Incudostapedial Joint Research Articles

Otological manifestations in head injury and their management - a case report

32 year old male presented with right facial palsy following head injury. Clinical evaluation showed hemotympanum on right with moderately severe conductive hearing loss, grade III LMN facial palsy and BPPV. HRCT of temporal bone demonstrated fracture base of skull involving the roof of mastoid with no evidence of bony injury to fallopian canal. Conservative management of head trauma resulted in satisfactory outcome except for conductive hearing loss and faciel palsy. Facial palsy was managed conservatively [physiotherapy and oral steroids] with full recovery of function after 4 weeks. Conductive hearing loss was managed by combined approach tympanaplasty. Preoperutively incudostapedial joint dislocation and fracture anterior crus of stapes were noted. Type II tympanoplasty with horizontal incus repositioning was carried out.PTA after 6 weeks showed 15-20 dB air-bone gap compared to 50-55dB air-bone gap preoperatively. BPPV recovered spontaneously. This case is reported to highlight:Importance of imaging of temporal bone.Spontaneous recovery of facial nerve function in neuropraxtc injury.Timely and appropriate surgical intervention of ossicular damage following head injury resulting in satisfatctory outcome.

Clinical evaluation of congenital cholesteatoma of the middle ear

We conducted a retrospective study to identify the clinical features and surgical observations of congenital cholesteatoma. Sixty patients were diagnosed and underwent surgery for congenital cholesteatoma between April 1987 and May 2002. All diagnoses were made on the basis of two operative findings: 1. the tympanic membrane manifested neither retraction, perforation, nor granulation. 2. the tympanic membrane was not continuous with the cholesteatoma. In this series, congenital cholesteatoma accounted for 7% of all cholesteatomas (853 ears). The patient age ranged from 2 to 48 years. The male to female ratio was 4:1. Seventeen patients had multiple cholesteatoma. Fifty-three patients exhibited closed-type cholesteatomas, while the remaining 7 patients had open-type cholesteatomas that had formed as a flat surface of the epidermis. Patients with open-type cholesteatomas presented with a much more pronounced conductive hearing loss and ossicular erosion or malformation. Twenty-two patients with relatively small cholesteatomas were analyzed to estimate the origin of their cholesteatomas. Of the 22 patients, 13 had anterior superior quadrant (ASQ-type) and 9 had posterior superior quadrant (PSQ-type) cholesteatomas. The mean age at the time of detection was older in the PSQ-type group than in the ASQ-type group and the frequency of ossicular erosion or malformation was more prominent in the PSQ-type group than in the ASQ-type group. The primary site of origin was thought to be the portion between the tympanic ostium of the auditory canal and the semicanal for tensor tympani in the ASQ-type group and near the incudostapedial joint in the PSQ-type group. A planned staged procedure was performed in 29 patients, 15 patients (52%) had residual lesions situated mostly on the oval window, the round window, an exposed facial nerve or an exposed lateral semicircular canal. The frequency of residual lesions in patients who presented with extended, multiple cholesteatoma and those with ossicular malformation was comparable to the frequency of patients who did not present with these features.

Factors contributing to bone conduction: the middle ear.

Measurement of the motion of the malleus umbo and stapes footplate during bone conduction (BC) stimulation was conducted in vitro in 26 temporal bones using a laser Doppler vibrometer over the frequency range 0.1 to 10 kHz. For lower frequencies, both ossicular sites followed the motion of the temporal bone. The differential motion between the malleus and the surrounding bone was greater than the differential motion of the stapes footplate; both resonated near 1.5 kHz. Different lesions were shown to affect the response: (1) a mass attached to the umbo lowered the resonance frequency of the ossicular vibration; (2) fixation of either the malleus or stapes increased the stiffness and shifted the resonance frequency upward; and (3) dislocation of the incudo-stapedial joint did not significantly affect the ossicular vibration. The sound radiated from the tympanic membrane was approximately 85 dB SPL at an umbo differential velocity of 1 mm/s for low frequencies in an open ear canal and about 10 dB higher for an occluded one; at higher frequencies (above 2 kHz) resonances of the canal determine the response. It was also found that the motion between the footplate and promontory was within 5 dB when the specimen was stimulated orthogonal to the vibration direction of the ossicles than in line with the same. Measurement of the differential motion of the umbo in one live human skull gave similar response as the average result from the temporal bone specimens.

