Stapes fixation flange for inner ear electrodes

Abstract

A vestibular electrode fixation methodology and device for implantation in a subject is provided. The methodology includes making an opening through both a stapedial footplate and the oval window of the subject, through which the electrode is inserted. The electrode may pass through a flange which contacts the posterior and anterior crus, securely fixing the electrode in a predetermined position so as to stimulate the sensory epithelia in the vestibule. The flange may sit on the stapedial footplate.

Description

Stapes Fixation Flange for Inner Ear ElectrodesCross-Reference to Related Applications

[0001] This application claims priority from United States Provisional Application No. 63 / 645,098, filed May 9, 2024, which is hereby incorporated herein by reference in its entirety.Technical Field

[0002] The present invention relates to implant systems and electrode arrangements for treatment of a vestibular disorder. More particularly, the present invention relates to a vestibular electrode that enters through the stapes footplate and oval window. A flange may be embedded in the structure of the electrode. The flange is positioned adjacent the stapes cmra so as to be clamped and securely attached to the stapes. The flange may be configured to rest on the base of the stapes.Background Art

[0003] A normal ear directs sounds as shown in Figure 1 from the outer ear pinna 101 through the generally cylindrical ear canal 110 to vibrate the tympanic membrane 102 (eardrum). The tympanic membrane 102 moves the bones of the middle ear 103 (malleus, incus, and stapes) that vibrate the cochlea 104, which in turn functions as a transducer to generate electric pulses to the brain that are interpreted as sounds.

[0004] The balance sensing functionality of the brain is developed based on neural signals from the vestibular structures of the inner ear, one on each lateral side of the body. The balance sensing vestibular system involves the vestibular labyrinth, its three interconnected and mutually orthogonal semi-circular canals: the superior (anterior) canal 106, posterior canal 107, and horizontal (lateral) canal 108 — which sense rotational movement, as well as the macular organs 116 in the utricle and saccule, which sense linear movement. The canals 106, 107, 108 and the otolith organs 116 of the vestibular labyrinth contain hair cells 118 in a viscous endolymph 117 that sense head orientation and head movements, thereby activating vestibular nerve fibers 119that send an electrical balance signal to the brain 105.

[0005] When the head is stationary, the vestibular system generates neural activity at a certain rate that is transmitted by the vestibular nerve to the brain. When the head moves in a given direction, the vestibular system changes the neural activity rate on the affected nerve branch of the vestibular nerve which correlates with the head movement. Unfortunately some people suffer from damaged or impaired vestibular systems or from various diseases that affect intact vestibular systems such as Meniere’s disease. Dysfunction of the vestibular system can cause problems such as unsteadiness, vertigo (feeling of rotation) and unsteady vision. To treat such problems, electrical stimulation of the vestibular system can help to restore the balancing function, and vestibular implants are currently under development to provide such an artificial balance signals.

[0006] Fig. 1 also shows some components of a conventional vestibular implant system such as is described in U.S. Patent 8,751,012 (incorporated herein by reference in its entirety). An external movement signal (from one or more sensors not shown) is processed by an external processor 111 to produce a vestibular stimulation signal. An external transmitter coil 112 couples the stimulation signal through the skin to an implanted receiver coil 113. An implanted vestibular stimulator 114 than delivers the stimulation signal through an electrode 140 to vestibular stimulator electrodes that electrically stimulate target neural tissue such as the semicircular canals 106, 107, 108, one or both otolith organs, and / or the vestibular nerve 105 or ganglion for vestibular sensation by the patient as a balance signal.

[0007] The electrode typically includes an electrode lead 109 and an electrode array 115. The electrode lead 109 includes the proximal end or basal portion of the electrode that typically goes from the stimulator 114 to the electrode array 115. The electrode lead 109 usually has no electrode contacts and encloses wires that connect to, and deliver the electrical stimulation signals to, electrode contacts 130 associated with the electrode array 115. The electrode array 115, which is typically inserted through an opening in the temporal bone or other insertion site into the inner ear, includes one or more electrode contacts 130 on its outer surface that provide electrical stimulation.

