Patent Application
20250058110
The present disclosure relates generally to the implantable portion of implantable cochlear stimulation (or “ICS”) systems and, in particular, to electrode arrays.
Referring to
ICS systems are used to help the profoundly deaf perceive a sensation of sound by directly exciting the intact auditory nerve with controlled impulses of electrical current. Ambient sound pressure waves are picked up by an externally worn microphone and converted to electrical signals. The electrical signals, in turn, are processed by a sound processor, converted to a pulse sequence having varying pulse widths, rates, and/or amplitudes, and transmitted to an implanted receiver circuit of the ICS system. The implanted receiver circuit is connected to an implantable lead with an electrode array that is inserted into the cochlea of the inner ear, and electrical stimulation current is applied to varying electrode combinations to create a perception of sound. The electrode array may, alternatively, be directly inserted into the cochlear nerve without residing in the cochlea. A representative ICS system is disclosed in U.S. Pat. No. 5,824,022, which is entitled “Cochlear Stimulation System Employing Behind-The-Ear Sound processor With Remote Control” and incorporated herein by reference in its entirety. Examples of commercially available ICS sound processors include, but are not limited to, the Advanced Bionics™ Harmony™ BTE sound processor, the Advanced Bionics™ Naida™ BTE sound processor and the Advanced Bionics™ Neptune™ body worn sound processor.
As alluded to above, some ICS systems include an implantable cochlear stimulator (or “cochlear implant”) having a lead with an electrode array, a sound processor unit (e.g., a body worn processor or behind-the-ear processor) that communicates with the cochlear implant, and a microphone that is part of, or is in communication with, the sound processor unit. The cochlear implant electrode array includes a flexible body formed from a resilient material and a plurality of electrically conductive contacts (e.g., sixteen platinum contacts) spaced along a surface of the flexible body. The cross-sectional size of the flexible body may taper from the base (or “basal”) end to the tip (or “apical”) end. The contacts of the array are connected to lead wires that extend through the flexible body. Exemplary cochlear leads are illustrated in WO2018/031025A1 and WO2018/102695A1, which are incorporated herein by reference in their entireties.
The precise insertion and accurate placement of the electrode array within the cochlea are important aspects of ICS therapy in that they reduce the likelihood of tissue damage and increase the likelihood of effective electrical stimulation. For example, the electrode array should stay within the scala tympani of the cochlea and be oriented correctly. In those instances where the patient has residual hearing, which is important to preserve so that the patient can benefit from combined electro-acoustic hearing assistance, trauma to the intracochlear structures during electrode array insertion should be minimized.
The present inventors have determined that conventional electrode array insertion techniques can result in less than optimal insertion and placement of the electrode array and are susceptible to improvement. Flexible electrode arrays are pushed by a surgeon into the cochlea from the basal end of the array and, as a result, the surgeon has limited and indirect control over the movement and position of the tip end. Given that the cochlea is a helical structure that varies considerably in size and morphology from patient to patient, that the electrode array is flexible, and that surgeon must rely on tactile feedback after the tip end has passed the first turn of the cochlea, pushing the electrode array from the basal end with limited control can result in damage to and/or misplacement of the electrode array as well as unwanted trauma to the cochlea. Misplacement of the electrode array reduces the effectiveness of the cochlear implant and may necessitate a revision surgery to more accurately place the electrode array. Misplacement of the electrode array as it is moving in the apical direction can result in scraping of the cochlea, folding of the electrode array, buckling of the electrode array, and breaching of the basilar membrane. The associated damage to the inner ear can result in a reduction in (or loss of) the residual hearing that was present prior to the cochlear implant insertion, thereby reducing the likelihood that the cochlear implant recipient will be able to benefit from combined electro-acoustic hearing assistance.
A cochlear implant in accordance with at least one of the present inventions comprises a housing, an antenna within the housing, a stimulation processor within the housing operably connected to the antenna and an electrode array, operably connected to the stimulation processor, including a flexible array body, a plurality of electrically conductive contacts on the flexible array body, a plurality of flexible projections that extend outwardly from the flexible array body, and a vibration device.
A method in accordance with at least one of the present inventions comprises moving a cochlear implant electrode array, including a flexible array body, a plurality of electrically conductive contacts on the flexible array body, and a plurality of flexible projections that extend outwardly from the flexible array body, in an apical direction by vibrating the flexible body with a vibration device.
There are a number of advantages associated with such apparatus and methods. By way of example, but not limitation, the present electrode arrays are capable of moving through the narrow passages and curves of the cochlea without pushing by the surgeon, and will stop moving if the resistance is too great, thereby preventing trauma to the cochlea and damage to the electrode array. The present electrode arrays may also be moved through the cochlea solely by vibration-based driving force or by a combination of vibration-based driving force and force applied by the surgeon. The configurations of the flexible projections may be such that, once inserted, the flexible projections prevent unintended post-surgical electrode array movement in the basal direction while also allowing for a surgeon to move the electrode array in the basal direction, if necessary, without cochlear trauma.
The above described and many other features of the present inventions will become apparent as the inventions become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings.
Detailed descriptions of the exemplary embodiments will be made with reference to the accompanying drawings.
The following is a detailed description of the best presently known modes of carrying out the inventions. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the inventions.
