FR3092245A1 - Implantable system comprising a filling device, associated system and method - Google Patents

Abstract

Implantable system comprising a filling device, associated system and method Implantable system (10) comprising at least one electrode (16) defining an interior space (22), the electrode (16) being configured to exchange an electric current with an organic material (14) capable of being located outside the interior space (22), and at least one control device (20) electrically connected to the electrode (16), characterized in that the implantable system (10 ) further comprises a filling device (18) disposed in the interior space (22), the filling device (18) comprising a filling material at least partially occupying the interior space (22), the filling material being distinct from organic matter. Figure for abstract: 1

Description

Implantable system comprising a filler device, associated system and method

The present invention relates to an implantable system. The present invention also refers to a communication and/or energy transfer system comprising an implantable system. The present invention further relates to a communication and/or energy transfer method implemented by an implantable system.

Implantable systems capable of being placed in a living body for monitoring parameters in the body of a patient are known. Generally, such implantable systems include at least one sensor configured to measure parameters in the patient's body tissues. The sensor comprises for example at least one electrode.

Also known are implantable systems that include an actuator configured to stimulate bodily elements, such as nerves or muscles. These actuating devices comprise for example an electrode.

Additionally, some implantable systems include at least one antenna configured to exchange data and/or energy with a device disposed outside the living body.

In particular, some implantable systems include a communication system equipped with an antenna. Generally, the communication system is configured to establish communication with an external system, such as a smartwatch, intended to control the implantable system. According to one example, the communication system is configured to supply the implantable system with a communication signal coming from the external system.

However, such implantable systems are not entirely satisfactory. Indeed, these systems are very bulky, which is detrimental to patient comfort, for example, or even prevents implantation.

An object of the present invention is therefore to provide an implantable system of small size while having a high quality of communication with an external system.

To this end, the subject of the present invention is an implantable system comprising:

- at least one electrode defining an interior space, the electrode being configured to exchange an electric current with an organic material likely to be located outside the interior space, and

- at least one control device electrically connected to the electrode,

the implantable system further comprising a filler device disposed in the interior space, the filler device comprising a filler material at least partially occupying the interior space, the filler material being distinct from an organic material.

According to other advantageous aspects of the invention, the implantable system comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:

- the filling material of the filling device has a dissipation factor strictly less than 0.1.

- wherein the filling device has a surface complementary to a surface of the electrode, the complementary surface being configured to guide the electric field between the electrode and the filling device.

- Which the filling device is made of a material comprising at least 80% ceramic.

- the filling device is made of a material comprising at least 80% polymer.

- the electrode forms an antenna configured to communicate with an external device remote from the implantable system and/or to receive electrical energy from the external device.

- the electrode comprises at least one turn wound in the form of a spiral around a central axis comprising at least one loop.

- the filling device comprises at least one groove configured to receive the turn.

- the electrode forms an outer coating of the filling device.

- the electrode is configured to measure an impedance of the organic matter.

- the electrode is configured to convert a quantity of chemical energy available in the organic matter into a quantity of electrical energy.

The invention also relates to a communication and/or energy transfer system comprising an implantable system as described above and an external device disposed outside an implantation zone in which the implantable system is capable of being arranged, the external device being configured to generate a magnetic field creating a magnetic induction in the electrode.

The invention also relates to a communication and/or energy transfer method implemented by an implantable system comprising at least one electrode defining an interior space, at least one control device electrically connected to the electrode, and a filler device disposed in the interior space, the filler device comprising a filler material at least partially occupying the interior space, the filler material being distinct from an organic material, the electrode being configured to exchange a current electric with an organic matter likely to be located outside the interior space, the method of communication and/or transfer of energy comprising the reception by the implantable system of a magnetic field comprising a radio signal or comprising receiving an electrical charge.

These characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings, in which:

- FIG. 1 is a schematic sectional view of a communication and/or energy transfer system according to a first embodiment of the invention;

- FIG. 2 is a schematic perspective view of part of a communication and/or energy transfer system according to a second embodiment, and

- FIG. 3 is a diagram showing an example of a communication quality factor of the communication and/or power transfer system of FIG. 1 as a function of several factors.

In FIG. 1, a communication and/or energy transfer system 1 comprises an external device 8 and an implantable system 10 configured to be placed in an implantation zone 12.

The implantation zone 12 comprises, for example, organic matter 14, such as body tissues (not shown) comprising, for example, nerves or muscles. The implantation zone 12 is for example limited by the skin 13.

The external device 8 is configured to be placed outside the implantation zone 12.