[0008] In contrast to auditory nerve afferents which are located along the cochlea, the vestibular nerve afferents are located at specific sites, viz. the three semicircular canal ampullae and the two otolith organs. Consequently, this limits the spots for vestibular stimulation. Essentially two surgical approaches for vestibular stimulation of the ampullary nerves have been developed: an extralabyrinthine approach (e.g., shown in Fig. 1) in which, for example, a hole is placed in the hard temporal bone through which flexible electrodes are placed attached / fixed adjacent the ampullary nerve canals; and an intralabyrinthine approach with each electrode lead inserted in the semicircular canal with the stimulating electrode in the ampulla near the ampullary nerves.

[0009] Implanting an electrode array may require some form of fixation to ensure that the electrode does not move after implantation. For example, products exist (such as the muller clip) to ensure that a cochlear implant is fixed properly after insertion. The problem with such clips is that not only could it be difficult to use such clips in certain circumstances, or with certain electrode designs, but it also does not allow for automatic orientation of an electrode array.Careful insertion and immediate fixation of the electrode may be required to ensure it is oriented properly. This may be difficult to achieve, particularly in implantation sites in which visibility is limited regardless of surgical perspective.Summary of the Embodiments

[0010] In accordance with embodiments of the invention, a vestibular electrode fixation device for implantation in a subject is provided. The device includes a flange having a top and bottom surface, and an edge between the top and bottom surface defining an outer perimeter. The outer perimeter of the flange has a first fixation feature configured to contact a posterior crus of the stapes, and a second fixation feature configured to contact an anterior crus of the stapes, such that the flange is clamped and securely attached to the stapes. The bottom surface of the flange may be configured to rest on the stapes footplate.

[0011] In accordance with related embodiments of the invention, at least one of the first and second fixation features may include a notch configured to contact one of the anterior crus and the posterior crus. The notch may be a triangular notch, a semi-circular notch, a semi-ellipticalnotch, a u-notch, a square notch, and / or a rectangular notch. The notch may have an irregular shaped bottom and / or wall.

[0012] In accordance with further related embodiments of the invention, the vestibular electrode fixation device further includes an electrode that passes through the top and bottom surface of the flange. The electrode includes an electrode lead portion above the top surface of the flange, and an electrode array portion having one or more electrode contacts below the bottom surface of the flange. The electrode array portion may be pre-shaped at a predefined angle such that when the flange is securely attached to the stapes, the electrode array passes through an opening in both the stapes footplate and the oval window, and is automatically orientated in a desired position with respect to target sensory epithelia. Illustratively, when the flange is securely attached to the stapes, at least one electrode contact of the electrode array may face a saccule and / or at least one electrode array of the electrode array may face a utricle.

[0013] In accordance with still further embodiments of the invention, a stopper ring may be positioned on the electrode that provides a predefined position of the flange relative to the electrode array portion. The electrode and the flange may form an integral device. The electrode lead portion may be angled and not at a normal angle relative to the flange, such that the electrode lead portion does not collide with the crus or head of the stapes when the flange is securely attached to the stapes. The outer perimeter flange may not be symmetrical, and may be configured to be larger at an end facing the posterior crus when the flange is attached to the stapes.

[0014] In accordance with another embodiment of the invention, a method of implanting a vestibular electrode in a subject is provided. The electrode includes an electrode array portion that includes at least one electrode contact. The method includes performing a stapedotomy by, without limitation, drilling or using a laser, so as to make an opening through both a stapedial footplate and an oval window of the subject. The electrode array portion is inserted through the hole. Electrical stimulation is provided to sensory epithelia in the vestibule via the at least one electrode contact.

