A new device for real-time peroperative monitoring of ossicular chain reconstruction during middle ear surgery.

To limit functional surgical failure and reduce the rate of revision surgery in case of surgical ossicular chain reconstruction, a piezoelectric device was developed for assessment of ossicular chain vibrations during the middle ear surgery. The device resembled a pen and consisted of a reusable main body and a disposable sensitive head including piezoelectric polymer sensor. Almost all of components of the device were made of polymer for light weight and for acoustic impedance matching to the middle ear system. Several frequencies can be analyzed simultaneously and several measures can be taken by time. The results showed that the device can record normal and reconstructed ossicular chain vibration in response to an acoustic stimulation, with similar results to those achieved by laser Doppler vibrometer. This light, handheld and low-cost device allows fast, easy and safe assessments of normal ossicular chain mobility and ossicular chain reconstruction efficiency. Primary pre-clinical trial showed very promising performance of the device that could be used to qualitatively control ossiculoplasty during real-time surgical procedure. Clinical assessments will be done to further evaluate the real-life performance of the device.

Ossicular chain defects in adults with chronic otitis media.

BACKGROUND AND OBJECTIVE: Chronic otitis media (COM) is a common condition characterized by the perforation of the tympanic membrane and inflammation of the mucosal lining the hollow space in the middle ear and airy spaces of the temporal bone for at least 2-6 week. This study was carried out to find out the status of the middle ear ossicles in patients with COM and to correlate their status with clinical parameters. METHODS: This retrospective clinical study was conducted on 107 COM patients (52 males and 55 females; age range: 18 to 75 years) submitted to surgery in the Otology Clinic at Imam Khomeini Hospital, Ahvaz Jundishapur University of Medical Sciences, Iran. Initially, a comprehensive case-history was obtained from patients and their hearing thresholds were recorded. Then, ossicles status and their junction condition were evaluated intraoperatively. RESULTS: The malleus was found intact in 70 (65.42%), absent in 10 (9.34), and eroded in 27 (25.24%) patients. Our results revealed that the incus was intact in 33 (30.84%), eroded in 55 (51.41%) and absent in 19 (17.75%) subjects. Stapes was found intact in 54 (50.46%) cases and eroded in 53 (49.54%) cases. The mean Pure Tone Average (PTA) and Air-Bone Gap (ABG) comparisons in "intact" and "discontinuous" ossicular chain groups was not significant (Independent sample t-test, p>0.05). CONCLUSION: Our results demonstrated that incus was the most susceptible middle ear ossicle to erosion in COM, whereas the malleus was the most resistant ossicle. Furthermore, ABG and PTA values cannot be considered as a potential preoperative predictor for ossicular chain status.

[The prevalence of tympanosclerosis and the effectiveness of its surgical treatment]. / Rasprostranennost' timpanoskleroza i éffektivnost' ego khirurgicheskogo lecheniia.

The objective of the present study was to characterize the epidemiological variants of tympanosclerosis and the effectiveness of the surgical treatment of the patients presenting with this condition. We have undertaken the analysis of the results of 1965 surgical interventions on the patients suffering from different forms of chronic otitis media (COM) performed during the period from 2009 till 2014 with a view to determining the frequency of tympanosclerosis (TSC). In 542 cases, it proved possible to evaluate the intraoperative findings, stages and methods of reconstructive surgery, the anatomical and functional outcomes and effectiveness of the intervention. At present, the signs of tympanosclerosis are identified in 27.6% of the patients presenting with chronic otitis media including 88.7% and 11.3% suffering from the perforating and non-perforating forms of this pathology, respectively. In 74% of the cases its manifestations are diagnosed in the patients having the tubotympanic form of COM. In 53.3% of the patients TSC foci are responsible for the fixation of the ossicular chain whereas in 46.7% of the cases the auditory ossicles retain mobility. As many as 88.6% of the patients underwent the one-step surgical intervention, 10.7% were managed using two-step surgery, and 0.7% of the patients were given the three-stage treatment. Type I tympanoplasty was performed in 62% of the patients, type III tympanoplasty in 30.4%, and various types of stapedoplasty in 4.6% of the cases. The favourable anatomical and functional outcomes at the first stage of the surgical intervention with the use of the autogenous tissues for tympano- and ossiculoplastic surgery were achieved in 87.9% of the patients on the average (by means of the closure of the tympanic defect in 92.2% and by re-fixation of the selected elements of the ossicular chain in 17.3%of the cases). The anatomical and functional effectiveness of the second-stage surgical intervention was estimated at 93.1%.

