Artificial Ossicle Research Articles

Mechanical effect of reconstructed shapes of autologous ossicles on middle ear acoustic transmission.

Conductive hearing loss is caused by a variety of defects, such as chronic otitis media, osteosclerosis, and malformation of the ossicles. In such cases, the defective bones of the middle ear are often surgically reconstructed using artificial ossicles to increase the hearing ability. However, in some cases, the surgical procedure does not result in increased hearing, especially in a difficult case, for example, when only the footplate of the stapes remains and all of the other bones are destroyed. Herein, the appropriate shapes of the reconstructed autologous ossicles, which are suitable for various types of middle-ear defects, can be determined by adopting an updating calculation based on a method that combines numerical prediction of the vibroacoustic transmission and optimization. In this study, the vibroacoustic transmission characteristics were calculated for bone models of the human middle ear by using the finite element method (FEM), after which Bayesian optimization (BO) was applied. The effect of the shape of artificial autologous ossicles on the acoustic transmission characteristics of the middle ear was investigated with the combined FEM and BO method. The results suggested that the volume of the artificial autologous ossicles especially has a great influence on the numerically obtained hearing levels.

Development of an Assessment Model for the Effect of the Replacement of Minimal Artificial Ossicles on Hearing in the Inner Ear

Due to ethical issues and the nature of the ear, it is difficult to directly perform experimental measurements on living body elements of the human ear. Therefore, a numerical model has been developed to effectively assess the effect of the replacement of artificial ossicles on hearing in the inner ear. A healthy volunteer's right ear was scanned to obtain CT data, which were digitalized through the use of a self-compiling program and coalescent Patran-Nastran software to establish a 3D numerical model of the whole ear, and a frequency response of a healthy human ear was analyzed. The vibration characteristics of the basilar membrane (BM) after total ossicular replacement prosthesis (TORP) implantation were then analyzed. The results show that although the sound conduction function of the middle ear was restored after replacement of the TORP, the sensory sound function of the inner ear was affected. In the low frequency and medium frequency range, hearing loss was 5.2~10.7%. Meanwhile, in the middle-high frequency range, the replacement of a middle ear TORP in response to high sound pressure produced a high acoustic stimulation effect in the inner ear, making the inner ear structures susceptible to fatigue and more prone to fatigue damage compared to the structures in healthy individuals. This developed model is able to assess the effects of surgical operation on the entire hearing system.

Processing Methods for Type III Tympanoplasty with Artificial Ossicles

Processing Methods for Type III Tympanoplasty with Artificial Ossicles

Effects of age-related tympanic-membrane material properties on sound transmission in the middle ear in a three-dimensional finite-element model

Background and objectivesThe Young's modulus of the tympanic membrane (TM) is an important modeling parameter in computer simulations of the sound transmission in the ear. Understanding the material mechanics of the TM is essential to improve the coupling between the tympanic membrane and the auditory ossicles. However, the impact of the age-related Young's modulus of the TM on sound transmission is not well known. The objective of this study was to use a comprehensive finite element (FE) model to assess the impact of Young's modulus on sound transmission from the ear canal to the stapes footplate over acoustic frequencies. MethodsThe FE model of the ear canal, the middle ear, and the inner ear, was constructed. The model was constructed with identical geometries and boundary conditions, but with three different Young's moduli for the TMs. The auditory ossicles, suspensory ligaments and tendons, and manubrium were also modeled as isotropic elastic materials. Beside, we evaluated the age-related Young's moduli of the TMs on sound transmission with the FE element fluid-structural interaction (FSI) model under acoustic loading conditions. ResultsThe impact of the age-related Young's moduli on the sound pressure distributions in the ear canal was significant over two frequency ranges of 1.4–3.2 and 8.6–10 kHz. Meanwhile, the significant differences of the displacement of the stapes occurred at around 1.6 kHz, where the displacement of the stapes decreased from 0.352 nm to 0.287 nm. ConclusionsThe FSI model could demonstrate the influence of Young's modulus of the TM on the transfer of sound-induced vibrations form the ear canal to the stapes footplate. The FE model may provide appropriate information to the medical device development of artificial ossicles and hearing aids.

