Otosclerotic Stapes Research Articles

Genetic variants and altered expression of SERPINF1 confer disease susceptibility in patients with otosclerosis.

Otosclerosis (OTSC) is a focal and diffuse bone disorder of the human middle ear characterized by abnormal bone growth and deposition at the stapes' footplate. This hinders the transmission of acoustic waves to the inner ear leading to subsequent conductive hearing loss. The plausible convections for the disease are genetic and environmental factors with yet an unraveled root cause. Recently, exome sequencing of European individuals with OTSCrevealed rare pathogenic variants in the Serpin Peptidase Inhibitor, Clade F (SERPINF1)gene. Here, we sought to investigate the causal variants of SERPINF1 in the Indian population. The gene and protein expression was also evaluated in otosclerotic stapes to ameliorate our understanding of the potential effect of this gene in OTSC. A total of 230 OTSC patients and 230 healthy controls were genotyped by single-strand conformational polymorphism and Sanger sequencing methods. Bycomparing the case controls, we identified five rare variants (c.72 C > T, c.151 G > A, c.242 C > G, c.823 A > T, and c.826 T > A) only in patients. Four variants c.390 T > C (p = 0.048), c.440-39 C > T (p = 0.007), c.643 + 9 G > A (p = 0.035), and c.643 + 82 T > C (p = 0.005) were found to be significantly associated with the disease. Down-regulation of SERPINF1 transcript level in otosclerotic stapes was quantified by qRT-PCR, ddPCR and further validated by in situ hybridization. Similarly, reduced protein expression was observed by immunohistochemistry and immunofluorescence in otosclerotic stapes that corroborate with immunoblotting of patients' plasma samples. Our findings identified that SERPINF1 variants are associated with the disease. Furthermore, reduced expression of SERPINF1 in otosclerotic stapes might contribute to OTSC pathophysiology.

The risks of RELN polymorphisms and its expression in the development of otosclerosis.

Otosclerosis (OTSC) is the primary form of conductive hearing loss characterized by abnormal bone remodelling within the otic capsule of the human middle ear. A genetic association of the RELN SNP rs3914132 with OTSC has been identified in European population. Previously, we showed a trend towards association of this polymorphism with OTSC and identified a rare variant rs74503667 in a familial case. Here, we genotyped these variants in an Indian cohort composed of 254 OTSC cases and 262 controls. We detected a significant association of rs3914132 with OTSC (OR = 0.569, 95%CI = 0.386–0.838, p = 0.0041). To confirm this finding, we completed a meta-analysis which revealed a significant association of the rs3914132 polymorphism with OTSC (Z = 6.707, p<0.0001) across different ethnic populations. Linkage analysis found the evidence of linkage at RELN locus (LOD score 2.1059) in the OTSC family which has shown the transmission of rare variant rs74503667 in the affected individuals. To understand the role of RELN and its receptors in the development of OTSC, we went further to perform a functional analysis of RELN/reelin. Here we detected a reduced RELN (p = 0.0068) and VLDLR (p = 0.0348) mRNA levels in the otosclerotic stapes tissues. Furthermore, a reduced reelin protein expression by immunohistochemistry was confirmed in the otosclerotic tissues. Electrophoretic mobility shift assays for rs3914132 and rs74503667 variants revealed an altered binding of transcription factors in the mutated sequences which indicates the regulatory role of these variations in the RELN gene regulation. Subsequently, we showed by scanning electron microscopy a change in stapes bone morphology of otosclerotic patients. In conclusion, this study evidenced that the rare variation rs74503667 and the common polymorphism rs3914132 in the RELN gene and its reduced expressions that were associated with OTSC.

