Patent Application
20230355974
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.
Stimulation devices for use in the detection and treatment of sleep apnea prevention are known in the prior art. For example, US 2003/0153953 A1 discloses a stimulator and a stimulation method for treating sleep apnea. However, the stimulator is dependent on the use of lead wires, which can be subject to fatigue caused by muscle movement.
U.S. Pat. No. 6,240,316 B1 teaches about the treatment of sleep apnea using injectable microstimulators having a tubular housing and no external lead wires. However, said injectable microstimulators do not necessarily stay in the required position, since they are designed for easy implantation through injection rather than for fixed and stable positioning.
One of the objectives of the present disclosure is to respond to the disadvantages of the prior art and to provide an improved system for electrical nerve stimulation in a recipient of the stimulation. In particular, an objective of this disclosure is to present a device that is highly durable and ensures accurate nerve stimulation, while reliably staying in a desired position with respect to the tissue to be stimulated.
According to one aspect of the disclosure, an implantable device for use in the treatment of sleep disordered breathing is provided, the device comprising a flexible body and at least one stimulator unit attached to the flexible body, wherein the at least one stimulator unit comprises a receiving antenna, a plurality of passive electric components encapsulated in a hermetically sealed enclosure, and at least one electric conductor in electrical connection with the plurality of passive electric components. Preferably, the electric conductor is a pair of electrodes.
The device as described above allows for an easy and stable positioning of the electrical stimulator in a subject, patient or recipient of the stimulation, e.g. on or around a muscle of the subject. The flexible body may be formed from any suitable, biocompatible material, such that it may be configured to conform to a desired location. The material of the flexible body may include, but is not limited to, silicone, plastic and/or other suitable polymers, copolymers, as well as combinations thereof. The implantable device is implanted at chosen locations within the subject and may be controlled or configured to stimulate muscle and nerve tissue in a constructive manner to help open blocked airways. Providing of a device as described herein eliminates the need for additional anchorage. For example, the flexible implantable device can easily adapt and thus attached to a desired tissue due to its flexibility. Thus, a key aspect of the present disclosure can be regarded as treatment of obstructive sleep apnea by electrically stimulating certain muscles of the oropharynx using one or more implantable devices each having one or more stimulator unit in order to contract and thereby pull open the obstructed airway.
The stimulator unit (or “microstimulator”) is preferably leadless and receives power signals, stimulation signals and/or recharging signals from a radio frequency (RF) magnetic field generated outside the subject's body. Thus, the stimulator unit comprises the following: a receiving antenna that receives the power signals, stimulation signals and/or recharging signals; a plurality of electric components encapsulated in a hermetically sealed enclosure, wherein the enclosure is preferably made from a made from a biocompatible and/or RF (radio frequency) transparent material; and at least one electric conductor, which is in electrical connection with the plurality of electric components, wherein the at least one electric conductor is configured for application of stimulation signals to a surrounding tissue. With such a stimulator unit, the need for electrical leads to connect the implantable device to another central implanted or external controller can be avoided.
It is possible that each stimulator unit includes at least one processor that may be configured to perform a logic operation. The at least one processor may therefore 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 known to those skilled in the art that may be suitable for executing instructions or performing logic operations. The device as described herein may comprise at least two stimulator units. In such a case, each of the stimulator units can be controlled separately or both stimulator units may be controlled simultaneously, allowing for a singular (unilateral) or a bilateral stimulation of the muscle to stimulated.
As described above, the stimulator unit may be configured to be leadless and thus avoid the necessity of leads or lead wires. An implantable device according to the above has the advantage of comprising only very few parts and therefore being very compact. Moreover, the lack of external lead wires (or other or loose parts) drastically minimalizes the number of parts being subjected to stress and/or fatigue, since lead wires they can be damaged over time as a result of the movement of the stimulated muscle. The stimulator may also be fabricated with a thickness suitable for implantation under a patient's skin. For example, the stimulator may have a thickness of less than 4 mm. Furthermore, the microstimulator may receive electromagnetic signals (such as power signals and stimulation signals) from an external source. When the stimulator unit receives an appropriate signal, it generates a required stimulation pulse releasing energy stored in the capacitor, and then recharging the capacitor between output pulses.
