Ossicular Joints Research Articles

Ossicular joint histopathology in cases of age-related hearing loss.

Age-related hearing loss (presbycusis) is a prevalent condition traditionally attributed to inner ear dysfunction. Little is known about age-related changes in the ossicular joints or their contribution to presbycusis. Herein, we performed an otopathologic evaluation of the ossicular joints in cases of presbycusis without a clear sensorineural explanation. Histopathologic analysis of the incudomallear (IM) and incudostapedial (IS) joints was performed in specimens from the National Temporal Bone Registry with audiometrically confirmed presbycusis but without histologically observed sensorineural, strial, or mixed features; deemed cases of "indeterminate" presbycusis. Specimens identified as "indeterminate" presbycusis (IP, n = 18) were compared to specimens with histologically confirmed sensorineural presbycusis (n = 16) and strial presbycusis (n = 11). Presbycutic specimens were also compared to age-matched controls (n = 9) and young controls (n = 14). The synovial space at the center of the IM joint was wider in the IP group (194 ± 36.8 μm) compared to age-matched controls (138 ± 36.5 μm), young controls (149 ± 32.2 μm), and ears with sensorineural presbycusis (148 ± 52.7 μm) (p < .05). The synovial space within the IS joint was wider in the IP group (105 ± 33.0 μm) when compared to age-matched controls (57.9 ± 13.1 μm) and ears with sensorineural presbycusis (62.3 ± 31.2 μm) (p < .05). IP ears have wider IM and IS joints when compared to ears with sensorineural presbycusis and age-matched controls. Findings point to a potential middle ear source of high frequency conductive hearing loss in a subset of presbycutic ears. Retrospective study.

The onset of nonlinear growth of middle-ear responses to high intensity sounds

The human tympanic membrane (TM) and ossicles are generally considered to act as a linear system as they conduct low and moderate level environmental sounds to the cochlea. At intense stimulus levels (> 120 dB SPL) there is evidence that the TM and ossicles no longer act linearly. The anatomical structures that contribute to the nonlinear responses and their level and frequency dependences are not well defined. We used cadaveric human ears to characterize middle-ear responses to continuous tones between 200 and 20,000 Hz with levels between 60 and 150 dB SPL. The responses of the TM and ossicles are essentially sinusoidal, even at the highest stimulus level, but grow nonlinearly with increased stimulus level. The umbo and the stapes show different nonlinear behaviors: The umbo displacement grows faster than the stimulus level (expansive growth) at frequencies below 2000 Hz, while the stapes exhibits mostly compressive growth (grows slower than the stimulus level) over a wide frequency range. The sound pressure level where the nonlinearity first becomes obvious and the displacement at that level are lower at the stapes than at the umbo. These observations suggest the presence of multiple nonlinear processes within the middle ear. The existence of an expansive growth of umbo displacement that has limited effect on the stapes compressive growth suggests that the ossicular joints reduce the coupling between multiple nonlinear mechanisms within the middle ear. This study provides new data to test and refine middle-ear nonlinear models.

Histopathology of the Incudomalleolar Joint in Cases of "Indeterminate" Presbycusis.

Retrospective study.

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

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. 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). 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. 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.

A Non-linear Viscoelastic Model of the Incudostapedial Joint.

The ossicular joints of the middle ear can significantly affect middle-ear function, particularly under conditions such as high-intensity sound pressures or high quasi-static pressures. Experimental investigations of the mechanical behaviour of the human incudostapedial joint have shown strong non-linearity and asymmetry in tension and compression tests, but some previous finite-element models of the joint have had difficulty replicating such behaviour. In this paper, we present a finite-element model of the joint that can match the asymmetry and non-linearity well without using different model structures or parameters in tension and compression. The model includes some of the detailed structures of the joint seen in histological sections. The material properties are found from the literature when available, but some parameters are calculated by fitting the model to experimental data from tension, compression and relaxation tests. The model can predict the hysteresis loops of loading and unloading curves. A sensitivity analysis for various parameters shows that the geometrical parameters have substantial effects on the joint mechanical behaviour. While the joint capsule affects the tension curve more, the cartilage layers affect the compression curve more.

