WO2016092611A1

WO2016092611A1 - Nerve stimulation device

Info

Publication number: WO2016092611A1
Application number: PCT/JP2014/082397
Authority: WO
Inventors: 萌後藤
Original assignee: オリンパス株式会社
Priority date: 2014-12-08
Filing date: 2014-12-08
Publication date: 2016-06-16
Also published as: JPWO2016092611A1

Abstract

A nerve stimulation device that is to be indwelled in a living body for electrically stimulating nerves, said nerve stimulation device comprising: a first electrode part that is provided with a first stimulation electrode and to be disposed inside the living body; a second electrode part that is provided with a second stimulation electrode having a larger area than the first stimulation electrode and to be disposed on the body surface or under the skin; a stimulator that is provided with a stimulus-generating part generating a nerve stimulating signal for applying electrical stimulation; and a lead part that connects the first and second electrode parts to the stimulator.

Description

Nerve stimulator

The present invention includes a nerve stimulation apparatus, and more particularly, a stimulation electrode that is used in nerve stimulation treatment by being placed in a luminal tissue such as a blood vessel (blood vessel, lymph vessel), digestive tract, airway, urinary tract, and the like. The present invention relates to a nerve stimulation device.

Conventionally, research on treatment methods by applying electrical stimulation to nerve tissue has been performed. As one of the nerve stimulation devices, a medical electrode lead described in Patent Document 1 is known. The medical electrode lead is configured to apply an electrical pulse across a blood vessel wall, and a conductive lead body (lead portion) having a proximal end configured to be connected to a pulse generator (stimulus generator). A distal end portion (electrode portion) including at least one electrode (stimulation electrode) formed, and a lead anchor formed in a shape for expanding from a folded shape to a preformed expanded shape.
The medical electrode lead and the pulse generator constitute a nerve stimulation device.

When the lead anchor is in a folded shape, the distal end portion has an effective length substantially equal to the effective length of the lead anchor at the time of folding, and the distal end portion is coupled to the outside of the lead anchor. When the lead anchor is in a folded shape, the lead tip is pressed against at least one blood vessel wall of the blood vessel in which the lead is expanded, and the lead tip is deployed and fixed in the blood vessel.
The medical electrode lead is configured to be delivered to a stimulation site in a blood vessel adjacent to the nerve to be stimulated. When the lead anchor reaches the stimulation site in the blood vessel adjacent to the nerve to be stimulated, the lead anchor expands into a pre-expanded shape, and the tip attached to the outside of the lead anchor is brought into contact with the blood vessel wall to make friction Combine.

Special table 2010-516405 gazette

However, in the case where stimulation is performed using only the electrodes arranged in the blood vessel, there is a problem that the electrode fixed to the blood vessel moves and the stimulation may not be applied to the nerve to be stimulated.
The present invention has been made in view of such a problem, and provides a nerve stimulation apparatus having a wide arrangement range of stimulation electrodes capable of applying electrical stimulation to nerves to be stimulated in a blood vessel. Objective.

In order to solve the above problems, the present invention proposes the following means.
A nerve stimulation apparatus according to an aspect of the present invention is a nerve stimulation apparatus that is placed in a living body and performs electrical stimulation on a nerve, and includes a first stimulation electrode and is disposed inside the living body. A second stimulation electrode having a larger area than the first stimulation electrode, a second electrode portion disposed on the body surface or subcutaneously, and generating a nerve stimulation signal for applying the electrical stimulation A stimulus generation device having a stimulus generation unit that performs the above operation, and a lead unit that connects the first electrode unit and the second electrode unit to the stimulus generation device.

Further, in the above nerve stimulation apparatus, the first electrode unit includes a pair of the first stimulation electrodes, the state in which the electrical stimulation is performed between the pair of first stimulation electrodes, and the pair of the first stimulation electrodes. More preferably, it can be switched between one of the stimulation electrodes and the state where the electrical stimulation is performed between the second stimulation electrode.
The nerve stimulation apparatus may further include a control unit that controls the stimulus generation unit. The control unit may include a search mode in which a plurality of stimulation pulses are continuously applied without a break, and a plurality of stimulation pulses continuously. When the search mode is set as the mode, the treatment mode in which the stimulation cycle is configured by the application time applied to the signal and the off time when the stimulation pulse is not applied is included in the mode of the nerve stimulation signal. When performing the electrical stimulation between the first stimulation electrodes, and setting the treatment mode as the mode, between at least one of the pair of first stimulation electrodes and the second stimulation electrode, More preferably, the electrical stimulation is performed by switching between the pair of first stimulation electrodes.

The nerve stimulation apparatus may further include a control unit configured to control the stimulation generation unit, and the control unit may change the first electrode when impedance between the pair of first stimulation electrodes changes by a predetermined value or more. It is more preferable to determine that the part has moved.
In the above nerve stimulation apparatus, it is more preferable to acquire biological information using the first stimulation electrode or the second stimulation electrode.

According to the nerve stimulation apparatus of the present invention, it is possible to widen the arrangement range of the stimulation electrodes in which electrical stimulation can be applied to the nerve to be stimulated in the vessel.

