF-alpha positive specimens, which was independent from virus positivity. In about one-third of stapes fixations, the etiology is non-otosclerotic stapes ankylosis. Histologic otosclerosis exhibits a strong correlation with MV presence in the bone as a sign of persistent MV infection and related inflammation with TNF-alpha release. This causes SNHL in the function of time. Non-otosclerotic stapes fixations do not cause high-frequency SNHL.

Post-traumatic otosclerosis: coincidence or trigger factor?

OBJECTIVE

The etiology of otosclerosis is poorly understood and environmental as well as genetic factors have been implicated. In this paper we will present 3 cases of otosclerosis with a clinical history of trauma and we will discuss with a literature review the place of trauma in otosclerosis etiology.

CLINICAL CASES

3 patients with clinically diagnosed otosclerosis, operated, and with a clinical history of previous head trauma.

DISCUSSION AND CONCLUSION

It is probable that environmental factors could be involved in the development of the disease and we think that trauma could be one of them. The mechanisms by which it could results in otosclerosis remain unknown. However these cases appear to be rare and under studied.

Séquelles otologiques dans les fentes palatovélaires. Analyse et prise en charge

As early as in 1878, medical teams managing children born with a velopalatine cleft had noted the prevalence of middle-ear pathologies largely related to anatomic and inflammatory Eustachian tube dysfunction. The aim of this study was to describe otologic sequels related to a velopalatine cleft and to suggest an adapted management. These sequels are evolving presentations of chronic serous otitis; they worsen the functional prognosis (hypoacousia) and more rarely the vital prognosis (cerebral or infectious complications of cholesteatoma). We must stress the importance of prevention: during the initial management, by Eustachian tube rehabilitation, and by ENT (Ear, Noseand Throat) follow-up allowing to prevent these sequels and to bring hearing to normal as soon as possible, so as to support cognitive development, language skills, and sociofamilial integration of the children.

The coding polymorphism T263I in TGF-β1 is associated with otosclerosis in two independent populations

Otosclerosis is a progressive hearing loss characterized by an abnormal bone homeostasis of the otic capsule that leads to stapes fixation. Although its etiology remains unknown, otosclerosis can be considered a complex disease. Transforming growth factor-beta 1 (TGF-beta1) was chosen for a case-control association study, because of several non-genetic indications of involvement in otosclerosis. Single nucleotide polymorphism (SNP) analysis in a large Belgian-Dutch sample set gave significant results (P = 0.0044) for an amino acid changing SNP, T263I. Analysis of an independent French population replicated this association with SNP T263I (P = 0.00019). The results remained significant after multiple testing correction in both populations. Haplotype analysis and the results of an independent effect test using the weighted haplotype (WHAP) computer program in both populations were both compatible with SNP T263I being the only causal variant. The variant I263 is under-represented in otosclerosis patients and hence protective against the disease. Combining the data of both case-control groups for SNP T263I with a Mantel-Haenszel estimate of common odds ratios gave a very significant result (P = 9.2 x 10(-6)). Functional analysis of SNP T263I with a luciferase reporter assay showed that the protective variant I263 of TGF-beta1 is more active than the WT variant T263 (P = 1.6 x 10(-6)). On the basis of very low P-values, replication in an independent population and a functional effect of the protective variant, we conclude that TGF-beta1 influences the susceptibility for otosclerosis, and that the I263 variant is protective against the disease.

Transient depression of inner ear function after stapedotomy: skeeter versus CO(2) laser technique

Performing stapes surgery for otosclerosis is known to be potentially irreversibly harmful to the inner ear function in about 1% of the cases. An early postoperative transient depression of the bone conduction thresholds is frequently detected after stapes surgery. The purpose of this study was to compare the evolution of bone conduction thresholds after primary stapedotomy with two different techniques: skeeter versus CO(2) laser stapedotomy. Audiological data of 336 otosclerosis operations performed by 2 surgeons between 1997 and 2003 were subjected to analysis. The calibrated hole in the footplate was performed randomly either with the skeeter drill or with the CO(2) laser. Preoperative bone conduction thresholds were compared with the postoperative levels (day 2-3, week 2, week 6 and month 6) in all patients. Evolution of the bone conduction was compared for the two studied subgroups (laser versus skeeter).