Preoperative Predictors in Chronic Suppurative Otitis Media for Ossicular Chain Discontinuity: A Cross-Sectional Study.

OBJECTIVE: Ossicular discontinuity may result from chronic suppurative otitis media and is usually detected intraoperatively. Our objective is to determine whether a preoperative audiogram can preoperatively predict the presence or absence of ossicular discontinuity. METHODS: A cross-sectional study was prospectively run on our patients, aged 12-75 years, ultimately operated on for chronic suppurative otitis media. Preoperative audiograms were analyzed to measure frequency-specific air-bone gap (ABG) cutoff values. Intraoperatively, ossicular chain integrity was carefully checked. Logistic regression analysis was done to obtain a predictive model. RESULTS: A total of 270 patients (306 ears) were included. Frequency-specific ABG cutoff values can predict ossicular discontinuity, namely: high ABGs at 1,000 Hz (>27.5 dB) and 2,000 Hz (>17.5 dB) are the most reliable variables associated with ossicular discontinuity. CONCLUSION: Preoperative audiograms can predict the presence of ossicular discontinuity in chronic suppurative otitis media. Large ABGs at both 1,000 and 2,000 Hz can predict ossicular discontinuity with a great degree of certainty.

The Audiometric and Mechanical Effects of Partial Ossicular Discontinuity.

OBJECTIVES: Ossicular discontinuity may be complete, with no contact between the disconnected ends, or partial, where normal contact at an ossicular joint or along a continuous bony segment of an ossicle is replaced by soft tissue or simply by contact of opposing bones. Complete ossicular discontinuity typically results in an audiometric pattern of a large, flat conductive hearing loss. In contrast, in cases where otomicroscopy reveals a normal external ear canal and tympanic membrane, high-frequency conductive hearing loss has been proposed as an indicator of partial ossicular discontinuity. Nevertheless, the diagnostic utility of high-frequency conductive hearing loss has been limited due to gaps in previous research on the subject, and clinicians often assume that an audiogram showing high-frequency conductive hearing loss is flawed. This study aims to improve the diagnostic utility of high-frequency conductive hearing loss in cases of partial ossicular discontinuity by (1) making use of a control population against which to compare the audiometry of partial ossicular discontinuity patients and (2) examining the correlation between high-frequency conductive hearing loss and partial ossicular discontinuity under controlled experimental conditions on fresh cadaveric temporal bones. Furthermore, ear-canal measurements of umbo velocity and wideband acoustic immittance measurements were investigated to determine the usefulness regarding diagnosis of ossicular discontinuity. DESIGN: The authors analyzed audiograms from 66 patients with either form of surgically confirmed ossicular discontinuity and no confounding pathologies. The authors also analyzed umbo velocity (n = 29) and power reflectance (n = 12) measurements from a subset of these patients. Finally, the authors performed experiments on six fresh temporal bone specimens to study the differing mechanical effects of complete and partial discontinuity. The mechanical effects of these lesions were assessed via laser Doppler measurements of stapes velocity. In a subset of the specimen (n = 4), wideband acoustic immittance measurements were also collected. RESULTS: (1) Calculations comparing the air-bone gap (ABG) at high and low frequencies show that when high-frequency ABGs are larger than low-frequency ABGs, the surgeon usually reported soft-tissue bands at the point of discontinuity. However, in cases with larger low-frequency ABGs and flat ABGs across frequencies, some partial discontinuities as well as complete discontinuities were reported. (2) Analysis of umbo velocity and power reflectance (calculated from wideband acoustic immittance) in patients reveal no significant difference across frequencies between the two types of ossicular discontinuities. (3) Temporal bone experiments reveal that partial discontinuity results in a greater loss in stapes velocity at high frequencies when compared with low frequencies, whereas with complete discontinuity, large losses in stapes velocity occur at all frequencies. CONCLUSION: The clinical and experimental findings suggest that when encountering larger ABGs at high frequencies when compared with low frequencies, partial ossicular discontinuity should be considered in the differential diagnosis.