Otosclerosis and Measles: Do Measles Have a Role in Otosclerosis? A Review Article

Otosclerosis is a common cause of conductive hearing loss which is an autoimmune inflammatory disorder related to abnormal bone remodeling of the human otic capsule that has complex etiopathogenesis attributed to genetics, autoimmunity, viral infection, inflammation, hormonal factor, environmental factor, and disturbed bone metabolism. It has a prevalence of 0.3%-0.4% in Caucasians, which makes up 5-9% of all hearing loss and 18-22% of all conductive hearing loss. This review article aims to study the postulated role of sustained measles virus infection in the etiopathogenesis of otosclerosis, among others. A PubMed search of the related topic identified 97,990 articles. After we applied the inclusion and exclusion criteria, it was determined that 52 articles were relevant, which included 38 observational studies, 13 review articles, and a systematic review. Among them, 33 observational studies, 13 review articles and a systematic review spotted a positive association between persistent measles virus infection and otosclerosis. On the contrary, five observational studies reported no evidence of the association. The majority of the current literature supported the presence of the measles virus component in the otosclerotic stapes samples and its role in the etiopathogenesis of otosclerosis. Measles virus infection may have the amplitude to initiate a pathological process, which in the presence of other factors like autoimmunity and genes plays a significant role in causing otosclerosis. However, other studies have failed to show the presence of the measles virus component in otosclerotic stapes. So, more studies are needed to probe the role of persistent measles virus infection in the etiopathogenesis of otosclerosis.

Finite element analysis of round-window stimulation of the cochlea in patients with stapedial otosclerosis.

An active actuator coupled to the round window (RW) can transmit mechanical vibrations into the cochlea and has become a therapeutic option of hearing rehabilitation for patients with stapedial otosclerosis. A finite-element model of the human ear that includes sound transmission effects of the vestibular and cochlear aqueducts of the inner ear is adopted in this study for investigating the cochlear response to RW stimulation under stapes fixation. There are two effects due to otosclerosis of the stapes: the fixation of the stapedial annular ligament (SAL) and the increase of the stapes mass. The frequency responses of the middle ear and cochlea with normal and otosclerotic stapes are calculated under sound and RW stimulations. The results show that changes in the material property of the stapes have different effects on the cochlear responses under sound and RW stimulations. Because of the vestibuli aqueduct, the reduction in the low-frequency magnitude of the pressure difference across the cochlear partition due to SAL fixation is much smaller under RW stimulation than under sound stimulation. The results of this study help understand sound transmission during RW stimulation in patients with stapedial otosclerosis.

Optical Coherence Tomography Doppler Vibrometry Measurement of Stapes Vibration in Patients With Stapes Fixation and Normal Controls.

Ears with otosclerotic stapes fixation will exhibit lower-than-normal levels of ossicular mobility as measured by Optical Coherence Tomography Doppler Vibrometry (OCT-DV). OCT-DV measures the vibration of middle ear structures in response to sound non-invasively through the intact tympanic membrane. This allows, in particular, direct measurement of the vibration at the lenticular process of the incus which is expected to be lower in patients with otosclerotic stapes fixation. OCT-DV was performed on ears presumptively diagnosed with otosclerosis (n = 13) and a group of normal control ears (n = 42). Displacement was measured at the umbo and the lenticular process of the incus in response to 500 and 1000 Hz stimulus tones at 100 dBSPL. The ability to discriminate between groups was assessed using receiver operator characteristic analysis, with the main outcome measures being the area-under-curve (AUC) and the sensitivity and specificity. For the best condition tested (500 Hz at the incus), the AUC was 0.998 and discriminated the otosclerotic from normal ears with a sensitivity/specificity of 1.00/0.98. One anomalous patient with surgically confirmed stapes fixation exhibited hypermobility at the umbo, possibly due to a partial ossicular discontinuity. Despite the high umbo mobility, this patient's stapes fixation was correctly discriminated based on the measured incus vibration levels. OCT-DV is a promising tool for preoperatively assessing ossicular mobility non-invasively in the clinic. Our results suggest OCT-DV may also be useful in discriminating other ossicular pathologies that result in conductive hearing loss.

Primary stapedotomy in children with otosclerosis: A prospective study of 41 consecutive cases.

