JP4686772B2 - Bipolar stimulation electrode - Google Patents

Description

  The present invention relates to a bipolar stimulation electrode for confirming a nerve fiber in a cerebral white matter when removing a lesion such as a cerebral tumor, and in particular, easily locates a pyramidal tract existing deep from the brain surface. The present invention relates to a bipolar stimulation electrode that can be confirmed.

  Traditionally, it has been important to remove lesions in the vicinity of the cerebral motor area so that nerve fibers (mainly pyramidal tracts) of the patient's cerebral white matter are not damaged in the operation of removing the brain such as a brain tumor. It was. In particular, if the pyramidal tract is cut, various after-effects such as paralysis of the patient's half body after surgery and narrowing of the patient's visual field may remain.

  Therefore, when such lesions in the cerebrum are removed, a bipolar electrode such as Ojemann Cortical Stimulator is applied to the surface of the cerebral cortex or cerebral white matter portion, a voltage is applied to the electrode, and electrical stimulation is applied to the surface. While giving, the method of confirming the presence or absence of the cone path has been taken.

  As an example of such a bipolar electrode, as shown in FIG. 4, an electrical stimulus is applied to the cerebrum 10, and the presence or absence of the pyramidal tract 15 is mainly confirmed among the nerve fibers of the cerebrum 10 by the stimulus. A bipolar electrode 63 of a cone path confirmation device 60 for performing an operation for removing a lesion of the cerebrum 10 is disclosed. The bipolar electrode 63 is disposed in the cerebral cortex or cerebral white matter at the time of surgery, and is energized by a current output from the stimulation device 61 to give electrical stimulation. When the tumor is removed, if there is a cone path 15 at a depth of about 2 to 3 mm from the white matter stump (excision surface) 12, the cone path 15 is given to the white matter stump 12. It is induced by the applied electrical stimulation and responds to the electromyogram recorder 62. Through such a series of operations, the presence or absence of the pyramidal tract 15 can be confirmed, and the cerebral cortex and white matter lesions can be removed little by little so as not to damage the pyramidal tract 15 (non-patented). Reference 1).

  In addition to this, an electrode that contacts the brain surface under the dura mater to detect the brain surface potential, and the contact portion that contacts the brain surface is composed of a plurality of flexible conductive fibers. A subdural electrode has been proposed (Patent Document 1).

Fumio Yamaguchi, Akira Teramoto, Electrophysiological monitoring, Intraoperative brain function monitoring, CLINICAL NEUROSCIENCE separate volume, Chugai Medical, 2002.9.1, Vol. 20, no. 9, P.I. 1003-1007 Japanese Patent Laid-Open No. 2002-301038

  However, when an electrode is placed on the cerebral white matter stump and the lesion is excised, only tissue up to about 3 mm from the white matter stump can be electrically stimulated. It was difficult to confirm the presence or absence of the pyramidal tract. For this reason, it is necessary to remove the white matter stump tissue little by little at the time of excision of the lesion, place electrodes on the excision surface again, and check the pyramidal tract. It was also a burden.

  Furthermore, even if the lesion is removed by such a surgical method without damaging the pyramidal tract in the cerebral white matter, the pyramidal tract may become ischemic. That is, in order to supply a sufficient amount of blood to the cone path, it is necessary to leave a brain tissue having a thickness of about 3 mm from the cone path. In the method, even if the operation is performed without damaging the pyramidal tract, the excised surface approaches 3 mm from the pyramidal tract, causing ischemia of the pyramidal tract and There was also a risk of remaining sequelae.

  The present invention has been made in view of such problems, and the object of the present invention is to confirm the position of the cone path existing deep from the brain surface of the surgical field and preserve the cone path. In addition, it is an object of the present invention to provide a bipolar stimulation electrode that can rapidly perform an operation for preventing the occurrence of ischemia in a pyramidal tract.

  In order to solve the above-mentioned problems, the present inventors consider that it is an effective method to insert an electrode into the white matter in order to give electrical stimulation to the deep part of the cerebral white matter. As a method of applying electrical stimulation to the cerebral white matter, we focused on stereotaxic surgery in which a monopolar electrode was inserted into the brain. As a result of many experiments and researches, by inserting a pair of needle-like electrodes into the cerebral white matter, electrical stimulation is given to the cone path at a depth of about 3 to 5 mm from the tip of the electrodes. The knowledge that it was possible was obtained.