The external device 8 is for example a smart watch (or “smartwatch”), for example worn on the wrist. According to another example, the external device 8 is integrated into a system worn with a harness on the torso.

The external device 8 is intended to be placed outside in the vicinity of the implantation zone 12. The external device 8 is configured to generate an electromagnetic field. The electromagnetic field includes an electric field and a magnetic field.

The magnetic field and the electric field are preferably used in their near field region.

In particular, the external device 8 is configured to establish communication with the implantable system 10 by a radio signal.

The external device 8 is for example configured to generate the magnetic field comprising the radio signal and/or comprising the electrical energy suitable for supplying the implantable system 10. The radio signal notably comprises data. The data includes, for example, instructions to the implantable system 10. The instructions depend in particular on the type of the implantable system 10. According to one example, the implantable system 10 is configured to monitor a glucose level in the organic matter 14, in particular in the blood. According to this example, the data of the radio signal includes, for example, an instruction to perform a measurement of the glucose level. Other data type examples are possible.

In addition, the external device 8 is for example configured to generate the magnetic field comprising for example energy intended to be transmitted to the implantable system 10.

In a first embodiment of the implantable system 10, described with reference to FIG. 1, the implantable system 10 comprises at least one electrode 16, at least one filling device 18 and at least one control device 20.

The electrode 16 is in particular an electrical conductor. The electrode 16 is in particular configured to function as an antenna and furthermore configured to function as an electrode, namely for example to exchange an electric current with the organic matter 14.

For example, the electrode 16 is configured to circulate a radiofrequency current, in particular for communication. In addition, the electrode 16 is for example configured to circulate a current at low frequency, or in direct current, in particular according to an electrode function.

The electrode 16 defines an interior space 22. The interior space 22 is for example a substantially cylindrical volume. In particular, the electrode 16 is configured to form at least part of a wall 24 of the substantially cylindrical volume. According to an alternative embodiment, the volume is a volume having rectangular sections.

According to the example of Figure 1, the electrode 16 comprises a coil 30 wound in the form of a spiral around a central axis 32. The coil comprises at least one loop. According to a particular example, the turn comprises a single loop. According to another example, the turn comprises several loops.

The turn 30 comprises for example a circular section. Thus, according to this example, the interior space 22 is a substantially cylindrical volume whose axis coincides with the central axis 32, and whose lateral area is delimited by the surface of the turn 30 oriented towards the central axis 32.

The electrode 16 is configured to exchange an electric current with the organic matter 14 likely to be located outside the interior space 22. For example, the electrode 16 is configured to generate a current transmitted to the organic matter 14 or to receive a current from the organic matter 14. In particular, the electrode 16 is configured to stimulate the organic matter 14, such as nerves or muscles, by means of the electric current.

The electrode 16 is in particular configured to be in direct contact with the organic matter 14, and in particular with the bodily tissues of the implantable zone 12.

In particular, an outer portion 26 of electrode 16 is configured to contact bodily tissue and an inner portion 28 of electrode 16 is configured to contact filler 18.

In particular, the outer part 26 is for example formed by a portion of the surface of the electrode 16 oriented away from the inner space 22, while the inner part 28 comprises a portion of the surface of the electrode 16 facing interior space 22.

The electrode 16 is in particular devoid of an insulating coating, its surface being in particular conductive.

In another example, the surface of electrode 16 may be covered with a biocompatible gel, for example an insulating biocompatible gel. The biocompatible gel is preferably configured to allow the species (such as glucose, oxygen, etc.) to diffuse towards a conductive part of the electrode 16.

The electrode 16 notably comprises a conductive material, such as gold.

According to one example, electrode 16 is associated with a second electrode (not shown). The electrode 16 and the second electrode form a fuel cell configured to generate a direct current by modifying the electrode 16 and/or the second electrode. The electrode 16 is in particular configured to convert a quantity of chemical energy available in the organic matter 14 into a quantity of electrical energy.

The electrode 16 is furthermore, for example, configured to measure an impedance of the organic matter 14, for example an impedance of the body tissues.

The electrode 16 also forms, for example, an antenna configured to communicate with the external device 8 remote from the implantable system 10 and/or to receive electrical energy from the external device 8.

For example, the electrode 16 is configured to be exposed in the magnetic field created by the external device 8. In particular, the electrode 16 is configured to generate an electric current following a magnetic induction in the electrode 16, resulting from exposure to the magnetic field created by the external device 8.

The filling device 18 is arranged in the interior space 22.

Filling device 18 includes a filling material at least partially occupying the interior space 22. Preferably, the filling material fills the majority of the interior space 22, preferably at least 80% of the interior space 22, even more preferably 100%.