To prospectively evaluate hearing outcomes in children with otosclerosis undergoing primary stapes surgery. A nonrandomized, nonblinded, prospective case series. Thirty-four consecutive pediatric patients who underwent 41 primary stapedotomies for otosclerosis in a tertiary referral center were included. Patients were included when there was evidence of otosclerotic stapes fixation and they had available postoperative pure-tone audiometry. Patients underwent primary stapedotomy with vein graft interposition and reconstruction with a regular piston, bucket handle prosthesis, or total ossicular replacement prosthesis. Hearing results were evaluated using pre- and postoperative four-frequency (0.5, 1, 2, and 4 kHz) audiometry. Air-conduction thresholds, bone-conduction thresholds, and air-bone gaps were measured. Postoperative audiometry was performed at 3, 6, 9, 12, 18, and 24 months after surgery and at a yearly interval thereafter. Overall, a postoperative air-bone gap closure of 10 dB or less was achieved in 93% of cases and to within 20 dB in 98% of cases. Mean gain in air-conduction threshold was 23 dB for the entire case series, and mean air-bone gap closure was 23 dB. Postoperative sensorineural hearing loss, defined as changes in bone-conduction thresholds exceeding 10 dB, occurred in one case at last follow-up. The bone-conduction threshold deteriorated 13 dB in this case. Primary stapedotomy is a safe and feasible treatment option in children with juvenile otosclerosis. 4.

Expression of TNF-α, OPG, IL-1β and the presence of the measles virus RNA in the stapes of the patients with otosclerosis

Persistent measles virus infections play a crucial role in the pathomechanism of otosclerosis. The study was undertaken to investigate the role of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β) and osteoprotegerin (OPG) in otosclerotic bone remodeling and to assess the relation of TNF-α, OPG and IL-1β expression levels in otosclerotic stape footplates to the occurrence of measles virus infection. 61 patients with otosclerosis were treated surgically. Thirty-one stapes obtained from cadavers of people, who had died from a sudden cause were used as a control group. The presence of measles virus RNA and the expression levels of TNF-α, IL-1β and OPG in otosclerotic foci were assessed using one-step RT-PCR. The presence of measles virus RNA was noted in 80.3 % of otosclerotic stapes (49 out of 61) and 9.7 % of normal tissues (3 out of 31). Transcript of TNF-α, IL-1β and OPG was detected in 40, 46 and 18 virus-positive stapes, respectively. The transcript level of TNF-α and IL-1β was significantly higher in otosclerotic tissues comparing to normal tissue. The OPG expression level was significantly lower in otosclerotic tissues comparing to controls. The presence of measles virus RNA in the stapes may indicate its role in the pathogenesis of otosclerosis. The presence of TNF-α and IL-1β mRNA in the virus-positive stapes could be the result of viral antigen stimulation and may be a marker of inflammation the otosclerotic focus. The lack of OPG mRNA and the presence of TNF-α and IL-1β mRNA in the majority of otosclerotic tissues reflect the bone remodeling process occurring in the stapes.

Exclusion of TNFRSF11B as Candidate Gene for Otosclerosis in Campania Population.

The etiology of otosclerosis is unknown. The etiopathogenesis of otosclerosis seems similar to that occurring in Paget's disease of bone, for which mutations or polymorphisms in several genes have been identified. Among these, TNFRSF11B gene encoding the osteoprotegerin is produced at high levels in the normal inner ear and at low level in active otosclerotic stapes footplates. The aim of this work was to verify the presence of a correlation between the rs2073618 (N3K) polymorphism in the TNFRSF11B gene and otosclerosis. Mutational screening in the TNFRSF11B gene was performed by direct sequencing. SNPs analysis was performed by PCR and by specific restriction enzyme assay with HpaI. The significance of the association was analyzed by statistical specific software. No causative mutation has been identified but the data suggested a strong correlation between the rs2073618 (N3K) polymorphism and otosclerosis. This correlation, however, has been excluded in a case-control study. This study excluded the association between the N3K polymorphism and otosclerosis in Campania region population.

No Evidence for the Expression of Renin-Angiotensin-Aldosterone System in Otosclerotic Stapes Footplates

Recent studies have reported genetic associations between with single nucleotide polymorphism (SNP) of the several genes of the renin-angiotensin-aldosterone (RAA) system in otosclerosis without the confirmation of RAA system expression in human stapes footplates. There are conflicting results. These results are conflicting because RAA system expression has been attributed exclusively to neural, vascular, and renal tissues, exclusively. Ankylotic stapes footplates (n = 20), cortical bone fragments (n = 10), and human kidney tissue specimens (n = 10) were processed to hematoxylin-eosin (HE) staining and RAA system-specific immunofluorescent assay (IFA), respectively. Histologic diagnosis of otosclerosis was established in all ankylotic stapes footplates. Histologically active- (n = 13) and inactive (n = 7) foci of otosclerosis were consequently characterized by negative immunoreactions for renin, angiotensin converting enzyme (ACE), angiotensin-II (AT-II), and angiotensin-II receptor (AT-IIR), consequently. In cortical bones, a considerable RAA system expression was observed confirmed in the perivascular bone marrow progenitor cells. Kidney specimens, applied as positive controls, showed intense RAA system-specific immunoreactions. Concerning current observations, the 4 studied members of RAA system that did not display active expression were not expressed at protein level in otosclerotic stapes footplates. This phenomenon was independent from the histologic activity of otosclerosis. Between these conditions, the etiologic role of RAA system is questionable in the pathogenesis of otosclerosis.

