WO2006061804A1

WO2006061804A1 - Secure device for neuromuscular stimulator

Info

Publication number: WO2006061804A1
Application number: PCT/IB2005/054153
Authority: WO
Inventors: Félix Buhlmann; Pierre-Yves Lampo; Etienne Dunant; Pierre-Yves Müller; Klaus SCHÖNENBERGER
Original assignee: Compex Medical S.A.
Priority date: 2004-12-09
Filing date: 2005-12-09
Publication date: 2006-06-15
Also published as: WO2006061804A8

Abstract

The invention concerns a device for neuromuscular stimulator comprising an electric pulse generator (3) arranged in a housing including at least one stimulating channel and three electrodes (1, 1', 2, 2') connected by a wiring to said stimulating channel. The device further comprises a current divider arranged between the electrodes and the stimulating channel so as to define a primary current flowing between the stimulating channel and the divider as well as multiple secondary currents flowing between the divider and the electrodes.

Description

Secure device for neuromuscular stimulator

Field of the invention

The present invention is in the field of neuro-muscular electrostimulation carried out by means of external or implantable systems. It relates more specifically to neuromuscular electrostimulation devices formed of an electrical pulse generator disposed in a housing having at least one stimulation channel and at least three electrodes connected by a wiring to said stimulation channel. In the present text, by neuromuscular means not only the stimulation of the muscles, but also that of the nerves (eg TENS stimulation).

STATE OF THE ART Known neuromuscular electrostimulation devices consist of an electrical pulse generator disposed in a housing comprising at least one stimulation channel and at least two electrodes connected by a wiring to said stimulation channel. See for this purpose the European patent application EP 1 095 670 A1 held by the applicant. As is indicated in this state of the art, the use of a current pulse generator in such a stimulator makes it possible to overcome the drawbacks of a voltage pulse generator because the pulse is kept constant regardless of the impedance of the skin and the electrode, and thus allow to maintain the same number of fibers recruited for stimulation. It is also known to use such devices for single-channel stimulation with two pairs of electrodes.

This procedure is illustrated schematically in Figure 1 where it can be seen that the electrode of a pair 1 ', 1 ", 2', Z" is commonly connected to the housing 3 with an electrode of the other pair 2,2 ', 1', I ^11. as a result, the total current I ₀ of the pacing channel is equal to the sum of h and current I ₂ flowing respectively between the first and the second pair of electrodes. In this case, the currents h and I ₂ are not known. They depend in particular on the impedance of the muscles m1 and m2 which are respectively stimulated by the first and the second pair of electrodes.

This results in several disadvantages, in particular:

Impossibility for the user to control / adjust the stimulation between the first muscle m1 and the second muscle m2.

In case of opening of a circuit (eg accidental detachment of an electrode), all of the current I ₀ passes into the circuit which remains closed (so either li = l ₀ if I ₂ = O, or I ₂ = I ₀ if li = 0), without the stimulation ceasing. The user can therefore feel an electric shock related to the switchover of the entire power on the remaining channel.

Moreover, the current systems do not guarantee that the current compensation is total, hence a risk of chemical burn (non-zero residual charge after each pulse).

There is therefore a need to secure the single-channel pacing with several pairs of electrodes.

With such a system, there is also a need to be able to control and / or differentiate the stimulation between the muscles.

SUMMARY OF THE INVENTION The present invention overcomes the aforementioned drawbacks.

For this purpose, it relates to a neuromuscular electrostimulation device comprising an electrical pulse generator disposed in a housing comprising at least one stimulation channel and three electrodes connected by a wiring to said stimulation channel. The device according to the invention is characterized in that it comprises a current divider arranged between the electrodes and the stimulation channel so as to define a primary current flowing between the stimulation channel and the divider as well as several secondary currents which circulate between the divider and the electrodes, the divider further comprising means for freely setting the ratio between the primary current and the secondary currents and / or the ratio between the secondary currents.

Advantageously, the device according to the invention comprises at least two pairs of electrodes per stimulation channel.

According to one embodiment of the invention, the divider is arranged so that the secondary currents are all equal.

Alternatively, the ratio between the secondary currents can be controlled by means of a member disposed on the divider.

With the device according to the invention, the current is always distributed correctly between the circuits.