Human ossicular-joint flexibility transforms the peak amplitude and width of impulsive acoustic stimuli.

The role of the ossicular joints in the mammalian middle ear is still debated. This work tests the hypothesis that the two synovial joints filter potentially damaging impulsive stimuli by transforming both the peak amplitude and width of these impulses before they reach the cochlea. The three-dimensional (3D) velocity along the ossicular chain in unaltered cadaveric human temporal bones (N = 9), stimulated with acoustic impulses, is measured in the time domain using a Polytec (Waldbronn, Germany) CLV-3D laser Doppler vibrometer. The measurements are repeated after fusing one or both of the ossicular joints with dental cement. Sound transmission is characterized by measuring the amplitude, width, and delay of the impulsive velocity profile as it travels from the eardrum to the cochlea. On average, fusing both ossicular joints causes the stapes velocity amplitude and width to change by a factor of 1.77 (p = 0.0057) and 0.78 (p = 0.011), respectively. Fusing just the incudomalleolar joint has a larger effect on amplitude (a factor of 2.37), while fusing just the incudostapedial joint decreases the stapes velocity on average. The 3D motion of the ossicles is altered by fusing the joints. Finally, the ability of current computational models to predict this behavior is also evaluated.

Effect of ossicular-joint flexibility on bone conduction hearing—A finite-element model analysis

The mammalian ossicular chain contains three distinct bones typically connected by synovial joints, comprising of a flexible coupling path between the eardrum and cochlea. It is hypothesized that one role for ossicular joint flexibility is to reduce the ossicular input to the cochlea in response to self-generated bone-conducted sounds, but without significantly affecting the normal air-conduction pathway. This hypothesis is tested using a finite-element (FE) model of the human middle ear terminated in a cochlear load impedance. The FE model of the middle ear with accurate representations of the ossicles and ossicular-joint flexibility was developed from micro-CT images. The model was validated using experimental data taken with air-conduction stimulation. Calculations of 3D ossicular motion and intracochlear sound pressure in response to bone-conduction stimulation from 0.1 to 20 kHz were performed with the natural ossicular chain as well as with modifications in which one or both ossicular joints were fu...

Flexibility of ossicular joints reduces damaging impulse peaks

The presence of three distinct middle-ear ossicles is a uniquely mammalian trait whose benefits are still debated. One hypothesis is that the flexibility afforded by the two synovial joints connecting the ossicles provides a protective advantage by dispersing potentially damaging impulsive stimuli before they reach sensitive cochlear structures. The 3D velocity of points along the ossicular chain in unaltered cadaveric human temporal bones (N = 9), stimulated with acoustic impulses, was measured in the time domain using a Polytec CLV-3D laser Doppler vibrometer. The measurements were then repeated after fusing one or both of the ossicular joints. Sound transmission was characterized by measuring the amplitude, width, and delay of the impulsive velocity profile as it traveled from the eardrum to the cochlea. In most cases, a delay was noted across either or both of the ossicular joints, and the velocity profile at the stapes was lower in amplitude and broader than at the umbo. Typically, fusing the incus-s...

STUDY ON THE ROLE OF OSSICULAR JOINT USING FINITE ELEMENT METHOD

The lever ratio, the vibration mode and the stiffness of the ossicular joints were studied using the finite element (FE) analysis of the response of human ear under the outer ear sound excitation. The three-dimensional FE model was constructed based on serial micro CT images of a temporal bone block, and validated through comparison with the experimental data from previous literatures. The displacements of the umbo and stapes footplate and the vibration mode of the ossicles under different grades of stiffness of middle ear components were derived. It is suggested that the flexible ossicular joint combined with the shift of rotation axis causes the increase of lever ratio at high frequency. In addition, the flexible incudostapedial joint (ISJ) can reduce sound transmission especially at high frequency, meanwhile it also permits more vibration energy transmitted to the piston-like directions.