KTP Versus CO2 Laser Fiber Stapedotomy for Primary Otosclerosis

To compare the 3-month postoperative hearing results after laser stapedotomy using a flexible potassium titanyl phosphate (KTP) or CO2 laser fiber in patients with primary otosclerosis. Prospective nonrandomized clinical study. Tertiary referral center, 862 stapedotomies were performed in 818 study patients between November 2006 and July 2011. Otosclerotic stapes fixation was treated with flexible KTP laser fiber in 410 patients (431 stapedotomies) and with flexible CO2 laser fiber in 408 patients (431 stapedotomies). Their preoperative and postoperative audiometric results were compared.Logistic regression analyses were performed to evaluate the main effect of laser fiber type and the effect after adjustment for independent predictors of a postoperative air-bone gap (ABG) 10 dB or lower. In the KTP laser group, the mean postoperative ABG was 4.3 dB compared with 3.1 dB in the CO2 group (difference, 1.1; 95% confidence interval, 0.4-1.9). In 90.4% of the patients in the KTP group, the postoperative ABG was 10 dB or lower, as compared with 96.5% in the CO2 group. The mean postoperative ABG at 4 KHz was 5.4 dB with KTP and 2.2 dB with CO2 (difference, 3.2; 95% confidence interval, 2.2-4.2). Sensorineural hearing loss was reported by 1 patient with KTP laser (0.3%) and by none with CO2 laser. "Type of laser" and "sex" were independent predictors of ABG 10 dB or lower. The chance to achieve a postoperative ABG 10 dB or lower for male subjects is 95%, when treated with CO2 laser and 85% when treated with KTP laser. For female subjects, these chances are 97% and 94%, respectively. The use of the CO2 laser fiber may be associated with better hearing results than the KTP laser fiber, regarding the ABG closure within 10 dB.

Piezoelectric stapedotomy: the importance of a micropulse program

Conclusions: We can consider the micropulse program as the best level of safety that should be used in all cases of piezoelectric stapedotomy. Objectives: The aim of this study was to describe the importance of a micropulse program in determining the success of piezoelectric stapedotomy. Methods: A total of 112 patients (group A) affected by primary otosclerosis underwent piezoelectric stapedotomy for otosclerotic stapes fixation. A specific operative program was created to perforate the stapes footplate: this program makes it possible to perforate the footplate of the stapes with a predetermined and non-modifiable temporization. Before and 1 year after surgery, all the patients underwent the following instrumental examinations: pure-tone audiometry, tympanometry, transient-evoked otoacoustic emissions, distortion product otoacoustic emissions, and auditory brainstem response. Results were compared with those obtained from 30 patients who underwent piezoelectric stapedotomy without the specific operative program (group B). Results: At 1 year after surgery, with regard to the pure-tone audiometry test, all patients had an air–bone gap (ABG) reduction: no worsening of the bone conduction and no postoperative sensorineural hearing loss were found. In group A, there was a closure of the ABG within 10 dB in all patients.

A nonrandomized comparison of potassium titanyl phosphate and CO2 laser fiber stapedotomy for primary otosclerosis with the otology‐neurotology database