As illustrated for example in
Referring first to the exemplary cochlear implant 100, the stimulation assembly 102 includes a flexible housing 112 formed from a silicone elastomer or other suitable material, a processor assembly 114, an antenna 116 that may be used to receive data and power by way of an external antenna that is associated with, for example, a sound processor unit, and a positioning magnet 118 located within a magnet pocket 120. The magnet 118 is used to maintain the position of a sound processor headpiece over the antenna 116. The cochlear implant may, in some instances, be configured in a manner that facilitates magnet removal and replacement. Here, the housing 112 may be provided with a magnet aperture (not shown) that extends from the magnet pocket 120 to the exterior of the housing.
In addition to the electrode array 106, the exemplary cochlear lead 104 includes, in at least some instances, a wing 122 that functions as a handle for the surgeon during the implantation surgery. Other types of handles may also be employed. Referring also to
The exemplary projections 108, which extend outwardly from the electrode array flexible body 124 and rearwardly toward the basal region 130, include a base end 142 at the flexible body and a tip end 144. The projections 108 also define an angle θ with the adjacent portion of the flexibly body outer surface 132, which may range from about 30° to about 80° and is an acute angle of about 45° in the illustrated embodiment. As used herein, the word “about” means±10%. So oriented, the projection base end 142 of each projection 108 is closer to flexible body tip end 128 than the tip end 144 of the projection. There are three pluralities 108-1 to 108-3 of longitudinally spaced projections 108, with the projection pluralities 108-1 and 108-2 on either side of the flexible body 124 and the projection plurality 108-3 in between the projection pluralities 108-1 and 108-2 and on the side opposite the windows 134, in the illustrated embodiment. The projection pluralities 108-1 and 108-2 are offset by about 180° around the longitudinal axis LA. The number and location of the projection pluralities may be different in other implementations. By way of example, but not limitation, other implementations may include only two projection pluralities that are offset by about 180° around the longitudinal axis LA, there may be more than three projection pluralities within the 180° range, and/or the projection pluralities may be within a range that extends more than 180°, or less than 180°, around the longitudinal axis LA.
Although the present inventions are not so limited, the flexible body 124 of the exemplary electrode array 106 illustrated in
Suitable materials for the contacts 122 include, but are not limited to, platinum, platinum-iridium, gold and palladium. Although the present inventions are not limited to any particular electrode configuration, the exemplary contacts 126 may be generally U-shaped and may be formed by a placing a tubular workpiece into an appropriately shaped fixture, placing the end of a lead wire 136 into the workpiece, and then applying heat and pressure to the workpiece to compress the workpiece onto the lead wire. The insulation may be removed from the portion of the lead wire within the workpiece prior to the application of heat and pressure or during the application of heat and pressure. Various examples of tubular workpieces being compressed onto lead wires are described in WO2018/031025A1 and WO2018/102695A1. The contact windows 134 extend from the outer surface 132 of the flexible body 124 to the contacts 126, thereby exposing portions of the contacts. In the exemplary implementation, the windows 134 are the same shape and expose the same portion of the associated contacts 126.
The exemplary electrode array 106 may in some instances have preset spiral shape (e.g. a helical shape) with a tight curvature (resulting from the mold shape) in an unstressed state that corresponds to the interior geometry of the cochlea. The spiral electrode array 106 may maintained in a straightened until it is inserted into the cochlea with a stylet (not shown) or an embedded shape memory polymer element (not show) that will soften and allow the flexible body to return to the pre-curved shape during implantation.
Although the contacts 126 are all the same size and the windows 134 are all the same size in the illustrated embodiment, the contacts and/or windows may be different in sizes and/or shapes in other implementations. For example, the contacts may be larger in the portion of the array that will be positioned in the basal region of the cochlea than the contacts in the portion that will be positioned in the apical region of the cochlea. The position of the contacts may be such that a portion of each contact is aligned with the flexible body outer surface, thereby eliminating the need for a window.
A wide variety of vibration devices may be employed. The exemplary vibration device 110 illustrated in
The vibration device 110 (or 110a or 110b) is located within the flexible body 124 in the exemplary electrode array 106 illustrated in
As illustrated for example in
The vibration-induced movement of the above-described electrode arrays may be controlled by controlling the amplitude and frequency of the vibrations which, in turn, may be controlled by controlling power supplied to the associated vibration devices. Referring for example to
The user interface 208 may be used to vary the supplied power as necessary to achieve the desired vibration of the electrode array (e.g., array 106) and the corresponding movement in the apical direction. In some instances, amplitude of the vibrations may range from 5 μm to 50 μm and frequency may range from 0 Hz to 200 Hz. For example, the speed of apical movement of the electrode array may be controlled by setting an amplitude and frequency that will produce the desired speed. The driving force in the apical direction may also be limited to a predetermined level by adjusting the amplitude and frequency. For example, the driving force may be limited to a level below which the associated electrode array will cause trauma to the cochlea. In other words, if the resistance is too great, the cochlear lead will simply stop moving. Power delivery times limits may also be set by way of the user interface 208.
Turning to
Power for the vibration device may be wirelessly provided in other implementations. To that end, and referring to
Although the inventions disclosed herein have been described in terms of the preferred embodiments above, numerous modifications and/or additions to the above-described preferred embodiments would be readily apparent to one skilled in the art. The inventions also include any combination of the elements from the various species and embodiments disclosed in the specification that are not already described. It is intended that the scope of the present inventions extend to all such modifications and/or additions and that the scope of the present inventions is limited solely by the claims set forth below.