Some remarks on the histopathology of otosclerosis

The histopathology of otosclerosis is described in detail in classical textbooks like Schuknecht's Histopathology of the Ear or Friedmann and Arnold's Pathology of the Ear. In this article, some of the important and new facts will be summarized which might affect the understanding of the pathomechanism of this unique measles-virus-associated inflammatory disease of the temporal bone.

Evidence of increased average age of patients with otosclerosis

Otosclerosis is an inflammatory disease of the human temporal bone which was assumed to affect up to 10% of the Caucasians. Histologic otosclerosis has an incidence of 3.4%. It is considered as a major cause of hearing loss in Western countries while a low incidence is observed among Africans. Many hypotheses about its origin had been formulated in the past. Otosclerosis genes (OTSC1-5) and collagen 1 genes are mutated in some familial cases of otosclerosis. On this genetic background, a common environmental factor such as a measles virus infection might be the triggering factor. Studies in the past indicated a distribution of otosclerosis among men and women of 1:1.4. Our study was designed to analyze the age of patients with otosclerosis at the time of surgery in the eighties and the nineties of the last century. Patients suffering from clinical otosclerosis who underwent stapedectomy between 1978 and 1999 with complete clinical data available (n = 1,351) were included in the study. Age and gender distribution, the age difference between men and women and the influence of gender and the year of recruitment were evaluated. Statistical analyses demonstrated an increase in the average age of patients with clinical otosclerosis from the eighties to the nineties (p = 0.012). The gender distribution showed no statistically significant variation (p = 0.398). These data might reflect an improved health consciousness among the elder population or could be the result of increased health awareness in the seventies and eighties. Finally, in the early seventies, measles virus vaccination was introduced in Germany and the shift of age could be the result of the measles virus immunization campaign.

Otosclerosis: a review of aetiology, management and outcomes

Otosdcerosis is an autosomal dominant condition affecting the temporal bone. It presents predominantly with deafness in a young population. This review looks at the aetiological theories, present treatment strategies and surgical outcomes of this condition.

Detection of osteoprotegerin and TNF-alpha mRNA in ankylotic Stapes footplates in connection with measles virus positivity

HYPOTHESIS

Otosclerosis is a bone remodeling disorder of the otic capsule causing conductive and sensorineural hearing loss. Persistent measles virus infection of the temporal bone with increased tumor necrosis factor (TNF)-alpha and decreased osteoprotegerin mRNA expression is supposed to be the main etiologic factor in otosclerosis.

BACKGROUND

Determinants of measles virus infection and reactive inflammation were studied in otosclerosis. The presence of measles virus was shown in otosclerotic patients by reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of the viral RNA. No report is available, however, about the role and interactions of bone-specific cytokines in otosclerosis.

METHODS

: Nucleic acid was extracted from stapes footplates of clinically otosclerotic patients. Measles virus nucleoprotein RNA was amplified by seminested RT-PCR. TNF-alpha and osteoprotegerin mRNA coexpression was detected by RT-PCR in otosclerotic bone and was correlated to measles virus positivity.

RESULTS

Among 154 clinically stapes fixation otosclerotic patients, 99 stapedes contained measles virus RNA. TNF-alpha mRNA was detectable in 88 virus-positive and in 6 virus-negative stapes footplates. Osteoprotegerin mRNA expression was significantly lower in the TNF-alpha-positive specimens (P < .0001) that was independent from virus positivity.

CONCLUSION

Detection of TNF-alpha mRNA demonstrates activated osteoclast functions and inflammatory pathways in otosclerotic stapes footplates associated with measles virus presence. Increased expression of TNF-alpha and its action on RANK production inhibits the protective functions of osteoprotegerin on normal bone turnover in the otic capsule.

Otosclerosis: etiopathogenesis and histopathology

Otosclerosis is a disease of the bony labyrinth manifesting clinically as a progressive conductive hearing loss, a mixed-type hearing loss, or a sensorineural hearing loss. The age of onset of the hearing loss caused by otosclerosis is principally between 15 and 40 years. Although histopathological inner ear changes due to otosclerosis have been very well documented, the true etiopathogenesis of the disease has yet to be described despite intensive research. Both genetic and environmental factors have been implicated, however.