To compare short-term hearing results in patients undergoing laser stapedotomy for primary otosclerosis using either the flexible potassium titanyl phosphate (KTP) or CO(2) laser fiber. Prospective nonrandomized clinical study at a tertiary referral center. Two hundred fourteen patients undergoing 214 stapedotomies for otosclerotic stapes fixation were enrolled in this study from January 2008 to January 2010. Comparative analyses were made between a group of 107 patients who underwent stapedotomy with the flexible KTP laser fiber and 107 patients who underwent stapedotomy with the flexible CO(2) laser fiber. Preoperative and postoperative audiometric evaluation at 3 months using conventional audiometry, namely, air-bone gap (ABG), bone-conduction thresholds, and air-conduction thresholds, were assessed. In the KTP laser group the postoperative ABG was 4.3 dB compared to 3 dB in the CO(2) group, which is a mean difference of 1.3 dB (95% confidence interval [CI], -0.3 to 2.8; P = .10). Of the patients from the KTP group, 92% had a postoperative ABG of 10 dB or less, as compared to 97% in the CO(2) group (mean difference 5%; 95% CI, -10 to 1; P = .14). The postoperative ABG at 4 kHz was 4.9 dB in the KTP and 2.2 dB in the CO(2) group, which is a mean difference of 2.7 dB (95% CI, 0.6-4.7, P = .01). No sensorineural hearing loss was reported. The use of the CO(2) laser fiber appears to be associated with slightly better hearing results than the KTP laser fiber, especially when assessed at the 4 kHz frequency.

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.

Disease‐Associated Novel CD46 Splicing Variants and Pathologic Bone Remodeling in Otosclerosis

Otosclerotic bone is supposed to show unique CD46 expression pattern because otosclerosis is an organ-specific disease with viral etiology. Otosclerosis is a complex bone remodeling disorder of the human otic capsule, which is associated with persisting measles virus infection. The general cellular receptor of measles virus is the CD46, which has 14-known splicing isoforms. Nucleic acid was extracted from ankylotic stapes footplates (N = 99) removed during stapedectomies. Consecutive histological, CD46 specific immunohistologic analysis, and multiple polymerase chain reaction (PCR) amplifications were performed. Measles virus was detected by seminested reverse transcriptase-PCR. Splicing variants of CD46 were identified by nested reverse transcriptase-PCR and finally determined by mass sequencing of complementary DNA. Measles virus RNA was detectable only in histologically otosclerotic stapes footplates. Virus negative-fixed stapes represent degenerative disorders of variable histopathology. Otosclerosis is featured by an increased number of osteoclasts showing strong CD46 immunoreaction in contrast to nonotosclerotic stapes fixations. Normal and nonotosclerotic stapes footplates show consistent expression of "c," "d," "e," "f," and "l" CD46 splicing isoforms. In contrast, four novel CD46 splicing variants were additionally detected in otosclerosis: os1, os2, os3, and os4. Newly described CD46 isoforms have shorter or missing transmembrane domain and a rare cytoplasmic tail with pathological or uncommon signal transduction; however, virus binding ability remains equal and invariable. These changes may be responsible for the smooth virus replication. A special expression pattern and altered functions of CD46 could explain the organ-specific and virus-associated pathogenesis of otosclerosis.

Laser Stapedotomy – an Up-To-Date Solution in Otosclerotic Stapes Fixation

Introduction: Development of surgical treatment of otosclerotic stapes fixation is one of the success stories of otology during the past five decades. Nowadays not only stapedectomy and partial stapedectomy but stapedotomy can also be considered a well-established otological procedure. Aim: To introduce this minimally invasive surgical technique into the Hungarian otolaryngology practice, to gain useful experiences, and to analyze the hearing improvements and postoperative complications. Methods: The authors give account of their first clinical experiences with 14 patients with KTP laser assisted stapedotomies using the self-crimping Nitinol piston. A total of 14 patients (11 females, 3 males) who have undergone the procedure between March 2006 and April 2007 were reviewed. The average age of the patients was 42.2 years, 6 procedures were carried out on left ears and 8 on right ones. The average length of follow-up was 9 months (ranging from 6 weeks to 1 year). Results: Pure tone audiograms documented a hearing threshold improvement of 21.5 dB averaged across 0.5–1–2–3 kHz frequencies. The air-bone gap improvement averaged on the same frequencies was 18.7 dB. After an average 9 months postoperative follow-up period, the average air-bone gap was < 10 dB in 85% of the patients, however < 20 dB in 100% of the patients. As for the average air conduction result: it was < 30 dB in each patient except one. In this series, neither facial nerve paresis nor high frequency deterioration of the bone conduction thresholds was reported in the postoperative follow-up period. Conclusions: Based on the authors’ favourable experiences and the review of the literature, KTP laser assisted stapedotomy with the use of Nitinol piston has several advantages: 1. the laser-activated memory effect of the piston prevents the disadvantages of the crimping manouvre made around the long process of the incus; 2. vertigo, experienced in the early postoperative period is milder and takes shorter time, reducing the length of hospitalisation; 3. the procedure is cost-effective and minimally-invasive; 4. application of KTP laser assures a bloodless operating field and minimal cochlear trauma; 5. migration of the prosthesis can be prevented, the degree of the surrounding granulation is less; 6. high frequency hearing improvement can be achieved on the long run; 7. the frequency and seriousness of complications are less, therefore this technique can be reccommended for unexperienced ear surgeons too; 8. the procedure can be used in difficult situations, too, e.g. in the presence of stapedial artery, obliterative otosclerosis, floating footplate, abnormal position of the facial nerve in the middle ear, revision cases; 9. the interindividual differences of hearing results are much less. Based on their favourable initial experiences, the authors plan to conduct a long-term follow-up on a greater number of patients.