  The present invention is basically based on the above-mentioned new knowledge, and the bipolar stimulation electrode according to the present invention applies electrical stimulation to the cerebrum and confirms the presence or absence of cerebral nerve fibers by the stimulation. A bipolar stimulation electrode for performing a surgical operation for removing a cerebral lesion, the bipolar stimulation electrode having two needle-shaped electrode bodies each having a pointed tip for insertion into the cerebrum. The electrode body is arranged between the tips thereof so as to be energized so as to give an electrical stimulus to the cerebrum when inserted into the cerebrum.

  The bipolar stimulation electrode as in the present invention is such that two needle-shaped electrode bodies with sharp tips are inserted into the cerebral cortex and also the cerebral white matter of the cerebrum to energize between the tips of the electrodes for electrical stimulation. Can be given to cerebral white matter. As a result, electrical stimulation can be applied to a depth of about 30 mm from the lesion excision stump, and the position of nerve fibers existing at that depth can be confirmed. Furthermore, by inserting this needle-shaped electrode body, it is possible to confirm the position of the pyramidal tract composed of nerve fibers in the cerebral white matter before the lesion is removed. Since the position of the pyramidal tract can be confirmed in advance as described above, it is possible to quickly remove the lesion and prevent the occurrence of ischemia in the pyramidal tract without damaging the pyramidal tract.

  Such a needle-shaped electrode body has a cylindrical shape with a sharp tip, and the diameter of the cylindrical rod for ensuring the rigidity of the electrode body without affecting the cerebral cortex and cerebral white matter when the electrode body is inserted is The thickness is preferably about 0.5 mm to 2 mm, but is not particularly limited as long as the shape and size do not damage the cerebral cortex and cerebral white matter at the time of insertion.

  In addition, the two needle-like electrode bodies of the bipolar stimulation electrode according to the present invention are arranged in parallel so that the distance between the electrode bodies is a constant distance, and each needle-like electrode body is predetermined along the base end from the distal end. It is preferable that a scale is attached at every interval. By arranging the needle-like electrode bodies in parallel in this way, two needle-like electrode bodies can be inserted simultaneously from the same direction to the surface without damaging the cerebral cortex and cerebral white matter.

  Furthermore, since the scale is attached at predetermined intervals from the distal end to the proximal end, the operator inserts the needle electrode body into the cerebral cortex and further into the cerebral white matter while grasping this electrode. And the penetration depth can be easily grasped visually. Therefore, in the conventional stereotaxic surgery method, a large-scale apparatus configuration in which the electrode is movably fixed in one direction and the insertion depth of the electrode body is measured from the movement distance of the electrode becomes unnecessary. Further, since the two needle-shaped electrode bodies are arranged in parallel and are graduated with such a scale from the tip, the surgeon can see a desired scale while observing the scale on the two needle-shaped electrode bodies. Since two acicular electrode bodies can be inserted into the cerebrum in a well-balanced manner to the depth, the position of the cone path can be confirmed more accurately and safely.

  Furthermore, in order to confirm the existence of the pyramidal path in the white matter over a wide range, it is better to increase the distance between the needle-shaped electrode bodies, but this is where the pyramidal path is running in the white matter. It is difficult to identify. In order to efficiently perform electrical stimulation on the pyramidal tract and perform an operation while confirming the spatial position in the brain, the distance between the needle electrodes is preferably about 5 mm.

  As a method for attaching the scale, it is preferable to attach a scale of a color different from that of the needle-shaped electrode body in the circumferential direction of the body of the electrode body. For example, when the needle-shaped electrode body is black, it is easily visible. Thus, it is preferable to mark the scale with yellow, white, or red. Furthermore, as a preferable aspect, the operator marks the scale with a certain color (for example, white) at intervals of 1 mm from the tip, and marks with a different color (for example, red) at intervals of 5 mm from the tip. The depth at which the electrode body is inserted can be grasped instantaneously. As another mode, a ruled line is put on the half circumference around the trunk of the needle electrode body every 1 mm from the tip, and a ruled line is put on the entire circumference of the needle electrode body every 5 mm from the tip. May be.