Activated Osteoclasts with CD51/61 Expression in Otosclerosis

HYPOTHESIS

Stapes ankylosis is supposed to be a disease with variable histopathology caused by otosclerosis or pseudo-otosclerosis. Persistent measles virus infection of the otic capsule could induce reactivation of quiescent embryonic osteoclasts in otosclerosis.

BACKGROUND

Presence of measles virus RNA was demonstrated in the footplates of otosclerotic patients by reverse-transcription polymerase chain reaction (RT-PCR). Histology of active otosclerosis is featured by the presence of numerous osteoclasts with unknown phenotype.

METHODS

Nucleic acid was extracted from stapes footplates of clinically otosclerotic patients (n = 261). Genomic RNA of measles virus was amplified by RT-PCR. Amplification results were correlated to postoperative histologic and CD51/61 specific immunohistologic findings. A parallel alcalic phosphatase activity assessment was performed to evaluate the metabolic activity of osteoclasts in each section.

RESULTS

Among 261 stapes fixation cases, 175 otosclerotic stapes contained measles virus RNA. Histology for virus negative stapes (n = 86) represented nonotosclerotic, degenerative disorders. Histologically confirmed otosclerosis was featured by the presence of osteoclasts with renewed, embryonic phenotype. In otosclerosis, alcalic phosphatase activity was significantly higher compared with nonotosclerotic stapes ankylosis (P < .001).

CONCLUSION

The presence of CD51/61 positive osteoclasts in otosclerotic bone containing viral sequences provides the basis for an inflammatory bone remodeling disorder. Otosclerosis is a disease caused by persistent measles virus infection and reactivation of resting embryonic osteoclasts in the otic capsule.

[Surgical treatment of otosclerosis]

A significant step forward in otosclerosis surgery was made in 1956 with the advent of stapedectomy. This led to a significant reduction in surgical complications and to a high level of patient satisfaction. Hearing aids are the alternative to surgery, and have themselves undergone considerable technical improvements. In advanced otosclerosis, cochlear implants can improve hearing when stapes surgery and a conventional hearing aid are inadequate. These advances are modifying the surgical indications.

Audiovestibular disorders in patients with ankylosing spondylitis

OBJECTIVE

Audiovestibular disorders have been described in several autoimmune diseases but have not been studied in patients with ankylosing spondylitis (AS). The aim of this study was to evaluate the audiovestibular function in patients with AS.

METHODS

We prospectively evaluated 22 consecutive patients with AS. Clinical, radiologic, and immunogenetic features were analyzed. All patients underwent a complete ear, nose, and throat physical examination and audiologic evaluation that included pure-tone audiometry thresholds at octave frequencies of 250 to 8000 Hz, impedance audiometry (tympanogram, static compliance, acoustic reflexes, and reflex decay), and speech audiometry. Thirty-one healthy volunteers and 26 patients with rheumatoid arthritis (RA) were included as controls.

RESULTS

Patients with AS had a median age of 45.5 years (interquartile range [IQR] 38-54) and a median disease duration of 20 years (IQR 12.5-26.2). Otosclerosis was observed in 2 patients with AS (9.1%), 3 patients with RA (11.5%), but not in any healthy controls (P = not significant). Sensorineural hearing loss (SNHL) was observed in 13 patients with AS (59%), 17 patients with RA (65.4%), and 13 healthy controls (41.9%) without statistically significant differences. Because age can influence audiometric results, patients and controls were divided into 4 age groups. A higher frequency of SNHL was observed in patients with AS from 45 to 59 years compared with healthy controls and patients with RA (87% versus 20%, P = 0.03, versus 70%, P = not significant, respectively).

CONCLUSION

Middle-aged patients with AS had a significantly higher frequency of SNHL compared with controls. SNHL should be considered as a possible complication of AS as well as of RA and other autoimmune diseases. Possible toxic effect of nonsteroidal antiinflammatory drugs should also be considered in such patients.

Selected complex auditory disorders

This article provides an overview of four auditory disorders relevant generally to adults and especially to veterans. The disorders are noise-induced hearing loss, idiopathic sudden sensorineural hearing loss, otosclerosis, and Méniàre's disease. Sensorineural hearing loss characterizes each, but additional aspects vary with each of the four conditions. This article describes the conditions, discusses their diagnoses and treatments, and outlines current and suggested rehabilitation. The emphasis is on recent advances, some of which await confirmation prior to possible acceptance as standard practice.