It is a mimetic diagram showing the whole nerve stimulation device composition of a 1st embodiment of the present invention. It is a figure explaining the state which introduced the 1st electrode part of the same nerve stimulation apparatus into the blood vessel of a patient, and attached the 2nd electrode part to the back part. It is a principal part enlarged view in FIG. It is a side view of the linear elastic member of the nerve stimulating device. FIG. 5 is a cross-sectional view taken along a cutting line A1-A1 in FIG. It is a schematic diagram which shows the external appearance of the stimulus generator of the nerve stimulator. It is a functional block diagram of the nerve stimulation apparatus. It is a figure which shows the aspect of the nerve stimulation signal in search mode. It is a figure which shows the aspect of the nerve stimulation signal in a treatment mode. It is sectional drawing explaining the effect | action at the time of use of the nerve stimulation apparatus of this embodiment. It is a side view of the 1st electrode part of the nerve stimulation apparatus of 2nd Embodiment of this invention. It is sectional drawing explaining the effect | action at the time of use of the nerve stimulation apparatus of this embodiment.

(First embodiment)
Hereinafter, a first embodiment of a nerve stimulation apparatus according to the present invention will be described with reference to FIGS. 1 to 10.
As shown in FIGS. 1 and 2, the nerve stimulation apparatus 1 performs electrical stimulation on a vagus nerve (nerve) Vn such as a patient (living body) P to treat tachycardia, myocardial infarction, chronic heart failure, and the like. is there. The nerve stimulation apparatus 1 includes a stimulation generator 10 that generates a nerve stimulation signal for applying electrical stimulation, and a nerve stimulation electrode 20 that is connected to the stimulation generator 10 and placed in a blood vessel (vessel). ing.
The nerve stimulation electrode 20 includes a first electrode portion 22 having one first stimulation electrode 21, a second electrode portion 24 having one second stimulation electrode 23, a first electrode portion 22, and a first electrode portion 22. It has the lead part 25 which connects the second electrode part 24 and the stimulus generator 10. Hereinafter, the nerve stimulation electrode 20 side with respect to the stimulus generation device 10 is referred to as a distal end side, and the stimulus generation device 10 side with respect to the nerve stimulation electrode 20 is referred to as a proximal end side.

The configuration of the first electrode part 22 is not particularly limited as long as the first electrode part 22 has one first stimulation electrode 21. In the present embodiment, as shown in FIG. 3, the first electrode portion 22 is formed in a bowl shape in which three linear

elastic members

28, 29, and 30 are arranged at equal angles around the axis C.
The linear elastic member 28 is a member in which a three-dimensional loop shape is formed by bending one linear elastic member.

As shown in FIGS. 4 and 5, the linear elastic member 28 covers a wire main body 32 made of a metal wire, an inner coating 33 that covers and insulates the outer peripheral surface of the wire main body 32, and an outer peripheral surface of the inner coating 33. And an outer coating 34 for insulation.
The wire main body 32 may be an appropriate metal wire that does not undergo plastic deformation even by an external force that changes the outer diameter of the first electrode portion 22 and has good elasticity to return to a natural state when the external force is released. . Examples of metal wires suitable for the wire body 32 include shape memory alloys and superelastic wires.

The inner cover 33 may be formed of an appropriate synthetic resin material that can be deformed together with the wire body 32 and has an electrical insulation property, such as a polyurethane resin.
The outer covering 34 is a covering member that forms the outermost peripheral surface of the linear elastic member 28 except for the exposed portion of the first stimulation electrode 21. Therefore, when the outer coating 34 is introduced into the blood vessel, the outer peripheral surface of the outer coating 34 comes into contact with blood, a living tissue such as the inner wall of the blood vessel. For this reason, the outer covering 34 is an insulating material that can be deformed together with the wire body 32 and the inner covering 33 and is formed of a material that is excellent in biocompatibility. As a material suitable for the outer coating 34, for example, a polyurethane resin, a polyimide resin, or the like can be used.

The inner coating 33 is inserted through a metal tube 21a having biocompatibility such as platinum iridium alloy. A part of the metal tube 21 a that is exposed to the outside of the linear elastic member 28 through the opening 34 a of the outer coating 34 is the first stimulation electrode 21. The shape of the first stimulation electrode 21 viewed from the direction perpendicular to the axis of the metal tube 21a is a rectangular shape.
However, the shape of the first stimulation electrode 21 is not limited to this, and for example, an elliptical shape or an elliptical shape that is long in the axial direction of the metal tube 21a is also possible.

A tubular insulating member 36 for preventing a short circuit with the wire main body 32 is inserted into the metal tube 21a, and the inner coating 33 and the wire main body 32 are inserted into the insulating member 36.
A wiring 37 is electrically connected to the inner peripheral surface of the metal tube 21 a buried in the outer coating 34. As the wiring 37, for example, a stranded wire made of a nickel cobalt alloy (35NLT25% Ag material) having bending resistance is covered with an electrical insulating material (for example, ETFE (polytetrafluoroethylene) having a thickness of 20 μm). A thing can be used suitably.
The wiring 37 is disposed in the outer coating 34 and extends toward the proximal end along the wire body 32.