[0015] In accordance with related embodiments of the invention, the electrode may pass through a top and bottom surface of a flange. The flange includes an outer perimeter having a first fixation feature configured to contact a posterior crus of the stapes, and a second fixation feature configured to contact an anterior crus of the stapes. The method may include positioning the flange such that the first fixation fixture contacts the posterior crus of the stapes and the second fixation fixture contacts the anterior crus of the stapes, so that the flange is securely attached to the stapes, and such that the electrode array passes through the opening in the footplate of the stapes and the oval window. The method may further include positioning the flange to rest on the stapedial footplate. The electrode array portion may be pre-shaped at a predefined angle such that when the flange is securely attached to the stapes, the electrode array passes through the opening in the stapes footplate and the oval window, and is automatically orientated in a desired position with respect to target sensory epithelia. When the flange is securely attached to the stapes, at least one electrode may face the saccule and / or at least one electrode may face the utricle. The electrode and the flange may form an integral device.

[0016] In still further related embodiments of the invention, at least one of the first and second fixation features may include a notch configured to contact one of the posterior and anterior crus, and wherein positioning the flange includes inserting the one of the posterior and anterior crus into the notch, with the one of the posterior and anterior crus making contact with one or more surfaces of the notch. The notch may be a triangular notch, a semi-circular notch, a semielliptical notch, a u-notch, a square notch, and a rectangular notch. The notch may have an irregular shaped bottom and / or wall.

[0017] In accordance with yet further related embodiments of the invention, the electrode may include an electrode lead portion above the top surface of the flange. The electrode lead portion is angled and not at a normal angle relative to the flange, such that the electrode lead portion does not collide with the crus or head of the stapes when the flange is securely attached to the stapes.Brief Description of the Drawings

[0018] The foregoing features of embodiments will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:

[0019] Fig. 1 shows various anatomical structures in a human ear including a conventional vestibular implant system;

[0020] Fig. 2 shows a top view of a flange for a vestibular electrode fixation device, in accordance with an embodiment of the invention;

[0021] Fig. 3 shows an electrode passing through the top and bottom surface of a flange, in accordance with an embodiment of the invention;

[0022] Fig. 4 shows a flange positioned and resting on a stapedial footplate, in accordance with an embodiment of the invention;

[0023] Fig. 5 shows a flange resting on the stapedial footplate, with at least one electrode contact facing a saccule and at least one electrode facing an utricle, in accordance with an embodiment of the invention;

[0024] Figs. 6A, 6B, and 6C each show an electrode lead portion that includes an angled portion, in accordance with an embodiment of the invention; and

[0025] Fig. 7 is a process flow diagram of an exemplary methodology for implanting a vestibular electrode in an inner ear of a subject, in accordance with an embodiment of the invention.Detailed Description of Specific Embodiments

[0026] In illustrative embodiments, a vestibular electrode fixation methodology and device for implantation in a subject is provided. The methodology includes performing a stapedotomy by, without limitation, drilling or using a laser to make an opening through both a stapedial footplate and an oval window of the subject, through which the electrode is inserted. The electrode may pass through a flange which contacts the posterior and anterior crus, securely fixing the electrodein a predetermined position so as to stimulate the sensory epithelia in the vestibule. The flange may sit on the stapedial footplate. Details are described below.

[0027] Fig. 2 shows a top view of a flange 201 for a vestibular electrode fixation device, in accordance with an embodiment of the invention. The flange 201 includes a top 203 and bottom surface and has an edge 302 (shown in Fig. 3) between the top 203 and bottom surface defining an outer perimeter.

[0028] The outer perimeter of the flange 201 includes a first fixation feature 205 configured to contact a posterior crus of the stapes, and a second fixation feature 207 configured to contact an anterior crus of the stapes, such that the flange 201 is securely attached to the stapes. The bottom surface of the flange 201 may be configured to rest on a stapedial footplate of a subject (see Fig. 3).

