Subdural Sensor

Abstract

To provide a subdural sensor that can be safely and easily inserted into the subdural space.SOLUTION: The subdural sensor includes: a substrate formed of a flexible material; and at least one type of sensor part mounted on the substrate. The substrate has an elongated shape as a whole, and includes: a sensor area in which the at least one type of sensor part is mounted and a wiring pattern connected to the at least one type of sensor part is formed; a wiring area contiguous with the sensor area on one end thereof, the wiring pattern extending in the wiring area; and a connector area contiguous with the other end of the wiring area, the connector area being an area on which a connector to be connected to the wiring pattern extending from the wiring area is mounted. A tip part of the sensor area has a planar shape that curves convexly toward an outer periphery, and a side shape that curves toward a first surface, the first surface being on the side of a dura mater when the subdural sensor is inserted into the subdural space.SELECTED DRAWING: Figure 1B

Description

[Technical field]

[0001] The present invention relates to a subdural sensor that is placed in the subdural space to obtain biological information. [Background technology]

[0002] When treating patients with brain diseases or brain injuries, it is extremely important not only to identify symptoms such as increased intracranial pressure, epilepsy, and decreased cerebral circulation, but also to accurately monitor brain pathology in order to identify danger earlier, before such symptoms appear or serious events occur.

[0003] Regarding the acquisition of biological information of the brain, for example, Patent Document 1 and Non-Patent Document 1 disclose a subdural sensor that is abutted against or inserted into the subdural space and measures blood dynamics at least near the surface of the brain. The subdural sensor disclosed in Patent Document 1 and Non-Patent Document 1 can simultaneously measure cerebral blood flow, electroencephalogram, and brain temperature.

[0004] Incidentally, when edema or hematoma occurs due to cerebral infarction or trauma, the brain tissue pressure or intracranial pressure may increase, which may cause cerebral hypoxia or neuronal death due to reduced cerebral blood flow. Decompressive craniotomy may be performed as a method for reducing intracranial pressure, but one of the causes of serious sequelae after decompressive craniotomy is an increase in brain temperature. In order to suppress such an increase in brain temperature, brain hypothermia therapy is known, which reduces the brain temperature to a predetermined range. As an example, Patent Document 2 discloses a local cooling device for locally cooling the brain. However, although the brain protection effect by cooling is guaranteed in brain hypothermia therapy (hypothermia therapy) that cools the whole body, there is not much knowledge yet about cooling only a local area in the brain. Therefore, in order to realize the brain protection effect by local cooling, a technology that can acquire sufficient biological information about brain tissue is required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6296606 [Patent Document 2] JP 2011-83315 A [Non-patent literature]

[0006] [Non-Patent Document 1] Toshitaka Yamakawa et al. “Implantable Multi-Modality Probe for Subdural Simultaneous Measurement of Electrophysiology, Hemodynamics, and Temperature Distribution”, IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 66, NO. 11, NOVEMBER 2019 (P. 3204- 3211) Summary of the Invention [Problem to be solved by the invention]

[0007] There are two methods for placing a sensor under the dura: one is to open the craniotomy and incise the dura, exposing the brain and placing the sensor there, and the other is to make a small incision in the dura through a small hole called a burr hole in the skull, and insert the sensor into the subdural space along the brain surface through this small incision in the dura. For example, to monitor vital signs in brain hypothermia, the sensor is placed for a certain period of time (e.g., about two weeks), so from the standpoint of infection risk and stable retention of the sensor, the method of inserting the sensor through a small incision in the dura is more desirable.

