Anchoring means for implantable microphone

0001The invention concerns a fixation element for an implantable microphone that with one provided with a sound entry membrane cylindrical housing part in a rear bony wall of the canal traversing hole is used and the example form part of a fully implantable hearing aid partly or can.

0002An embodiment of a microphone of the aforementioned kind is the subject the earlier EP patent application 97114603 and in the article "An implantable . Microphone Electronic Implants "by H. Leysieffer et al, HNO 45: 816-827 (October 1997) described in detail. From the mentioned article it is known to the microphone housing to fix in the mastoid bone cement by mechanically. A cement fixation however, has numerous problems. Thus, the bone cement at the implantation cause undesirable side effects under certain circumstances. The handling given the limited space and the low visibility conditions at the implantation difficult. Bone cement can also undesirable to Make go where it interferes. A subsequent correction of the microphone position in the Bore the ear canal wall is practically impossible. It is conceivable that screwed microphone housing in the bore of the canal wall. Clinical Experiments show, however, that this is due to the small thickness of the bony canal wall is problematic. Furthermore, screws are in the field of implant site often even a long time after surgery painful perceived.

0003The invention is based on the object, a fixation element of the aforementioned create type that a substantially simplified and yet highly precise implantation of the microphone while avoiding the use of bone cement disadvantages permitted.

0004This object is achieved with a fixation element for an implantable microphone with a provided with a sound entry membrane cylindrical housing part in a rear bony wall of the canal traversing bore is used, dissolved, which is according to the invention characterized by a sleeve with a cylindrical sleeve part surrounding the cylindrical housing part and the against the auditory canal facing the skin side of the canal wall can be applied, projecting, comprises elastic flange.

0005The fixation element according to the invention allows the microphone housing in the bony canal wall traversing bore easy to clip. The use of bone cement is avoided. The is investing in the bony canal wall Flange ensure precise alignment of the microphone housing with With respect to the ear canal wall. Together with the bore wall in engagement stationary cylindrical sleeve portion they provide a safe and long-term stability Holding the microphone implanted safely.

0006In a further embodiment of the invention is the sleeve with further projecting Flange provided that the against the averted from the ear canal skin side are bony canal wall can be applied. Thereby the hold of the microphone in the implanted state further improved. Further, an unintentional tilting of the Microphone housing against the canal wall during the implantation process or later reliably excluded.

0007Preferably, the entire sleeve of biocompatible elastic material made, the appropriate from the group consisting of silicones and polyurethanes is selected. Such a material allows a limited deformation of the collar upon insertion into the bore of the bony canal wall. It allows there the flange to properly against the respective side of the canal wall to apply. In the area of ​​the cylindrical sleeve portion can easily for a clamping force can be ensured.

0008Another embodiment of the invention, the sleeve part of a sheath be that at least for the microphone except for the sound entry membrane larger part and preferably completely surrounds. This is a particularly safe achieved anchoring of the sleeve with respect to the microphone housing.

0009The flange, which in the implanted state against the ear canal skin to create the side facing the wall of the canal, can be in implanting hold by a tool in a position in which it the through bore Canal wall can be passed. The implantation of the microphone but is particularly simple if the mount is in development of the invention is provided which is the opposite of the auditory canal facing the skin side Canal wall can be applied prior to implantation flange against a resilient Restoring force of the flange in an insertion through the hole in the holds meatus permitting bent position. Here are the against the Auditory canal facing the skin side of the canal wall can be applied preferably flange so designed and dimensioned that it in after removing the holder a jump position in which they from the cylindrical sleeve portion substantially protrude radially. The surgeon needs in such a design of the fixation element only the jacketed cylindrical housing part of the microphone together insert holder in the bore of the rear bony wall of the meatus and then to make the holder ineffective or remove in order for the exact and secure fit of the microphone to provide at the implant site. As holder can, for example, simply provided a durchtrennbarer during the implantation thread be the first the associated flange in an implanting non-interfering Position holding and then the respective flange parts due to its elastic Properties can pass in a relaxed position in which your holding function take. As holder, according to an advantageous modified Embodiment also provided an attached on the bent flange cap be.