Laser stapedotomy – the up-to-date solution of otosclerotic stapes fixation

Development of surgical treatment of otosclerotic stapes fixation has been one of the success stories of otology for the past five decades. Nowadays not only stapedectomy and partial stapedectomy, but stapedotomy can also be considered a well established otological procedure. To introduce this minimally invasive surgical technique into the Hungarian otolaryngology practice, to gain useful experiences, and to analyze the hearing improvements and postoperative complications. The authors give account of their first clinical experiences with 14 patients with KTP laser assisted stapedotomies using the self-crimping Nitinol piston. A total of 14 patients (11 females, 3 males) who have undergone the procedure between March 2006 and April 2007 were reviewed. The average age of the patients was 42,2 years, 6 procedures were carried out on left ears and 8 on right ones. The average length of follow-up was 9 months (ranged from 6 weeks to 1 year). Pure tone audiograms documented a hearing threshold improvement of 21,5 dB averaged across 0,5-1-2-3 kHz frequencies. The air-bone gap improvement averaged on the same frequencies was 18,7 dB. After an average 9 months postoperative follow-up period, the average air-bone gap was < 10 dB in 85% of the patients, however, < 20 dB in 100% of the patients. As for the average air conduction result: it was < 30 dB in each patient except for one. In this series, neither facial nerve paresis nor high frequency deterioration of the bone conduction thresholds was reported in the postoperative follow-up period. Based on the authors' favourable experiences and the review of the literature, KTP laser assisted stapedotomy with the use of Nitinol piston has several advantages: 1) the laser-activated memory effect of the piston prevents the disadvantages of the crimping manoeuvre made around the long process of the incus; 2) vertigo, experienced in the early postoperative period is milder and takes shorter time, reducing the length of hospitalisation; 3) the procedure is cost-effective and minimally invasive; 4) application of KTP laser assures bloodless operating field and minimal cochlear trauma; 5) migration of the prosthesis can be prevented, the degree of the surrounding granulation is less; 6) high frequency hearing improvement can be achieved in the long run; 7) the frequency and seriousness of complications is less, therefore this technique can be recommended for inexperienced ear surgeons, too; 8) the procedure can be used in difficult situations, too, e.g.: in the presence of stapedial artery, obliterative otosclerosis, flooting footplate, abnormal position of the facial nerve in the middle ear, revision cases; 9) the interindividual differences of hearing results are much less. Based on their favourable initial experiences, the authors plan to conduct a long-term follow-up on greater number of patients.