Fetal Development of the Human Tympanic Ossicular Chain Articulations

Objectives: To obtain further knowledge on the morphogenesis of the articulations in the tympanic ossicular chain in humans. Material and Methods: In 25 temporal bones of human fetuses the structural development of incudomallear, incudostapedial and stapediovestibular articulations was studied. The chronological ages were between the 7th week (21 mm) and the 29th week (270 mm). Results and Discussion: Incudomallear articulation showed diarthrosis and sellar joint characteristics. It showed a homogenous interzone in the 7th week of development, a three-layered interzone in the 8th week, the first cavitation signs in the 9th week and the presence of an articular cavity in the 10th week. The presence of a hyaline cartilage covering articular surfaces was observed starting in the 20th week of development. Incudostapedial articulation showed typical characteristics of a diarthrosis and spheroidal joint with a homogenous interzone at the 7th week, showing similar characteristics for 12 weeks, and completed its cavitation at the 16th week. We observed hyaline cartilage on articular surfaces from 29 weeks. Stapediovestibular articulation showed typical characteristics of syndesmosis. The annular ligament primordium derived from cartilage differentiation, both from stapedial footplate and from the surrounding otic capsule, into mesenchyme and its subsequent transformation into fibrous tissue, reaching definitive characteristics from the 12th week.

Classical Neo-stapedotomy

Preservation of stapedius muscle and incudo-stapedial joint during stapedotomy for otosclerosis is the motto of the dat. The Study was carried out in 500 patients. In Group A (n = 140), the stapedius muscle and incudostapedial joint were preserved. In Group B (n = 360), the stapedius muscle was cut. One month after surgery in Group A patients, the Stapedius-Reflex (SR) was evoked in 75% and three months later in 90%. The mean Loudness Discomfort Level (LDL) after one month of surgery in Group A was 95dB while three months after it was increased to 110dB. Speech discrimination score (SDS) in Group A with 80 dB suprathreshold is 93% and in Group B it is only 72%. This study established the fact that the preservation of stapedial muscle and incudo stapedial join is beneficial and essential, whenever possible, in the surgery for otosclerosis.

Mass loading on the ossicles and middle ear function.

The middle ear as a levered vibrating system for sound transmission from the external to the inner ear is affected by changes in ossicular chain mass. Mass loading of the ossicles may impair ossicular dynamics and sound transmission to the inner ear. It is incumbent on otologic surgeons and researchers of middle ear mechanics to consider the mass loading effect on middle ear function in clinical and physiological applications. The residual hearing and frequency response can change after surgery or implantation of middle ear prostheses. We conducted experiments on mass loading effects on the middle ear transfer functions by using laser Doppler interferometry and a human temporal bone model. Two implant mass loading conditions were tested on 17 fresh or fresh-frozen temporal bones and compared with the unloaded condition for the frequencies 250 to 8,000 Hz. The results show that the linearity of the middle ear function did not change, although displacement of the stapes footplate decreased after the increased masses were placed on the incudostapedial joint. The greater the mass of the implant, the less displacement was measured at the stapes footplate. We conclude that there is a quantitative limit to increased mass on the ossicular chain above which the mass will remarkably impair hearing thresholds.

耳かき外傷によるアブミ骨底板骨折例

A case of fracture of the stapes footplate with ossicular disruption and perilymph fistula caused by earpick-induced trauma is reported. A 51-year-old female was presented with hearing loss and vertigo just after sticking an ear pick into her left ear. Pure tone audiometry showed a mixed hearing loss of 67.5dB. Nystagmus was not observed, and vertigo improved in a week. On exploratory tympanotomy, the fracture of the stapes footplate accompanying a dislocation of the incudo-stapedial joint and perilymphatic leakage from the oval window were found. The perilymph fistula was sealed with temporal fascia, and ossicular chain continuity was reconstructed by type N tympanoplasty. After the operation, the cochlear and vestibular symptoms improved.