0010According to another embodiment of the invention are directed against the ear canal skin the side facing the wall of the canal can be applied flange starting inclined from the cylindrical sleeve part towards this cuff part. This contributes to the proper application of the flange to the ear canal skin the side facing the auditory canal wall when, even if the surface in question the Canal wall due to the anatomical characteristics certain irregularities having. For the same reason, preferably, the wall thickness of the against the the auditory canal facing the skin side of the canal wall can be applied flange radially from the outside.

0011which can be placed against the auditory canal facing the skin side of the canal wall Flange can, in particular as an in the relaxed condition, starting from the formed cylindrical sleeve portion substantially radially projecting annular flange be. However, other geometric configurations come in Considered where only one hand, the required holding function is ensured and On the other hand, the flange in the space between the ear canal skin and ear canal wall easily find space.

0012Preferably, the against the auditory canal facing the skin side of the canal wall can be applied flange with through holes provided, in particular, have the task of a nutritional transition between the bony canal wall to allow the ear canal and skin in the area of ​​the annular flange.

0013It is understood that fixation element of the invention in principle for microphones any shape, for example, for microphones with a continuous cylindrical Housing, is suitable. When the microphone but in a conventional manner (article "An implantable microphone for electronic hearing implants" by H. Leysieffer et al, ENT. 45: 816-827 (October 1997)) with a multi-leg microphone housing is provided, wherein a first housing leg forming the cylindrical-shaped housing part and a second housing leg about an approximately the thickness of the rear bony Meatus corresponding distance relative to the plane of the sound entry membrane is set back, advantageously forms a second housing leg itself or the second housing leg ummantelnder part of the fixation element at least a portion of the flange that against averted from the ear canal skin side the canal wall can be applied. In this case, one of the flange portions against the of the ear canal skin averted side of the canal wall can be applied, preferably a shoulder on said second housing leg diametrically opposite Side of the cylindrical sleeve portion protrudes.

0014Suitably at least the cuff of a material with a Shore A hardness made of 20 to 70.

0015Preferred embodiments of the invention are described below with reference explained in greater detail on the accompanying drawings. They show:<dl tsize="7" compact="compact"><dt>FIG. 1</dt><dd>a schematic representation of a bone in the rear wall of the meatus implanted microphone, the fixation element of the invention by means of a is maintained;</dd><dt>FIG. 2</dt><dd>on a larger scale a view of when the microphone of FIG. 1 provided Fixation element in the direction of arrow A in FIG. 1;</dd><dt>FIG. 3</dt><dd>a plan view of the fixation element according to FIG. 2;</dd><dt>FIG. 4</dt><dd>a sectional view of the fixation element according to the line IV-IV in FIG. 3;</dd><dt>FIG. 5</dt><dd>a detailed view on an even larger scale of the in FIG. 4 by a circle V indicated portion of the fixation element;</dd><dt>FIG. 6</dt><dd>a view similar to FIG. 2 except that the annular flange schematically in the State is shown, in which it brought to the implantation in preparation becomes;</dd><dt>FIG. 7</dt><dd>is a plan view similar to FIG. 3 for a fixation element according to a modified embodiment; </dd><dt>FIG. 8th</dt><dd>a side view of the fixation element according to a further modified embodiment and</dd><dt>FIG. 9</dt><dd>a view similar to FIG. 6, but showing a cap for retaining the which can be placed against the auditory canal facing the skin side of the canal wall Flange before and placed during implantation is.</dd></dl>

0016FIG. 1 schematically shows a microphone 10, which is part of a partially or fully implantable may be hearing aid. The hearing aid as such can in a conventional manner be formed. Examples of such hearing aids are electronic in the article "Active Implants for middle and inner ear hearing loss - a new era of ear surgery " HP Zenner et al, ENT. 45: 749-757 (October 1997) described in detail. The microphone 10 has a two-leg microphone housing 11, shown in FIG. 1 for simplicity of illustration only indicated schematically and is therefore not illustrated in section is. In a first leg 12 of the microphone housing 11 is a microphone capsule housed, and the leg 12 forms a sound entry membrane 13 provided cylindrical housing part 14. A second housing leg 15 takes a schematically indicated at 16 electrical feedthrough for an electrical Lead 17.