According to one embodiment disclosed herein, the flexible body at least partially consists of silicone. The implantable device may further be characterized in that the flexible body comprises suture holes for connecting the implantable device to a tissue of a subject. Silicone is flexible and biocompatible and facilitates alignment of the implantable device in a desired orientation within a subject's or patient's body. The suture holes provide attachment points for fixing and securing the implantable device at a desired location. Additionally, the flexible body may be formed with a generally triangular, circular, or rectangular shape. The shape of the flexible body may facilitate orientation of the implantable device with respect to a particular nerve or muscle to be modulated. Thus, other regular or irregular shapes may be adopted in order to facilitate implantation in differing parts of the body. The implantable device may additionally be coated with a protective coating. In some embodiments, the protective coating may be made from a flexible material to enable bending along with the flexible body. The encapsulation material of the protective coating may also resist humidity penetration and protect against corrosion.
The implantable device may in particular be configured in such a way that the flexible body has a first arm and a second arm, wherein each arm comprises at least one suture hole. This way, the flexible body of the implantable device may be attached in a desired manner with respect to a particular muscle (e.g. the genioglossus muscle), a nerve within a patient's body, or a surface within a body above a nerve. For example, the first and the second arm may be configured to enable the flexible body to conform at least partially around soft or hard tissue beneath a patient's skin (e.g. nerve, bone, or muscle tissue). With the suture holes placed on the first arm and the second arm of the flexible body, the implantable device may further be secured in a more conforming manner to the desired location, thus keeping the stimulator units of the implantable device in its required position.
The implantable device is configured for implantation proximal to a genioglossus muscle in the vicinity of a hypoglossal nerve of the subject. The hypoglossal nerve, through its lateral branch and medial branch, innervates the muscles of the tongue and other glossal muscles, including the genioglossus muscle and the geniohyoid muscle. The horizontal compartment of the genioglossus muscle is mainly innervated by the medial terminal fibers of the medial branch of the hypoglossal nerve, which diverges from the lateral branch at terminal bifurcation. The distal portion of the medial branch then variegates into the medial terminal fibers. Contraction of the horizontal compartment of the genioglossus muscle may serve to open or maintain a subject's airway. Contraction of other glossal muscles may assist in other functions, such as swallowing, articulation and opening or closing of the airway. Because the hypoglossal nerve innervates several glossal muscles, it may be advantageous for OSA treatment, to confine modulation of the nerve to the medial branch, or maybe even to the medial terminal fibers or the terminal fibers of the nerve. This way, the genioglossus muscle, being most responsible for tongue movement and airway maintenance, may be selectively targeted for contraction inducing neuro-modulation. Alternatively, the horizontal compartment of the genioglossus muscle may be selectively targeted.
It may also be intended that each of the flexible bodies arm has at least one stimulator unit attached to it. This way, more “intelligent”, i.e. advanced stimulation strategies may be applied during treatment, since the tissue to be stimulated may be stimulated from at least two different sites. Preferably, the different stimulator units, i.e. the first arm's stimulator and the second arm's stimulator, may be configured to operate independently, thus further increasing the amount of possible stimulation strategies. In a preferred embodiment, the implantable device comprises a flexible body having a first and a second arm, each arm having one microstimulator attached to it, wherein each microstimulator operates independently. Operation of such an “intelligent” stimulation, i.e. the independent stimulator units may be controlled by a logical unit or processor, which may for example be located external to the subject's body.
It is also possible that the receiving antenna is configured to receive power signals and stimulation signals from a transmitting antenna located outside the subject's body via coupling between the transmitting antenna and the receiving antenna. Said coupling of the receiving antenna and an external transmitting may include any interaction between the receiving antenna and the transmitting that causes a signal on the receiving antenna in response to a signal applied to the transmitting antenna. The coupling between the antennas may include capacitive coupling, inductive coupling, radio frequency (RF) coupling and any combinations thereof.
In addition to the above, the stimulator unit comprises at least one electrical circuit for electrically connecting the receiver antenna to the plurality of passive electrical components and back to the at least one electric conductor. The circuit may include conductive materials, such as gold, platinum, titanium, or any biocompatible conductive material or combination of materials. Furthermore, the circuit may include one or more of the following components: resistor, inductor, and/or capacitor.