Bone conduction hearing in congenital aural atresia.

Previous researches focusing on BC hearing mechanisms proved that the two routes, (1) EAC sound radiation and (2) inertial of ossicular chain, partially contribute to normal BC hearing. Therefore, the BC hearing for those patients with congenital aural atresia should partially decrease theoretically due to their abnormal anatomy. However, there are not many studies which mention these patients' BC hearing up till now. The objective of this study is to investigate congenital aural atresia patient's BC hearing by analysis of pre-surgical audiogram and to study their potential BC hearing mechanisms using animal modeling and their ABR measurements. The study methoed involves analyzing 75 patients' pre-operative audiogram. Then we produced an animal model by surgery to measure their BC hearing threshold changes. Clinical data showed that those patients had some BC hearing loss; and there were 25 cases (25/75, 33.3 %) which present with typical Carhart's Notch. The animal experiments proved that inertia of ossicular chain contribute to partial BC hearing, which demonstrated that the inertia produced more affects on high frequencies by comparing with low frequencies. The patients with congenital aural atresia present BC hearing loss, which could be mainly ascribed to the absence of inertia of ossicular chain.

Is endoscopic ear surgery an alternative to the modified Bondy technique for limited epitympanic cholesteatoma?

The objective of this study is to evaluate the outcomes of the modified Bondy's technique performed at our center and for limited epitympanic cholesteatomas and to debate the purported benefits of endoscopic surgery for the same indication. This is a retrospective study. 269 ears of 258 patients with a minimum of 5-year follow-up that were operated for limited epitympanic cholesteatoma using the modified Bondy's technique were included in the study. All patients had primary acquired cholesteatoma with good preoperative hearing in the affected ear and an intact ossicular chain. The outcomes of were analyzed and the results were compared with a literature review of outcomes of endoscopic ear surgery for the same indication. The mean follow-up was 81.63 months. The mean preoperative air-bone gap was 13.6 ± 7 dB. Intraoperatively, the ossicular chain was preserved in all patients. Postoperatively, there was no significant change from preoperative levels in mean air conduction, mean bone conduction and the air-bone gap. There were no recurrent cholesteatomas in our series. A residual pearl-like cholesteatoma was found lateral to the tympanic membrane in 8.1 % of ears, which was removed in the outpatient clinic. Three patients (1.2 %) developed stenosis of the meatoplasty. Eight (3.1 %) ears exhibited retraction pockets involving the attic. Postoperative ear discharge was observed in 1.5 % cases. The modified Bondy technique, which provides excellent postoperative outcomes, is the surgery of choice for limited epitympanic cholesteatomas. The endoscope, despite its better visualization of hidden areas does not provide a distinct overall technical advantage or better results over the microscope.

Air, bone and soft tissue excitation of the cochlea in the presence of severe impediments to ossicle and window mobility.

