Patent Application
20240024689
The disclosed subject matter described hereafter refers to a device for electrical nerve stimulation. Furthermore, reference is made to a use of the device for electrical nerve stimulation to correct sleep disordered breathing.
Neural modulation, e.g. electrical stimulation of nerves, is known in the prior art as a reliable and effective type of medical treatment. It presents the opportunity to tackle many physiological conditions and disorders by interacting with the body's own natural neural processes. Neural modulation includes inhibition (e.g. blockage), stimulation, modification, regulation, or therapeutic alteration of activity, electrical or chemical, in the central, peripheral, or autonomic nervous system. By modulating the activity of the nervous system, several different goals may be achieved. For instance, motor neurons may be stimulated at appropriate times to cause muscle contractions. Further, sensory neurons can be blocked to relieve pain or stimulated to provide a signal to a subject or patient. In yet other examples, modulation of the autonomy nervous system may be used to adjust various involuntary physiological parameters, such as heart rate and blood pressure. Neural modulation may provide the opportunity to treat several diseases or physiological conditions. Various devices and techniques have been used in attempts to provide optimum stimulation of a tissue of interest.
One of the conditions to which neural modulation can be applied to is obstructive sleep apnea (OSA), a respiratory disorder characterized by recurrent episodes of partial or complete obstruction of the upper airway during sleep. One of the causes of OSA is the inability of the tongue muscles to resist negative inspiratory pressure in the pharynx due to the sleep-related loss in muscle tone. As the tongue is pulled backwards, it obstructs the upper airway, decreasing ventilation and lowering lung and blood oxygen levels. Stimulation of the hypoglossal nerve for, example, causes the tongue muscles, e.g. the genioglossus muscle, to contract, thereby maintaining an open, unobstructed airway, since the genioglossus muscle is responsible for the forward movement of the tongue as well as for the stiffening of the anterior pharyngeal wall.
Another condition to which neural modulation may be applied is the occurrence of migraine headaches. Pain sensation in the head is transmitted to the brain via the occipital nerve, specifically the greater occipital nerve, and the trigeminal nerve. When a subject experiences head pain, such as during a migraine headache, the inhibition of these nerves may serve to decrease or eliminate the sensation of pain.
Neural modulation may also be applied to hypertension. Blood pressure in the body is controlled via multiple feedback mechanisms. For example, baroreceptors in the carotid body in the carotid artery are sensitive to blood pressure changes within the carotid artery. The baroreceptors generate signals that are conducted to the brain via the glossopharyngeal nerve when blood pressure rises, signaling the brain to activate the body's regulation system to lower blood pressure, e.g. through changes to heart rate, and vasodilation/vasoconstriction. Conversely, parasympathetic nerve fibers on and around the renal arteries generate signals that are carried to the kidneys to initiate actions, such as salt retention and the release of angiotensin, which raise blood pressure. Modulating these nerves may provide the ability to exert some external control over blood pressure.
The aforementioned are just a few examples of conditions to which neuromodulation may be of benefit. However, embodiments of the disclosure described hereafter are not limited to treating only the above-described conditions.
Prior Art
According to conventional solutions, the application range of an implant device used for functional electrical stimulation (FES) is limited to only few areas, since it often lacks functional and structural flexibility. Furthermore, conventional devices using lead electrodes for stimulation are often susceptible to lead damages due to inevitable movement of parts of the device, thus leading to low durability of the device.
One of the objectives of the present disclosure is to respond to the demands of different areas of application of FES and to provide an improved device and system for electrical nerve or muscle stimulation in a patient or recipient. In particular, an objective of this disclosure is to present a device that can be used for a wide range of applications in FES. The device and the system should allow for flexible arrangement while being easy to manufacture as well as highly durable.
According to one aspect of the disclosure, a modular stimulation device configured for implantation inside a body of a subject is provided, the device comprising: a housing, and at least one electrical lead and/or at least one stimulation electrode, wherein the at least one electrical lead is partly attached to the housing, and wherein the housing comprises modular elements, the modular elements being arranged in a stack. Such a modular design is beneficial, since it is applicable for different product variants of stimulation devices. Furthermore, a stack design has the advantage of simplifying otherwise intricate manufacturing processes. Also, since the modular elements are preferably standardized, the manufacturing process can be accelerated significantly. Preferably, the stack comprises at least two modular elements attached to each other along a vertical axis, wherein the individual modular elements may be attached to each other via gluing, brazing, welding, or by any other hermetic fixation system.