[0029] The fixation features 205 and / or 207 may be, without limitation, a notch or other opening configured to contact one of the anterior crus and posterior crus of the stapes. The notch may be, for example, a triangular notch, a v-notch, a u-notch, a semi-circular notch, a semi-elliptical notch, a square notch, and / or a rectangular notch. The notch may have irregular shaped bottoms / walls. When securely attached to the stapes, illustratively each of the crus will fit and make contact with both walls of their associated notch, clamping and fixing the position of the flange 201 on the stapes. Frictional forces between the bottom of the flange 201 and the stapedial footplate may also assist in keeping the flange 201 securely attached to the stapes. Adhesives known in the art may be applied at the notch or bottom of the flange if desired, but typically are not needed.

[0030] The flange 201 may be patient specific, with various measurements / imaging used to determine its dimensions. However, in illustrative embodiments a single size flange may suffice to cover the dimensional variation in the stapes between subjects. Illustratively, the notch 205, 207 may define two walls that expand outward at an angle. This advantageously allows different size stapes to be accommodated by a single flange. The smallest stapes would have the smallest diameter crura, but also the smallest distance between the crura. As the distance between the crura grows, the diameter of the crura grow and thus will fit into a more “outward” part of therespective opening / notch. Additionally, the diameter of the anterior crus is often slightly smaller than the posterior. This may be reflected, for example, in slightly differing posterior and anterior diameters of the notch. In various embodiments, outer dimensions of the flange 201 (and the diameter of the opening, described below) may be based on studies analyzing historical images of stapes).

[0031] The flange 201 may include an opening or passageway 210 through which an electrode can be inserted. The opening or passageway 210 is positioned on the flange 201 such that it will rest above an opening drilled or otherwise created in the stapedial footplate and the oval window.

[0032] The electrode and flange 201 may be integrally fabricated as a single component. Where the flange 201 is, without limitation, embedded and fabricated to be part of the electrode silicone carrier, the surgeon advantageously does not have to combine a fixation component with the electrode during surgery to achieve the desired coupling. The flange 201 may be made of silicone, or other biocompatible materials. Silicone is a soft structure compared to metal clips, resulting in potentially less damage to surrounding structures and the stapes.

[0033] Fig. 3 shows an electrode 301 that passes through the top and bottom surface of the flange 303, in accordance with an embodiment of the invention. The electrode 301 includes an electrode lead portion 305 above the top surface of the flange 303, and an electrode array portion 307 having one or more electrode contacts 309 below the bottom surface of the flange 303. The electrode contacts 309 may be used, without limitation, to provide electronic stimulation to target sensory epithelia in the inner ear. In illustrative embodiments, the electrode array portion 307 may be short (e.g., 2-3 mm) such that is designed to be inserted into the vestibule via the stapes footplate. In such embodiments, due to its relatively small size, the electrode array portion 307 may tend to pop back out of place and would therefore need a type of fixation or feature, such as flange 303 to keep it in place.

[0034] As described above with regard to Fig. 1, the electrode lead portion 305 may be connected to an internal stimulator 114. An external movement signal (from one or more sensors not shown) is processed by an external processor 111 to produce a vestibular stimulation signal. An external transmitter coil 112 couples the stimulation signal through the skin to an implantedreceiver coil 113. Implanted vestibular stimulator 114 then delivers the stimulation signal through an electrode 140 to the vestibular stimulator electrode contacts that electrically stimulate target neural tissue.

[0035] In illustrative embodiments, the electrode 301 and flange 303 define a rotation and / or insertion depth for the electrode array portion 309. For example, the electrode 301 may include a stopper ring 320, which ensures correct placement of the electrode array portion 307, relative to the flange 303, during manufacturing (or alternatively, in embodiments where the electrode 301 and flange 303 are not integral, and the electrode 303 is inserted into the opening of the flange during, for example, surgery). The stopper ring 320 may be keyed, in combination with the top surface of the flange, to ensure proper rotation of the electrode array relative to the flange. However, alternative means to ensure correct placement such as markers, templates etc... may be used. The correct placement of electrode contacts is particularly relevant for vestibular electrodes as opposed to cochlear electrodes as the array may, without limitation, run past the utricle towards the saccule. An incorrect rotation or insertion depth may result in the contacts not stimulating the vestibular organ, or the intensity would decrease relative to the delta of the incorrect placement.

