WO1990007915A1

WO1990007915A1 - Auditory prosthesis for the middle ear of living organisms, in particular humans

Info

Publication number: WO1990007915A1
Application number: PCT/EP1990/000124
Authority: WO
Inventors: Klaus Schumann
Original assignee: Klaus Schumann
Priority date: 1989-01-20
Filing date: 1990-01-22
Publication date: 1990-07-26

Abstract

An auditory prosthesis for the middle ear of living beings, in particular humans, optimizes the harmonic response in a manner which is simple, reliable and acceptable for the patient. The auditory prosthesis comprises a wire (11) having an essentially straight first section (12) for connection to the stirrup (5) of the middle ear, a second, curved section (13) adjacent to the first section, for connection to the third section (14) of the wire and a third, curved section (14) the end of which rests against the hammer (3) of the middle ear. The curvature of the third section (14) is opposite to that of the second section (13).

Description

Ear prostheses for the middle ear of living beings, especially humans

The invention relates to newly developed hearing prostheses for the middle ear of living beings, especially humans. Furthermore, the invention relates to the use of cement, preferably glass ion cement, for fastening such a hearing prosthesis. Furthermore, the invention relates to a further developed, improved cement and the use of such a cement for attaching a newly developed hearing prosthesis and the use of such a cement for other purposes.

Hearing disorders can be caused by inner ear disorders. A distinction is made between fresh, up to one year old, inner ear damage, more than one year old, inner ear damage, and inner ear damage and deafness bordering on deafness. Older, more than one year old, inner ear damage is characterized primarily by hearing loss above 3 kHz. These include presbyacus damage after chronic noise pollution, damage after bang, damage after hearing loss and damage in Meniere's disease. According to estimates, a total of 11 million people in the Federal Republic of Germany have been affected by such diseases and damage. So far, all older inner ear deafness has been provided externally with hearing aids. Since these facilities are only accepted by the population, an external hearing prosthesis that is not secure is desirable. As older inner ear damage mainly affects frequencies above 3 kHz, the primary concern is to optimize the vibration behavior of the organ in the high frequency range. l

From US-PS 46 24 671 a hearing prosthesis for the ear is known which consists of a prestressed wire.

From DD-PS 126 349 a prefabricated wire prosthesis for replacing the auditory bone chain is known, which fixes itself due to its own spring tension between the lateral legs. With this wire prosthesis, hammer, anvil and stirrup or hammer and anvil can be replaced.

The wire prostheses known from the aforementioned publications serve only to replace extensive bone defects. These extensive defects primarily cause chronic inflammation in the middle ear or are secondary consequences of the resulting surgical measures. With the known prostheses, it is only possible to understand the natural sound conduction apparatus with the optimum frequency at 3 kHz, which is why these prostheses have not become established in practice. Furthermore, the known prostheses cannot be fixed on the stirrups or on the footplate. In addition, secondary fixation of atrophies can be expected after fixation on the ossicular chain, so that the whole system loosens up secondarily. Known solutions can therefore only be used to correct a disturbed ear function (= formwork lead), as it most often occurs after otitis media.

The object of the invention is to propose a hearing prosthesis for the center of living beings, in particular humans, which ensures good frequency response optimization in a simple, reliable and acceptable manner for the patient.

According to a first proposal, this object is achieved by the features specified in the drawing part of claim 1. Wire has a first, a second and a third section. The first section is essentially straight; he the connection to the stirrup of the middle ear. The first section is followed by a second, curved section for connection to the third section. The third section i is also curved, the curvature being opposite to that of the second section; the third section serves as an end-to-end contact with the middle ear hammer.

The solution according to the invention optimizes the frequency response. The narrowband frequency response optimum of the healthy auditory bones at 3 kHz should be shifted from 3 kHz to the frequency optimum between and 10 kHz. This can compensate for hearing loss in the high frequency range from the inner ear. Loss of hearing in the high frequency range most often occurs as a result of chronic noise pollution and in old age. The prostheses according to the invention can best be accomplished with wire made of V2A steel. It is a loan to destroy intact structures of the middle ear in order to replace them with structures that are more suitable and that are intended to shift the narrowband frequency optimum (3 kHz) to higher frequencies over a broadband range. The prostheses according to the invention thus function as a hearing aid. Steel prostheses are best suited for this; these must be installed safely, for which glass ionomer cement is best suited. The hitherto practiced clamping has not proven itself since loosening occurs secondarily.

Advantageous further developments are described in the subclaims.