Influence of Hypercalcemia in the Formation of Tympanosclerosis in Rats

HYPOTHESIS

Hypercalcemia is thought to perform an important role in the etiopathogenesis of tympanosclerosis. The purpose of the present study was to assess the influence of hypercalcemia in the development of tympanosclerosis in rats with or without acute otitis media.

BACKGROUND

The pathogenesis of tympanosclerosis is still unclear. Histologically, it is characterized by a hyaline degeneration in the lamina propria of the middle ear and mastoid mucosa and may lead to a calcification process. The process of calcification is similar to that of other pathologically calcified tissues, such as vessels, heart valves, cornea, and others, which depend on calcium serum levels.

METHODS

Twenty-four Wistar rats were divided into two different groups, with one group submitted to hypercalcemia status through calcium diet supplementation and the other used as a control group (normal calcium content diet). Both were submitted to induction of tympanosclerosis by inoculation of Streptococcus pneumoniae on the right middle ear only. Otomicroscopy was conducted every 15 days, and after 7 weeks of inoculation, the animals were killed and the tympanic bullae were resected to be analyzed through light and electron microscopy.

RESULTS

The group submitted to hypercalcemia presented a prevalence of tympanosclerosis of 25% against 16.7% in the control group, presenting a relative risk of 1.27 (p=0.72).

CONCLUSION

The results suggest that hypercalcemia can have an influence in the development of tympanosclerosis.

Otosclerosis--do we have a viral aetiology?

The etiology of otosclerosis remains an enigma though there are evidences suggesting a viral involvement. This study aimed to find out the relationship between viral infections and otosclerosis. Twenty two patients with otosclerosis and 10 healthy controls were included in the study. IgM antibodies to varicella zoster virus (VZV), measles, rubella, human cytomegalovirus (HCMV) and herpes simplex virus (HSV) were detected using micro ELISA. Paul Bunnel Davidsohn test was performed to rule out Ebstein Barr virus (EBV) infection. Overall, 5(22.7%) patients showed antibodies to one or more viruses. IgM antibodies against measles and VZV could be demonstrated in 4(18.1%) and 1(4.5%) patients respectively. None of the samples were found to be positive for HSV, HCMV, rubella and EBV antibodies. Controls were negative for all the viruses tested. The difference in seropositivity between the patient and control group was not statistically significant (p>0.05). Thus, this study suggests that otosclerosis is not commonly associated with a systemic viral infection.

Two Subgroups of Stapes Fixation: Otosclerosis and Pseudo-Otosclerosis

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.

[Long-term results of stapes surgery--over 1000 patients]

Authors present audiometric results of 1200 patients with otosclerosis post stapedotomy. Air-conduction, bone-conduction and air-bone gap was measured prior the surgery and 12 months post stapedotomy for frequencies 0.5, 1.0, 2.0 and 3.0 kHz. In the analysed group of 1200 patients a postoperative air-bone gap 0-10 and 11-20 dB was obtained in 93.7% patients. The result of stapedotomy in reference to tinnitus based on the patients' subjective opinion showed that 78.0% patients were either free from tinnitus or tinnitus was subjectively decreased. Authors stress that some anatomical abnormalities in the tympanic cavity might influence on the result of stapes surgery.

[Is imaging possible for otosclerosis? Characteristics of the disease and a survey of the clinical relevance of imaging]

Otosclerosis is a localized progressive disease of bone remodeling within the otic capsule of the human temporal bone. Histomorphologically, active cochlea otosclerosis (otospongiosis) is diagnosed in the presence of foci of demineralization in the otic capsule. The clinical symptoms of otosclerosis are associated with mixed and sensorineural hearing loss. With recent technological advances, diagnostic imaging of the inner ear is becoming more and more important in the evaluation of diseases affecting the cochlea. Studies could demonstrate that otosclerosis has a characteristic appearance on high-resolution computed tomography (HRCT), producing a distinctive pericochlear hypodense double ring. Its appearance on MRI is not as readily appreciated, producing a ring of intermediate signals in the pericochlear and perilabyrinthine regions on T1-weighted images, demonstrating mild to moderate enhancement after gadolinium administration. The ethiology and pathophysiology of otosclerosis are described and a review of the literature is given to illustrate the clinical relevance of imaging in otosclerosis.