外傷性アブミ骨転位例

We report a case of traumatic dislocation of the stapes without disruption of the ossicular chain.An 8-year-old boy visited our clinic because of left-sided hearing impairment. Pure tone audiography showed average conductive hearing loss of 50dB. Stapedial dislocation was suspected by temporal bone CT. Exploratory tympanotomy revealed that the stapes was dislocated inf eriorly with its footplate fused with the bony promontory wall. Both malleo-incudal and incudo-Stapedial joints were intact. The oval window was closed with thin scar tissue being covered by intact mucosa. When the superstructure of the stapes was removed and the overlying tissue of the oval window was incised, outflow of perilymph was observed. With the placement of a 4.5mm-long teflon wire piston, his hearing improved to 13dB on average, without particular complications. Although the history of head trauma he experienced was not severe enough to explain the dislocation of the stapes, a mechanical cause was more likely in this case than a congenital anomaly because there were no anomalies in his middle ear or any other parts of his body.

Experimental and clinical results of Er:YAG laser stapedotomy.

At the beginning of the 1980s, different laser types were used for stapes surgery to reduce potential harm to inner ear structures through manipulation with conventional instruments during stapedotomy. Most clinical studies were carried out with the CO2 or the argon laser. The Er:YAG laser has been used rarely in patients with otosclerosis. In an experimental study on 54 human petrous bones, the optimal laser energy parameter for dissection of the posterior stapes crus and the footplate perforation were determined. With these parameters, stapedotomy was carried out with the Er:YAG laser in 29 patients with otosclerosis with a conventional dissection of the incudostapedial joint and the stapedius muscle tendon. The Er:YAG laser was used (60 or 100 mJ, 3-6 pulses) for dissection of the posterior stapes crus and footplate perforation. No intra- or postoperative complications were observed in all 29 patients. Vertigo and hearing loss were not observed intra- or postoperatively. The postoperative hearing results (improvement of the air-bone gap) was in all cases satisfactory (median remaining air bone gap, 8.1 dB). The median operation time was 29 minutes (15-42 minutes) and did not show a significant prolongation in comparison to the conventional technique. In 1 of the 29 patients, the footplate perforation needed to be carried out conventionally. For the first time, Er:YAG laser parameters have been optimized and refined in a human petrous bone model and were then used in a clinical setting. According to the presented results, the Er:YAG laser seemed to be a very suitable instrument for stapedotomy.

Ossiculoplasty in young children with the Applebaum incudostapedial joint prosthesis.

To evaluate the performance of the Applebaum incudostapedial joint prosthesis in young children in terms of hearing results and long-term stability despite continuing eustachian tube dysfunction and otitis media. Retrospective review of all Applebaum prostheses placed in children at our institution from June 1993 to June 1998. In 1993 Applebaum proposed the use of a hydroxylapatite ossicular prosthesis as an alternative to incus interposition for the repair of incudostapedial discontinuity. We have used this prosthesis exclusively for the repair of such defects in children over the past 5 years. Among 12 operated ears, all healed, all prostheses remain in place (average duration, 2.6 y), and all children have excellent hearing (mean air-bone gap, 15 dB; range, 5-25 dB). The Applebaum incudostapedial joint prosthesis restores conductive hearing even in young children. It has been stable in the face of recurrent otitis media and has not interfered with revision surgery. Placement of the prosthesis at primary cholesteatoma surgery should be considered in children.

Three-dimensional reconstruction of the incudostapedial joint with helical computed tomography.

Three-dimensional images of the incudostapedial joint (I-S joint) were reconstructed using helical computed tomography (CT). The images of the joint were most often reconstructed when threshold values were selected at -500 to -700 Hounsfield Units. These shapes were changed by choosing various threshold values. Histological examinations of the cadaver specimen indicate that these changes are due to structure of the I-S joints. We conclude that these 3-D images may be useful in assessing pathology of the I-S joint.

Iatrogenic incudostapedial joint dislocation in transcanal tympanoplasty

Purpose: To report the result of transcanal tympanoplasty using Lyodura as a graft. Materials and Methods: One hundred thirty-seven patients with chronic suppurativeas otitis media with a dry perforation were considered for tympanoplasty. The transcanal permeatal approach was adopted. Lyodura as a ready-made graft was used. Results: The success rate of the graft was 78%. latrogenic incudostapedial joint dislocation was found in six patients (4.4%), and sensorineural hearing loss occurred in nine patients (6.5%). Conclusion: The use of thick dura as a graft for repair of the tympanic membrane may result in damage to the ossicular chain or dislocation of the incudostapedial joint when used as underlay. Excessive manipulation of the ossicles or drilling should be avoided.