[0008] The present invention has been made in view of the above, and one of its objects is to provide a subdural sensor that can be safely and easily inserted into the subdural space. [Means for solving the problem]

[0009] In order to solve the above problems, one embodiment of the present invention provides a subdural sensor that is placed in the subdural space to acquire biological information related to the brain, the subdural sensor comprising: a substrate made of a flexible material; and at least one type of sensor unit mounted on the substrate, the substrate having an elongated shape overall, the substrate including a sensor region in which the at least one type of sensor unit is mounted and a wiring pattern connected to the at least one type of sensor unit is formed; a wiring region that is continuous with the sensor region at one end and in which the wiring pattern extends; and a connector region that is continuous with the other end of the wiring region and in which a connector that is connected to the wiring pattern extending from the wiring region is mounted, the tip of the sensor region having a planar shape that is curved convexly toward the outer periphery, and a side shape that is curved toward the first surface that becomes the dura side when the subdural sensor is inserted into the subdural space.

[0010] The subdural sensor may further include a cover made of a soft material and covering the tip of the sensor region.

[0011] In the subdural sensor, the at least one type of sensor unit may include a brain pressure sensor mounted in a region near the tip of the substrate, and in this case, the subdural sensor may further include a cover made of a soft material, covering the tip of the sensor region, and disposed around the brain pressure sensor.

[0012] In the above subdural sensor, the width of the wiring region in the short side direction may be smaller than the width of the sensor region in the short side direction, and a connection region between the sensor region and the wiring region may be tapered.

[0013] In the above subdural sensor, the at least one type of sensor unit in the sensor section may be arranged in a row along the longitudinal direction of the substrate, and the width of the wiring area in the short direction may be greater than or equal to the maximum width of the at least one type of sensor unit arranged in the sensor area in the short direction of the substrate.

[0014] In the above-mentioned subdural sensor, the wiring pattern may include a signal line pattern and a power line pattern, and the signal line pattern may be formed on one side of the wiring area in a wave-like pattern with alternating peaks and valleys, and the power line pattern may be formed on the other side of the wiring area in a wave-like pattern with alternating peaks and valleys compared to the signal line pattern.

[0015] In the above subdural sensor, at least a portion of the wiring region may be housed inside a tube made of a flexible material.

[0016] In the subdural sensor, at least a portion of the wiring region may be wound to define a cylindrical outer circumferential shape as a whole. In this case, at least a portion of the wiring region may be wound in a coil shape.

[0017] In the above subdural sensor, at least a portion of the wiring region may be divided into a plurality of strip-shaped regions along the longitudinal direction, and each of the plurality of strip-shaped regions may be wound around one core wire.

[0018] In the above subdural sensor, the wiring pattern includes a signal line pattern and a power line pattern, and at least a portion of the wiring area is divided along the longitudinal direction into a first strip-shaped area in which the signal line pattern is formed and a second strip-shaped area in which the power line pattern is formed, and the first strip-shaped area and the second strip-shaped area may be wound in opposite directions around the core wire.

[0019] In the above subdural sensor, an outer circumferential surface of a wound portion of the wiring region may be covered with a biocompatible material.

[0020] In the above subdural sensor, the wiring pattern may include a signal line pattern that transmits a signal output from the at least one type of sensor unit, and each signal line included in the signal line pattern may branch into two in the connector area and be respectively connected to two different pins provided on the connector.

[0021] In the above subdural sensor, the at least one type of sensor unit includes a blood flow measuring unit having a light emitting element capable of emitting near-infrared light, a light receiving element capable of receiving near-infrared light, and a light reflecting unit disposed between the light emitting element and the light receiving element, and the light reflecting unit may have a shape in which at least the peripheral portion rises toward the inner circumference. In this case, the light reflecting unit may also serve as an electrode for measuring electrocortical electroencephalograms. The at least one type of sensor unit may also include a temperature measuring element disposed inside the light reflecting unit. Effect of the Invention

[0022] One aspect of the present invention allows for safe and easy insertion of a subdural sensor into the subdural space. [Brief description of the drawings]