The linear

elastic members

29 and 30 are different from the configuration of the linear elastic member 28 in that the metal tube 21a, the insulating member 36, and the wiring 37 are not provided, and the opening 34a is not formed in the outer covering 34. That is, the first stimulation electrode 21 is not formed on the linear

elastic members

29 and 30.
As shown in FIG. 3, the linear

elastic members

28, 29, and 30 arranged around the axis C are fixed to each other by the elastic member fixing portion 38 at the intermediate portion in the direction of the axis C, and the converging portion 39 at the base end portion. Are fixed to each other.
The first stimulation electrode 21 is disposed so as to be exposed outward in the radial direction of the first electrode portion 22. The first electrode unit 22 is disposed (indwelled) in the blood vessel of the patient P. At this time, the first stimulation electrode 21 becomes an intravascular electrode.

The second stimulation electrode 23 is used by being attached to the body surface of a patient, for example, as will be described later. The second stimulation electrode 23 is formed in a flat and rectangular plate shape shown in FIGS. The shape of the second stimulation electrode 23 is not limited to a rectangular plate shape, and may be a polygonal shape such as a hexagon or an octagon, or a rounded shape such as a circle or an ellipse.
As a material for forming the second stimulation electrode 23, the same material as that of the first stimulation electrode 21, or aluminum and Ag / AgCl (silver-silver chloride) can be used. As for the 2nd electrode part 24, it is desirable that the surface is covered with the adhesive gel etc. which have electroconductivity. When the second stimulation electrode 23 is used while being fixed under the skin of a patient, the material forming the second stimulation electrode 23 is a material having biocompatibility and conductivity such as platinum iridium alloy or titanium. Can be used.

The area of one main surface of the second stimulation electrode 23 (area of the second stimulation electrode 23) is larger than the area where the first stimulation electrode 21 is exposed to the outside. When a current is applied to a narrow area, muscle contraction is induced. In particular, in the case of high-frequency stimulation, there is a possibility that muscle spasm may occur and patient P may have discomfort such as pain. For this reason, the area of the second stimulation electrode 23 needs to be a certain size or more.
Since the muscle stimulation threshold is set to several hundred mA / m ² , it is preferable to install the second stimulation electrode 23 having a size such that the current density is less than or equal to this in the muscle. For example, the area of the second stimulation electrode 23 is 30 cm ² or more.

The second electrode portion 24 is disposed on the body surface or subcutaneously outside the patient P. For example, the second electrode part 24 is disposed on the body surface or subcutaneously outside the patient P so as to sandwich the nerve to be stimulated together with the first electrode part 22. As will be described later, when a nerve stimulation signal is output, an electric field line is formed between the first stimulation electrode 21 and the second stimulation electrode 23. If there is a nerve to be stimulated on this electric field line, The nerve can be stimulated with a nerve stimulation signal.
At this time, the second stimulation electrode 23 becomes a body surface electrode or a subcutaneous electrode, and is disposed so as to face the first stimulation electrode 21.
The impedance between the first stimulation electrode 21 and the second stimulation electrode 23 is preferably about 1000Ω (ohms).

As shown in FIGS. 1 and 2, the lead portion 25 includes a first lead 42 that connects the first stimulation electrode 21 of the first electrode portion 22 and the stimulus generator 10, and a second electrode portion 24. It has the 2nd lead | read | reed 43 which connects the 2nd stimulation electrode 23 and the irritation | stimulation apparatus 10. FIG.
Although not shown, the first lead 42 has a known configuration including a coil, a covering material that has an insulating property and covers the outer periphery of the coil, and a connector provided at the base end of the coil. ing. The coil of the first lead 42 has its distal end connected to the wiring 37 of the first electrode portion 22 and its proximal end connected to the connector.

The second lead 43 is configured in the same manner as the first lead 42. The coil of the second lead 43 has a distal end side connected to the second stimulation electrode 23 of the second electrode portion 24 and a proximal end side connected to the connector.

As shown in FIG. 6, the stimulus generator 10 includes a display unit 11 that displays various types of information on the outer surface, and an interface unit 12 that performs various operations of the stimulus generator 10.
As the display unit 11, a known configuration such as a display using a liquid crystal screen or an LED can be appropriately selected and used. The interface unit 12 includes a setting button group 13 for performing various settings, an output button 14 for performing stimulation under conditions set by the setting button group 13, and a stop button 15 for canceling the output of the output button 14. And.
The connector of the first lead 42 and the connector of the second lead 43 are detachable from the stimulus generator 10.

FIG. 7 is a functional block diagram of the nerve stimulation apparatus 1. The stimulus generator 10 includes a stimulus generator 16 that generates a nerve stimulus signal, and a controller 17 that controls the entire nerve stimulator 1 such as the stimulus generator 16.
The control unit 17 is connected to each button of the display unit 11 and the interface unit 12. Based on the input from the interface unit 12, the control unit 17 determines various parameters (voltage value, pulse width, frequency, etc.) of the nerve stimulation signal and transmits them to the stimulation generation unit 16. The stimulation generation unit 16 generates a nerve stimulation signal based on the setting by the control unit 17 and sends it to the

electrode units

22 and 24 via the lead unit 25.
At this time, the first stimulation electrode 21 of the first electrode portion 22 functions as a minus (−) electrode, and the second stimulation electrode 23 of the second electrode portion 24 functions as a plus (+) electrode.