The at least two modular elements may thereby consist of one electrically active module and one passive module (i.e. without ceramics), or they may comprise of two electrically active modules. In case of two electrically active modules, the two modules may be electrically connected with each other internally (e.g. in a hermetic cavity generated by the modules). It is also possible to stack the modular elements in an interchangeable order, allowing for an even higher flexibility in application. The modular implant device as described herein is applicable in any appropriate FES context. For example, the modular implant device may be used for stimulation therapies in cases of head or neck pain, spinal cord injuries, stroke and upper limb recovery, drop foot and hypoglossal stimulation.
According to one embodiment disclosed herein, each modular element comprises a frame, wherein said frame may furthermore be four sided, each side having a width. However, the frame may be of any shape, e.g. round. As part of a preferred embodiment, the frame may at least partly made from a titanium alloy. Additionally, titanium is biocompatible and can therefore be used for implantation in a subject's body without the risk of being rejected or causing inflammations or allergies. Further, titanium alloys are highly durable, long lasting, light weight, without compromising strength. Providing frames for the modular elements drastically increases stability of the modular elements and thus of the housing and the modular implant device, respectively. In addition, the frames facilitate manufacturing of the modular implant device, since they provide a working surface for assembling the modular elements to a stack. Furthermore, they allow handling of the modular elements without having to operating any intricate components.
The modular device may, in particular, be configured in such a way that at least one modular element is a strain relief module, wherein the strain relief module comprises a cavity enclosed by the frame and wherein the frame is configured as a strain relief ring. Such a strain relief module has the advantage of increasing the durability of the modular device, since it drastically minimizes the risk of lead damages. To further increase durability and to hermetically seal the housing, the cavity enclosed in the frame of the strain relief module may be backfilled with an insulating material, wherein the insulating material may comprise silicone. Silicone is flexible and biocompatible and therefore highly suitable for any application in FES.
Further to the above, the at least one electrical lead may comprise an electrical contact tip on at least one of its ends. It may then be preferable that the electrical contact tip is disposed in the housing. Each electrical lead is configured to electrically communicate signals from another circuit or from a power supply. According to yet another beneficial improvement, the electrical lead passes through a lead exit disposed in at least one of the sides of the strain relief ring of the strain relief module. Preferably, the width of a side of the strain relief ring having a lead exit is bigger than the width of a side of the strain relief ring having no lead exit. This way, the strain relief module provides more space for the electrical lead to pass through, including a strain relief functionality. For example, the wider side allows for the electrical lead to form a double bend when passing through the lead exit of the strain relief ring. Such a double bend prevents the lead from losing contact to a electric contact or a feedthrough of its respective circuit board or from being pulled out of the housing when accidently experiencing a tug force, e.g. from movement of the device or the electrical lead inside the body. Furthermore, the above concept allows for maximum freedom of electrical contact tips and lead exit position and orientation, since the strain relief ring can easily adapt for any lead exit location or orientation. This provides the modular device with a high flexibility with regards to applications in FES.
It may also be intended that at least one of the electrical leads is a stimulation lead configured for electrical stimulation of a nerve of the subject, or a power lead configured for delivering power from a power supply, or a connection lead configured for electrically connecting the modular device to another electrical device. According to a preferred embodiment, each stimulation lead comprises a tip electrode at one of its ends that is disposed on an outer surface of the housing of the modular device, electrically connected with the feedthrough, but that is positioned in a desired location with respect to the tissue to be stimulated. The stimulation of tissue using stimulation leads (e.g. in a location further away from the housing) can also be referred to as lead stimulation.
According to another example of the modular device, the at least one stimulation electrode is disposed on an outer surface of a housing side of the modular device. It may furthermore be intended that the modular device comprises a plurality of stimulation electrodes, wherein the plurality of stimulation electrodes is preferably arranged in an array. Theoretically, the number of electrodes arranged on the surface of the housing is only limited by the size of the modular implant device. An array being very densely packed with stimulation electrodes is for example suitable for being used in scanning applications. In order to provide stimulation to a desired tissue, the modular device may also be equipped with stimulation electrodes of any shape and/or size (e.g. electrode pads), since the outer surface of the housing sides modular implant device allows for freedom of form. Further, the electrodes can be custom-sized electrodes applied to a ceramic outer surface, instead of an array. Advantageously, large shapes of outer stimulation electrode do not compromise valuable component space inside the modular device. Thus, beside conventional stimulation through electrical leads having tip electrodes at their ends (also referred to lead stimulation), the implant device as described herein also provides the option of performing local stimulation at the exposed surface of the implant itself. The stimulation of tissue using stimulation electrodes (e.g. in the surrounding vicinity of the housing) can also be referred to as local surface stimulation.