In case of opening of a circuit, primary or secondary, the current (s) flowing in the circuit (s) remaining closed (s) cease (s) immediately because the stimulator is able to detect an interruption of the circulation of the secondary current, and by repercussion, of the primary side.

In other words, seen from the stimulator, the function of the current divider is to pass on the highest impedance among the secondary circuits.

Note also that the currents flowing in the secondary circuits remain compensated, that is to say that the total load of each pulse is zero. This avoids the chemical burn resulting from the appearance of a non-zero residual charge.

It thus becomes possible to safely stimulate two muscle groups at the same time by means of a single stimulation channel. The present invention thus makes it possible to divide the current on more than two muscles. The primary current can for example be divided on three or four pairs of electrodes.

Alternatively, it is also possible to have several current dividers in cascade, that is to say divide a primary current into two secondary currents and then divide each secondary current into two tertiary currents, etc. In this way, with p. For example, three current dividers can provide four stimulation channels.

The invention will be described in more detail below by means of examples illustrated by the following figures:

Figure 1 schematically shows a device according to the state of the art.

Figure 2 shows a schematic view of a device according to the invention comprising two pairs of electrodes which are stimulated by a single channel.

Figure 3 shows an embodiment of a divider for use of three electrodes.

FIG. 4a shows an exemplary embodiment of a divider made with semiconductors and resistors for use of four electrodes.

Figure 4b shows an embodiment of a divider made with transformers for use of four electrodes.

The device illustrated in FIG. 2 differs from that of FIG. 1 in that all the electrodes 1 ', 1 ", 2', 2" are connected to a current divider 4, itself being connected to the stimulation channel arranged in the case 3.

The divider 4 comprises a button 5, for example a potentiometer, allowing the user to define himself the distribution, therefore their intensity, of the currents of stimulation li, I ₂ between the pairs of electrodes 1 ', 1 ", 2 \ 2". Typically, the stimulation currents have an intensity of 20 to 100 mA and are biphasic.

The current divider can be made in any manner known to those skilled in the art.

By way of non-limiting example, a configuration for three electrodes (see FIG. 3) and a configuration for four electrodes (see FIG. 4) with alternative embodiments (FIGS. 5A-5C and 6A) will be described below. 6C).

Figure 3 shows a current divider realized by means of semiconductors (npn and pnp transistors and diodes) and resistors. The total current

1 ₀ is separated into two currents U and I ₂ whose ratio can be set or adjusted by the resistors Ri, R ₂ (of the order of 10 ohms) and by the control member 5. This configuration allows the use of 3 electrodes, the electrode referenced 1 "+2" being a common electrode.

FIG. 4a shows a configuration for 4 electrodes using the same principle as that described in FIG. 3. The current dividing circuit 4 has been doubled. In this configuration, there are two separate channels for stimulating two zones of muscles.

Figure 4b shows a configuration identical to that of Figure 4a which differs only in that transformers are used to adjust the current intensities for each pair of electrodes.

It goes without saying that the invention is not limited to the previously discussed embodiments but that equivalent variants are possible.

In FIGS. 5A to 5C and 6A to 6C, alternative embodiments of the system according to the invention are illustrated. In the variants of FIGS. 5A to 5C, "snap" type connections are used to connect the cables to the electrodes. More particularly, in FIG. 5A, there are two connectors 10, 10 'each comprising a male connection 11, 11' and a female connector 12, 12 ', the connections 12, 12' being intended to fit directly on electrodes (not -represented) for example 1 "and 2" of Figure 4a. Each connector 10, 10 'contains a part of the electronics shown in FIG. 4a (for example) dedicated to a channel, that is to say to a pair of electrodes 1', 1 'or 2', 2 " in Figure 4a, and may also include a potentiometer 5 (not shown) The other electrodes 1 'and 2' of Figure 4a are connected to the female connections 13 and 13 '.

In the variant of Figure 5B, using a connector 14 containing all the electronics with two male connections 15, 15 'type "snap" for the stimulator cable. Then there are two pairs of female connections 16, 16 ', respectively 17, 17' which are intended to connect to two pairs of electrodes, for example the, 1 ", respectively 2 ', 2" of the figure 4a.