  As a preferable aspect of the bipolar stimulation electrode according to the present invention, it is possible to bend and adjust the distal direction of the needle-like electrode body to a desired direction on the proximal end side of the needle-like electrode body and hold in that direction. A direction adjustment unit is provided. By providing such a direction adjustment unit, the surgeon can adjust the tips of the two needle-like electrode bodies in a desired direction and insert the electrode bodies in a stable posture that facilitates surgery. it can.

  As a more preferred aspect, the bipolar stimulation electrode includes a grip portion for the operator to grip the electrode, and the direction adjusting portion is disposed between the grip portion and the needle electrode body. ing. As described above, by providing the direction adjusting portion in the vicinity of the grip portion and in the vicinity of the proximal end of the needle-like electrode body, the operator can accurately insert the needle-like electrode body without shaking. Further, such a direction adjusting portion is preferably a material or shape that can be easily bent by an operator and can maintain the bent state, for example, a metal having toughness such as copper or an alloy thereof. A rod made of a material is preferable.

  Each acicular electrode body is preferably made of a conductive material, and an insulating coating is preferably formed on the surface of the body of each acicular electrode body. In this way, by forming the insulating coating on the body of the needle electrode body, electricity can be efficiently passed only between the tips of the needle electrode body without leakage of current from the body section. . As a result, the presence or absence of the pyramidal tract can be confirmed accurately with a small current, and the electrical load on the cerebral cortex and cerebral white matter can be reduced. Furthermore, as a material for the needle-shaped electrode body, for example, a metal material having excellent corrosion resistance and high electrical conductivity is preferable, and materials such as stainless steel, tungsten, and platinum iridium are exemplified. Moreover, as a material of an insulating film, the material which does not affect a human body is preferable, and materials, such as an epoxy resin, a urethane resin, and a fluororesin, are mentioned.

  According to the bipolar stimulation electrode of the present invention, it is possible to confirm the position of the pyramidal tract existing deep from the surface of the brain of the surgical field, and to appropriately perform the operation without damaging the pyramidal tract. It is possible to safely remove cerebral white matter lesions. As a result, it is possible to avoid worsening of neurological symptoms (exacerbation of paralysis) of the patient after surgery.

  Hereinafter, embodiments of a bipolar stimulation electrode according to the present invention will be described in detail with reference to the drawings. 1 is an overall configuration diagram of a bipolar stimulation electrode according to the present embodiment, FIG. 2 is a schematic diagram for explaining a cross section of the bipolar stimulation electrode shown in FIG. 1, and FIG. 3 is a bipolar stimulation shown in FIG. It is an enlarged view of the tip vicinity of an electrode. The bipolar stimulation electrode 1 according to the present embodiment is an electrode used in place of the bipolar electrode 63 of FIG. 4 described above, and the cone path confirmation device 60 is basically the same as the conventional one except for the electrode structure. Since devices are used, a detailed description of these devices is omitted.

  The bipolar stimulation electrode 1 according to the present embodiment applies electrical stimulation to the cerebrum 10 and extracts lesions of the cerebrum 10 while confirming mainly the presence or absence of the pyramidal tract 15 of nerve fibers of the cerebral white matter by the stimulation. As shown in FIGS. 1 and 2, the bipolar stimulation electrode 1 is mainly composed of two needle-like electrode bodies 2, 2, an electrode body fixing portion 3, a direction adjusting portion 4, and A grip 5 is provided.

  These two acicular electrode bodies 2, 2 are arranged so that they can be energized to give electrical stimulation to the cerebrum 10 when the acicular electrode bodies 2, 2 are inserted into the cerebrum 10. . Specifically, the two needle-like electrode bodies 2 and 2 are arranged in parallel while maintaining a constant distance (a distance of about 5 mm) so that electricity can be passed between the electrode bodies. Further, the base end side of each needle-like electrode body 2 is fixed through a through hole 31 of the electrode body fixing portion 3 as shown in FIG. 2 so that the relative positional relationship thereof does not change. Furthermore, the lead wire 7 is connected to the base end 22 of each acicular electrode body 2 that has passed through the through hole 31, and a predetermined current adjusted by the stimulation device 61 (see FIG. 4) is supplied to the acicular electrode body 2. It is possible to energize between the tips 21 of the two.