[Failure of regain full function after surgery for otosclerosis: causes, diagnosis and treatment]

OBJECTIVE

The aim of this study was to evaluate the causes, the diagnosis, the treatment and the results obtained by revision surgery, in cases of stapedectomy failures.

MATERIALS AND METHODS

Retrospective study of 50 recent cases operated on between January 1997 and December 2001. DIAGNOSIS OF THE FAILURE: All reoperated patients had clinical and audiological assessment; CT scan with virtual endoscopy.

RESULTS

The mean time of onset of failure was 23 months. The mean preoperative air bone gap was 25.5 dB. Otoscopy revealed a retraction pocket caused by poor eustachian tube function in 9 cases. CT scan proved to be very effective at differentiating the cause of the failure.

OPERATIVE FINDINGS

In 11 cases the prosthesis was too short, in 8 cases the prosthesis had migrated out of the hole of stapedotomy and in 6 cases the piston was fixed in the stapedotomy hole. A partial or complete lysis of the long process of the incus was frequently associated, but in 9 cases it was the only cause of the failure. In all the cases when the piston was displaced, the stapedotomy was found to be covered by a thin mucous membrane, avoiding labyrinthine fistula. In 3 cases, the failure was due to recurrent otosclerosis. In 5 cases the failure was due to a local anomaly at the level of the oval window niche, 2 cases of failure were due to a malleus ankylosis. In 5 cases fibrous adhesion was found between the incus and the mucosa of the promontory. In one case a reparative granuloma was found at the level of the oval window.

TREATMENT

In cases of partial lysis of the long process of the incus, a new prosthesis was placed in a 0.4 mm diameter stapedotomy, performed using a KTP laser. A 0.4 mm diameter piston was extended 0.2 mm below stapedotomy to avoid a new extrusion. Indeed some prosthesis extrusion could be due to increased movements of the ossicular chain in cases of eustachian tube dysfunction. In cases of complete lysis of the long process of the incus, or in cases of a very short long process of the incus, a piston was put in the stapedotomy and attached to the malleus manubrium. The results of revision stapedotomy were favorable in the absence of associated fibrous tissue adhesion or local malformation. The air bone gap was found to be less than 10 dB in 40 cases and between 10 and 20 dB in 8 cases. An impairment of the air bone gap was found in 2 cases. No case of bone conduction impairment was found in this series.

The aetiology of otosclerosis: a review of the literature

During the last century, hundreds of studies have been performed to identify factors that are involved in the aetiology of otosclerosis. These studies include a variety of aetiological factors and, although many theories have been postulated, the process of the development of the disease remains unclear. A historical overview and analysis of the literature dealing with the aetiology of otosclerosis is presented. The role of collagen disorders, genetic linkage studies, associations with the HLA system and measles virus infection as causal factors is discussed. From an epidemiological point of view, the disease has an autosomal dominant mode of inheritance. Therefore, since the introduction of new genetic research techniques over the last decades, more studies have been performed to find evidence of a genetic factor that initiates the development of otosclerosis. In this review, we tried to categorize the most prominent studies in sections according to their subjects within the diversity of aetiological factors that have been studied.

Ossicular fixation caused by bone dust after saccus decompression surgery

HYPOTHESIS

To highlight the clinical and histologic features of ossicular fixation produced by bone dust during mastoid surgery.

BACKGROUND

Bone dust deposition in the middle ear may occur during temporal bone surgery, but the ossicular fixation that may result from it remains underreported.

METHODS

A case is reported of delayed conductive hearing loss after saccus decompression surgery resulting from ossicular fixation by bone dust deposition.

RESULTS

Six months after the initial surgery, the patient experienced a 45 dB conductive hearing loss. The findings on second-look tympanotomy were stapes fixation and round window niche occlusion by newly formed tissue. Histologic examination of the latter showed fibrosis and new bone formation in reaction to particles of bone dust. New bone formation is a frequent concomitant of fibrosis in the middle ear and is probably not a growth from the bone dust.