The control unit 17 includes two modes of a nerve stimulation signal, a search mode suitable for the placement technique of the first electrode unit 22 and a treatment mode suitable for treatment.
FIG. 8 shows an example of an aspect of the nerve stimulation signal in the search mode. In FIG. 8, the horizontal axis represents the stimulation time of the nerve stimulation signal, and the vertical axis represents the stimulation intensity. In the search mode, a plurality of stimulation pulses are continuously applied without a break during the stimulation cycle Sc, which is the basic unit. In the search mode, there is no off time, which is a time during which no stimulation pulse is applied, after a stimulus start instruction by operating the output button 14 until a stimulus end instruction by operating the stop button 15 or the like.
The search mode is a mode for searching for the position of the vagus nerve Vn (see FIG. 2).

FIG. 9 shows an example of the nerve stimulation signal in the treatment mode. The treatment mode has, as a basic unit, a stimulation cycle Sc composed of an application time T1 in which a plurality of stimulation pulses are continuously applied and an off time T2 that is continuous with the application time T1 and in which no stimulation pulse is applied. The treatment mode is a mode in which energy is continuously given to the vagus nerve Vn for the purpose of treatment.
In this example, the stimulation pulse in the search mode and the stimulation pulse in the treatment mode have the same waveform with the same pulse width and stimulation intensity.
The nerve stimulation signal in the treatment mode has an application time T1 of 10 to 30 seconds when the stimulation cycle Sc is 60 seconds, for example. That is, the off time T2 is 30 to 50 seconds.

The stimulation intensity of the nerve stimulation signal in the treatment mode may be determined in the search mode or in the treatment mode.
When determining the stimulation intensity of the neural stimulation signal in the treatment mode in the search mode, stop applying electrical stimulation, measure the heart rate (reference heart rate) with almost no change in heart rate, and measure the reference heart rate. The lesser of the intensity at which the heart rate decreases by about 10% and the intensity at which no significant blood pressure decrease due to stimulation is selected as the stimulation intensity in the treatment mode.
The heart rate used as the reference heart rate may be the heart rate before searching for the position of the vagus nerve Vn in the search mode.
The stimulation intensity of the nerve stimulation signal can be adjusted by measuring the impedance.

When determining the stimulation intensity of the nerve stimulation signal in the treatment mode in the treatment mode, first, the search mode is terminated, the application of electrical stimulation is stopped, and the heart rate is measured. Then switch to treatment mode and apply electrical stimulation. The stimulation intensity is adjusted by operating the interface unit 12, and the smaller one of the intensity at which the heart rate decreases by about 5 to 10% compared to the measured heart rate and the intensity at which no significant blood pressure decrease due to stimulation is determined in the treatment mode. Select as stimulus intensity.

When the treatment period in the treatment mode is a relatively short time, for example, less than 6 hours, the off time T2 of the stimulation cycle Sc in the treatment mode may be relatively short.
When the treatment period is relatively long, for example, 6 hours or more, it is preferable that the off time T2 of the stimulation cycle Sc is relatively long.
When stimulating continuously over a long period of time, the heart rate that serves as a reference for lowering the heart rate cannot be measured, so the heart rate is within a certain range (from the heart rate at the start of treatment in the treatment mode to 5 Stimulation intensity maintained at a level reduced by about 10%).

The parameters that can be input from the interface unit 12 differ depending on each mode. In the treatment mode, in addition to parameters for determining the mode of one stimulation pulse such as a voltage value, a pulse width, and a frequency, the length of the stimulation cycle Sc, the lengths of the application time T1 and the off time T2, and the like can be set.
On the other hand, in the search mode, the off time T2 cannot be set. Further, since the length of the stimulation cycle Sc and the application time T1 are the same, only one of them can be set.

When the stimulus generator is fixed subcutaneously as described later, for example, the stimulus generator is preferably configured as follows.
As a first example, the stimulus generation device may not include the display unit 11 and the interface unit 12, and the display unit and the interface unit may be included in a wireless operation device separated from the stimulus generation device. The stimulus generator and the wireless operation device can transmit and receive signals by known wireless communication. The outer surface of the stimulus generator is flat and has no buttons or the like. By operating the interface unit while confirming information displayed on the display unit of the wireless operation device, various settings such as the stimulus generation unit 16 and the control unit 17 can be performed. With this configuration, even after the stimulus generator is fixed subcutaneously, the stimulus generator can be operated by the wireless operation device.

As a second example, the display unit 11 and the interface unit 12 of the stimulus generator may be configured to be detachable from the main body of the stimulus generator. Various settings are performed using the interface unit 12 with the display unit 11 and the interface unit 12 attached to the main body. Thereafter, the display unit 11 and the interface unit 12 are removed from the main body, and the main body of the stimulus generator is fixed subcutaneously.