[0023] [Figure 1A] FIG. 1 is a schematic plan view of a portion of a subdural sensor according to one embodiment of the present invention. [Figure 1B] FIG. 1 is a schematic side view of a portion of a subdural sensor according to one embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic plan view of a portion of a subdural sensor according to one embodiment of the present invention. [Diagram 3] 1B is a partial cross-sectional view showing the vicinity of a light reflecting portion shown in FIG. 1A. [Figure 4] FIG. 1 is a schematic diagram illustrating an example of use of a subdural sensor according to one embodiment of the present invention. [Figure 5A] FIG. 11 is a plan view illustrating a first modified example of the tip portion of the substrate. [Figure 5B] FIG. 13 is a side view illustrating a first modified example of the tip portion of the substrate. [Figure 6] FIG. 13 is a plan view illustrating a second modified example of the tip portion of the substrate. [Figure 7] FIG. 11 is a plan view illustrating a first modified example of a wiring region of a substrate. [Figure 8] FIG. 13 is a plan view illustrating a second modified example of a wiring region of a substrate. [Figure 9A] FIG. 13 is a plan view illustrating a third modified example (sensor region side) of a wiring region of a substrate. [Figure 9B] FIG. 13 is a plan view illustrating a third modified example (connector area side) of the wiring area of ​​the substrate. [Figure 9C] FIG. 13 is a plan view illustrating a third modified example (connector area side) of the wiring area of ​​the substrate. [Figure 10A] FIG. 2 is a plan view (front side) showing a schematic example of a mounting example of a brain pressure sensor. [Figure 10B] FIG. 2 is a side view showing a schematic example of an implementation of the brain pressure sensor. [Figure 10C] FIG. 2 is a plan view (rear side) showing a schematic example of a mounting example of a brain pressure sensor. [Figure 11] FIG. 13 is a plan view (rear side) showing a schematic diagram of another mounting example of the brain pressure sensor. [Figure 12] 13 is a partial cross-sectional view showing a modified example of the light reflecting portion. FIG. [Figure 13] FIG. 11 is a partial cross-sectional view showing another modified example of the light reflecting portion. [Figure 14] FIG. 11 is a plan view showing a schematic modification of the substrate shape. [Figure 15] FIG. 13 is a plan view showing a schematic diagram of another modified example of the substrate shape. [Figure 16] 11 is a plan view illustrating wiring in a connector region. FIG. [Figure 17] 13 is a plan view showing a modified example of a wiring pattern in a wiring region. FIG. [Figure 18] FIG. 2 is a partial cross-sectional view for explaining an example of mounting an element. [Figure 19] FIG. 13 is a plan view illustrating a schematic diagram of yet another modified example of the subdural sensor. [Figure 20]FIG. 13 is a plan view illustrating a schematic diagram of yet another modified example of the subdural sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, a subdural sensor according to an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. In addition, in the description of each drawing, the same parts are indicated by the same reference numerals.

[0025] The drawings referred to in the following description merely show the shape, size, and positional relationship in a schematic manner to the extent that the contents of the present invention can be understood. In other words, the present invention is not limited to the shape, size, and positional relationship exemplified in each drawing. In addition, there may be cases where the dimensional relationship and ratio of each part differs between the drawings.

[0026] Subdural Sensor Embodiments FIG. 1A is a plan view showing a schematic representation of a portion of a subdural sensor according to an embodiment of the present invention. FIG. 1B is a side view showing a schematic representation of a portion of the same subdural sensor. FIG. 2 is a plan view showing a schematic representation of another portion of the same subdural sensor. The subdural sensor 10 according to this embodiment is a device that is placed in the subdural space and is used to acquire biological information related to the brain, and includes a substrate 100 formed of a flexible material and at least one type of sensor unit mounted on the substrate 100.

[0027] The substrate 100 is a so-called flexible substrate having flexibility, and is formed of a resin material such as polyimide. The substrate 100 and the sensor unit are integrally covered with a biocompatible material such as Parylene (registered trademark), except for the vicinity of the apex of the light reflecting unit 113 described later. The thickness of the coating 107 is not particularly limited, but when Parylene (registered trademark) is used, it is preferable to set the thickness to, for example, about 5 μm to 20 μm in order to prevent the flexibility of the substrate 100 from being significantly impaired.