The Audiometric and Mechanical Effects of Partial Ossicular Discontinuity

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. 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. (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. 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.

Fluctuating mixed-type hearing loss associated with synovitis–acne–pustulosis–hyperostosis–osteomyelitis (SAPHO) syndrome

Synovitis, acne, palmoplantar pustulosis (PPP), hyperostosis, and osteitis (SAPHO) are the characteristic features of SAPHO syndrome. A 53-year-old woman had been treated for PPP for 2 years. She complained of hearing loss in the right ear, and otitis externa was diagnosed. The pure-tone audiogram (PTA) indicated mild hearing loss in the right ear, and her hearing continued to deteriorate despite recovery from inflammation. Her tympanogram was of the As-type, and acoustic reflex was absent in the right ear. A computed tomography (CT) scan revealed bilateral normal ossicles and cochleas. Bone scintigraphy revealed tracer uptake in the bilateral sternoclavicular joints, glenohumeral joints, and the capital humerus. She was hospitalized for arthralgia, and the pain was controlled with steroid therapy. Her right hearing deteriorated soon after the tapering of the steroid; her hearing recovered after cyclosporine therapy was initiated. The first tonsil provocation test showed increased blood cells in the urine, and the second test showed exacerbation of pustulosis. Despite immunosuppressant therapy, the arthritis attacks and hearing loss persisted; therefore, tonsillectomy was performed, which improved PPP. However, her hearing remained unchanged after the operation. We considered that irreversible changes might have already developed in the ossicular joints, and ossicular reconstruction was performed. Thereafter, her hearing and earache improved.

Results after Revision Stapedectomy with Malleus Grip Prosthesis

Revision stapedectomy with a malleus grip prosthesis is a technically challenging otologic procedure. The prosthesis is usually longer and extends deeper into the vestibule than a conventional stapes prosthesis, creating the potential to affect the vestibular sense organs. The prosthesis also bypasses the ossicular joints, which are thought to play a role in protecting the inner ear from large changes in static pressure within the middle ear. The prosthesis is in close proximity to the tympanic membrane, thus increasing the risk for its extrusion. We reviewed our experience with revision stapedectomy with the Schuknecht Teflon-wire malleus grip prosthesis in 36 ears with a mean follow-up of 23 months. The air-bone gap was closed to within 10 dB in 16 ears (44%) and to within 20 dB in 26 ears (72%). The incidence of postoperative sensorineural hearing loss was 8% (3 ears). There were no dead ears. Extrusion of the prosthesis occurred in 1 case (3%). Nearly 50% of patients reported various degrees of vertigo or disequilibrium during the first 3 weeks after surgery. These vestibular symptoms resolved by 6 weeks in all but 1 case. We did not find evidence of damage to the inner ear due to the length of the prosthesis or due to the potential for direct transmission of changes in static pressures within the middle ear to the labyrinth. Our results are similar to those published in the literature for malleus attachment stapedectomy and conventional revision incus stapedectomy.

Experimental ossicular fixations and the middle ear’s response to sound: Evidence for a flexible ossicular chain

A human temporal-bone preparation was used to determine the effects of various degrees of artificial ossicular fixation on the sound-induced velocity at the input-side (the umbo of the malleus) and the output-side (the stapes) of the ossicular chain. Construction of various degrees of attachment between an ossicle and the surrounding temporal bone provided a range of reduction in ossicular mobility or “fixations”. The results demonstrate different effects of the fixations on the umbo and stapes velocity: fixations of the stapes or incus produce larger reductions in sound-induced stapes velocity (as much as 40–50 dB with extensive stapes fixation), than reductions in umbo velocity (typically less than 10 dB). Fixations of the malleus produce similar-sized changes in both umbo and stapes velocity. These differential effects are consistent with significant flexibility in the ossicular joints (the incudo-malleolar joint and the incudo-stapedial joint) that permits relative motion between the coupled ossicles. The existence of flexibility in the ossicular joints indicates that joints in the ossicular chain can effect a loss of sound-induced mechanical energy between the umbo and the stapes, with a concomitant reduction in the sound-induced motion of the stapes. The introduction of such losses in sound transmission by the joints raises questions concerning the utility of three ossicles in the mammalian ear. The consequences of ossicular flexibility to ossicular-chain reconstruction is discussed. Also, as examined in a more clinically directed paper [Laryngoscope 115 (2005) 147], the different effects of the various ossicular fixations on the motion of the umbo and malleus may be useful in the diagnosis of the site of fixations in humans with conductive hearing losses caused by such pathologies.