When the nerve stimulation apparatus 1 configured as described above is activated, the mode of the nerve stimulation signal in the control unit 17 is in the search mode.
The operator makes a small incision in the blood vessel of the patient P, inserts the nerve stimulation electrode 20 into the blood vessel, and places the first electrode portion 22 at an appropriate position in the blood vessel. Specifically, as shown in FIG. 2, the first electrode portion 22 is placed in the superior vena cava P3 through the neck P1 and the right external jugular vein P2 of the patient P. In the superior vena cava P3, the vagus nerve Vn is running in parallel. Downstream of the superior vena cava P3 is the right atrium P4 of the heart Ht.
Although the first electrode portion 22 is passed through the right external jugular vein P2, the first electrode portion 22 may be passed through the right internal jugular vein instead.

Thereafter, the stimulus generator 10 is fixed to the body surface, subcutaneously, clothes, or the like. As shown in FIG. 10, in many cases, the second electrode part 24 is attached to the body surface of the back part P6 of the patient P. FIG. 10 is a cross-sectional view taken along a plane perpendicular to the vagus nerve Vn and the spine of the patient P. An electrocardiograph (not shown) for measuring the heart rate is attached to the patient P.
When the operator presses the output button 14, the control unit 17 causes the stimulation generation unit 16 to generate a nerve stimulation signal in the search mode shown in FIG. 8 under the set conditions, and this nerve stimulation signal is output from the

electrode units

22 and 24. And applied to the patient P. In the search mode, a plurality of stimulation pulses are continuously applied without a break during the stimulation cycle Sc.

As shown in FIG. 10, the electric lines of force S <b> 2 are formed so as to go from the second stimulation electrode 23 that is a positive pole toward the first stimulation electrode 21 that is a negative pole. Electrical stimulation is applied to the vagus nerve Vn when the vagus nerve Vn is arranged in the space S1 where the electric field lines S2 are formed. In this example, the space S1 has a quadrangular pyramid shape with the second stimulation electrode 23 as a bottom surface and the first stimulation electrode 21 as a vertex. As described above, the shape of the second stimulation electrode 23 is not limited to a rectangle. When the second stimulation electrode 23 is circular, for example, the space S1 has a conical shape.
When the vagus nerve Vn is arranged in the space S1, the vagus nerve Vn is stimulated through the blood vessel wall of the superior vena cava P3, and a desired effect such as normalization of the heart rate is exhibited.

In the nerve stimulation apparatus 1, it is important for treatment that the first electrode unit 22 is placed at an appropriate position. However, it is not easy to directly observe the inside of the blood vessel with an endoscope or the like, and even if the inside of the blood vessel is observed, the positional relationship between the vagus nerve Vn that runs parallel to the outside of the blood vessel and the first electrode portion 22 can be immediately grasped. That's not true.
Therefore, since it is difficult to specify an appropriate position of the first electrode part 22 by one arrangement, a test stimulus signal is applied from the arranged first electrode part 22 and a biological reaction to this is confirmed. Accordingly, an appropriate placement position of the first electrode portion 22 is specified and placed.

More specifically, the first electrode portion 22 of the nerve stimulation electrode 20 of the nerve stimulation device 1 is pushed or pulled back in the direction of the axis C with respect to the superior vena cava P3, or rotated around the axis C. Observe the heart rate of patient P. The position in the direction of the axis C with respect to the superior vena cava P3 of the first electrode part 22 when the heart rate of the patient P is the lowest and the position around the axis C are the appropriate placement position of the first electrode part 22. . Since electrical stimulation is applied to the vagus nerve Vn when the vagus nerve Vn is disposed in the space S1, the first stimulation electrode 21 is in the direction of the axis C or around the axis C with respect to the superior vena cava P3. Even if it moves, it is easy to apply electrical stimulation to the vagus nerve Vn.

When the indwelling position of the first electrode unit 22 is determined, the operator operates the setting button group 13 of the stimulation generator 10 to change the mode of the nerve stimulation signal in the control unit 17 from the search mode to the treatment mode. In the treatment mode, a nerve stimulation signal whose basic unit is a stimulation cycle Sc composed of an application time T1 in which the stimulation pulse is continuously applied and an off time T2 in which the stimulation pulse is not applied is used.

In order to confirm that the first electrode portion 22 is not displaced from the vagus nerve Vn, if the heart rate during the stimulation is not reduced, the stimulation intensity of the electrical stimulation is about once every 1 to 3 hours. Raise the to stimulate and see if there is a decrease in heart rate.
This is because, when the stimulation is continuously performed for a long time, the possibility that the stimulation effect that the heart rate decreases due to adaptation of the living body is not observed increases.

As described above, according to the nerve stimulation apparatus 1 of the present embodiment, the vagus nerve Vn is disposed in the space S1 defined between the first stimulation electrode 21 and the second stimulation electrode 23. For example, electrical stimulation is applied to the vagus nerve Vn. For this reason, the arrangement | positioning range of the 1st stimulation electrode 21 which can apply an electrical stimulation to the vagus nerve Vn becomes wide. In other words, the position of the first stimulation electrode 21 becomes tolerant.

In the present embodiment, the control unit 17 may not be provided in the stimulus generation device 10 when the mode of the nerve stimulation signal has only the treatment mode. In this case, the nerve stimulation apparatus includes the first electrode unit 22, the second electrode unit 24, the lead unit 25, and the stimulus generation unit 16.