Clinical conditions have been described in which one of the two cochlear windows is immobile (otosclerosis) or absent (round window atresia), but nevertheless bone conduction (BC) thresholds are relatively unaffected. To clarify this apparent paradox, experimental manipulations which would severely impede several of the classical osseous mechanisms of BC were induced in fat sand rats, including discontinuity or immobilization of the ossicular chain, coupled with window fixation. Effects of these manipulations were assessed by recording auditory nerve brainstem evoked response (ABR) thresholds to stimulation by air conduction (AC), by osseous BC and by non-osseous BC (also called soft tissue conduction-STC) in which the BC bone vibrator is applied to skin sites. Following the immobilization, discontinuity and window fixation, auditory stimulation was also delivered to cerebro-spinal fluid (CSF) and to saline applied to the middle ear cavity. While the manipulations (immobilization, discontinuity, window fixation) led to an elevation of AC thresholds, nevertheless, there was no change in osseous and non-osseous BC thresholds. On the other hand, ABR could be elicited in response to fluid pressure stimulation to CSF and middle ear saline, even in the presence of the severe restriction of ossicular chain and window mobility. The results of these experiments in which osseous and non-osseous BC thresholds remained unchanged in the presence of severe restriction of the classical middle ear mechanisms and in the absence of an efficient release window, while ABR could be recorded in response to fluid pressure auditory stimulation to fluid sites, indicate that it is possible that the inner ear may be activated at low sound intensities by fast fluid pressure stimulation. At higher sound intensities, a slower passive basilar membrane traveling wave may serve to excite the inner ear.

[A new method for the fixation of sound-conducting elements of the middle ear during ossiculoplasty].

The objective of the present work was to estimate the possibilities of the application of platelet-enriched plasma as a filtering material for ossiculoplasty. The results of surgical interventions on 120 patients presenting with chronic suppurative otitis media are reported. All the patients underwent closed-type sanation surgery (differential atticoanthrotomy) including either complete or partial restoration of the sound conduction mechanism in the middle ear. Platelet-enriched plasma was applied into the tympanic cavity of 55 patients as a fixing material for the reconstruction of the chain of the auditory ossicles. Ossiculoplasty without additional fixation was performed in 65 patients comprising the control group. The results of the study indicate that a clot of platelet-enriched plasma may be a good fixing material for the reconstruction of the entire chain of auditory ossicles and can be used for all types of ossiculopasty.

Fallopian canal stapedotomy in congenital stapes fixation with aberrant facial nerve.

Congenital stapes ankylosis is reported to have an occurrence rate of 3% to 4%, and it represents 20% to 35% of ossicular malformations. Surgical treatment of congenital stapes ankylosis is described to be satisfactory in the large majority of the case series reported in the literature. In these cases, special attention should be paid to exclude any aberrations of the course of the facial nerve, which have been demonstrated to be frequently associated with congenital middle ear malformations. We describe a case of congenital stapes ankylosis associated with a previously unreported facial nerve abnormality, characterized by the presence of an empty fallopian canal in combination with a dehiscent facial nerve running over the footplate and almost totally covering it.

Traumatic dislocation of middle ear ossicles: A new computed tomography classification predicting hearing outcome.

OBJECTIVES: To assess the feasibility of radiologic measurements and find out whether hearing outcome could be predicted based on computer tomography (CT) scan evaluation in patients with temporal bone fractures and suspected ossicular joint dislocation. METHODS: We assessed 4002 temporal bone CT scans and identified 34 patients with reported ossicular joint dislocation due to trauma. We excluded those with no proven traumatic ossicular dislocation in CT scan and patients with bilateral temporal bone fractures. We measured four parameters such as malleus-incus axis distance, malleus-incus angle at midpoints, malleus- incus axis angle and ossicular joint space. The contralateral healthy side served as its own control. Hearing outcome 1-3 months after the index visit was analyzed. We assessed diagnostic accuracy and performed a logistic regression using radiologic measurement parameters for outcome prediction of conductive hearing loss (defined as >20dB air-bone gap). RESULTS: We found excellent inter-rater agreement on the measurement of axis deviation between incus and malleus in CT scans (interclass correlation coefficient 0.81). The larger the deviation of incus and malleus axis, the higher probability of poor hearing outcome (odds ratio (OR) 2.67 per 0.1mm, p = .006). A cut-off value for the axis deviation of 0.25mm showed a sensitivity of 0.778 and a specificity of 0.94 (p < .001) for discrimination between poor and good hearing outcome in terms of conductive hearing loss. CONCLUSION: Adequate assessment of high resolution CT scans of temporal bone in which ossicular chain dislocation had occurred after trauma was feasible. Axis deviations of the incus and the malleus were strongly predictive for poor hearing outcome in terms of air conduction 1-3 months after trauma. We propose a 3-level classification system for hearing outcome prediction based on radiologic measures.