Histochemical Characterization of the Rat Ossicular Joint Cartilage with a Special Reference to Stapediovestibular Joint

The stapes footplate articulates the vestibular window (stapediovestibular joint; SV joint). The SV joint is known as crucial region of otosclerosis. To shed a light on pathogenesis of otosclerosis, we have examined the histochemical characteristics of the rat ossicular joint cartilage. Interestingly, glycoconjugate histochemistry revealed that the cartilage matrix components of the SV joint were significantly different from those of the other ossicular joints, i.e. incudomalleolar (IM) and incudostapedial (IS) joints. Alcian blue, pH 2.5 and high-iron diamine procedures vividly stained the cartilage matrices of the IM and IS joints, while those of the SV joint were faintly stained. Chondroitin sulfate immunohistochemistry revealed intense labeling of the cartilage of the IM and IS joints, while the immunolabeling of the SV joint was negligible. On the contrary, keratan sulfate immunolabeling was discernible on the cartilage matrices of the SV joint, but not on those of the IM and IS joints. Type II collagen immunolabeling revealed that the marginal region of the IM and IS joint cartilage matrices was devoid of the immunostaining, while the SV joint cartilage matrices were uniformly labeled with this antibody. In this study, we have succeeded in demonstrating the histochemical characteristics of the rat SV joint cartilage matrices of which is quite different from those of the other ossicular joints.

The acoustic aspect of ossicular joints fixation in human temporal bones

Problem: The middle ear mechanism involves the conduction of mechanical vibrations along the ossicular chain. Although the functional mechanism and ossicular motion of the middle ear have been revealed in many papers, the acoustic role of ossicular joints is still unclear in human temporal bones. Methods: Eleven fresh human temporal bones with intact middle and inner ear were measured for the peak-to-peak displacement and phase on umbo and stapes footplate using a laser Doppler vibrometer system. Sound was generated and controlled by a SYSid 6.5 audio analysis system and the stimulus was a sound input of 80 to 120 dB SPL at the tympanic membrane over the 0.1 to 10 kHz frequency range. After the baseline measurements, incus was carefully removed and replaced to ordinary position with cyanoacrylate glue. Measurements of umbo and stapes footplate motion were repeated. Results: The average time lag between umbo and footplate in the middle ear was 89 μs, which was constant at a measured frequency range from 0.1 to 10 kHz. After the fixation of ossicular joints, the delay was reduced to 35 μs for sound transmission between umbo and stapes footplate. With the incus removed and reglued, the footplate displacement was about 7 dB lower than for the intact middle ear at frequencies below 1 kHz. Conclusion: The time lag in the middle ear seems to be caused by the slippage of the ossicular joints, not only the I-S joint but also the M-I joint. The 89 μs delay means that when malleus moves inward, stapes footplate moves outward at 5.6 kHz. Significance: In middle ear surgery, the surgical exposure could be improved by resection of incus, because the acoustic damage of the incus reposition was less than 6 dB. Support: None reported.

Functional and systematic implications of the ear in golden moles (Chrysochloridae)

Golden moles (Chrysochloridae) are fossorial mammals known to have unusual mallei. The aim of this study was to describe and quantify aspects of the auditory morphology of golden moles in order to determine their systematic and functional implications. Observations were made on skeletal material as well as histological sections. The results of this study do not support the separation of the genus Calcochloris from Amblysomus. It was found that the morphology shared by all the studied genera is indicative of specialization for hearing low frequency sound. The tympanic membrane to stapes footplate ratios, ossicular lever arm ratios and incudomallear joint morphology suggest low frequency specializations in genera with small mallear heads and high frequency specializations in genera with large mallear heads. However, the size and degree of trabeculation of the tympanic cavity are not consistent with this result. It is proposed that all golden moles are low frequency hearers with differences in their range of sensitivity according to how much time they spend foraging above ground.