(Second Embodiment)
Hereinafter, a second embodiment of the nerve stimulation apparatus according to the present invention will be described with reference to FIGS. 11 and 12.
As shown in FIG. 11, in the nerve stimulation apparatus 2 of the present embodiment, the first electrode portion 22 of the nerve stimulation apparatus 1 of the first embodiment includes a pair of

first stimulation electrodes

21 and 46. The configuration of the first stimulation electrode 46 is the same as the configuration of the first stimulation electrode 21. The first stimulation electrode 46 is provided on the proximal end side of the linear elastic member 28 with respect to the first stimulation electrode 21.

When the connector of the lead part 25 is attached to the stimulus generator 10, the controller 17 can control the

first stimulus electrodes

21 and 46 and the second stimulus electrode 23 independently. The control unit 17 includes an in-body energized state in which electrical stimulation is performed between the pair of

first stimulation electrodes

21, 46, at least one of the first stimulation electrode 21 and the first stimulation electrode 46, and the second stimulation electrode 23. It is possible to switch between an internal and external energized state in which electrical stimulation is performed between the two.
In addition, when the search mode is set as the mode of the nerve stimulation signal, the control unit 17 is in the energized state in the body. Become.

When the nerve stimulation device 2 configured as described above is activated and the first electrode portion 22 is placed in the superior vena cava P3, the first stimulation on the distal end side relative to the first stimulation electrode 46 on the proximal end side. The electrode 21 is disposed at a position closer to the heart Ht.
When the mode of the nerve stimulation signal in the control unit 17 is the search mode, that is, when the control unit 17 is in a state of being energized in the body, for example, the first stimulation electrode 21 is a negative pole and the first stimulation electrode 46 is a positive pole. Yes. In this case, electric lines of force S2 are formed so as to go from the first stimulation electrode 46 to the first stimulation electrode 21 as shown in FIG.

While observing the heart rate of the patient P, the position of the first electrode unit 22 in the direction of the axis C relative to the superior vena cava P3 and the position around the axis C are adjusted so that the heart rate of the patient P is the lowest. .
In the search mode, the electric field lines are applied compared to the case where the first stimulation electrode 21 and the second stimulation electrode 23 are used by applying the electrical stimulation using the

first stimulation electrodes

21 and 46 in the energized state in the body. The range in which S2 is formed becomes narrow. For this reason, electrical stimulation can be efficiently applied to the vagus nerve Vn with smaller energy.

When the placement position of the first electrode unit 22 is determined, the mode of the nerve stimulation signal in the control unit 17 is changed from the search mode to the treatment mode.
In the treatment mode, the internal / external energization state and the internal energization state are switched. Here, it is assumed that the internal / external energization state is established. In the external and external energized state, for example, electrical stimulation is performed between the first stimulation electrode 21 and the second stimulation electrode 23 of the second electrode portion 24. At this time, the first stimulation electrode 21 functions as a negative electrode, and the second stimulation electrode 23 functions as a positive electrode.
As a negative pole, the heart rate is higher when electrical stimulation is performed between the first stimulation electrode 21 and the second stimulation electrode 23 and between the first stimulation electrode 46 and the second stimulation electrode 23. It is possible to select a reduced first stimulation electrode. Alternatively, it is also possible to perform electrical stimulation with the second stimulation electrode 23 using both the

first stimulation electrodes

21 and 46 as negative poles.
If there is no difference in the decrease in heart rate, the first stimulation electrode 21 on the distal end side is selected.

Generally, when the electrode part moves with respect to the superior vena cava due to the influence of the heartbeat or the lead part being pulled by an external force, the positional relationship between the vagus nerve and the electrode part changes. Thereby, it may become impossible to apply electrical stimulation to the vagus nerve at the electrode part.
In the nerve stimulation apparatus 2 of the present embodiment, in the treatment mode, the internal and external energization state is established, and electrical stimulation is performed between the first stimulation electrode 21 and the second stimulation electrode 23, whereby the superior vena cava P3 is Thus, the influence of the movement of the first stimulation electrode 21 can be reduced, and the electrical stimulation can be continuously applied to the vagus nerve Vn.

When the first stimulation electrode 21 is installed in the superior vena cava P3, the

first stimulation electrodes

21 and 46 should be installed in a place where the stimulation can be effectively performed as close to the vagus nerve Vn as possible. At this time, if stimulation is performed in a state where the

first stimulation electrodes

21 and 46 are forgiving in a tolerable external / internal conduction state, it becomes difficult to place the

first stimulation electrodes

21 and 46 at appropriate positions. For this reason, when searching for the position of the vagus nerve Vn, it is better to perform stimulation between the first stimulation electrodes 21 and 46 (internally energized state) installed in the blood vessel.
On the other hand, when the

first stimulation electrodes

21 and 46 are actually installed and stimulation is performed over a long period of time, the internal and external energized state that is tolerant to movement so that the stimulation is continuously transmitted to the vagus nerve Vn. It is better to stimulate with.
In other words, the nerve stimulation apparatus 2 can be used more efficiently and effectively by selecting which stimulation electrode is used for stimulation according to the stage.