Further, at least one modular element may be a circuit module, wherein the circuit module comprises a circuit board enclosed by its frame. Preferably, the circuit board is brazed to the frame, although other means of connecting the board to the frame are possible. In accordance with yet another embodiment, the circuit board is a printed circuit board (PCB), wherein the PCB comprises a ceramic material, and wherein the PCB comprises at least one electric contact and/or at least one feedthrough. The electric contacts are configured for connection with an electric contact tip of one of the leads. The feedthroughs are used to carry a signal through the circuit board, e.g. to anther circuit board. Such a design leads to the dispensability of separate PCBs or feedthroughs, since all components are readily integrated in the circuit modules. The PCB may also contain one or more processors configured for wired or wireless communication with a source located external to the housing. The PCB may include any electric circuit that may be configured to perform a logic operation on at least one input variable. Therefore, the PCB may include one or more integrated circuits, microchips, microcontrollers, and microprocessors, which may be all or part of a central processing unit (CPU), a digital signal processor (DSP), a field programmable gate array (FPGA), or any other circuit that may be suitable for executing instructions or performing logic operations.
It may also be beneficial when the at least one electric contact or the at least one feedthrough of each circuit module is configured for electrical connection with the electrical contact tip of at least one electrical lead disposed on an outer surface of the housing of the modular device stacked just over or just beneath said circuit module. This way, different modular elements can be electrically connected to each other in a simple manner, allowing for a highly modular and flexible way of stacking the modular elements. Thus, any combination of lead stimulation and local surface stimulation is easily achievable with the modular implant device as described herein. Furthermore, either just one housing side (top or bottom) of the housing stack may be functionally used for stimulation (single-sided) or both housing sides may be functionally used for stimulation (double-sided). In a double-sided use, either the same type of stimulation (i.e. lead stimulation or local surface stimulation) may be implemented on both housing sides (e.g. both housing sides are configured for lead stimulation), or different types of stimulation may be implemented on each housing side (e.g. lead stimulation on one housing side and local surface stimulation the other). Lastly, both types of stimulation can be parallelly implemented on the same housing side.
According to another aspect of this disclosure, a system for electrical nerve stimulation is provided, the system comprising a network of at least two modular devices, each device configured for implantation inside a body of a subject, wherein each modular device is electrically connected to at least one other modular device through electrical leads. Such a system may be applicable in any appropriate FES context. For example, the system as described herein may be used for stimulation therapies in cases of head or neck pain, spinal cord injuries, stroke and upper limb recovery, drop foot and hypoglossal stimulation.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several examples of the disclosed subject matter. The drawings depict the following:
According to the preferred embodiment, each modular element 210 comprises a frame 220 having four sides 221a,b,c,d, each side 221a,b,c,d having a width 222. In the embodiment shown in
According to the embodiment of
The circuit modules 600 comprise a circuit board 610 enclosed by the frame 220. The circuit board 610 is preferably brazed to the frame 220. In accordance with a preferred embodiment, the circuit board 610 is a printed circuit board (PCB), wherein the PCB 610 further comprises a ceramic material. Furthermore, the circuit board 610 comprises at least one feedthrough 620. Such a circuit may also be referred to as a hybrid ceramic and requires no separate PCBs or feedthroughs, since all components are readily integrated in the circuit modules. The PCB may include any electric circuit that may be configured to perform a logic operation on at least one input variable. Therefore, the PCB may include one or more integrated circuits, microchips, microcontrollers, and microprocessors, which may be all or part of a central processing unit (CPU), a digital signal processor (DSP), a field programmable gate array (FPGA), or any other circuit that may be suitable for executing instructions or performing logic operations.
The electrical leads 300 as shown in
It may also be beneficial when the at least one electric contact 630 or the at least one feedthrough 620 of each circuit module 600 is configured for electrical connection with the electrical contact tip 310 of at least one electric lead 300 disposed in the cavity 520 of the strain relief module 500 stacked just over or just beneath said circuit module 600. This way, different modular elements 210 may be electrically connected with each other in a simple manner, allowing for a highly modular and flexible way of stacking the modular elements 210. Thus, any combination of lead stimulation and/or local surface stimulation is easily achieved with the modular implant device 100.
The embodiment as depicted to
The embodiment as shown in
The embodiment as shown in
The invention is not limited to one of the embodiments described herein but may be modified in numerous other ways.
All features disclosed by the claims, the specification and the figures, as well as all advantages, including constructive particulars, spatial arrangements and methodological steps, can be essential to the invention either on their own or by various combinations with each other.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/082564 | 11/18/2020 | WO |