Fill material is distinct from organic matter.

This means that the filling material differs from the material which would be present in the implantation zone 12 in the absence of the implantable system 10. In particular, the filling material is distinct from the organic matter 14.

In another example, the filler material is separate from the body tissues.

The filling device 18 preferably has a geometry adapted to confine the dielectric losses in a volume (external to 22) of minimum biological tissue.

In particular, the filling device has a geometry configured to reduce the biological volume exposed to the electric field. The electric field is likely to be generated during operation.

In particular, the guiding device is adapted to guide the electric field so that it is contained in the interior space 22.

The electric field is capable of being generated during the operation of the implantable system 10. In particular, the electric field forms a component of the electromagnetic field capable of being generated by the external device 8. According to a variant, the electric field is a component of an electromagnetic field likely to be generated by the implantable system 10, in particular by the antenna 16.

The material of the filling device 18 is in particular a material with a low dissipation factor DF (described below) configured to minimize the dielectric losses associated with the electric field present inside the interior space 22. In particular, the material has dielectric losses significantly lower than those of organic matter 14.

In other words, the filling device 18 is configured to isolate at least a part of the electric field generated during the operation of the implantable system 10 in the interior space 22 by minimizing the losses. In particular, the filling device 18 is configured to limit, preferably minimize, the volume of penetration of the electric field in the organic material 14.

Preferably, the filling device 18 consists of at least 80%, more preferably at least 95%, of dielectric material having a dissipation factor DF adapted to minimize the dielectric losses in the interior space 22.

For example, the filling device has a dissipation factor that is strictly less than 0.1.

According to another example, the filling device 18 is made of a material comprising at least 80% polymer.

Preferably, the filling device 18 is made of a biocompatible material.

Preferably, the material of the filling device 18 also has a magnetic permeability μ configured not to influence the magnetic field likely to be generated by the external device 8. For example, the material of the filling device 18 has a magnetic permeability relative μ _r substantially equal to 1. According to variants, the material has other permeability values.

The filling device 18 is for example made of a material comprising at least 80% ceramic, preferably at least 90% and even more preferably at least 99%.

According to particular embodiments, the filler material comprises, for example, at least one of a plastic material and a composite material incorporating carbon.

The filling device 18 has in particular a complementary surface 33 to a surface of the electrode 16. The complementary surface 33 is in particular configured to guide the electric field between the electrode 16 and the filling device 18.

For example, the filling device 18 is of substantially cylindrical shape, with an axis coinciding with the central axis 32. In particular, the filling device 18 has the shape of a solid cylinder.

In particular, in the embodiment illustrated in Figure 1, comprises a wall 34 having a groove 36 adapted to receive the electrode 16, in particular to receive the turn 30. The groove 36 has in particular a spiral shape around the central axis 32.

The groove 36 has for example a rounded bottom 37, configured to come into contact with the electrode 16, in particular with the inner part 28 of the electrode 16 (visible in particular in Figure 1). According to a particular example, the groove 36 is adapted to the shape of the electrode 16 so that at most half of the surface of the electrode 16 is in contact with the filling device 18.

In Figure 3, examples of a quality factor Q are shown. The quality factor Q defines in particular the damping of an oscillator, for example the damping of an oscillating signal in the electrode 16 by the material in which the electrode 16 is placed. In particular, the quality factor Q defines the ratio between the energy stored and the energy dissipated from an object, for example the electrode 16. The quality factor Q is defined as follows:

In other words, the dissipation factor DF relates to an electrical loss of the entire electric field in the material of the filling device 18 as well as in the tissues. The dissipation factor DF makes it possible in particular to quantify the amount of energy dissipated by oscillation in the material in the filling device 18. In particular, the dissipation factor DF makes it possible to quantify the losses.

The dissipation factor DF is reciprocal of the quality factor of the material of the filling device 18. The dissipation factor DF is in particular defined as follows:

The dissipation factor is preferably strictly less than 0.1, namely

A tan loss rate per oscillation is defined as follows:

The quality factor Q also has an influence on communication efficiency. When the communication efficiency of the implantable device 10 is increased, for example, communication over a greater distance is possible at the same transmitted power.

Communication efficiency is defined as follows:

, with

power of a received signal;

power of the transmitted signal;

k the coupling factor;

Q ₁ the quality factor of the transmitter, and

Q ₂ the quality factor of the receiver.

Thus, the effectiveness of communication is approximately equal to the product of the coupling factor k with the quality factor of the transmitter Q ₁ and of the quality factor of the receiver Q ₂ . The transmitter is for example the external device 8 and the receiver is for example the implantable device 10.