[0028] As shown in FIGS. 1A to 2, the substrate 100 has an elongated shape as a whole, and includes a sensor region 101 in which at least one type of sensor unit is arranged, a wiring region 102 that is continuous with the base end of the sensor region 101 at one end side, and a connector region 103 that is continuous with the other end side of the wiring region 102. The sensor region 101, the wiring region 102, and the connector region 103 are preferably integrally formed by one flexible substrate. A wiring pattern connected to the sensor unit is continuously formed in the sensor region 101, the wiring region 102, and the connector region 103. The wiring pattern may be formed on only one side or on both sides. Alternatively, it may be formed across multiple layers.

[0029] The sensor region 101 is an area to be inserted into the subdural space, where a sensor unit is mounted and a wiring pattern to be connected to the sensor unit is formed. Here, the sensor region 101 is inserted into the subdural space so that the front surface (first surface) 104 faces the dura mater and the back surface (second surface) 105 faces the brain surface. Fig. 1A shows a state in which a plurality of sensor units are arranged in a line along the longitudinal direction on the back surface 105 of the sensor region 101.

[0030] Preferably, the tip 10a of the sensor region 101 has a planar shape that is curved convexly toward the outer periphery as shown in Fig. 1A. Also, preferably, the tip 10a has a side shape that is curved toward the surface 104 as shown in Fig. 1B.

[0031] The portion of the wiring region 102 on the sensor region 101 side is placed inside the living body together with the sensor region 101. On the other hand, the portion of the wiring region 102 on the connector region 103 side is placed outside the living body together with the connector region 103. It is preferable that the wiring region 102 and the sensor region 101 are connected at an obtuse angle or in a gentle curve to prevent the substrate 100 from being cut. The same applies to the connection portion between the wiring region 102 and the connector region 103.

[0032] A wiring pattern formed in the sensor area 101 extends into the wiring area 102. The wiring pattern includes a signal line for transmitting a signal output from a sensor unit mounted in the sensor area 101 and a power line for supplying power to the sensor unit.

[0033] In Fig. 2, at least a part of the wiring region 102 is wound in a coil shape so as to have a cylindrical outer peripheral shape as a whole. This allows the scalp to be easily and safely sutured around the wound part using a general suturing technique such as purse string suture when placing the subdural sensor 10 in a living body. The wound part may be covered with a biocompatible material such as Parylene (registered trademark) or silicone rubber. This makes it easier to maintain the wound shape.

[0034] A connector 108 for connecting the subdural sensor 10 to an external device such as a control device is mounted on the connector region 103. The connector 108 is connected to a wiring pattern extending from the wiring region 102, and transmits a signal output from the sensor unit mounted on the sensor region 101 to the external device, and supplies power supplied from the external device to the sensor unit. The connector 108 may be a wired connector (e.g., a male connector for board-to-board connection) or a wireless connector. From a hygienic standpoint, the end portion 10b of the connector region 103 is preferably formed into a planar shape tapering toward the tip so that it can be drawn out from the inside of the scalp to the outside.

[0035] Next, the sensor unit mounted in the sensor region 101 will be described. As the sensor unit, a blood flow measurement unit using the principle of near-infrared spectroscopy (NIRS), a temperature measuring element (thermistor), an electrode for measuring electrocorticogram (EcoG), a brain pressure sensor, an acceleration sensor, a Doppler blood flow meter, and the like can be mounted. In Figs. 1A and 1B, as examples of the sensor unit, a plurality of blood flow measurement units 110, a plurality of temperature measuring elements 120, and a brain pressure sensor 130 are illustrated. In addition, as described later, an electrode 114 for measuring electrocorticogram (EcoG) (see Fig. 3) is disposed on the bottom of the light reflecting portion 113 of the blood flow measurement unit 110. These sensor units are mounted on the back surface 105 side of the substrate 100.