OTOSCLEROSIS IN THE INCUS

To the Editor: The last issue of the journal (Otology & Neurotology, 28:301-3) published a paper titled "Otosclerosis of the Incus." Escada et al. (1) describes a bony lesion in the incus that is considered to be otosclerotic upon hematoxylin-eosin staining and a single light microscopic histological examination (1). A series of articles have been published during the last 3 years about the pathogenesis of otosclerosis (Karosi et al. 2-4). These reports clearly call the attention to the fact that all histologically otosclerotic stapes fixations are associated with the presence of measles virus genomic RNA. Otosclerotic stapes fixations are, however, only two thirds of the stapes fixations in a series of more than 300 stapes footplates consecutively operated on during the last 4 years (3,4). Similar histological lesions and/or presence of measles virus in the stapes superstructure or other bones are not found. Those ankylotic stapes that do not represent otosclerosis show heterogeneous histological pattern of localized hemosiderosis, lymphocytic-plasmocytic infiltration with thickened stapedial mucosal layer, globular fibrosis, or annular calcification (3,4). The otic capsule shows inevitable affinity to persisting measles virus infection and replication, which coincides with the organ-specific localization of otosclerotic foci. The subsequent inflammatory process is characterized by pseudovascular, irregular, and hypercellular absorption lacunae bordered by numerous osteoclasts and multi-nucleated giant cells in the active stage. In contrast, the inactive phase of otosclerosis is featured by almost total absence of bone-derived cells with woven and mosaiclike pattern of cement lines. In these cases, the osteoid substance represents homogeneous eosinophilia. Nevertheless, cement lines cannot be visualized without polarizing light microscopic analysis (3,4), and cement line pattern is a structure of inorganic bony material that is not identical with the osteoid rings bordered by osteocytes. The presented histological section of the incus in the cited article shows no sign of the aforementioned histological features; rather, it shows regular vascular cross sections and Haversian lacunae (1). The section shows normal cellularity and concentric disposition of regular osteocytes. No osteoclasts or giant cells can be identified. The osteoid substance is eosinophilic, only the bulky perivascular connective tissue and vascular endothelial cells are characterized by basophilia. It does not represent information about the pattern of osteoid cement lines. It would be helpful to identify the sectioned part of the incus because intraosseal vascular network is different in the long process and in the body. In addition, the serological diagnosis of otosclerosis is based upon the antimeasles immunoglobulin G low concentration (<12 IU/mL) in the sera of these patients versus healthy immunized individuals' high titer (>100 IU/mL) (5). The specificity and sensitivity of this test for otosclerosis in conductive hearing loss are around 95% (5). Today, we do think, that the diagnosis of otosclerosis cannot be established without detecting low antimeasles immunoglobulin G in the serum and/or detecting measles virus RNA in the affected bone specimen. István Sziklai, M.D., D.Sc. Tamás Karosi, M.D., Ph.D. Department of Otolaryngology- Head and Neck Surgery University Medical School of Debrecen Debrecen, Hungary

Expression of measles virus receptors in otosclerotic, non-otosclerotic and in normal stapes footplates

Otosclerosis is a bone remodeling disorder of complex etiology. Persistent measles virus infection of the otic capsule could increase the expression level of measles virus receptors (CD46) on the osteoclasts and endothelial cells of the otosclerotic foci. Presence of measles virus RNA was demonstrated in the footplates of histologically diagnosed otosclerotic patients by RT-PCR; however, no reports were available about the CD46 expression pattern and level in otosclerosis. Nucleic acid was extracted from stapes footplates of clinically otosclerotic patients (N = 116). Genomic RNA of measles virus was amplified by RT-PCR. Amplification results were correlated with postoperative histologic and CD46 specific immunhistologic findings. Among 116 stapes fixation cases, 87 otosclerotic stapes contained measles virus RNA. Histology for virus negative stapes (N = 29) represented degenerative disorders with heterogeneous histopathology. Active otosclerosis was featured by increased numbers of osteoclasts showing strong CD46 expression. In virus negative, non-otosclerotic stapes fixation and in normal stapes footplates weak CD46 immunoreaction was demonstrated on the osteocytes and fibroblasts. In otosclerosis, it is reasonable to assume that measles virus increases the expression level of its own cellular receptor. Furthermore, intensive CD46 reaction could relate to active virus replication and continuous receptor internalisation. Otosclerosis is a disease of disturbed osteoid turnover due to persistent measles virus infection and special CD46 receptor pattern of the otic capsule.