In Figure 5C another variant is shown. In this variant, the stimulator cables are directly connected to a pair of connections 18, 19 which each have their male connection element 18 ', 19' and female 18 ", 19". Then there is an element 20, 21, per channel which contains the necessary electronics and which is connected to a connection 22, 23, each connection having a female connection element 22 ', 23' each for an electrode.

In Figures 6A-6C, alternative embodiments are shown, variants that use "pin" rather than "snap" connectors.

In FIG. 6A, there is shown a connector 25 containing the necessary electronics (see FIGS. 4a and 4b) which comprises two female connections 25 'and 25 ", from which connector the connection cables to the electrodes which comprise their end of the male connections 26, 26 'respectively 27, 27' for the electrodes (for example, the, 1 "and 2 ', 2" of Figure 4a). Figure 6B shows an alternative configuration in which the connections of the male connectors 29, 29 ', 30, 30' for the electrodes are different from the variant of Figure 6A. In this variant, there is also a connector 28 containing the necessary electronics with two connections 28 'and 28 "female for the stimulator cables.

In Figure 6C, another configuration has been illustrated. In it, the electronics required for each channel (for each pair of electrodes) is distributed in each channel in a housing 31, 32, to which the stimulator cables are connected by female connections 31 ', 32' and male connections 31 ", respectively 32" which allow the contact on the electrodes (for example the, 1 "and 2 ', 2" of Figure 4a).

Of course, the examples illustrated in FIGS. 5A to 5C and 6A to 6C can be used correspondingly for the embodiment of FIG. 4b, with the necessary adaptations.

Numerical references used in the figures: 1 ', 1 ": First pair electrodes 2', 2": Second pair electrode

3: Stimulator

4: Divider

5: Control organ 10,10 ': connectors 11, 11': male connection type "snap"

12,12 ': female connection type "snap"

13,13 ': female connection type "snap"

14: connector

15,15 ': male connection of type "snap" 16,16': female connections of type "snap"

17,17 ': female connections of type "snap"

18.19: connection

18 ', 19': male connector type "snap" 18 ", 19": female connector type "snap"

20,21: element containing the electronics

22,23: connection

22 ', 23': female connector type "snap" 25: connector

25 ', 25 ": female connection type" pin "

26,26 ': male connection type "pin"

27,27 ': male connection type "pin"

28: connector 28 ', 28 ": female connection type" pin "

29,29 ': male connection type "pin"

30,30 ': male connection type "pin"

31: housing

31 ': female connection type "pin" 31 ": male connection type" pin "

32: housing

32 ': female connection type "pin"

32 ": male connection type" pin "

Claims

claims

A neuromuscular electrostimulation device comprising an electrical pulse generator disposed in a housing (3) having at least one primary stimulation channel and three electrodes (1 ', 2', 1 "+ 2") connected by a wiring to said stimulation channel, characterized in that it further comprises a current divider (4) disposed between the electrodes (1 ', 2', 1 "+ 2") and the primary stimulation channel so as to define a primary current flowing between the primary stimulation channel and the divider (4) and a plurality of secondary currents flowing between the divider (4) and the electrodes (1 ', 2', 1 "+ 2").

2. Device according to revendication icationi, wherein the divider (4) comprises means (5) which allow to freely set the ratio between the primary current and the secondary currents and / or the ratio between the secondary currents.

3. Device according to claim 1 or 2 comprising two pairs of electrodes (1 ', 1 ", 2', 2").

4. Device according to claim 2 or 3 comprising two stimulation channels and at least five electrodes.

5. Device according to any one of the preceding claims comprising a cabling between the stimulation channel or channels and the divider.

6. Device according to any one of claims 1 to 4 characterized in that the divider is fixed on the housing (3).

7. Device according to any one of the preceding claims characterized in that the divider (4) is arranged so that the secondary currents are equal.

8. Device according to any one of claims 1 to 5 characterized in that the divider (4) comprises a control member allowing the user to define the relationship between the secondary currents.

9. Device according to any one of the preceding claims characterized in that the divider (4) comprises transistors for dividing the primary current.

10. Device according to any one of the preceding claims characterized in that it comprises a plurality of current dividers (4) arranged in cascade so as to divide each secondary current into two tertiary currents and so on.

11. Device according to any one of the preceding claims characterized in that it comprises at least one divider (4) adapted to divide a current in more than two currents.