Developmental anatomy of the mouse stapediovestibular and temporomandibular joints.

The genesis, development and growth of the mouse stapediovestibular joint (SVJ), which contains the annular ligament, and the temporomandibular joint (TMJ) were examined in an attempt to study the stress-bearing articular tissue that is thought to be derived from embryonic mesenchyme; the findings were also compared with those in the ossicular joints. The following conclusions were obtained: 1) The articular cartilage of the mandibular condylar process, stapedial foot plate and otic capsule is derived from fetal fibrous articular tissue. 2) The fetal TMJ developed into a typical double diarthroses containing an articular disc. 3) The fetal syndesmodial SVJ differentiated into the annular ligament containing characteristic palisade-like fibroblasts and hammock-like fibers; no interzone formation or synovial cavities were observed in the completed and mature syndesmodial SVJ. 4) Like the TMJ, the major elastic system fibers in the annular ligament were also mechanical-resistant elaunin. 5) Elastogenesis was closely related to functional and mechanical factors in the auditory ossicular chain, TMJ and annular ligament; the mature incudomalleal and incudostapedial joints contained mainly mature elastic fibers, but the mature SVJ and immature TMJ contained mainly pre-elastic elaunin fibers. 6) Stress elastosis, turnover of the fibrillar component and age changes in cellular and fibrous components were not evident in either the mature SVJ or the young functional TMJ.

Die Mechanik und Funktion des Mittelohres - Teil 1: Die Ossikelkette und die Mittelohrmuskeln

The revelation of a sophisticated micro-mechanism within the ossicular chain--the gliding of the joints results in a characteristic change of the ossicular movement--extended our conception of the function of the ossicular chain. Contrary to our former ideas of the transmission of sound during hearing, the ossicles do not rotate around an axis, which runs through the center of mass of the malleus and anvil. The imaginary rotational axis is located outside the ossicles, resulting in a more piston-like vibration of the complete chain. The ossicular joints are rigid. This acoustic function of the ossicular chain must rigorously be separated from its behaviour at changes of static, ambient air pressure. The middle ear, working as a sensitive pressure receptor also reacts to these pressure changes with comparatively huge displacements of the drum membrane (visible in pneumatic otoscopy). Only now the malleus rotates around its axial ligaments. These movements cause a gliding motion in the malleus-incus joint, which results in a predominant up- and downward movement of the anvil; the incudo-stapedial joint glides, too, and the stapes (and the inner ear) are decoupled. This micro-mechanism explains several anatomical features of the middle ear construction, as there are the vertical alignment of the incudo-stapedial joint, the suspension of the anvil, the design of the malleus joint, etc. It also accounts for the peculiar anatomical arrangement of the middle ear muscles. Their function can be interpreted as preserving the intact cartilage of the ossicular joints.(ABSTRACT TRUNCATED AT 250 WORDS)

Nature of the ossicular joints and their involvement in rheumatoid arthritis.

Nature of the ossicular joints and their involvement in rheumatoid arthritis.

Ossicular abnormality in Larsen's syndrome: A case report

Larsen's syndrome consists of a skeletal dysplasia with multiple joint abnormalities and a characteristic facies. No reports of this syndrome have documented hearing loss due to ossicular joint abnormalities. A 6-year-old girl is presented with the characteristic abnormalities of Larsen's syndrome, a normal otoscopic examination, and significant bilateral conductive hearing loss. Exploratory tympanotomy demonstrated an incudostapedial joint abnormality, as well as a fixed stapes footplate. The possibility of ossicular joint abnormalities, in addition to the other joint abnormalities associated with this syndrome, must be considered.