0017The microphone 10 is equipped with a fixation member 20 illustrated in Embodiment provides an all microphone receiving shell. Part of the fixation element 20 is, as shown in detail in Figures 2 to 5 is a sleeve 21, which with a cylindrical sleeve portion 22 the cylindrical Housing portion 14 encloses. At the cuff 21 further includes flange 23, 24 and 25, which at both axial ends of the cylindrical cuff portion 22 projecting radially outwards. According to FIG. 1 is the cylinder-shaped housing part from 14 together with the cylindrical sleeve portion 22 of a mastoid cavity 27 inserted into a bore 28 which crosses a rear bony wall of the meatus 29th In FIG. 1 are lined ear canal skin ear canal 30 at 31 and the eardrum 32 indicated. The dimensioning is so chosen that in the the implanted state of the microphone 10, the flange portions 23, 24 and 25 on the one hand against the ear canal skin 30 the side facing 33 and the other hand against the Ear canal skin averted side 34 of the wall of the canal to create 29 while the Sound entry membrane 13 in direct mechanical contact with the ear canal skin 30 comes. Accordingly, the axial distance is<i><u><b>a</b></u></i> between the flange 23 and the Flange members 24 and 25 are sized to the average wall thickness of the osseous Meatus 29 matches. The distance<i><u><b>a</b></u></i> is generally in the range from 1.0 to 2.5 mm. Preferably, it is about 1.6 mm. The sound entry membrane 13 preferably has the interest of good contact with the ear canal skin 30 a Diameter of less than 5.0 mm. For example, accordingly, the cylindrical housing part 14 has an outer diameter of about 4.5 mm, and the cylindrical sleeve portion 22 has an outer diameter of about 5.3 mm.

0018is in the shown in the figures 1-6 embodiment, the fixation element 20 the with the sound entry membrane 13 substantially flush lying flange 23 formed as an annular flange, the relaxed state auditory canal side of the End of the cylindrical sleeve portion 22 projecting substantially radially. The annular flange 23 is provided with a series of circumferentially arranged distributed perforations 36 provided. The object of the openings 36, it is primarily a nutrient transport between the bony canal wall 29 and the ear canal skin 30 permit in the area of ​​the annular flange 23rd Shape and number of openings 36 are immaterial so long as the perforations fulfill this purpose and the necessary mechanical strength of the annular flange 23 remains received.

0019Prior to implantation, is by the series of apertures 36 a surgical Thread threaded 37 and, for example, by twisting, knotting or the like in a state temporarily fixed, in which the annular flange 23 corresponding to FIG. 6 in axially away folded and contracted by the flange portions 24 and 25 is. In this form, can be of 22 surrounded by the cylindrical sleeve portion cylindrical housing part 14 passes through the hole 28 in the wall of the canal 30th Then, when the yarn 37 is severed, the ring flange 23 returns to its relaxed form back according to Figures 1 to 4. FIG. To such behavior to force is at least of the annular flange 23 forming part of the fixation element 20 elastically.

0020The annular flange 23 is located in the implanted state (FIG. 1) to the ear canal skin 30 the side facing the 33 canal wall 30 regardless of unevenness this panel conform as closely as possible. To promote this, in addition to a appropriate choice of material for at least the ring flange 23, in the illustrated Embodiment three measures provided particularly clear from FIG. 5 to are seen. On the one hand, the wall thickness of the annular flange 23 is reduced as far as this is without prejudice to the holding function of the annular flange. Furthermore is the annular flange 23, starting from the cylindrical sleeve part 22 in Towards the flange parts 24, 25 inclined. Finally, the wall thickness increases the Annular flange 23 radially from the outside. The wall thickness of the annular flange 23 can suitably from about 0.1 to 0.2 mm near the cuff portion 22 about 0.03 to 0.1 mm may be reduced at the outer edge of the annular flange 23rd The inclination angle α of the Annular flange 23 may be in the range of 0 to 20 degrees, preferably at about 5 degrees, lie.

