JP2002017872A - Electrode embedded into body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode which can be implanted into a body with low invasion, especially a diaphragm pacing electrode which can be implanted with low invasion under the use of a thorascope. SOLUTION: In the electrode provided with conductors 2 and a rubber insulator 3 coating the conductor, the insulator is provided with a holding part 4 having a through hole which can hold a nervous system and opening at one side of a cross section in the radial direction of the through holes, an extension part 5 to be extended elongated from the other side of the holding part, an upper bill 6 extended forward from the upper end of the opening, having its tip thickened and having a small hole formed at its tip and a lower bill 7 extended forward from the lower end of the opening. The conductor passes through the inside of the extension part 5, its lower end is exposed to outside from the end of the extension part and its upper end is exposed to the inside of the through hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to an implantable electrode in a body, and is particularly preferably used as a thoracoscopic implantable diaphragm pacing electrode by electrical stimulation.

[0002]

BACKGROUND OF THE INVENTION Diaphragm pacing, which provides functional electrical stimulation of the phrenic nerve, is mainly used for central alveolar hypoventilation syndrome (a syndrome of hypercapnia despite normal lung function; Hypoventilation worsens, meaning that it cannot take in oxygen and produce carbon dioxide) and higher cervical spinal cord injury (C6; {sixth from the top of the cervical spinal cord}). Has been performed on patients.

[0003] All of these treatments involve ventilating a patient who needs assistance from a ventilator to stimulate the phrenic nerve or diaphragm to make the breathing artificial, thereby removing the patient from the ventilator. The purpose is. This is because the ventilator impairs the functions of the mouth such as vocalization and eating, and is not portable and has a limited range of action. Conventionally, as a diaphragm pacing electrode, a type sewn to the phrenic nerve (SURG
ICALCLINICS OF NORTH AMERICA, VOL.60, NO.5, OCTOBER 1
980, P1055) and a type directly sewn into the diaphragm (IEEE TRAN
SACTIONS ON BIOMEDICAL ENGINEERING, VOL.44, NO.10, OC
TOBER 1997, P921).

[0004]

However, it has not become as widespread as a cardiac pacemaker. One of the reasons may be that the electrode implantation procedure is invasive (stress on the human body) because it involves thoracotomy. Therefore, one object of the present invention is to solve this problem and to provide an electrode which can be implanted in the body in a minimally invasive manner. In particular, it is an object of the present invention to provide a minimally invasive diaphragm pacing electrode under thoracoscopy.

[0005]

According to the present invention, there is provided an implantable electrode having a conductor and a rubber insulator covering the conductor, wherein the insulator grasps a nerve. A grip portion having a through hole as much as possible and having an opening formed on one side of a radial cross section of the through hole,
An extension that extends longer than the other side of the grip, an upper beak that extends forward from the upper edge of the opening, has a thicker tip, and has a small hole formed at the tip, and a lower beak that extends forward than the lower edge of the opening Wherein the conductor passes through the extension, the lower end of which is exposed outside the end of the extension, and the upper end of which is exposed in the through hole.

When using this implantable electrode,
Open the upper and lower beaks by passing a thin wire such as a thread through the small hole and pulling the thread inside the body. Then, using the beaks as a guide, move the opening of the grasping part to the nerve, insert the nerve into the through hole from the opening, and then fix the upper and lower beaks to each other with fixing means such as clips to grasp the nerve. Can be. Since the insulator is made of rubber, opening and closing of the upper and lower bills and enlargement / reduction of the opening are performed by elastic deformation of the insulator. Since the upper end of the conductor is exposed inside the through-hole, the nerve can be stimulated by applying a current to the lower end of the conductor that extends outside from the end of the extension.

At present, thoracoscopic surgery is widely used as a surgical technique for various thoracic diseases. According to the electrode of the present invention, the nerve can be grasped only by fixing the upper and lower beaks to each other with a fixing means such as a clip, so that neither sewing nor touching the electrode is required. Therefore, it is minimally invasive. Since it is an easy procedure for a thoracic surgeon who is familiar with thoracoscopic surgery to perform electrode implantation, it is suitable for various treatments such as diaphragm pacing if clinical application becomes possible.