CONCLUSION

The use of high-speed drilling of bone in temporal bone surgery carries the risk of bone dust particle deposition in the middle ear. Measures are discussed that can be used to prevent this complication.

Etiopathogenesis of otosclerosis

Otosclerosis is a frequent cause of nonsyndromic hearing loss which affects exclusively the human temporal bone. Various etiopathogenetic hypotheses have been proposed. The major hypotheses considered are genetic factors, immunologic factors and viral infection. Since the familial incidence of otosclerosis is known a recent genetic analysis has given evidence of three otosclerosis genes (OTSC1-3). Mutations in the collagen gene COL1A1 have been found in one large family with several cases of otosclerosis. Concerning an immunologic etiopathogenetic process, the presence of serum antibodies against collagen II and IX in patients with otosclerosis confirms the hypothesis of a collagen autoimmune mechanism. Finally as a possible cause of this chronic inflammatory disease morphologic and biochemical investigations have revealed a measles virus association. In conclusion, various etiopathogenetic factors may contribute to the genesis of otosclerosis.

The effect of local administration of N-acetylcysteine in perforated rat tympanic membrane: an experimental study in myringosclerosis

Myringosclerosis (MyS) is a common sequela of acute and chronic otitis media and ventilation tube treatment of serous otitis media. We aimed to study the effect of topical administration of N -acetylcysteine (NAC) on MyS by assessment of otomicroscopic evaluation, lipid peroxidation and nitric oxide (NO) (nitrite/nitrate) levels in experimental myringotomized rat tympanic membrane. Thirty adult rats were used and the upper posterior quadrant of the tympanic membranes of rats was myringotomized. Thereafter, they were divided into four groups. Group I received no treatment, group II was treated with saline, groups III and IV were treated with topical NAC (0.1 ml of 6 and 12 mg ml(-1), respectively). The levels of nitrite/nitrate and malondialdehyde (MDA) were measured in serum samples. In the otomicroscopic evaluation, non-treated and saline treated ears (controls) showed extensive occurrence of myringosclerotic plaques. Groups III and IV showed fewer occurrences of sclerotic plaques. There was no significant difference between groups III and IV regarding the development of MyS. The development of myringosclerotic lesion was found to be significantly different between NAC treated groups (III and IV) and the control groups (I and II). The levels of nitrite/nitrate of both groups III and IV were significantly lower than the control groups. The levels of MDA of these groups were also significantly lower than the control group. The relationship between groups III and IV was not statistically significant for the levels of nitrite/nitrate and MDA. We conclude that the topical treatment of NAC reduces the levels of MDA and NO products in rats. These results suggest that topical NAC application may be useful for the prevention of MyS.

Prevalence of chronic otitis media in a randomly selected population from two communes in southern Vietnam

The prevalence of chronic otitis media was studied in an urban and a rural community in southern Vietnam in 1995. A total of 3,300 children, aged from 6 months to 10 years, were selected randomly by taking every third child on the vaccination list. In this cross-sectional study, 453 ears were found to have chronic otitis media or sequelae otitidis, giving an overall prevalence of 6.86%. A total of 140 ears had perforations. Various attic changes were found in 73 ears and other chronic tympanic membrane changes, such as atrophy, tympanosclerosis and adhesions, in 219 ears. Cholesteatoma was seen in two ears.

[Otosclerosis in populations living in northern Tunisia: epidemiology and etiology]

Otosclerosis is a hereditary disease frequently encountered in Caucasian populations (0.1 to 2% prevalence). In Tunisia, prevalence varies from 0.4% to 0.8%. The presence of a genetic factor associated with hormonal, biochemical or environmental factors, probably lead to variable expression of the otosclerosis according to age and sex. Mean age at onset of disease is 25 years (range 16-35 year) for 61.5% of affected women. In men this proportion is 50.2%. The incidence of otosclerosis is high in the 26-35 year age group. Our study showed that in northeastern areas of Tunisia, women in this age group were affected twice as often as men in this age group. This probably suggests that an endocrine mechanism is involved in disease etiology. However, in northwestern areas, there was no significant difference between the rates of otosclerosis between sexes. Geographical distribution of affected subjects according to the ethnic origin of their parents showed that the areas with the highest concentration of affected individuals were urban or seaside areas such as the gouvernorate of Nabeul. The frequency of otosclerosis was lower in rural areas and/or areas far from the seaside.