Analysis of clinical characteristics of middle ear osteoma at different locations

Objective: To explore the clinical characteristics, intervention and treatment of tympanic osteoma at different locations. Methods: The medical history, audiological and imaging examination, operation and follow-up results of two patients with tympanic osteoma at different sites were reviewed and summarized. Furthermore, the clinical characteristics and interventions of 36 patients reported in literatures with tympanic osteomas were also summarized and analyzed. Results: Osteoma of the two patients collected in this study located at promontory and incus respectively;both of them presented with intact tympanum and conductive deafness, without obvious etiology or predisposing factor. Both of them underwent surgeries and the hearing improved significantly. For patient one, the ossicular chain was intact and restored to activity after removed the osteoma. For patient two, an artificial ossicle was implanted after removed the osteoma and incus. In the 36 patients reported in literatures, the average age was 26.5 years, and 39.47% of them located at promontory; in addition, the main symptoms of them were progressive hearing loss, tinnitus and ear stuffy. Conclusions: Patients with tympanic osteoma are characterized by conduction deafness with intact tympanic membrane, and the most common lesion is promontory. Hearing can be restored by excision of the osteoma and maintenance or reconstruction of the ossicle chain.

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.

Finite Element Dynamics of Human Ear System Comprising Middle Ear and Cochlea in Inner Ear

A human middle ear consists of an eardrum and three ossicles which are linked by each other, and connect with the eardrum and an inner ear. The inner ear consists of a cochlea and a vestibular system. An abnormality of the human middle ear such as ossicular dislocation may cause conductive hearing loss. The conductive hearing loss is generally treated by surgery using artificial ossicles. The treatments of conductive hearing loss require a better understanding of characteristics and dynamic behaviors of the human middle ear when the sounds transmit from outer inner to inner ear. The purpose of this research is to simulate the dynamic behaviors of a human ear system comprising the middle ear and the cochlea in the inner ear using the finite element method (FEM). Firstly, the eigen-value analysis was performed to obtain the natural frequencies and vibration modes of the total ear system. Secondly, the frequency response analysis was carried out. Thirdly, the time history response analyses were performed using human voices as the external forces. In the time history response analyses, the sounds created as input sound pressures were used. Human voices, for example vowels “I”, “u” and “e” as input sound pressures were created by using the sound pressures downloaded from the opening samples of human voices as wav files in a website. Then it was clarified that the high frequency components of sounds are reduced by the middle ear system.

Infection associated with hydroxyapatite prosthesis and related factors

Background The purpose of otomicrosurgery in modern times is to achieve complete removal of disease, which is the basis for hearing rehabilitation. Artificial ossicles are important for hearing rehabilitation. One of the materials is hydroxyapatite that acts as ossicular replacement prosthesis (HA prosthesis, PORP & TORP) and is commonly used as substitute bone in clinics. Although HA prostheses feature good biocompatibility, stability and certain resistance to infection, the structure of the material can be decomposed and absorbed. Based upon animal experiments and clinical application, this article explores the infectivity of HA prostheses and influencing factors. Materials and Methods HA prostheses were implanted in the bulla in guinea pigs. Infected HA prostheses were examined under a scanning electron microscope. Ninety patients implanted with HA prostheses were followed for more than 3 months. Five cases that had undergone revision operations were reported. Results Scanning electronic microscopy showed that the normal compact structures had disappeared and become loose in infected HA prostheses, with their micropores infiltrated with effusion, fibrous tissue and inflammatory cells. As a result, the normal ceramic structure was decomposed and the micropores structure disappeared. The infected mesotympanum in the reported cases also led to HA infection. The shape and structure of bone were destroyed, which was visible by visual examination and light microscopy. The process of cholesteatoma recurrence was always associated with infection, although the HA prosthesis was sometimes spared. Conclusion While HA prosthesis is anti–infective to some extent, long–term infection and cholesteatoma recurrence can lead to destruction and decomposition of HA prostheses. Long–term infected middle ear cavity, dysfunctional Eustachian tube, residual and recurrent cholesteatoma and other factors can cause decomposition of HA prosthesis and result in hearing loss.