[0036] In further embodiments, the electrode array portion 309 may be pre-shaped with a predefined curvature 311. Advantageously, as shown in Fig. 4, when flange 402 is positioned and securely attached to the stapes 405, the electrode array 407 is automatically orientated in a predetermined rotation, depth and / or curvature with respect to target sensory epithelia. Fig. 5 shows flange 502 attached to the stapes, with at least one electrode contact 506 facing, without limitation, a saccule 508 and / or at least one electrode facing an utricle 510. The electrode contacts 506 may contact the saccule 508 or utricle 510, or may be positioned close enough such that electrical stimulation signals applied to the electrode(s) provide the desired stimulation. The electrode contacts 506 may be positioned to stimulate other areas of the inner ear, such as the vestibular nerve or ganglion for vestibular sensation by the patient as a balance signal.

[0037] As shown in Figs. 6A, 6B, and 6C, the electrode lead portion 605 may include at least one angled and / or curved portion 625 that is not at a normal angle relative to the flange 602, such that the electrode lead portion 605 does not collide with, and bypasses, a crus or head of thestapes when the flange 602 is securely attached to the stapes. Alternatively, the electrode lead portion 605 may be substantially straight, particularly in embodiments where the crus or head of the stapes has been removed or naturally altered, as shown in Fig. 4.

[0038] Fig. 7 is a process flow diagram 700 of an exemplary methodology for implanting a vestibular electrode in an inner ear of a subject, in accordance with an embodiment of the invention. The electrode includes an electrode array portion that includes at least one electrode contact, as described in above embodiments. The method includes making an opening e.g. using a laser or by drilling a hole, through both a stapedial footplate and the oval window of the subject, step 701. The electrode array portion is inserted through the hole, step 703. Electrical stimulation to sensory epithelia in the vestibule may then be provided via the at least one electrode contact, step 705.

[0039] The electrode may pass through a top and bottom surface of a flange. And as described above, the flange may include an edge between the top and bottom surface defining an outer perimeter. The outer perimeter of the flange may have a first fixation feature configured to contact a posterior crus of the stapes, and a second fixation feature configured to contact an anterior crus of the stapes, such that the flange is clamped and securely attached to the stapes, and such that the electrode array passes through the opening in the footplate of the stapes and the oval window. The method may further include positioning the bottom surface of the flange to rest on the stapedial footplate. The electrode array portion may be pre-shaped at a predefined angle such that when the flange is securely attached to the stapes, the electrode array contacts are automatically orientated in a desired position with respect to target sensory epithelia.

[0040] The embodiments of the invention described above are intended to be merely exemplary; numerous variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to be within the scope of the present invention.

Claims

What is claimed is:

1. A vestibular electrode fixation device for implantation in a subject, the device comprising: a flange having a top and bottom surface, and an edge between the top and bottom surface defining an outer perimeter, the outer perimeter of the flange having a first fixation feature configured to contact a posterior crus of a stapes, and a second fixation feature configured to contact an anterior crus of the stapes, such that the flange is securely attached to the stapes.

2. The vestibular electrode fixation device according to claim 1, wherein the bottom surface of the flange is configured to rest on a footplate of the stapes.

3. The vestibular electrode fixation device according to claim 1, wherein at least one of the first and second fixation features includes a notch configured to contact one of the anterior crus and posterior crus.

4. The vestibular electrode fixation device according to claim 3, wherein the notch is selected from the group consisting of a triangular notch, a semi-circular notch, a semielliptical notch, a u-notch, a square notch, and a rectangular notch.