Vibro-Acoustic Modelling of the Outer and Middle Ear Using the Finite-Element Method

In this study, a computer-based method called finite-element analysis is used to predict the forced-frequency response of the ear, with and without an ossicular replacement prosthesis (PORP 0362, Xomed Surgical Products). The method allows visualisation of the dynamical behaviour of the tympanic membrane (TM) and of the ossicles. The finite-element model is fully three-dimensional and includes both ligaments and muscles, and accounts for damping caused by the TM, ligaments, incudostapedial joint and the fluids of the inner ear. For validation, comparison is made with experimental measurements of umbo displacement taken from the literature. The translation and rotation (both anterior-posterior and inferior-superior) of the stapedial footplate are investigated. It is predicted that the translatory motion of the footplate decreases with increasing frequency, except when the frequency of the acoustic signal matches the natural frequencies of the ossicular chain or outer ear canal. The tilting motion of the stapedial footplate is also predicted to depend on frequency of excitation. The presence of a prosthesis changes the dynamical response considerably by shifting the natural frequencies of the ossicular chain. Ratios of stapes motion with and without the prostheses are plotted as a function of frequency allowing this effect to be clearly observed.

CT appearances of ossicular injuries.

Trauma of the ossicular chain is a frequent complication of temporal bone injury. Skull trauma from blows to the temporal, parietal, or occipital region (with or without fracture of the temporal bone) is the main cause of ossicular injury; other modes of injury are rare. Ossicular injury usually occurs as a dislocation, of which there are five types: incudostapedial joint separation, incudomalleolar joint separation, dislocation of the incus, dislocation of the malleoincudal complex, and stapediovestibular dislocation. Fracture of the malleus, incus, or stapes is uncommon. High-resolution computed tomography is the method of choice for evaluation of ossicular trauma. Joint separation and fracture of the stapes are seen on axial images; coronal images may aid visualization. Both axial and coronal images are needed for evaluation of a dislocated malleus or incus. Fracture of the malleus or incus is detected with axial or coronal images; reformatted images may also be useful.

Effects of middle ear pressure on otoacoustic emission measures.

An animal surgical model was established to manipulate pressure in the middle ear. The 2 f1-f2 cochlear microphonic distortion product (CMDP) and distortion product otoacoustic emission (DPOAE) were simultaneously measured in order to analyze the effects of middle ear pressure on sound transmission. The frequency ratio of the two stimulus tones f2/f1 was held at 1.2 and the level ratio L1/L2 was 10 dB. The effect of middle ear pressure on forward transmission was determined form the CMDP data. The effect on backward transmission was determined from the DPOAE data after the effect on forward transmission was subtracted out. The results showed a similar effect on forward and backward transmission. In general, negative pressure had a greater effect than positive pressure. Positive pressures of 10 and 20-cm H2O affected transmission for low-frequency stimuli (f2 = 1620 and 2680 Hz) but had little effect for high-frequency stimuli (f2 = 6980 and 10,250 Hz). Negative pressures of -2.5 to -10-cm H2O affected transmission across all frequencies tested. The effect at low frequencies is hypothesized to be related to tympanic membrane stiffness. The effect of negative pressure at high frequencies may be related to changes in the incudostapedial joint.

Normal and opacified middle ears: CT appearance of the stapes and incudostapedial joint.

To establish the computed tomographic (CT) visibility of the incudostapedial joint and of the stapes superstructure in normal and opacified middle ears. Two independent observers reviewed CT studies with 1-mm section thickness of the temporal bone in 75 normal ears and in 33 opacified middle ears (13 of which had definitive proof of disease) to establish the rate of visualization of the stapes and incudostapedial joint. In normal ears, both the stapes crura and the continuity between the incus and stapes were seen in almost 100% of cases, whereas the actual incudostapedial joint was identified in 86% (86 observations) and 67% (67 observations) of cases in the axial and coronal planes, respectively. The position of the incudostapedial joint was below footplate level on the axial images and mostly at or anterior to the midportion of the foot-plate on the coronal images. In 13 clinically confirmed diseased middle ears, the status of the stapes superstructure in all cases and that of the incus in 11 cases was correctly predicted with CT. It is now possible to visualize routinely the incudostapedial joint and stapes superstructure at CT. Absence of these structures in an opacified middle ear strongly indicates abnormality.