As part of preferred embodiment and to protect the receiving antenna, the circuit and the passive electrical components from the environment within a patient's body, the at least one stimulator unit comprises a main body. In particular, it may be intended that the receiving antenna is disposed in the main body. The main body may preferably be formed from a biocompatible material comprising, for example, ceramic. It is also possible that the ceramic material of the main body is sintered. In particular, the main body may comprise one or more distinct layers of ceramic, on which a platinum layer is deposited before the ceramic is sintered. That way, the receiving antenna and the electronic circuit may be enclosed or integrated in the main body. Furthermore, the electrodes as well as the passive electric components may be embedded on the main body. Furthermore, the main body may preferably be lenticularly shaped.
Preferably the stimulator unit has a first surface and a second surface, wherein, the stimulator unit comprises a cap disposed on the first surface of the main body, forming the hermetically sealed enclosure. According to further developments, the cap is at least partially made from titanium. The wall of the cap should be very thin, preferably less than 10 microns, as to absorb stress rather than to transfer it to the main body. It is also possible that the cap is attached to the main body through welding of the cap to an annular welding projection disposed on a first surface of the main body. This way, the electric components, which are also attached to the first surface, may be encapsulated in the hermetically sealed enclosure. The welding projection may be made from any biocompatible material, such as indium, gold-tin etc.
In addition to the above, the stimulation unit comprises a plurality of solder pads disposed on the first surface of the stimulation unit and located in the hermetically sealed enclosure, wherein the solder pads are configured for mounting the plurality of passive electric components, and wherein the plurality of passive electric components is soldered, in particular reflow soldered, to the plurality of solder pads.
The implantable device may further be configured such that the at least one electric conductor is disposed on a second surface of the main body. The electrodes may include any suitable shape and orientation on the stimulator so long as the electrodes may be configured to generate an electric field in the body of the patient or subject. The electrodes may also include any suitable conductive material like copper, silver, gold, platinum, iridium, platinum-iridium, platinum-gold, conductive polymers etc., or combinations of conductive materials. In some embodiments the electrodes may include short line electrodes, circular electrodes, and/or circular pairs of electrodes. In one embodiment, the field-generating electrodes may include two distinct electrodes, with one providing an anode and the other providing a cathode. According to a preferred embodiment, the at least one electric conductor is formed as a pair of electrode pads.
According to this disclosure, the receiving antenna can be, but is not limited to, a long-wire antenna, a patch antenna, a helical antenna, a coil antenna, a slow wave antenna, a monopole antenna, a dipole antenna, spiral, oval, rectangular etc. According to a preferred embodiment, however, the receiving antenna has a circular and/or coiled shape. It is furthermore confined to an outer annular area of the stimulation unit, thus increasing its efficiency. According to another embodiment of the implantable device, the hermetically sealed enclosure and the at least one electric conductor are located within an inner circular area of the stimulation unit.
According to the above, a preferred embodiment of the implantable device's stimulator unit or microstimulator comprises: electrode pads embedded on the main body's second surface; a receiver antenna integrated inside the main body at the main body's outer diameter, i.e. within an outer annular area, thus increasing efficiency; a cap welded to an annular welding projection that is disposed on an inner area of the first surface of the main body, providing a hermetically sealed enclosure; solder pads encapsulated in the sealed enclosure, configured to mount the passive electrical components, e.g. via reflow soldering; at least one electronic circuit integrated inside the main body connecting the receiver antenna to the passive electrical components and back to the electrode pads.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several examples of the disclosed subject matter. The drawings depicts the following:
Having two stimulator units 30, as is the case with the implantable device 10 shown in
Each stimulator unit comprises a receiving antenna 33, which, in case of the embodiment depicted in
According to the above, the stimulator units 30 shown in
The first arm 201 and second arm 202 further facilitate attachment of the implantable device 10 to the desired muscle tissue, since they enable the flexible body 20 to conform at least partially around soft or hard tissue beneath a patient's skin. The flexible body 20 has several suture holes 21 for attaching the implantable unit 10 to the muscle tissue. This way, the flexible body of the implantable device may be attached in a desired manner. With the suture holes 21 placed on the first arm 201 and the second arm 202 of the flexible body 20, the implantable device 10 may be secured more conformingly, thus keeping the stimulator units 30 of the implantable device 10 in their required positions.
The device 10 as shown in
The stimulator unit 30 further comprises a cap 321 attached to a first surface 41 (top side) of the main body 40. The cap 321, which according to the embodiment depicted in
As further depicted 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/EP2020/076190 | 9/18/2020 | WO |