Endoscopic Ossiculoplasty for the Management of Isolated Congenital Ossicular Chain Malformation: Surgical Results in 16 Ears.

OBJECTIVE: The aim of this study is to describe the clinical characteristics and intraoperative findings and further evaluate the efficacy of endoscopic ossiculoplasty for the management of isolated congenital ossicular chain malformation. METHODS: A retrospective study was performed on 16 ears (15 patients) with the isolated congenital ossicular chain malformation who underwent endoscopic ossiculoplasty in our department from May 2017 to January 2019. Endoscopic exploratory tympanotomy was conducted to check the ossicular chain; at the same time, endoscopic ossiculoplasty was performed depending on intraoperative findings. Air-conduction thresholds, bone-conduction thresholds, and air-bone gaps (ABGs) were measured before and after surgery, and the hearing outcome was assessed at 6 months postoperatively. RESULTS: The most common malformations of ossicular chain were the missing of the incus long process and stapes suprastructure. A serial assessment of the hearing status was conducted before and 6 months after surgery. It showed the mean postoperative pure-tone average (PTA) was significantly reduced, and the mean postoperative ABG was obviously closed, respectively (P < .001). The mean PTA gain was 36.3 ± 8.6 dB, and the ABG closure was 35.1 ± 8.3 dB; ABG closure to 20 dB or less and ABG closure to 10 dB or less were achieved in 14 cases (87.5%) and 5 cases (31.3%), respectively. No differences were observed in postoperative hearing outcome between type Ⅲ cases and type Ⅳ cases; however, cases with partial ossicular replacement prosthesis implantation showed a larger hearing gain (P = .049) and a higher proportion of postoperative ABG less than 10 dB (P = .021). No facial palsy and significant sensorineural hearing loss occurred; all patients completed the surgery without the need of canalplasty, and the chorda tympani nerve was preserved in all patients. CONCLUSIONS: This research showed endoscopic surgery was effective in the diagnosis and management of isolated congenital ossicular chain malformation; the endoscopic ossiculoplasty provides an alternative method to manage congenital ossicular chain malformation, with comfortable hearing outcome and the advantage of excellent vision and less invasion.

Wideband absorbance pattern in adults with otosclerosis and ossicular chain discontinuity.

OBJECTIVES: Evidence from previous literature had shown that the use of a single frequency probe tone is not sensitive enough to detect middle ear pathologies, especially related to the ossicles, which hinders accurate diagnosis. The goal of the present study was to compare the outcome of wideband absorbance (WBA) tympanometry and to determine the difference in WBA pattern in adults with otosclerosis and ossicular chain discontinuity. MATERIALS AND METHODS: Estimated adult cases of otosclerosis (10 ears) and ossicular chain discontinuity (06 ears) along with healthy individuals (10 ears) in the age range of 24 to 48 years (mean age: 38.6 years) were considered for the study. WBA was measured at peak and ambient pressure along with resonance frequency and compared with the data obtained from the healthy individuals to determine the WBA pattern. RESULTS: Data analysis revealed a distinct WBA pattern showing high absorbance at 750 Hz for ossicular chain discontinuity compared to healthy individuals, whereas the otosclerosis group showed reduced absorbance (p < 0.05) at low frequencies (250 Hz to 1500 Hz). WBA measured at the peak and ambient pressure did not elicit any significant difference across the frequencies. Also, the average WBA tympanogram measured between 375 Hz and 2000 Hz showed a significant difference in ambient pressure only in the otosclerosis group. In comparison to healthy individuals (901 Hz), ossicular chain discontinuity showed a significant reduction in resonance frequency (674 Hz), whereas in cases with otosclerosis had higher resonance frequency (1445 Hz). CONCLUSIONS AND SIGNIFICANCE: The present study showed different WBA patterns between the groups and the absorbance values were significantly different at the low frequencies. This suggests that WBA has the potential to differentiate ossicles related pathologies from normal and also between the ear with otosclerosis and ossicular chain discontinuity.