[0008] If a sheet having a large number of irregularities in the surface direction is attached to one or both of the upper surface of the upper beak and the lower surface of the lower beak, the sheet serves as a non-slip for fixing means such as the above-mentioned clip. The means is preferable because it is difficult to separate from the upper and lower bills. Further, if a reinforcing material is attached to one or both of the lower surface of the upper beak and the upper surface of the lower beak, the beaks maintain a predetermined shape even during the work of inserting the nerve, so that the nerve is fitted into the through hole. However, the operation of fixing the upper and lower bills to each other by the fixing means is easy, which is preferable. Furthermore, as the shape of the conductor, the conductor is exposed from the base of the upper beak through the thick portion of the grip portion to the inside of the through hole from the extension portion, is folded, and extends along the wall surface of the through hole to the base of the lower beak. Is preferred. Thereby, the nerve can be brought into contact with the nerve at any position on the wall surface of the through hole, and the electrical connection is ensured.

[0009]

Embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view showing an implanted electrode in the embodiment, FIG. 2 is a longitudinal sectional view, FIG. 3 is a rear view, and FIG. 4 is a front view. The electrode 1 is composed of two conductors 2 and 2 and an insulator 3 made of silicon rubber covering the conductors 2 and 2. The conducting wire 2 is formed by twisting three platinum wires each having a diameter of 0.03 mm together with a stainless steel wire.

The insulator 3 comprises a gripper 4, an extension 5, an upper beak 6, and a lower beak 7. The grip portion 4 has a through hole 41 having a thickness of 2 mm, a width of 7 mm, and an outer diameter similar to that of a nerve such as a phrenic nerve, for example, a diameter of about 3 mm. An opening 42 is formed on the side. The extension 5 has an outer diameter of 2 mm and an opening 4 of the gripper 4.
It extends from the position different from 2 to a length of 300 mm. The upper beak 6 extends forward by 5 mm with a thickness of 1 mm from the upper edge of the opening 42, is thickened to about 2 mm, and has a small hole 61 having a diameter of 0.5 mm formed at the tip.
A sheet 62 made of net-like silicon is embedded in the lower surface of the upper beak 6. The lower beak 7 extends forward with a substantially uniform thickness of 0.5 mm from the lower edge of the opening 42, and has a lower surface of a sheet 71 of the same quality as the sheet 62.
Is embedded.

The conducting wire 2 passes through the extension 5 in the length direction, and the lower end thereof is exposed outside from the end of the extension 5 and is connected to the connector 8. On the other hand, the upper end of the conducting wire 2 passes through the thick portion of the gripping portion 4 so as to bypass the through hole 41 and reaches the vicinity of the base of the upper beak 6.
1, it turns back, and reaches near the base of the lower beak 7 along the inner periphery of the through hole 41. In the conductive wire 2, the platinum wire portion is located on the upper side, and the stainless steel wire portion is located on the lower side, and both are joined near a boundary between the grip portion 4 and the extension portion 5. The stainless steel wire part was processed into a thread form, coated with Teflon (registered trademark), and had a diameter of 0.2
5 mm. The conductors 2 and 2 are separated from each other so as not to short-circuit each other, and the interval between the platinum wire portions exposed in the through-hole 41 is set to 3 mm.

As for the insulator 3, the grip portion 4, the extension portion 5, and the upper and lower beaks 6 and 7 may be integrally formed by a usual rubber molding technique, or each element may be fused after being formed separately. . In the case of integral molding, the conductors 2 and 2 are fixed in a mold and rubber is poured. In the case of separate molding, the gripping portion 4 is processed into a circular cross section with a silicone rubber sheet, and a small hole for passing the conducting wire 2 is formed. Then, the conductive wire 2 is passed through a silicon tube to thermally soften the tube to form an extension portion 5, which is thermally fused to the grip portion 4.

When the implanted electrode 1 is used, a thread is passed through the small hole 61 and the thread is pulled inside the body to open the upper and lower bills 6 and 7. Then, using the beaks 6 and 7 as guides, the opening 42 of the grip is moved to the nerve (not shown), and the nerve is inserted into the through hole 41 from the opening 42, and the upper and lower beaks 6 and 7 are fixed to each other with clips. Thereby, the nerve can be grasped. All of these operations are performed under thoracoscopy. The grasped nerve contacts the platinum wire portion of the conducting wire 2 in the through hole 41.

Since the insulator 3 is made of silicon rubber, opening and closing of the upper and lower bills 6 and 7 and enlargement and reduction of the opening 42 are performed by elastic deformation of the insulator 3. However, upper beak 6
Since the sheet 61 is provided on the lower surface of the sheet, the sheet is not excessively deformed. And since the upper end of the conducting wire 2 exposed inside the through hole is in contact with the nerve, the nerve can be stimulated by connecting the connector to a nerve stimulator outside the body.