Detection and localization of interleukin-6 in the rat middle ear during experimental acute otitis media, using mRNA in situ hybridization and immunohistochemistry

OBJECTIVE

Otitis media is one of the most common diseases among children. A well-known sequela of acute, chronic, and secretory otitis media is tympanosclerosis. With the exception of surgery, there is no causal treatment available for this condition, which may cause hearing disabilities. This study aimed to describe the localization of interleukin (IL)-6 mRNA and its gene product in the rat middle ear during pneumococcal otitis media. IL-6 is known to be involved in inflammatory and bone remodeling processes.

METHODS

Using an experimental model of pneumococcal acute otitis media, the expression of interleukin IL-6, was analyzed. Sprague-Dawley rats were sacrificed at different time points varying from 1 h to 6 days intervals after inoculation. The middle ears were analyzed by messenger RNA in situ hybridization, and by immunohistochemistry with cell-type specific antibodies directed against IL-6.

RESULTS

Transcripts of IL-6 were observed only on day 1 post-inoculation, whereas the final gene product was observed at all intervals after inoculation. IL-6 was localized in the bony part of the bulla nearest to the mucosa, around mucosal vessels, and in the ciliae of the mucosal epithelium. The results demonstrated that IL-6 was synthesized locally as early as 1 h after bacterial middle ear challenge, and that although transcription could not be detected after 24 h, the cytokine product persisted for at least 5 days after the infection was introduced.

CONCLUSIONS

IL-6 was shown to be produced early in the inflammatory process during induced pneumococcal otitis media in the rat. No production was seen after 24 h although the protein remained in the tissue for at least 5 days. IL-6 could initiate a differentiation of macrophages to osteoclasts and thereby participate in a bone remodeling process leading to tympanosclerosis development.

Shift of the distribution of age in patients with otosclerosis

Morphological and biochemical investigations have shown evidence of an association between measles virus and otosclerosis. Epidemiological analysis of age and gender distributions in the 1960s and 1970s revealed a higher incidence of otosclerosis in women, the average age of onset of clinical disturbances and need for surgery being between 15 and 40 years. In the late 1960s and early 1970s a campaign to vaccinate children against measles was started in Germany. The aim of our study was to evaluate whether this campaign has had any influence on the distributions of the age and gender of patients affected by otosclerosis over the past 20 years. The study included patients suffering from clinical otosclerosis who had undergone stapedectomy between 1978 and 1999 and whose clinical data were complete (n = 1351). Statistical analysis during the recruitment period indicated a significant increase in the average age of the otosclerosis patients (p = 0.012). With regard to the gender distribution it was found that the increase of otosclerosis in women compared to men was statistically insignificant (p = 0.418). These data strongly support the hypothesis of a measles virus involvement in otosclerosis and may reflect a decreased incidence of otosclerosis in the generation of patients vaccinated against measles virus.

Persistent measles virus infection as a possible cause of otosclerosis: state of the art

The etiopathogenesis of otosclerosis is still largely unexplained and remains controversial. Morphologic examinations have shown the presence of a chronic inflammation in otosclerotic tissue. Among the proposed explanations for this inflammation are an immunologic reaction against collagen, mutations of collagen gene 1A1, and a viral infection. In this paper, we focus on the role of measles virus in otosclerosis, and we review the current literature, devoting particular attention to a suspected paramyxoviral etiopathogenesis in Paget's disease. Our examination of footplate fragments by reverse transcription polymerase chain reaction testing in 95 patients with otosclerosis revealed the presence of measles virus RNA in 83% of cases. Quantification of measles virus immunoglobulin G (IgG) in otosclerosis patients indicated that the ratio of antimeasles virus IgG in total IgG was higher in perilymph than in serum. Furthermore, an almost identical incidence of otosclerosis and measles virus-caused mortality in women suggests that women are more susceptible to measles virus infection. Finally, since the introduction of the measles virus vaccination program in Europe, there has been a decline in the incidence of otosclerosis. Moreover, the average age of patients at diagnosis and surgery at our hospital has increased to 54 years. Our findings, when they are considered along with findings regarding the presence of paramyxoviral RNA in Paget's disease, support the hypothesis that measles virus is involved in the etiopathogenesis of otosclerosis.