Development of intra-operative assessment system for ossicular mobility and middle ear transfer function.

Objective measurements of the ossicular mobility have not been commonly performed during the surgery, and the assessment of ossicular mobility is made by palpation in most cases. Palpation is inherently subjective and may not always be reliable, especially in milder degrees of ossicular fixation and in the case of multiple fixation. Although several devices have been developed to quantitatively measure the ossicular mobility during surgery, they have not been widely used. In this study, a new system with a hand-held probe which enables intraoperative quantitative measurements of ossicular mobility has been developed. This system not only measures the ossicular mobility, but also investigates "local" transmission characteristics of the middle ear by directly applying vibration to the ossicles and measuring cochlear microphonic. The basic performance of this system was confirmed by measuring the mobility of artificial ossicles and cochlear microphonics in an animal experiment. Our system may contribute to selection of a better surgical method and reducing the risks of revision surgery.

Bone conduction hearing in the Guinea pig and the effect of artificially induced middle ear lesions.

Although human bone conduction (BC) hearing is well investigated, there is a lack of information about BC hearing in most other species. In humans, the amount of conductive loss is estimated as the difference between the air conduction (AC) and BC thresholds. Similar estimations for animals are difficult since in most species, the normal BC hearing thresholds have not been established. In the current study, the normal BC thresholds in the frequency range between 2 kHz and 20 kHz are investigated for the Guinea pig. Also, the effect of a middle ear lesion, here modelled by severing the ossicles (ossicular discontinuity) and gluing the ossicles to the bone (otosclerosis), is investigated for both AC and BC. The hearing thresholds in the Guinea pigs were estimated by a regression of the amplitude of the compound action potential (CAP) with stimulation level and was found robust and gave a high resolution of the threshold level. The reference for the BC thresholds was the cochlear promontory bone velocity. This reference enables comparison of BC hearing in animals, both intra and inter species, which is independent on the vibrator and stimulation position. The vibration was measured in three orthogonal directions where the dominating vibration directions was in line with the stimulation direction, here the ventral direction. The BC thresholds lay between -10 and 3 dB re 1 µm/s. The slopes of CAP growth function were similar for AC and BC at low and high frequencies, but slightly lower for BC than AC at frequencies between 8 and 16 kHz. This was attributed to differences in the stimulus levels used for the slope estimation and not a real difference in CAP slopes between the stimulation modalities. Two kinds of middle ear lesions, ossicular discontinuity and stapes glued to the surrounding bone, gave threshold shifts of between 23 and 53 dB for AC while it was below 16 dB when the stimulation was by BC. Statistically different threshold shifts between the two types of lesions were found where the AC threshold shifts for a glued stapes at 2 and 4 kHz were 9-18 dB greater than for a severed ossicular chain, and the BC threshold shifts for a glued stapes at 4 and 12 kHz were 8-9 dB greater than for a severed ossicular chain.

Differentiating among conductive hearing loss conditions with wideband tympanometry.

