JPS6319058Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a drive transducer used in a hearing aid intended to be implanted in a living body.

Currently, tympanoplasty is widely performed to improve hearing in cases of loss of the middle ear conductor due to otitis media or other diseases. He also suffers from problems with his sound system, and tympanoplasty surgery alone is not enough to improve his hearing, so he still requires hearing aids even after the surgery. In addition, there are cases where tympanoplasty surgery does not significantly improve hearing in the high-frequency range, and the use of hearing aids after surgery has become a reality.

On the other hand, although these hearing aids are useful enough to compensate for the lack of auditory function, they may cause the wearer to feel uncomfortable or depressed when wearing earphones.
Furthermore, issues such as awareness of disabled people due to their visibility remain unresolved. Furthermore, since there are many types of hearing impairments and their degrees vary widely, problems with existing hearing aids have been pointed out, such as difficulty in selecting and fitting hearing aids.

Therefore, in recent years, in conjunction with advances in tympanoplasty surgery and rapid advances in the miniaturization of biocompatible materials and electronic circuits, progress has been made in the development of ultra-compact hearing aids that can be implanted into the body.

This implantable hearing aid basically consists of (1) a microphone;
It consists of four elements: (2) an amplifier, (3) a battery, and (4) a drive transducer. Classified by method, only the drive transducer is placed inside the body, and the other elements are placed outside the body and electromagnetically coupled. There are four methods ranging from so-called semi-implantable methods, such as methods that send signals to the drive transducer using a method that transmits signals to the drive transducer, and methods that embed the microphone, amplifier, and drive transducer in the living body and place only the battery outside the living body to facilitate battery replacement. Several methods are possible, including a fully implantable hearing aid in which all elements are implanted in the body, but in any case, this implantable hearing aid is suitable for patients whose acoustic signals cannot efficiently reach the inner ear due to defects in the outer or middle ear. Instead, it performs signal transmission. In this case, the role of the transducer, which ultimately drives the inner ear lymph fluid, is important, and this has an extremely large effect on the characteristics of the implantable hearing aid.

The present invention relates to this drive transducer. By the way, the oval window, which is the original inner ear stimulation opening, is suitable as the site for driving the inner ear lymph fluid, and the present invention utilizes the stapes bone remaining in the oval window. That is, by fixing one end of the driving transducer of the present invention to the wall of the tympanic cavity near the oval window and connecting the other end to the head of the stapes bone, the vibration stimulation generated by the transducer can be applied to the inner ear lymph fluid. It is something that can be conveyed to people.

The present invention relates to a drive transducer pedestal having an optimal structure for coupling to the above-mentioned stapes head.One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing the drive transducer in use in a fully implantable hearing aid. Sound entering the microphone 1 is converted into an electrical signal through a sound processing device 2 including an amplifier, and is transmitted to a drive transducer 3 to generate vibrations. The drive transducer 3 is fixed at one end and connected to the stapes 4 at the other end. Note that 5 is a battery, 6 is an external auditory canal, 7 is an eardrum, 8 is a middle ear cavity, and 9 is a cochlea.

FIG. 2A and FIG. 2B are a side view and a top view of the transducer, respectively. The drive transducer 3 includes an element 3A that directly vibrates, a coupling part 3B that reliably transmits the vibration to the stapes 4, and a pedestal 3C that fixes the drive transducer 3 to the wall of the tympanic cavity near the oval window. It consists of The element 3A is a bending vibrator such as a piezoelectric bimorph element. The piezoelectric bimorph element is
A pair of rectangular piezoelectric plates polarized in the thickness direction are pasted together so that the polarization is opposite to each other, and electrodes are provided. Further, this element 3A is coated with a flexible biocompatible material such as urethane resin that does not hinder the bending vibration of the element 3A itself.
The connecting portion 3B is connected and fixed to the femoral head 4A of the stapes 4, and has an appropriate structure. This embodiment shows a coupling portion 3B having a key shape with a bent tip. To fix the joint 3B and the stapes 4, first connect the joint 3B to the stapes 4.
The connecting portion 3B is brought into contact with the femoral head 4A, and then the connecting portion 3B is tied to the femoral head 4A using fascial fibers or surgical threads passed through the crotch of the stapes 4. Note that since the joint portion 3B has a bent end, it is possible to prevent the binding members such as fascial fibers from falling off.

The pedestal 3C is fixed to one end of the element 3A, and is for fixing to the wall of the tympanic cavity near the oval window as described above. Therefore, it is required to be biohazardous and robust to the tympanic cavity wall, for example,
Composed of apatite or single/polycrystalline alumina. Of course, metals such as gold, platinum, and stainless steel may also be used, but in this case, it is necessary to ensure insulation between the elements 3A and the pedestal 3C, such as by using an insulating adhesive when fixing them together. The base 3C is fixed to the tympanic cavity wall with an appropriate means such as adhesive at its bottom. If 3C is constructed into a square shape and the installation position of the tympanic cavity wall is cut into a quadrilateral shape, the installation position of the pedestal 3C will inevitably be determined, and the direction of the drive transducer,
Angle is regulated. Therefore, the position of the coupling portion 3B, which is the tip of the drive transducer, is automatically determined. If the positional relationship between the connecting part 3B and the stapes 4 matches the expected positional relationship, no problem will occur, but if it does not, it is necessary to fix the connecting part 3B and the stapes 4. It is not possible to do so, and it is also not easy to change the installation posture of the pedestal 3C. Therefore, in order to avoid such inconvenience, the inventors of the present invention constructed the pedestal 3C into a hemispherical shape. That is, as shown in FIG. 3, by cutting the tympanic cavity wall surface into a hemispherical shape in advance so as to correspond to the hemisphere of the pedestal 3C, the pedestal 3C and the hemispherical recess 11A formed in the tympanic cavity wall surface 11 can be connected and fixed. At this time, the installation posture of the pedestal 3C can be set arbitrarily, and therefore the direction and angle of the drive transducer can be set arbitrarily, and the fixation can be achieved reliably and easily with respect to the unchangeable stapes 4.

The fixing of the base 3C to the element 3A and the fixing of the connecting portion 3B to the element 3A are performed by suitable means such as an adhesive that is safe for living bodies, taking into consideration biocompatibility. Similarly, the lead wire 10 is made of a silver wire or a stainless steel wire coated with Teflon or the like, taking into consideration biocompatibility.

As described above, in the present invention, the pedestal of the drive transducer for an implantable hearing aid is configured in a hemispherical shape, and the installation position of the coupling part of the drive transducer can be freely changed around the pedestal. , it is possible to easily secure the connection and fixation of this joint and the stapes.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing the driving transducer of the present invention in use in a fully implantable hearing aid.
FIG. 2A is a side sectional view showing one embodiment of the drive transducer of the present invention. FIG. 2B is also a plan view. FIG. 3 is a perspective view showing a state in which the drive transducer of the present invention is connected to the stapes. 3A: element, 3B: joint, 3C: pedestal.

Claims (1)

[Scope of utility model registration request] Pedestal 3 to be fixed to the drum wall near the oval window at one end
Element 3A that connects and fixes C, and connects and fixes the connecting part 3B that is to be connected to the head of the stapes at the other end.
A driving transducer for an implantable hearing aid, comprising a bending vibrator such as a piezoelectric bimorph element, and the pedestal 3C having a hemispherical shape.