The coupling factor k describes the exchange of a magnetic flux between the transmitter and the receiver. The coupling factor depends for example on the geometric configuration of the transmitter with respect to the receiver.

In the example of figure 3, the quality factor Q is shown as a function of the frequency of oscillation of the electrode 16 for different implantable systems.

Curve 1 corresponds to an electrode of an implantable system without a filling device. For example, a body fluid is likely to be present in the interior space 22 of the electrode 16. The maximum of the quality factor Q is substantially equal to 25 at a frequency of approximately 0.009 GHz. Consequently, such an implantable system has high dielectric losses.

Curves 2 and 3 show in particular quality factors Q of the implantable system 10 according to the invention.

The implantable system 10 having the curve 2 corresponds to a filling device 18 made of a material having a relative dielectric permittivity substantially equal to 120, and that of curve 3 a relative dielectric permittivity substantially equal to 1. The relative dielectric permittivity is a parameter describing the response of a material to the electric field.

The maximum of the quality factor Q according to curve 2 is substantially equal to 32 and that according to curve 3 substantially equal to 34 at a frequency of approximately 0.012 GHz. Thus, the quality factor Q is higher in the implantable system 10 comprising the filling device 18 (curves 2 and 3) than in the implantable system without the filling device (curve 1).

The implantable system showing curve 4 corresponds to a conductor forming an antenna comprising a coating covering the conductor. Although the quality factor Q of curve 4 of FIG. 3 exhibits a maximum substantially equal to 47 at a frequency substantially equal to 0.014 GHz, the conductor of the implantable system exhibiting curve 4 is incompatible with use as an electrode , due to the presence of the coating, preventing any contact between the conductive material and the environment, for example organic matter 14.

The control device 20 is electrically connected to the electrode 16, in particular by connections 42. The control device 20 is in particular configured to exchange electrical signals with the electrode 16. In addition, the control device 20 is configured to receive electrical energy from electrode 16, for example electrical energy transmitted by induction between external device 8 and electrode 16.

The control device 20 comprises for example a capacitor configured to select a resonance frequency of the implantable system 8, in particular to obtain a high quality factor Q, in particular to operate at a frequency in which the quality factor Q has a maximum ( as shown in particular in Figure 3). The control device 20 further comprises, for example, an electronic circuit (not shown) configured to apply a stimulation to the electrode 16 and/or to receive a measurement from the electrode 16, for example a measurement of an electric potential. The electronic circuit is further configured to exchange signals with the electrode 16 according to the function as antenna of the electrode 16. A second embodiment of the implantable system 10 is now described with reference to FIG. 2. The elements corresponding to the first embodiment are denoted by the same references with respect to the first embodiment. Only the differences between the first and the second embodiment are highlighted below.

Also, the example of Figure 2 illustrates only the filling device 18 according to the second embodiment. For reasons of visibility, the other elements of the implantable system 10 are not represented.

According to the example shown in Figure 2, the groove 36 has a flat bottom and groove walls 40 connecting the bottom 38 and the wall 34 of the filling device 18. According to this example, the groove walls 40 form an angle substantially perpendicular with the bottom 38 of the groove 36.

Preferably, the implantable system 10 is formed from a biocompatible material. By “biocompatible material”, is meant a material having the capacity not to interfere with and/or not to degrade the organic matter 14 of the implantation zone 12.

A communication and/or energy transfer method will now be described. The communication method is implemented by the communication and/or energy transfer system 1 comprising the implantable system 10.

The method includes a receiving step and a filling step.

During the reception step, the implantable system 10 receives a radio wave, in particular emitted by the external device 8. The radio signal is for example transmitted by a magnetic field

In another example, the implantable system 10 receives an electrical charge.

For example, this magnetic field includes a radio signal. The radio signal comprises in particular data, such as instructions to the implantable system 10. The instructions depend in particular on the type of the implantable system 10. If the implantable system 10 monitors a level of glucose in the organic matter 14, in particular in the blood, the Data from the radio signal includes, for example, an instruction to perform a glucose level measurement. Other data type examples are possible.

According to another example, the implantable system 10 receives the magnetic field to obtain electrical energy. In other words, the implantable system 10 is inductively charged.

The filling step is implemented during operation of the implantable system 10. For example, the filling step is implemented simultaneously with the receiving step. During the filling step, the filling device 18 sees the electric field establish itself within it, that is to say in particular in the interior space 22. The electric field is generated during the operation of the system implantable 10. The filling step is thus in particular implemented by the filling device 18. The electric field is for example generated by the flow of electrons in the electrode 16 (in other words, a current) induced by the device external 8 or generated by the implantable system 10.