The effect of topical adrenaline on the development of myringosclerosis after tympanostomy tube insertion

OBJECTIVE

To determine the effect of topical adrenaline application after myringotomy and before tympanostomy tube placement on the development of myringosclerosis.

STUDY DESIGN

A prospective, randomized, double-blind study, with each patient acting as his or her own control. Ethical approval and full parental consent were obtained.

SETTING

Department of Otorhinolaryngology-Head and Neck Surgery in a university teaching hospital.

PATIENTS

Fifty children satisfying inclusion and exclusion criteria for first-time tympanostomy tube insertion. THERAPEUTIC INTERVENTION: Myringotomy followed by adrenaline application to incision before tympanostomy tube insertion. Control contralateral ear received saline application after myringotomy. Follow-up examination was done 14 to 21 days after surgery and again after 1 year by a single blinded surgeon.

MAIN OUTCOME MEASURE

Comparison of myringosclerosis between adrenaline-treated ears and matched control ears.

RESULTS

No difference was found in early morbidity between the two groups of ears. Myringosclerosis after 1 year was not found to have been significantly affected by adrenaline application (p = 0.2)

CONCLUSION

The use of adrenaline on the myringotomy site before tympanostomy tube placement was not found to influence early postoperative morbidity or the later development of myringosclerosis.

[Current aspects of the pathogenesis and clinical characteristics of otosclerosis: possibilities of drug therapy]

Otosclerosis is a multifactorial disease. A number of theories on the pathogenesis of this disease have been established in the last decades. It is important to review recent data on the pathogenesis of otosclerosis as it is a severe inner ear disease leading to deafness in the majority of cases. Surgical therapy is not always successful or feasible. In this review, authors describe the most relevant genetic, infective, immunological, inflammatory factors, as well as the impaired bone metabolism underlying the pathogenesis of otosclerosis. It is likely that genetic predisposition associated with morbilli infection may lead to bone resorption in the stapes and cochlea followed by spongiosis, fibrosis and sclerosis. It has been suggested that immunological mechanisms play a central role in the development of the disease. Some authors consider otosclerosis as autoimmune disorder based on the presence of several autoantibodies. Apart from classical diagnostic methods, such as audiometry and X-ray, novel radiological techniques including CT, MRI or radionuclide scan are helpful in the localization of otosclerosis. As surgery is sometimes contraindicated or unsuccessful, drug therapy including the use of anti-osteoporotic on non-steroidal antiinflammatory drugs may be administered, especially in the early phase of the disease.

An immunohistochemical study of inducible nitric oxide synthase in the rat middle ear, with reference to tympanosclerosis

Tympanosclerosis and myringosclerosis are well-known sequelae after acute and chronic otitis media and are also often seen after treatment of secretory otitis media with ventilation tubes. They sometimes cause serious hearing disability. There is no successful treatment for these conditions. There might be factors triggering an immunological or autoimmune chain reaction, which leads to tympanosclerosis. Intervention with the aim of abolishing this type of response might be possible if an interruption of the chain reaction can be found. Nitric oxide is a radical molecule with the ability to kill pathogens and is produced by the enzyme nitric oxide synthase. Expression of inducible nitric oxide synthase (iNOS) was analysed immunohistochemically in a rat model of acute otitis media. In rats sacrificed at days 3 and 6 after inoculation. iNOS was also strongly expressed in the middle ear mucosa and in the tympanic membrane as well as in the inner ear. In control specimens as well as in infected ones. iNOS was expressed in the tissue of the external ear canal. In rats sacrificed at day 10 and after 3 months, iNOS was expressed at the same locations, although less frequently. These data indicate that iNOS expression is induced during acute otitis media and suggest that nitric oxide may be important in the host defence against ear infections.

[My adventure with otosclerosis]

The author presents his own experience in surgical treatment of otosclerosis in 373 patients. He particularly exposes results concerning hearing level after surgical procedures and discusses progress of symptoms which accompany otosclerosis like vertigo or dizziness and tinnitus in the context of bibliography data. He also looks at the complications occurring during procedures and following them. Worth noticing is presentation of long term results after 10-year follow-up.