5. The vestibular electrode fixation device according to claim 3, wherein the notch has an irregular shaped bottom and / or wall.

6. The vestibular electrode fixation device according to claim 1, further comprising an electrode that passes through the top and bottom surface of the flange, the electrode including: an electrode lead portion above the top surface of the flange; and an electrode array portion having one or more electrode contacts below the bottom surface of the flange.

7. The vestibular electrode device according to claim 6, wherein the electrode array portion is pre-shaped at a predefined angle such that when the flange is securely attached to the stapes, the electrode array passes through an opening in both a stapedial footplate and an oval window of the subject, and is automatically orientated in a desired position with respect to target sensory epithelia.

8. The vestibular electrode device according to claim 7, wherein when the flange is securely attached to the stapes, at least one electrode contact faces a saccule and / or at least one electrode may face a utricle.

9. The vestibular electrode device according to claim 6, further comprising a stopper ring positioned on the electrode that provides a predefined position of the flange relative to the electrode array portion.

10. The vestibular electrode device according to claim 6, wherein the electrode and the flange form an integral device.

11. The vestibular electrode device according to claim 6, wherein the electrode lead portion includes an angled portion that is not at a normal angle relative to the flange, such that the electrode lead portion does not collide with a crus or head of the stapes when the flange is attached to the stapes.

12. The vestibular electrode device according to claim 1, wherein the outer perimeter of the flange is not symmetrical, and is configured to be larger at the end facing the posterior crus when the flange is resting on the stapedial footplate.

13. A method of implanting a vestibular electrode in a subject, the electrode including an electrode array portion that includes at least one electrode contact, the method comprising: making an opening through both a stapedial footplate and the oval window of the subject;inserting the electrode array portion through the hole; providing electrical stimulation to sensory epithelia in the vestibule via the at least one electrode contact.

14. The method according to claim 13, wherein the electrode passes through a top surface and a bottom surface of a flange, the flange including an edge between the top and bottom surface defining an outer perimeter, the outer perimeter of the flange having a first fixation feature configured to contact a posterior crus of the stapes, and a second fixation feature configured to contact an anterior crus of the stapes, the method further comprising: positioning the flange such that the first fixation fixture contacts the posterior crus of the stapes and the second fixation fixture contacts the anterior crus of the stapes, so that the flange is securely attached to the stapes, and such that the electrode array passes through the opening in the footplate of the stapes and the oval window.

15. The method according to claim 14, wherein positioning further includes positioning the bottom surface of the flange to rest on the stapedial footplate.

16. The method according to claim 14, wherein the electrode array portion is pre-shaped at a predefined angle such that when the flange is securely attached to the stapes, the electrode array passes through the opening in the stapes footplate and the oval window, and is automatically orientated in a desired position with respect to target sensory epithelia.

17. The method according to claim 16, wherein when the flange is securely attached to the stapes, at least one electrode faces the saccule and / or at least one electrode faces the utricle.

18. The method according to claim 14, wherein the electrode and the flange form an integral device.

19. The method according to claim 14, wherein at least one of the first and second fixation features includes a notch configured to contact the crus, and wherein positioning theflange includes inserting the one of the posterior and anterior crus into the notch, with the one of the anterior and posterior crus making contact with one or more surfaces of the notch.

20. The method according to claim 19, wherein the notch is selected from the group consisting of a triangular notch, a semi-circular notch, a semi-elliptical notch, a u-notch, a square notch, and a rectangular notch.

21. The method according to claim 19, wherein the notch has an irregular shaped bottom and / or wall.

22. The method according to claim 14, wherein the electrode includes an electrode lead portion above the top surface of the flange, the electrode lead portion angled and not at a normal angle relative to the flange, such that the electrode lead portion does not collide with the crus or head of the stapes when the flange is securely attached to the stapes.

23. The method according to claim 13, wherein making the opening through both the stapedial footplate and the oval window of the subject includes using a laser or drilling.

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