It is understood that the implantable system 10 according to the invention has a small footprint and has a high quality of communication at the same time.

Indeed, the electrode 16 is configured to be used both as an antenna, namely for communication with the external device 8 and to receive electrical energy from the external device 8, and at the same time as an electrode , namely to exchange an electric current with organic matter 14.

Thus, the implantable system 10 has a small footprint, in particular because the electrode 16 provides dual functionality. Indeed, in the systems of the state of the art, the electrode 16 and the antenna are generally distinct devices.

In addition, the fact that the filling device 18 comprises a material having a dissipation factor DF adapted and a geometry adapted to reduce the volume of biological material exposed to the electric field outside the interior space 22, makes it possible to reduce the dielectric losses in the organic material 14. Consequently, the implantable system 10 makes it possible to send a magnetic field of higher amplitude and/or to receive a magnetic field of lower amplitude. For example, the material of the filling device 18 makes it possible to increase the communication distance at equal power and/or to minimize the current likely to flow in the electrode 16 at an equal communication distance.

By minimizing the biological (high-loss) volume exposed to the electric field and ensuring low losses in the non-biological volume exposed to the electric field, the filler 18 reduces the dissipation factor of the communication device.

Furthermore, since the electrode 16 is configured to exchange an electric current with the organic matter 14 likely to be located outside the interior space 22, it is possible for example to measure parameters in the organic matter 14 It is thus particularly advantageous for the electrode 16 to be in direct contact with the organic material 14, and for the electrode 16 to have no insulating coating.

Because the material of the filling device 18 has a relative magnetic permeability substantially equal to 1, it is possible to transmit energy by induction to the implantable system 10, without influence by the filling device 18 on the magnetic field.

Furthermore, the implantable device 10 makes it possible to increase the efficiency of communication.

Claims (13)

Implantable system (10) comprising:
- at least one electrode (16) defining an interior space (22), the electrode (16) being configured to exchange an electric current with an organic material (14) likely to be located outside the interior space (22), and
- at least one control device (20) electrically connected to the electrode (16),
characterized in that the implantable system (10) further comprises a filler (18) disposed within the interior space (22), the filler (18) comprising a filler material at least partially occupying the interior space (22), the filling material being distinct from an organic material. Implantable system (10) according to claim 1, in which the filling material of the filling device has a dissipation factor strictly less than 0.1. An implantable system (10) according to claim 1 or 2, wherein the filler (18) has a complementary surface (33) to a surface of the electrode (16), the complementary surface (33) being configured to guide the electric field between the electrode (16) and the filling device (18). An implantable system (10) according to any preceding claim, wherein the filler (18) is made of a material comprising at least 80% ceramic. Implantable system (10) according to any one of claims 1 to 3, in which the filling device (18) is made of a material comprising at least 80% polymer. Implantable system (10) according to any one of the preceding claims, in which the electrode (16) forms an antenna configured to communicate with an external device (8) remote from the implantable system (10) and/or to receive electrical energy from the external device (8). An implantable system (10) according to any preceding claim, wherein the electrode (16) comprises at least one coil (30) wound in a spiral shape around a central axis (32) comprising at least one loop. An implantable system (10) according to claim 7, wherein the filling device (18) includes at least one groove (36) configured to receive the coil (30). An implantable system (10) according to any of claims 1 to 6, wherein the electrode (16) forms an exterior coating of the filler (18). An implantable system (10) according to any preceding claim, wherein the electrode (16) is configured to measure an impedance of the organic material (14). An implantable system (10) according to any preceding claim, wherein the electrode (16) is configured to convert an amount of chemical energy available in the organic material (14) into an amount of electrical energy. Communication (1) and/or energy transfer system comprising an implantable system (10) according to any one of Claims 1 to 11 and an external device (8) arranged outside an implantation zone (12) in which the implantable system (10) is likely to be placed, the external device (8) being configured to generate a magnetic field creating a magnetic induction in the electrode (16). A method of communication and/or energy transfer implemented by an implantable system (10) comprising at least one electrode (16) defining an interior space (22), at least one control device (20) electrically connected to the electrode (16), and a filling device (18) disposed in the interior space (22), the filling device (18) comprising a filling material at least partially occupying the interior space (22), the material filler being distinct from an organic material, the electrode (16) being configured to exchange an electric current with an organic material (14) likely to be located outside the interior space (22), the method for communication and/or energy transfer comprising the reception by the implantable system (10) of a magnetic field comprising a radio signal or comprising the reception of an electric charge.