OBJECTIVE: This study was aimed to investigate whether wideband tympanometry (WBT) can distinguish among various kinds of conductive hearing loss and provide additional information. METHODS: We recruited normal subjects and patients with conductive hearing loss due to the following reasons: tympanic membrane perforation only, ossicular chain problem only, and one or other of those conditions combined with mastoid problems. Wideband absorbance at ambient pressure, peak pressure, resonance frequency, and averaged tympanogram data were measured by WBT and compared between the normal, tympanic membrane perforation only, ossicular chain problem only, and combined with mastoid problems groups. RESULTS: The normal subjects showed an average peak pressure of -19.51daPa and an average resonance frequency of 965.94Hz. Tympanic membrane perforation only patients showed a very low peak pressure (-124.93daPa) and resonance frequency (73.12Hz). When patients have ossicular chain problems, they showed slightly low peak pressures (43.08daPa) without changes in the resonance frequency (1024.8Hz). Mastoid problem subjects showed slightly decreased resonance frequencies (787.71Hz). Tympanic membrane perforation subjects showed decreased absorbance at low frequencies and ossicular chain problem subjects showed decreases at high frequencies. When comparing the perforation only and ossicular chain subjects by absorbance at 707Hz, the area under the ROC curve was 0.719 (P<0.022). Mastoid problems subjects showed decreased absorbance at all frequencies. CONCLUSION: WBT can help to distinguish tympanic membrane perforation only and ossicular chain problem patients. WBT may provide additional information on "combined with mastoid problems" patients.

Model-based hearing diagnostics based on wideband tympanometry measurements utilizing fuzzy arithmetic.

Today's audiometric methods for the diagnosis of middle ear disease are often based on a comparison of measurements with standard curves, that represent the statistical range of normal hearing responses. Because of large inter-individual variances in the middle ear, especially in wideband tympanometry (WBT), specificity and quantitative evaluation are greatly restricted. A new model-based approach could transform today's predominantly qualitative hearing diagnostics into a quantitative and tailored, patient-specific diagnosis, by evaluating WBT measurements with the aid of a middle-ear model. For this particular investigation, a finite element model of a human ear was used. It consisted of an acoustic ear canal and a tympanic cavity model, a middle-ear with detailed nonlinear models of the tympanic membrane and annular ligament, and a simplified inner-ear model. This model has made it possible for us to simulate pathologies like the stiffening of ligaments or joints, because we can simply change the corresponding mechanical parameters of the model. On the other hand, it is also possible to identify pathologies from measurements, by analyzing the parameters obtained by a system identification procedure. This reduces the number of required model parameters through sensitivity studies and parameter clustering. Uncertainties due to the lack of knowledge, subjectivity in numerical implementation and model simplification are taken into account by the application of fuzzy arithmetic. The most confident parameter set can be determined by applying an inverse fuzzy method on the measurement data. The principle and the benefits of this model-based approach are illustrated by the example of a two-mass oscillator, and also by the simulation of the energy absorbance of an ear with malleus fixation, where the parameter changes that are introduced can be determined quantitatively through the system identification.

Manubrio-incudo-stapedioplasty for reconstruction of Austin-Kartush type B ossicular defects.

OBJECTIVE: Manubrio-incudo-stapedioplasty functional outcomes were compared to those of other methods for reconstructing Austin-Kartush type B ossicular defects. METHODS: Forty-two patients underwent Austin-Kartush type B ossicular defect reconstruction using: manubrio-incudo-stapedioplasty (13 patients), an autologous incus (19 patients) or a titanium ossicular replacement prosthesis (10 patients). For manubrio-incudo-stapedioplasty reconstruction, the malleus head was removed, the manubrium was relocated posteriorly and the incus short process was placed on the mobile footplate. The manubrium was placed on the incus body groove and bone cement was applied to stabilise the manubrium-incus junction. Pre- and post-operative hearing thresholds were assessed. RESULTS: The air-bone gap decreased from 25.9 ± 6.0 dB to 12.3 ± 5.0 dB (p < 0.05) in the manubrio-incudo-stapedioplasty group. The hearing gain was 13.6 ± 5.2 dB for manubrio-incudo-stapedioplasty, 3.4 ± 14.2 dB with the autologous incus, and 3.3 ± 11.07 dB with the titanium ossicular replacement prosthesis. Hearing improvement was greater for manubrio-incudo-stapedioplasty compared to the other reconstruction methods (p < 0.05). CONCLUSION: Manubrio-incudo-stapedioplasty resulted in satisfactory hearing outcomes in patients with Austin-Kartush type B ossicular defects. This technique can be considered a stable, inexpensive and effective method to reconstruct Austin-Kartush type B ossicular defects.