As described above, according to the nerve stimulation apparatus 2 of the present embodiment, the arrangement range of the

first stimulation electrodes

21 and 46 that can apply electrical stimulation to the vagus nerve Vn can be widened.
The internal energization state and the external energization state can be switched. By setting the internal energization state in the search mode, the energy necessary for applying electrical stimulation to the vagus nerve Vn is changed to the energy necessary for the external energization state. It can be reduced as compared.
When the search mode is set as the mode of the nerve stimulation signal, the control unit 17 enters the in-body energized state when the search mode is set, and when the treatment mode is set as the mode of the nerve stimulation signal. Therefore, an electrode suitable for each mode can be automatically selected from the

first stimulation electrodes

21 and 46 and the second stimulation electrode 23.

As will be described below, the nerve stimulation apparatus 2 of the present embodiment can variously modify the control by the control unit 17.
For example, in the treatment mode, when electrical stimulation is applied only by the

first stimulation electrodes

21 and 46 disposed in the superior vena cava P3 (internally energized state), this electrical stimulation is the pulsation of the heart Ht. When the cardiac pacing that affects the above occurs, it is determined that the first stimulation electrode 21 has moved with respect to the superior vena cava P3, and the following control is performed. That is, the control unit 17 applies electrical stimulation between the first stimulation electrode 46 and the second stimulation electrode 23 far from the heart among the first stimulation electrodes 21 and 46 (external and external energized state).
By switching the stimulation electrodes to be used in this way, the influence of electrical stimulation on the heart Ht can be reduced.

The controller 17 may measure the impedance between the

first stimulation electrodes

21 and 46 while applying electrical stimulation only with the

first stimulation electrodes

21 and 46. When the measured impedance changes by a predetermined value or more compared to the impedance value when the

first stimulation electrodes

21 and 46 are placed, it is determined that the first electrode portion 22 has moved with respect to the superior vena cava P3. It switches so that an electrical stimulation may be applied between the 1st stimulation electrode 46 and the 2nd stimulation electrode 23. FIG.
The predetermined value mentioned here is, for example, 20% of the impedance value when the

first stimulation electrodes

21 and 46 are placed.

When the measured impedance changes by a predetermined value or more and decreases, the distal end side of the first electrode portion 22 falls into the right atrium P4, and at least one of the

first stimulation electrodes

21 and 46 is separated from the blood vessel wall. It may be the case. By using the first stimulation electrode 46 and the second stimulation electrode 23 on the proximal end side without using the first stimulation electrode 21 on the distal end side, the influence of electrical stimulation on the heart Ht can be reduced. it can.
As described above, in the nerve stimulation apparatus 2 according to the modified example, even if a part or all of the first electrode portion 22 falls into the atrium, the second stimulation electrode 23 is used to apply electrical stimulation to the heart Ht. Electric stimulation can be continuously applied to the vagus nerve Vn in a state where the influence is reduced.

Even when the control unit 17 detects the connection between the connector of the second lead 43 connected to the second electrode unit 24 and the stimulus generator 10, the mode of the nerve stimulation signal is switched from the search mode to the treatment mode. Good. Specifically, when the second lead 43 is removed from the stimulus generator 10, the mode is in the search mode, and when the second lead 43 is attached to the stimulus generator 10, the mode is in the treatment mode. Become.
With the second lead 43 removed from the stimulus generator 10, the first electrode portion 22 is placed in the superior vena cava P3. At this time, the control unit 17 switches the mode of the nerve stimulation signal to the search mode.
Here, when the second lead 43 is attached to the stimulus generator 10, the mode changes from the search mode to the treatment mode. The 2nd electrode part 24 is attached to the back part P6 of the patient P, and an electrical stimulation is applied in the state in the mode of treatment.

Moreover, you may comprise so that the nerve stimulation apparatus 2 may acquire an electrocardiogram signal (biological information) so that it may demonstrate below.
The nerve stimulation device 2 acquires an electrocardiogram signal using the second stimulation electrode 23. In order to minimize the influence of the electrical stimulation output on the electrocardiographic signal, the electrocardiographic signal is first acquired by the second stimulation electrode 23, and then the electrical stimulation is applied using the second stimulation electrode 23. The ECG signal is acquired by the method. A plurality of second stimulation electrodes 23 may be attached to the back P6 of the patient P, and an electrocardiogram signal may be acquired between the plurality of second stimulation electrodes 23. An electrocardiographic signal may be acquired between the second stimulation electrode 23 and the first stimulation electrode 21.
And it may determine with the 1st electrode part 22 having moved because the shape of the acquired electrocardiogram signal changed.

In this way, wiring is facilitated by sharing an electrode for acquiring an electrocardiogram signal and an electrode for applying an electrical stimulus. Furthermore, the number of locations to be confirmed when using the nerve stimulation device 2 is reduced, and the number of connectors of the nerve stimulation device 2 is reduced, which is effective for any medical staff, patient, or manufacturer. . If the number of wirings is reduced, the possibility of being caught by the wirings can be reduced, which leads to a reduction in the possibility that the first electrode portion 22 moves.
In addition, by switching the stimulation electrode using the analysis result of such an electrocardiogram signal, it is most effective when the first stimulation electrode 21 before movement and the vagus nerve Vn maintain an appropriate positional relationship. Can be stimulated between the first stimulation electrodes in the blood vessel that can transmit energy to the vagus nerve Vn and switched after movement. Therefore, the effect of electrical stimulation can be maximized.