The wire can be biased. The end of the third section may have a tip, which is preferably made by a diamond drill. The first section can be cemented, vo preferably glass ionomer cement, be verbi bar with the stirrup of the ear. The wire can be made of metal, preferably noble metal, stainless steel or V2A steel. The wire preferably has a round or circular cross section, the cross section diameter being less than 1 mm. The wire-V ^o rspannung kan mm to be. 4

A second solution to the problem, for which protection is claimed independently, is characterized by the features of the subordinate claim 9. In this case, the wire has a first and a second section, the first section being configured in exactly the same way as the first Solution. The second section adjoins the first section and is designed as an eyelet for connection to the hammer of the middle ear.

Advantageous further developments are again described in the subclaims.

A third solution to the problem, for which protection is also claimed independently, consists in the features of the secondary claim 16. This solution consists of a pin and a wire with two lever arms. The pin can be connected to the facial of the middle ear; the peg is therefore anchored in the facial area with cement, preferably glass ionomer cement. At the other end of the pin, the wire with the two lever arms is rotatably mounted. One lever arm is curved to rest against the stirrups of the middle ear. The other lever arm is oppositely curved to abut the hammer of the middle ear.

Advantageous further developments are described in the subclaims. s

The invention further relates to the use of cement for fastening the hearing prostheses described above to the middle ear, that is to say in particular to the stirrup and / or the hammer. The zem is preferably glass ionomer cement, that is to say a xenogenic material which is known in dentistry. In addition to good tolerance of vital tissue (pulp), its outstanding property is an active hold on tooth material, such as enamel and dentin, or bones, including auditory bones (stirrups, anvils, etc.).

Glass ionomer cement is a gel made of glass (calcium aluminum fluorosilicate) and polymeric carboxylic acids. Tartaric acid is added to shorten the curing time. The polymeric carboxylic acids adhere to enamel and dentin. Commercially available material is supplied in two components - glass powder and polycarboxylic acid.

When it is rubbed, a calcium polycarboxilate forms in a first reaction step, which is still relatively sensitive to water. Only the formation of aluminum complexes, which takes more time, leads to complete hardening. The higher the proportion of powder in a given amount of liquid (polycarboxylic acid solution), the greater the hardness, the lower the solubility, the higher the abrasion resistance (0. Gasser, Gl ionomer cements: present and future from a material science perspective, Swiss Monthly Bulletin for Dentistry 97 (1987), pages 328 to 335).

According to the presentation of the ket and the most careful hemostasis by permanent air suction, a particularly dry site is created to attach the hearing prosthesis. The assistant mixes liquid and powder on a glass plate. Experience has shown that after 1 mi the material changes into a tough, sticky consistency. The M adheres well as a drop to a pointed instrument, with which application at the intended location is possible.

The invention further relates to a glass ionomer cement, which is characterized in that polyacrylic acid is added to the glass ionomer cement. The polyacrylic acid is preferably vacuum dried. The addition of water releases the polyacrylic acid, which then reacts with the metal ions of the glass particles present in the glass ionomer zeolite. The resulting cement has a number of advantages: the hardening time is very short, but the processing time is still long enough. The load capacity that can be achieved is very high.

The invention further relates to the use of a glass ionomer cement mixed with polyacrylic acid for fastening one of the above-described hearing prostheses to the middle ear, that is to say in particular to the stirrup and / or the hammer. When mixed with acrylic acid, the glass ionomer zemen has flow properties, which is an advantage in middle ear surgery. In addition, when mixed with acrylic acid, the glass ionomer cement hardens more quickly and is not as sensitive to liquids, e.g. Flushing fluid and blood. The mixture is preferably made individually.

Finally, the invention relates to the use of glass ionoma cement with an admixture of polyacrylic acid in the reconstruction of midface and skull base fractures. With the Gla ionomer cement mixed with acrylic acid, bone defects can be bridged permanently without having to work with wire or screw (revision of ethmoid fractures, lower jaw fractures, midface fractures). The hearing aids known up to now are "BTE devices" (behind-the-ear devices) and "ITE devices" (in-the-ear devices). The device presented here could be called an "IdP device" (In der Pauke device).

Embodiments of the invention are explained below with reference to the accompanying drawings. In the drawing shows

1 shows the middle ear of the person in a schematic representation,

2 shows a first embodiment of the invention,

3 shows another example of the first embodiment of the invention;

Fig. 4 shows a second embodiment of the invention and

Fig. 5 shows a third embodiment of the invention.