  Further, as shown in FIG. 2, each needle-like electrode body 2 is made of cylindrical rod-shaped stainless steel having a diameter of about 0.6 mm, and is inserted into the cerebral cortex of the cerebrum 10 and further into the cerebral white matter. 21 is pointed. Further, an insulating coating 24 made of an epoxy resin is formed on the body portion 23 of each needle-like electrode body 2. As described above, by forming the insulating coating 24 on the body portion 23, it is possible to allow a current to flow appropriately only between the tips of the electrode bodies on which the insulating coating 24 is not formed during surgery.

  Further, as shown in FIG. 3, the surface of the insulating coating 24 is provided with a scale 25a at intervals of 1 mm from the tip 21 to the base 22 of the electrode body, and further at intervals of 1 mm every 5 mm. A scale 25b that can be distinguished from the scales attached to is provided with a scale 25c that can be distinguished from these scales every 10 mm. As shown in FIG. 3, the scales 25 a to 25 c may be distinguished by attaching circumferential lines having different lengths in the circumferential direction. For example, each needle electrode body 2 is covered with a black epoxy resin, A colored epoxy resin may be further coated along the circumference so that 25a is yellow, the scale 25b is red, and the scale 25c is white. In this way, since the graduations are attached at predetermined intervals from the distal end 21 to the proximal end 22 of the two needle-like electrode bodies 2, 2 arranged in parallel, how much depth the surgeon can have. Whether the electrode body has been inserted into the cerebrum 10 or its insertion depth can be visually confirmed easily and accurately.

  As a material of such needle-like electrode body 2, a material having high electrical conductivity, excellent corrosion resistance, and hardly affecting the human body is preferable. Besides stainless steel, for example, tungsten, platinum iridium, etc. The material of the insulating coating 24 may be any material as long as it has excellent insulating properties and does not affect the human body. In addition to the epoxy resin, examples thereof include materials such as urethane resin and fluororesin. It is done.

  Furthermore, a direction adjusting portion 4 is provided on the proximal end side of the needle-like electrode body 2 via an electrode body fixing portion 3 made of acrylic resin. The direction adjusting unit 4 adjusts the distal direction of the needle-shaped electrode body 2 (the direction along the distal end 21 from the proximal end 22) to a direction desired by the operator, and holds the needle-shaped electrode body 2 in the prepared direction. The direction adjustment unit 4 includes a copper rod 41 and a silicone tube 42.

  The copper rod body 41 is fixed so that one end is fitted in the recess 32 provided in the center of the electrode body fixing portion 3, and the other end is fitted in the recess 52 provided in the grip portion 5. So that it is fixed. Thus, by providing the copper metal rod body 41 rich in toughness, at the time of surgery, the operator easily bends the copper rod body 41 and holds the electrode body 2 in the desired distal direction. can do. Further, if such a function can be ensured, the rods disposed on the needle electrode body 2 and the grip portion 5 may be made of a metal material such as iron, aluminum, etc. In some cases, the rigidity of the rod body can be adjusted by changing the rod diameter.

  Further, the silicone tube 42 is disposed so as to cover the copper rod body 41 and the lead wire 7 described above, and the tube end face is fixed to the electrode body fixing portion 3 and the grip portion 5. In addition, the lead wire 7 is connected to the stimulation device 61 through the through hole 51 of the grip portion 5. Thus, by providing the electrically insulating and flexible silicone tube 42, not only can the surgeon operate more safely, but also the copper connected to each needle-like electrode body 2. Corrosion of the rod body 41 can also be prevented. Furthermore, even if the operator bends the direction adjusting unit 4 during the operation, the lead wire 7 is contained in the tube, so that the operator's workability is not deteriorated by the loosening of the lead wire 7.

  A method of using the bipolar stimulation electrode 1 configured as described above will be described below. First, the patient's head is opened so that a lesion in the patient's cerebrum 10 can be removed. On the other hand, as shown in FIG. 4, the needle electrode 64 connected to the electromyogram recording device 62 is set on the patient's peripheral muscle group 11 in order to obtain changes in the patient's myoelectricity due to electrical stimulation.