Outer- and middle-ear contributions to presbycusis in the Brown Norway rat.

This paper examines the contribution of the outer and middle ears to the hearing loss associated with presbycusis in Brown Norway rats. Animals were formed into two groups; young adults (2-3 months old) and aged animals (approximately 34 months old). Auditory brainstem response (ABR) thresholds were obtained with the outer ear intact or surgically removed. Tympanic membrane (TM) velocity transfer functions were measured from the umbo with the outer ear removed. The length of the auditory meatus, TM surface area, and TM thickness were quantified. The ABR thresholds were 17-26 dB less sensitive in the aged animals between 8.0 and 40.0 kHz when the outer ear was intact. A significant and reliable reduction in the aged rat velocity transfer function of 5-8 dB occurred between 10.0 and 32.0 kHz, while the low frequency velocity response was only a few decibels greater in the younger animals. The ABR threshold differences between young adult and aged ears were compensated by removing the outer/middle ear effects of aging to reveal a purely sensorineural component of presbycusis. The outer and middle ear effects were calculated directly when the ABR and TM velocity data were obtained with the outer ear removed. The outer ear intact condition was modeled in order to compare the ABR data obtained with the outer ear intact with the TM velocity data obtained with the outer removed. With either procedure, removal of the age-related contributions of the outer and middle ear to the ABR threshold resulted in similar age-related ABR threshold shifts between the two age groups. The pure sensorineural threshold shift component of the ABR response was restricted to frequencies between 5.0 and 20.0 kHz and reached a maximum of approximately 15 dB. These results support the conclusion that there is an outer- and middle-ear contribution to the threshold loss defining presbycusis.

Prognostic factors in ossiculoplasty.

OBJECTIVE: To analyze predictive factors of outcome after ossiculoplasty using a standard ossicular prosthesis system. STUDY DESIGN: Retrospective review of 140 ossiculoplasties, performed by the same senior surgeon, with titanium prostheses. SETTINGS: Academic hospital and tertiary referral center. PATIENTS: All patients undergoing ossiculoplasty with Spiggle and Theis or Kurz titanium total and partial prostheses. Documented, postoperative follow-up had to be provided. A total of 129 patients (140 ears; 53 men and 76 women) were evaluated. INTERVENTIONS: These included ossiculoplasties using 75 Spiggle and Theis prostheses (30 partial and 45 total) and 65 Kurz prostheses (35 partial and 30 total). MAIN OUTCOME MEASURES: Mean preoperative and postoperative air-bone gaps and the changes in mean hearing loss were analyzed using a four-frequency (500, 1,000, 2,000, and 3,000 Hz) pure tone average. Success rate was defined as postoperative air-bone gap within 20 dB. A one-way analysis of variance was used to analyze group differences. A multivariate statistical analysis was then undertaken to define the significant factors. RESULTS: There were no statistical difference between the Spiggle and Theis and the Kurz prostheses. Multivariate statistical analysis has identified the predictive value of the presence or absence of the malleus handle and the mucosal status of the middle ear in the prognosis of ossiculoplasties. CONCLUSION: Anatomical and technical factors diversely affect the functional outcome of tympano-ossiculoplasties. A better knowledge of their predictive value will enable accurate, preoperative, individual assessment when counseling patients with regard to the success of any proposed intervention. The use of these factors will also permit precise matching of future series to allow accurate comparisons.