As shown in Fig. 1, the eardrum 2 connects to the ear canal 1. The ossicular chain consists of the ham 3, the anvil 4 and the stirrup 5. The facial nerve is designated VII. At the lower end of the stirrup 5 is the snail (cochlea) 6 with inner ear fluid. The auditory ossicle chain 3, 4, 5 is located in the timpani (cavity) 7. The pivot point between the hammer 3 and anvil 4, that is to say the common pivot point between the hammer 3 and anvil 4, is designated by 8.

2 shows the first embodiment of the invention. The Hearing prosthesis consists of the wire 11, which sits a first section 12, a second section 13 and a third section 14 b. The first section 12 is essentially straight. He di for connection to the stirrup 5. The second section 13 connects to the first section 12. It is curved and is used for connection to the third section 14. The third section 14 is also curved, the curvature being opposite to that of the second section 13. The third section 14 is used for end-to-end contact with the ham 3. The first section 12 is connected by glass ionomer cement 15 to d stirrup 5. The scale is shown in mm at the bottom right.

The hearing prosthesis 11 is used as follows: First, the patient's part of the hammer shown on the left in FIG. 1 and the entire anvil 4 are removed, for example by punching or similar instruments. The first section 12 of the hearing prosthesis 11 is then attached to the stirrup 5 by glass ionomer cement. The free tip 16 of the third section 14 is under tension on the underside 17 of the remaining hammer 3. The tip 16 is thus clamped under tension on the underside 17 of the hammer 3.

The frequency response is optimized by reducing the ossicular masses (removing the left part of the hammer 3 and the entire anvil 4). In particular, the sensitivity of high frequencies is increased. This frequency response optimization was determined empirically. Furthermore, the damping in the so-called small and large joints (small joint: between stirrup and anvil; large joint: between anvil and hammer) is no longer present. By eliminating these attenuations, the sound transmission is also optimized. The tip 16 at the end of the third section 14 is made by a diamond drill in the usual way. The wire is made of V2A steel. It has a circular cross-section, the cross-sectional diameter being less than 1 mm. The wire pre-tension is 3 to 4 mm. The cross-section of the wire 11 preferably has a diameter of 0.2 mm. He is sharpened at Spit 16. The dashed lines a and b in the area of the third section 14 document other prostheses 11 of different lengths.

3 shows another example of the first embodiment of the invention. The middle ear prosthesis 11 is clamped between the hammer res and stirrup 5, the tip 16 boring into the underside 17 of the hammer 3 and being fixed with glass ionomer cement. The dashed lines a and b in the area of the third section 14 in turn document other, differently long middle ear prostheses 11.

4 shows the second embodiment of the invention. The hearing prosthesis consists of a wire 11 with a first, essentially straight section 12 for connection to the riser 5 of the middle ear. The second section 23 adjoining the first section 12 is designed as a right-angled eyelet. The first section 12 is fixed to the stirrup 5 with glass ionomer cement. With a screwing device 10, the eardrum center is pressed in by about 0.6 mm until there is contact with the 23. The eyelet 23 is then fixed with glass ionomer cement on the underside 17 of the hammer 3. In this case, too, the wire 11 is therefore prestressed. The pretensioning takes place without the action of the screwing device, there is a distance between the 23 and the underside 17 of the hammer 3. This distance overcome by the screw device 11. After the eyelet 23 has been fastened to the underside 17 of the hammer 3 by glass ionomer cement, the screwing device 10 can be loosened and removed again. The wire 11 is then pretensioned on both sides with G ionomer cement. In this case too, the wire is made of 0.2 mm thick V2A wire.

5 shows the third embodiment of the invention. The pin 31 is connected to the facial VII of the middle ear. The pin 31 is glued to the facial VII with glass ionomer cement 32. At the other, upper end of the pin 31 there is d axis of rotation 33, on which the wire 41 forming the hearing prosthesis is mounted in a bar. The wire 41 has a first lever arm 42 bearing on the stirrup 5 of the middle ear and a second lifting arm 43 for bearing on the hammer 3 of the middle ear. The first, shorter lever arm 42 is curved toward the stirrup; he wi placed on the stirrup 5 and fixed there with glass ionomer cement 1. The second, longer lever arm 43 is curved opposite to the first lever arm 42. Its end 46 is clamped under the hammer 3 and fixed there with glass ionomer cement.

The invention is based on the idea or the concept of removing mass from the ossicular chain and replacing it with the prosthesis, that is to say a wire or a similar component.