0021The flange portion 25 is formed by the part of the casing (fixation element 20) wherein the annular flange 23 the side facing the housing leg 15 covers. In the flange 24 there is a shoulder on the housing leg 15 diametrically opposite side of the cylindrical sleeve portion 22 protrude (see in particular Figures 3 and 4).

0022provided during implantation of the coated with the fixation element 20 microphone 10 the flange portions 23, 24 and 25 for an orientation of the sound entry membrane 13 and of the housing leg 15 parallel to the bony canal wall 29 in a Position in which the sound entry membrane 13 is substantially flush with that of the Ear canal skin 30 facing side 33 of the wall of the canal is 29. also a Tilting of the microphone 10, for example, by the implantation process accidentally the microphone housing 11 and / or the supply line 17 applied force, is effectively prevented. The fixation element 20 secures the headset at the implantation site, without additional measures or means, for example, bone cement, are required. If need be, the microphone can be during implantation, after introducing the cylindrical sleeve portion 22 in the bore 28 to the in FIG. 4 rotate at 40 indicated axis of the cylindrical housing part 14th

0023The fixation element 20 is suitably a microphone housing 11 receiving Molded part. The material used for the fixation element 20 is particularly a biocompatible Plastic with a Shore A hardness of 20 to 70. It may be before all act to silicones or polyurethanes.

0024The modified embodiment of the fixation element 42 shown in FIG. 7 differs from the previously described fixing element 20 substantially only in that when implanted between the canal wall 29 and the ear canal skin 30 lying flange not by an annular flange 23, but by a Series of circumferentially distributed the cylindrical sleeve portion flange segments 43 formed. Thereby, the flange segments 43, as shown, be provided with perforations 36th However, such perforations can also not be necessary, particularly if an already due to the shape of the flange guaranteed nutrient transport between meatus 29 and ear canal skin 30 is.

0025FIG. 8 shows a further modified, generally designated 46 embodiment the fixation element, which for microphones with einschenkligem, a cylindrical Microphone housing is. The fixation element 46 again has a cuff 48 , which with a cylindrical sleeve portion 49 has a cylindrical portion of the Microphone housing surrounds and. Against in FIG 1 shown, the ear canal skin 30 the side facing 33 and facing away from the ear canal skin Page 34 the ear canal wall 29 can be placed against projecting flange parts 50 and 51 having. The flange 50 may, in particular according to the flange 23 of the Figures 2 to 6 designed or flange segments 43 according to FIG. 7 be formed. The flange 51 may be appropriately constructed as an annular shoulder.

0026FIG. 9 shows a view similar to FIG. 6, but instead of the thread 37 a Cap 53 can be applied to retain the 33 against the side of the canal wall 29 Flange portions 23, 43 and 50, respectively provided before and during implantation is. The cap 53 is at least in the region of the hollow cylindrical portion 54 as thin carried out so that they together with the cylindrical sleeve portion 22 and 49 inserted into the bore 28 and then releasing the flange 23, 43 or 50 can be removed from the ear canal 31 of. In order that Grasp the cap 53 to facilitate using tweezers or the like, carrying the Cap at its closed end a nipple 55. In the hollow cylindrical part 54 the cap 53 is conveniently a relatively rigid and hard disk 56 used. The cap member 54 is preferably elastically stretchable to a limited extent. The cap material must be sterilized; otherwise takes a variety of materials, in particular Metals and plastics, into consideration. The cap 53 provides, especially if they is equipped with the plate 56, before the implantation for excellent protection the sound entry membrane. 13