Effects of ossicular reconstruction with Partial ossicular replacement prostheses in tympanoplasty

Objective OEvaluate the effect of ossicular reconstruction with partial ossicular replacement prostheses (PORP) or toutal ossicular replacement prostheses (TORP). Methods We effectively connected the ossicular chain used the PORP or TORP, replaced the destructive autologous ossicular. Results All the patients were followed-up for 6-47 months, the tympanic membrane got well, the averaged postoperative air conduction reduced 27.8 dB HL, the effectiveness was 79.3%. The recurrent and the reject reaction were zero. Conclusion It is considered that the PORP or TORP was a safety and useful material for ossicular reconstrction in the tympanoplasty. Key words: Otitis media; Middle ear malformation; Artificial ossicle; Tympanoplasty

Transmitting Vibration of Artificial Ossicle

Transmitting Vibration of Artificial Ossicle

ｖａｎ ｄｅｒ Ｈｏｅｖｅ 症候群例

A case of van der Hoeve syndrome in a 7-year-old Japanese male is reported here. He demonstrated three symptoms: blue sclera, osteogenesis imperfecta and conductive hearing loss.Pure tone audiometry showed a 61.7dB hearing loss in the left ear. Tympanogram was type Ad and stapedial reflex was absent. Therefore, dislocation of ossicular chain was suspected.At surgery, it was observed that the bilateral stapedial crura had fractured spontaneously, but the stapedial footplate was mobile. Using tympanoplasty IV-i type, we reconstructed the conduction with an artificial ossicle. The patient obtained an improvement in his hearing level in the immediate postoperative period.

7 cases of congenital aural atresia and stenosis

We have experienced 7 cases of congenital aural atresia or stenosis in the past 10 years. They include 3 males and 4 females, and all of them are under 10 years old except for one case (47-year-old man). We performed both a canalplasty and a tympanoplasty at the same time in all cases. We have treated 3 cases as tympanoplasty type I, 2 cases as tympanoplasty type II -c, 1 case as tympanoplasty typeIV-c, and 1 case without reconstruction of ossicle, The major cause of hearing loss after the operation was lateralization of the tympanic membrane and fixation of a collumela. We performed re-operations in 2 cases by establishing a bony annulus or replacing the collumela with an artificial ossicle. If the handle of malleus is there, the interdigited method is effective to prevent lateralization of the tympanic membrane.

骨パテにより生じた術後性耳小骨固着例

We report a case of ossicular fixation caused by bone pâté. A 57-year-old woman underwent staged tympanoplasty for right middle ear cholesteatoma. Bone pat6 was used for reconstruction of the scutum and for the prevention of the extrusion of an artificial ossicle at the second-stage operation. Although right hearing initially improved postoperatively, it gradually deteriorated 4 months after the operation. Revision surgery performed 1 year after the second-stage operation showed that the bone pâté used for scutumplasty had been incorporated with that used for eardrum augmentation, which resulted in ossicular fixation. After the removal of the part of the bone pat6 that was fixed to the artiflcial ossicle, both the mobility of the ossicle and right hearing markedly improved.

Electromechanical transducer for implantable hearing aids

Electromechanical transducer for implantable hearing aids. The transducer has a hermetically sealed and biocompatible housing, in which a wall is designed as a membrane that can oscillate, and which forms a heteromorphic connecting element together with a piezoelectric ceramic disk. Mechanical oscillations of the housing membrane are coupled to the middle ear or inner ear of the user by a mechanically rigid element attached in the central area of the membrane. This element is configured as a bow, so that in positioning the transducer housing from the direction of the mastoid adjoining the tympanic cavity, it acts as an artificial anvil to which coupling elements can be attached for mechanically transmitting oscillations of this artificial ossicle to the inner ear. Various coupling elements can be used, which correspond to the respective individual pathological situation. The application of the entire transducer system can be performed the operating surgeon having an unobstructed view, without extensive, space-creating interventions in the anatomical conditions of the middle ear.

セラミック人工耳小骨使用上の手技と改良について

The use of artificial ossicles in tympanoplasty, especially ceramic ossicles was reviewed. We designed new types of ceramic artificial ossicles whose head was semicircularly removed on both side. They can be easily grasped by ear forceps and a total view of the stapes is obtained through the opening, so the orientation of the tips of PORP and TORP can be done more easily and securely. We described the details of the techniques of ceramic artificial ossicles insertion during tympanoplasty.

Vibration analysis in middle ear model with artificial ossicles, total ossicular replacement prosthesis (TORP) by holographic interferometry

Vibration analysis in middle ear model with artificial ossicles, total ossicular replacement prosthesis (TORP) by holographic interferometry