In the present embodiment, when the control unit 17 determines that the first electrode unit 22 has moved with respect to the superior vena cava P3 when the control unit 17 is in the treatment mode and in the in-vivo state, the following control is performed. May be. That is, the polarity of the

first stimulation electrodes

21 and 46 is changed from the state in which the first stimulation electrode 21 is the negative pole and the first stimulation electrode 46 is the positive pole, The first stimulation electrode 46 is set to a negative pole.
Further, both the

first stimulation electrodes

21 and 46 may function as a negative electrode when the control unit 17 is in the treatment mode and in the external / internal energized state. In this case, the second stimulation electrode 23 becomes a positive electrode.

As mentioned above, although 1st Embodiment and 2nd Embodiment of this invention were explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The structure of the range which does not deviate from the summary of this invention Changes, combinations, deletions, etc. are also included. Furthermore, it goes without saying that the configurations shown in the embodiments can be used in appropriate combinations.
For example, in the first embodiment and the second embodiment, the nerve stimulation electrode 20 of the nerve stimulation apparatus has one second electrode part 24, but the nerve stimulation electrode 20 has a plurality of second electrode parts 24. May be included. In this case, for example, the plurality of second electrode portions 24 are mounted side by side at a position Q on the body surface of the back portion P6 of the patient P as shown in FIG. The plurality of second electrode portions 24 attached to the position Q or the like are attached side by side in a direction around the vagus nerve Vn of the patient P.

In the treatment mode, by applying electrical stimulation between the first stimulation electrode 21 disposed in the superior vena cava P3 of the patient P and the second stimulation electrodes 23 of the plurality of second electrode portions 24, Even if the first stimulation electrode 21 moves around the axis C, it becomes easy to apply electrical stimulation to the vagus nerve Vn.
Further, electrical stimulation may be applied between one second stimulation electrode 23 and the first stimulation electrode 21 among the plurality of second electrode portions 24. A second stimulation electrode in which an electrical stimulus is applied between one of the plurality of second stimulation electrodes 23 and the first stimulation electrode 21, and the second stimulation electrode 23 is sequentially changed to reduce the heart rate most. 23 is selected. By applying electrical stimulation between one second stimulation electrode 23 and the first stimulation electrode 21, electrical stimulation is applied to the vagus nerve Vn as compared with the case where a plurality of second stimulation electrodes 23 are used. The energy required to do so can be reduced.

Although the blood vessel of the patient P in which the first electrode unit 22 is placed is a blood vessel, the blood vessel may be a lymph vessel.

The nerve stimulation apparatus of the present embodiment can be suitably used for performing electrical stimulation on a patient's nerve.

DESCRIPTION OF

SYMBOLS

1, 2 Neural stimulation apparatus 10 Stimulation generator 16 Stimulation production | generation part 17

Control part

21, 46 1st stimulation electrode 22 1st electrode part 23 2nd stimulation electrode 24 2nd electrode part 25 Lead part P Patient (living body) )
Sc stimulation cycle T1 application time T2 off time Vn vagus nerve (nerve)

Claims

A nerve stimulation device that is placed in a living body and electrically stimulates nerves,
A first electrode portion having a first stimulation electrode and disposed inside the living body;
A second electrode part having a second stimulation electrode having a larger area than the first stimulation electrode, and disposed on the body surface or subcutaneously; and
A stimulus generator having a stimulus generator for generating a nerve stimulus signal for applying the electrical stimulus;
A lead part connecting the first electrode part and the second electrode part and the stimulus generator;
A nerve stimulation device comprising:
The first electrode portion has a pair of the first stimulation electrodes,
Switchable between a state in which the electrical stimulation is performed between the pair of first stimulation electrodes and a state in which the electrical stimulation is performed between one of the pair of first stimulation electrodes and the second stimulation electrode The nerve stimulation apparatus according to claim 1, wherein
A control unit for controlling the stimulus generation unit;
The controller is
A search mode in which a plurality of stimulation pulses are continuously applied without a break, a treatment mode in which a stimulation cycle is configured by an application time in which a plurality of stimulation pulses are continuously applied and an off time in which the stimulation pulses are not applied In the neural stimulation signal embodiment,
When the search mode is set as the aspect, the electrical stimulation is performed between a pair of the first stimulation electrodes,
When the treatment mode is set as the aspect, the electric mode is switched between at least one of the pair of first stimulation electrodes and the second stimulation electrode and between the pair of first stimulation electrodes. The nerve stimulation apparatus according to claim 2 which performs stimulation.
A control unit for controlling the stimulus generation unit;
The nerve stimulation device according to claim 2, wherein the control unit determines that the first electrode unit has moved when an impedance between the pair of first stimulation electrodes changes by a predetermined value or more.
The nerve stimulation apparatus according to claim 1, wherein biological information is acquired using the first stimulation electrode or the second stimulation electrode.