  The surgeon sets the voltage of the stimulation device 61 of the pyramidal tract confirmation device 60 to a predetermined voltage, and has the grasping portion 5 of the bipolar stimulation electrode 1, so that the surgeon has two needles in the lesion of the cerebrum 10. In order to facilitate insertion of the electrode bodies 2 and 2, the direction adjusting portion 4 is bent at a desired angle as shown by a broken line in FIG.

  The surgeon confirms the scales 25a to 25c attached to the two needle-like electrode bodies 2 and 2 with the naked eye so that the two needle-like electrode bodies 2 and 2 have the same depth. The two needle-like electrode bodies 2 and 2 are inserted. Thus, the surgeon can insert the two electrode bodies in a well-balanced manner while confirming the scales 25a to 25c, and can accurately grasp the position where the electrical stimulation is applied. Here, a predetermined voltage is applied to the two needle-like electrode bodies 2 and 2 in advance, but when this electrode body is inserted into the cerebrum 10, a voltage is applied between the electrode bodies. May be.

  Then, since the needle-like electrode bodies 2 and 2 to which voltage is applied are inserted into the cerebral white matter of the cerebrum 10, a current flows only between the tips of the electrode bodies 2 and 2 that are not covered with the insulating coating 24, When electrical stimulation is accurately given to the cerebral white matter at a desired position and the cone path 15 exists in the deep part of the cerebral white matter, it is reflected in the waveform of the electromyogram. Thus, since the electrode body can be inserted into the cerebral white matter and an electric current can be passed only to the tip of the electrode body, the position of the pyramidal path 15 at a depth of 30 mm from the cut end of the lesion is accurately confirmed can do. By this confirmation, the operator can leave the brain tissue around the pyramidal tract quickly without damaging the cerebral white matter pyramidal tract 15 and further preserve the blood flow to the conical tract 15. In addition, surgery to remove the lesion can be performed.

The whole block diagram of the bipolar stimulation electrode which concerns on this embodiment. The schematic diagram for demonstrating the cross section of the bipolar stimulation electrode shown in FIG. The enlarged view near the front-end | tip of a bipolar stimulation electrode. The figure for demonstrating confirmation of the pyramidal tract of the cerebral white matter using an electrode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Bipolar stimulation electrode, 2 ... Needle-shaped electrode body, 3 ... Electrode body fixing | fixed part, 4 ... Direction adjustment part, 5 ... Gripping part, 7 ... Lead wire, 10 ... Cerebrum, 11 ... Peripheral muscle group, 12 ... White matter stump, 15 ... cone path, 21 ... distal end, 22 ... proximal end, 23 ... trunk, 24 ... insulating coating, 25a to 25c ... scale, 60 ... cone path confirmation device, 61 ... stimulation device, 62 ... EMG recording device, 63 ... bipolar electrode, 64 ... needle electrode

Claims (3)

A bipolar stimulation electrode for performing an operation for removing a lesion of the cerebral while applying electrical stimulation to the cerebrum and confirming the presence or absence of nerve fibers of the cerebrum by the stimulation,
The bipolar stimulation electrode includes two needle-like electrode bodies having sharp tips to be inserted into the cerebrum, and the two needle-like electrode bodies are electrically stimulated into the cerebrum when inserted into the cerebrum. Is placed between the tips so that it can be energized ,
The bipolar stimulation electrode is further provided with a direction adjusting portion on the proximal end side of the needle-like electrode body, which is bent to adjust the distal end direction of the needle-like electrode body in a desired direction and can be held in that direction. bipolar stimulating electrode, characterized in that there.   The two needle-shaped electrode bodies are arranged in parallel so that the distance between the electrode bodies is a constant distance, and each needle-shaped electrode body is graduated from the distal end to the base end at predetermined intervals. The bipolar stimulation electrode according to claim 1. 3. The bipolar stimulation electrode according to claim 1, wherein each acicular electrode body is made of a conductive material, and an insulating film is formed on a surface of the body portion of each acicular electrode body.

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