As the above-mentioned clip, for example, Riga Clip E sold by Johnson & Johnson, Inc.
RCA. The front end of the upper beak 6 is formed to be thick, and the sheet 71 is provided on the lower surface of the lower beak 7, so that the thick portion and the sheet 71 prevent the clip from slipping. Therefore, there is no fear that the clip will come off during nerve stimulation. The connector 8 is a micro connector A-2P (made by Unique Medical Co., Ltd.)
Is exemplified. The shape of the conductor is not limited to the above-described conductor 2, and the upper end of the conductor 2 may directly protrude from the extension 5 into the through hole 41 as shown in a sectional view in FIG.
A foil may be used instead of the wire, and this may be lined with the wall surface of the through hole 41.

[0016]

EXAMPLES In order to confirm the effect of the present invention, a living body experiment was conducted using five mongrel dogs (15-25 kg). Olympus video monitor and Olympus video thoracoscope (a metal tube of about 5 mm in diameter and about 30 cm in length)
CCD camera and light source), 5mm port, 7mm
A port and thoracoscopic forceps were used. The procedure is as follows. [Experimental procedure]

1. Premedication for intramuscular injection of ketamine hydrochloride as a general anesthetic (trade name for intramuscular injection of ketalal, manufactured by Sankyo) 10 mg / k
g was injected intramuscularly, transferred to the operating table, and blood was collected from the right femoral artery to measure spontaneous breathing and blood gas partial pressure in the room air. Shaving the forelimb (forefoot) (shaving), securing an intravenous line (start of infusion), and intravenously injecting 10 mg / kg of pentobarbital salt (trade name Nembutal, manufactured by Dainippon Pharmaceutical Co., Ltd.) which is an intravenous anesthetic Introduction. Maintenance of anesthesia was performed by inhalation of halothane (Flosen, trade name, manufactured by Takeda Pharmaceutical Co., Ltd.) as an inhalation anesthetic.

2. Orally intubate the endotracheal tube and start artificial respiration. In the supine position (upturn), the stomach is shaved to expose the right femoral artery, an arterial line is inserted, and blood pressure, heart rate, and blood gas are monitored. Blood gas from bilateral lung ventilation was collected from the arterial line and measured. 3. Shaving the neck (neck), exposing the cervical trachea and making a tracheotomy. Remove the endotracheal tube once orally intubated, re-intubate it through the tracheostomy, and observe the tube with a bronchoscope to insert the tube into the left main bronchus (the left side where the trachea branches to the left and right). I do. This allows only the left lung to ventilate.

4. Left supine position (posture lying on the left side)
The right chest was shaved, a wound of about 2 cm was made on the right chest, and 5 mm and 7 mm ports were inserted between the right ribs at two places each (total of four places), and the intrathoracic cavity was observed with a video thoracoscopy. Then, the right lung is censored (displaced) caudally (downward) to confirm the superior vena cava, and the right phrenic nerve running just above (immediately above) the superior vena cava is confirmed.

5. Peel off the superior vena cava with a thoracoscopic forceps, taking care not to damage the right phrenic nerve. A 4-0 nylon thread is passed through the small hole 61 of the electrode 1 of the embodiment. 6. When fully detached, insert the electrode 1 into the thoracic cavity, pull the thread passed through the small hole 61, open the upper and lower beaks 6 and 7, and grasp the phrenic nerve. The beaks 6 and 7 are fixed by using the rigger clip ER220 at the point where the gripper 6 is gripped. Check the fixation and remove the nylon thread.

7. The connector 8 of the electrode 1 is taken out of the body through a subcutaneous tunnel (a tunnel made under the skin), one of the conducting wires 2 is connected to the ground, and the other one is an electric stimulator manufactured by Nihon Kohden. Electrical stimulation is sent to the cathode of SEN-3301, and thoracoscopic examination confirms contraction of the phrenic nerve. I.e. vide
o Check that the muscle (diaphragm) moves on the monitor. still,
The anode of the stimulator connects to the skin as an indifferent electrode.