Claims

PATENT CLAIMS

1. hearing prosthesis for the middle ear of living beings, especially humans,

marked by

a wire (11) with a first, essentially straight section (12) for connection to the stirrup (5) of the middle ear,

a second curved section (13) adjoining the first for connection to the third section (14)

and a third, curved section (14) for end-to-end contact with the hammer (3) of the middle ear,

the curvature of the third section (14) being opposite to that of the second section (13).

2. hearing prosthesis according to claim 1, characterized in that wire (11) is biased.

3. hearing prosthesis according to claim 1 or 2, characterized in that the end (16) of the third section (14) has a tip, which is preferably manufactured by a diamond drill.

4. hearing prosthesis according to one of the preceding claims, characterized in that the first section (12) with cement (1 preferably glass ionomer cement, with the stirrup (5) de ear can be connected.

5. hearing prosthesis according to one of the preceding claims, characterized in that the wire (11) made of metal, preferably noble metal, preferably stainless steel, preferably V2A steel.

6. Ear prosthesis according to one of the preceding claims, characterized in that the wire (11) has a round, preferably circular cross-section.

7. hearing prosthesis according to any one of the preceding claims, characterized in that the cross-sectional diameter of the wire (17) is less than 1 mm, preferably 0.2 mm.

8. hearing prosthesis according to one of claims 2 to 7, characterized in that the wire bias is 3 to 4 mm.

9. Hearing prosthesis for the middle ear of living beings, especially humans,

marked by

a wire (11) with a first, substantially straight section (12) for connection to the stirrup (5) of the middle ear

and with a second section adjoining the first and designed as (23) for connection to the hamm of the middle ear.

10. hearing prosthesis according to claim 9, characterized in that wire (11) is biased.

11. A hearing prosthesis according to claim 9 or 10, characterized in that the first section (12) and the second section (23) cement (15), preferably glass ionomer cement, with the stirrup (5) or with the hammer (3) of the ear is connectable.

12. Hearing prosthesis according to one of claims 9 to 11, characterized in that the wire (11) consists of metal, preferably noble metal, preferably stainless steel, preferably V2A steel.

13. hearing prosthesis according to one of claims 9 to 12, characterized in that the wire (11) has a round, preferably two circular cross-section.

14. A hearing prosthesis according to one of claims 9 to 13, characterized in that the cross-sectional diameter is less than mm, preferably 0.2 mm.

15. A hearing prosthesis according to one of claims 10 to 14, characterized in that the wire pretension is approximately 1 mm

16. Ear prosthesis for the middle ear of living beings, especially humans,

marked by

a pin (31) which is connected to the facial nerve (VII) of the middle ear can be connected and on which a wire (41) with two lever arms (42, 43) is rotatably mounted,

one of the lever arms (42) is curved and runs towards the stirrup (5) of the middle ear

and the other lever arm (43) is curved in the opposite direction to rest against the hammer (3) of the middle ear.

17. A hearing prosthesis according to claim 16, characterized in that one or both lever arms (42, 43) are biased.

18. A hearing prosthesis according to claim 16 or 17, characterized gekenn¬ characterized in that the end of a lever arm (42) ^" and / or de other lever arm (43) has a tip which is preferably made by a diamond drill.

19. Hearing prosthesis according to one of claims 16 to 18, characterized in that the one lever arm (42) and / or the lever arm (43) with cement, preferably glass ionomer cement, the stirrup (5) or the hammer (3) of the ear is connectable.

20. Hearing prosthesis according to one of claims 16 to 19, characterized in that the wire (41) consists of metal, preferably noble metal, preferably stainless steel, preferably V2A steel.

21. A hearing prosthesis according to one of claims 16 to 20, characterized in that the wire (41) has a round, preferably circular cross-section.

22. A hearing prosthesis according to one of claims 16 to 21, characterized in that the cross-sectional diameter is less than 1 mm, preferably 0.2 mm.

23. A hearing prosthesis according to one of claims 16 to 22, characterized in that the wire preload is approximately 1 mm

24. Use of cement, preferably glass ionomer cement, for fastening a hearing prosthesis according to one of claims 1 23.

25. Use of glass ionomer cement according to claim 24, characterized in that the glass ionomer cement is a gel made of glass (calcium aluminum fluorosilicate) and polymeric carboxylic acid, to which tartaric acid is preferably added to shorten the hardening time.

26. Glass ionomer cement, characterized in that polyacrylic acid is added to the glass ionomer cement.

27. Use of glass ionomer cement according to claim 26 for fastening a hearing prosthesis according to one of claims 1 23.

28. Use of glass ionomer cement according to claim 26 in the reconstruction of midface and skull base fractures