Surgical Findings and Long-Term Hearing Results in 3,050 Stapedotomies for Primary Otosclerosis

To evaluate with a new otologic database the results of primary stapes surgery for otosclerosis with up to 14 years of follow-up in a consecutive series of 2,525 patients operated on by the same surgeon with the same technique (stapedotomy and vein graft interposition) and to provide online access to the complete data of this study for the reviewers. To study the effect of specific operative findings (obliterative otosclerosis and simultaneous malleus ankylosis) and age at the time of surgery on the long-term outcome. Prospective clinical study using a new computerized otologic database. : Tertiary referral center. Two thousand five hundred twenty-five patients who underwent 3,050 stapedotomies for otosclerotic stapes fixation were enrolled in this study from January 1991 to December 2004. Separate analyses were made for two unique pathologies (92 cases of obliterative otosclerosis and 19 cases of simultaneous malleus ankylosis) diagnosed during surgery and for patients in two age brackets (<or=18 yr [28 patients] and >or=65 yr [302 patients]). Stapedotomy with vein graft interposition and reconstruction with either a Teflon piston, a bucket handle prosthesis, or a total prosthesis. Preoperative and postoperative audiometric evaluation using conventional audiometry. Air-bone gap (ABG), bone-conduction thresholds, and air-conduction thresholds were all assessed. Postoperative audiometry was performed at 3, 6, 9, 12, 18, and 24 months and then annually for 14 years. Overall, the postoperative ABG was closed to 10 dB in 94.2% of cases. The mean four-frequency postoperative ABG was 1.7 dB compared with 25.6 dB preoperatively. The mean four-frequency bone-conduction thresholds were unchanged postoperatively. A significant postoperative sensorineural hearing loss (SNHL; >15 dB) was seen in 0.5% of cases in this series. Postoperative ABG was achieved to within 10 dB in 95% of cases of obliterative otosclerosis and in 64.7% of cases of simultaneous malleus ankylosis. A significant postoperative SNHL (>15 dB) was seen in 4.8% of cases of obliterative otosclerosis and was not observed in any cases of simultaneous malleus ankylosis. Postoperative ABG was achieved to within 10 dB in 93.5% of cases in the pediatric series and in 94.5% of cases in the senior series. A significant postoperative SNHL (>15 dB) was seen in 0.7% of cases in the senior group but was not observed in the children. Using a new otologic database, our series confirms that stapedotomy with vein graft interposition for otosclerotic stapes fixation is a safe and successful treatment for long-term hearing improvement. The deterioration in hearing with time after stapedotomy did not exceed the rate of hearing loss because of presbyacusis. Therefore, argon laser stapedotomy with vein graft interposition is our preferred surgical technique in the treatment of otosclerosis. Obliterative otosclerosis and simultaneous malleus ankylosis may be encountered during stapedotomy. Our study shows that reasonable success rates can still be expected in these situations. Stapedotomy results in the elderly and in children are comparable to those obtained in patients of other groups of age undergoing surgery for otosclerosis without an increased risk for complications.

Glucocorticoids Inhibit Diastrophic Dysplasia Sulfate Transporter Activity in Otosclerosis by Interleukin‐6

Otosclerosis is a bone remodeling disorder localized to the otic capsule and associated with inflammation. In vitro, increased activity of the diastrophic dysplasia sulfate transporter (DTDST), which is implicated in bone metabolism, has been reported. Because glucocorticoids modulate the bone turnover and inhibit inflammatory processes, we investigated the effect of dexamethasone (Dex) on interleukin-6 and DTDST in otosclerosis. The authors conducted a prospective, case-control study. Primary cell cultures were obtained from stapes and external auditory canals in otosclerosis (n = 21) and control patients (n = 18). Assays with [H]Dex evaluated specific binding sites in otosclerotic and control stapes. The effects of Dex (10 to 10 M) and RU486 (10 M), a glucocorticoid antagonist, were studied on DTDST activity by sulfate uptake. IL-6 secretion was measured in culture media before and after Dex (10 M, 24 hours). The effect of IL-6 (10 M, 24 hours) was assessed on DTDST activity in control stapes. : The number of specific Dex-binding sites was similar in all stapedial cultures. Dex inhibited DTDST activity (19.4 +/- 1.02 vs. 29.4 +/- 3.94 pmol/microg prot/5 minutes) only in otosclerotic stapes. This effect was dose-dependent, antagonized by RU 486 and only observed 24 hours after Dex exposure. Interleukin (IL)-6 stimulated DTDST activity in normal stapes, whereas Dex inhibited IL-6 production only in otosclerotic stapes. Dex inhibits the DTDST activity, at least in part, through a reduction of IL-6 secretion only in otosclerotic cells. This effect is mediated through the glucocorticoid receptors and may lead to the reduction of bone turnover.