Middle ear mechanics in subjects with rheumatoid arthritis.

The incudo-malleolar and incudo-stapedial joints are true diarthroses and therefore may be subject to the same rheumatic lesions as any other articulation in the body. The existence of this involvement in rheumatoid arthritis (RA), however, is highly controversial. The present study investigates modifications of the mechanical properties of the middle ear in a group of subjects with RA by evaluating the resonance frequency obtained with multiple-frequency tympanometry (MFT). Thirty patients with RA, aged 20 to 68 years (mean age: 45.8 +/- 12.4 years), participated in the investigation. Their data were compared with those obtained in a control group of 48 age-matched subjects. Results obtained in both ears were examined in all subjects. The two groups displayed almost equal hearing levels with mean air conduction thresholds ranging from 10 to 22 dB HL. None of the subjects displayed an air-bone gap greater than 5 dB. Normal resonance frequency, calculated at the 95th percentile from the control group, ranged from 900 to 1250 Hz. Twelve rheumatoid arthritis patients (40 per cent) displayed abnormal resonance values. These findings were monolateral in 9 patients and bilateral in 3. Eleven out of 15 ears with abnormal multiple-frequency tympanometry data were characterized by an increase in resonance and 4 by a decrease. A correlation between abnormal resonance values and more aggressive RA was established. The results of this study suggest that rheumatoid arthritis may involve the incudo-malleolar and incudo-stapedial joints, altering the ossicular mechanics in response to static air pressure modifications. This does not impair sound conduction through the middle ear, but might reduce the protective mechanisms of the middle ear towards high static pressures.

Middle ear involvement in children with chronic rheumatoid juvenile arthritis.

In a selected sample of patients affected by juvenile rheumatoid arthritis (JRA) little is known about middle ear involvement, even though many synovial joints are affected. Multifrequency tympanometry was used to measure admittance, conductance, susceptance and phase angle at different probe frequencies and resonant frequencies. In all, 35 children with JRA and a control group (30 children) were studied. Findings showed that mean resonant frequency values in all children with JRA were greater than in the control children. The multifrequency tympanometry parameters measured in acute JRA subjects are not different from parameters of remission JRA subjects except for a change in the phase angle. The changes found are due to involvement of the incudomalleolar and incudostapedial joints.

Experimental Sensorineural Hearing Loss Following Drill-induced Ossicular Chain Injury

In a guinea pig model, a standardized drill-induced injury to the body of the incus was applied, and the effects on hearing were characterized by electrocochleography. Drilling resulted in a threshold shift within seconds, and after 15min it averaged 35.7 dB for clicks, 35 dB nHL for 4 kHz bursts, 36.7 dB nHL for 6 kHz bursts and 39 dB nHL for 8 kHz bursts. The deterioration of the threshold shift remained stable throughout the 5-week post-operative observation period. In five animals a disarticulation of the incudostapedial joint was performed prior to drilling, but this did not reduce the threshold shift. Caution is mandatory during drilling around an intact ossicular chain to avoid a permanent sensorineural hearing loss, and disarticulation of the incudostapedial joint prior to driling has no protective value.

The phenomena of time coincidence of change-point periods in different derivations of EEG

Analysis of indications for stapes revision surgery in patients qualified for the secondary procedure at the Otosurgery Dept. Medical University of Lodz.25 cases of stapes revision surgery out of the 385 total treated surgically otosclerosis cases are discussed.In group A (patients after total stapedectomy) the following indications for the secondary surgical procedure were observed: 12 cases – platinum wire prosthesis displacement with ossicular chain discontinuity; 3 cases – perichondrium or adipose tissue atrophy; 2 cases of incudo-stapedial joint luxation. Group B was composed of 8 patients after stapedotomy (teflon piston operation, 0.6 mm).1. The most common indication for the stapes revision surgery in patients after total stapedectomy were prosthesis displacement and necrosis of the long crus of the incus. 2. Obliteration of the stapes footplate after small fenestra operation was observed in our material to be the most frequent indication for the secondary stapes procedure.