8. Pull out the intubation tube several centimeters, return the end of the tube to the trachea, stop ventilation of only the left lung, remove 5mm and 7mm ports for bilung ventilation, and insert a 20fr trocar from one port insertion part Then, it connects to the Heimlich valve (removing the right lung, which is now deflated, by allowing the air that has entered the thoracic cavity to escape outside the body). The remaining port insert was closed with suture and blood gas was measured in both lung ventilation. Remove the ventilator and pace the phrenic nerve while monitoring the ventilation flow rate and volume without the addition of room air, or oxygen. Pacing conditions are [main int
erval: 3sec (RR20 / min), interval: 20msec, duratio
n (stimulation time): 150 μsec, train (continuous): 65 times, stimulation was twice the threshold (about 1-2 V)]. During this time, the anesthesia of the experimental dog was Nembutal (pentobarbital, manufactured by Dainippon Pharma Co., Ltd.)
Maintained by intravenous injection, spontaneous breathing is completely eliminated. 9. 5, 15, 30, 45, 60mi since pacing started
The carbon dioxide partial pressure (paCO ₂ ) of the blood gas after n (minutes) is measured. FIG. 5 shows the measurement results.

[Evaluation] In blood gas data, pCO _{2 was} gradually increased by pacing for 60 minutes (increased carbon dioxide in blood).
(See Fig. 6), which has the effect of neuromuscular fatigue (diaphragmatic nerves and diaphragm become fatigued by electrode stimulation and diaphragm movement slows down), but bilateral pacing also needs to be considered. It was considered. Literature shows that in adult clinical cases, electrodes were implanted in the bilateral phrenic nerve,
Start pacing a day later and monitor neuromuscular fatigue
It is said that the pacing time will be gradually increased from 2-3 minutes per hour to several minutes every day, and this will be performed on a strict schedule that requires at least 6 weeks. Non-fatigueing fibers, non-fatigue-registant fibers in which the muscle fibers of the diaphragm do not cause fatigue during this schedule
Will be replaced by We believe that an increase in pCO ₂ is inevitable for pacing on one side in this experiment. But,
In order to prevent neuromuscular fatigue, evaluation based on a rigorous schedule as is currently done in clinical cases,
The potential for clinical application is also expected.

[0024]

According to the present invention, an electrode can be implanted under a thoracoscopy. As an expected effect, the indication of diaphragm pacing has been extended to cases that cannot withstand general surgical invasion, and many patients with ventilatory insufficiency who were Withdrawal, closing tracheostomy, and opening the way to return to social activity. Electrode stimulation is expected to be applied not only to the phrenic nerve but also to multiple organs in the future.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an implantable electrode in an embodiment.

FIG. 2 is a longitudinal sectional view of the electrode.

FIG. 3 is a rear view of the same.

FIG. 4 is a front view of the same.

FIG. 5 is a longitudinal sectional view showing an implanted electrode according to another embodiment.

FIG. 6 is a graph showing a change over time in carbon dioxide partial pressure (paCO ₂ ) before and after diaphragm pacing using the electrode of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Embedded electrode in a body 2 Conductor 3 Insulator 4 Grasping part 5 Extension part 6 Upper beak 7 Lower beak 8 Connector

Continuation of the front page (71) Applicant 598090885 Kenji Onaka 570-8, South side of Gion-cho, Higashiyama-ku, Kyoto-shi, Kyoto (72) Inventor Hitoshi Koshiku 3-12 Kasumicho, Nishinomiya-shi, Hyogo (72) Inventor Go Tsuyoshi Shoji Kyoto-shi, Kyoto 40-1 Ichijoji Higashiuracho, Sakyo-ku Alcazar Hayama 303 F-term (reference) 4C053 CC10

Claims (4)

[Claims] 1. An electrode comprising a conductor and a rubber insulator covering the conductor, wherein the insulator has a through hole capable of gripping a nerve, and one side of a radial cross section of the through hole. A gripping portion having an opening formed therein, an extension extending longer than the other side of the gripping portion, an upper beak having a front end thicker and a small hole formed at the front end, extending forward from an upper edge of the opening, A lower beak extending forward from a lower edge of the opening, wherein the conductor passes through the extension, a lower end thereof is exposed outside the end of the extension, and an upper end is exposed in the through hole. Implanted electrode. 2. The electrode according to claim 1, wherein a sheet having a large number of irregularities in a surface direction is attached to one or both of an upper surface of the upper beak and a lower surface of the lower beak. 3. The electrode according to claim 1, wherein a reinforcing material is attached to one or both of a lower surface of the upper beak and an upper surface of the lower beak. 4. The conductor extends from the extension to the base of the upper beak through the thick portion of the gripping portion, is exposed into the through hole, is folded, and extends along the wall surface of the through hole to the base of the lower beak. The electrode according to claim 1.