[0036] It is preferable that biological information such as cerebral blood flow, brain temperature, and electroencephalogram can be obtained simultaneously from multiple locations in the brain. Therefore, in this embodiment, the blood flow measurement unit 110, the temperature measurement element 120, and the electrode 114 are provided with three channels each. The number of channels of these sensor units is not particularly limited. To increase the number of channels, the length of the sensor area 101 may be appropriately extended.

[0037] Each sensor part except for the light reflecting part 113 is preferably covered with an insulating part 106 made of a material having biocompatibility and high light transmittance, such as silicone rubber (e.g., polydimethylsiloxane: PDMS). The insulating part 106 is piled up in a round shape so as to enclose the edge of each sensor part. The coating 107 covers the entire surface of the substrate 100 and the insulating parts 106.

[0038] The blood flow measuring unit 110 includes a light emitting element 111 capable of emitting near-infrared light, a light receiving element 112 capable of receiving near-infrared light, and a light reflecting unit 113 disposed between the light emitting element 111 and the light receiving element 112. The light emitting element 111 emits near-infrared light toward the inside of the brain. The light receiving element 112 receives the near-infrared light reflected in the brain, converts the optical signal of this near-infrared light into an electrical signal, and outputs it.

[0039] 3 is a partial cross-sectional view showing the vicinity of the light reflecting portion 113. The light reflecting portion 113 is made of a metal having biocompatibility and good electrical conductivity, such as platinum (Pt). The coating 107 is formed so as to cover the boundary between the light reflecting portion 113 and the substrate 100, while exposing the vicinity of the apex of the light reflecting portion 113.

[0040] 3, the light reflecting portion 113 has a shape in which the peripheral portion rises toward the inner circumference. Since the surface of the light reflecting portion 113 comes into contact with the brain surface, the shape of the light reflecting portion 113 is preferably a dome-shaped shape without edges.

[0041] The light reflecting unit 113 reflects the near-infrared light emitted from the light-emitting element 111 and reflected in the brain back toward the inside of the brain. This reduces the near-infrared light that escapes to the outside of the brain, and efficiently allows the near-infrared light reflected in the brain to be incident on the light-receiving element 112, thereby improving the sensitivity to the gray matter portion located in a relatively shallow area in the brain. In addition, the light reflecting unit 113 reflects the near-infrared light emitted from the light-emitting element 111 toward the inside of the brain at the periphery. This prevents the near-infrared light from being directly incident on the light-receiving element 112 from the light-emitting element 111, and improves the S / N ratio of the signal acquired in blood flow measurement.

[0042] An electrode 114 mounted on the substrate 100 for measuring electrocortical electroencephalograms is disposed on the bottom of the light reflecting portion 113, and the light reflecting portion 113 is piled up so as to encase the electrode 114. In other words, the light reflecting portion 113 is electrically connected to the electrode 114 and also functions as an electrode for measuring electrocortical electroencephalograms. The light reflecting portion 113 is raised from the rear surface 105 side of the substrate 100 and can be easily attached to the brain surface, which makes it possible to improve the detection sensitivity of the cortical potential. In addition, the solder for mounting the electrode 114 is sealed by the light reflecting portion 113, so that the electrical connection between the electrode 114 and the living body is secured while the safety to the living body is guaranteed.

[0043] The height of the light reflecting portion 113 is preferably about 0.5 mm or more, and more preferably about 0.7 mm or more, in order to fully encase the electrode 114. Also, in order to smoothly insert the sensor region 101 under the dura mater, the height of the light reflecting portion 113 is preferably about 1 mm or less.

[0044] (Example of using a subdural sensor) FIG. 4 is a schematic diagram showing an example of use of the subdural sensor 10 according to one embodiment of the present invention. When using the subdural sensor 10, the scalp 201 is incised, a burr hole 203 is opened in the skull 202, and a small incision is made in the dura 204. The subdural sensor 10 is inserted into the subdural space 205 from the small incision so that the surface 104 of the sensor region 101 faces the dura 204. Then, the subdural sensor 10 is pushed along the brain surface 206 (on the arachnoid membrane) and placed in a target region of the brain surface 206. On the other hand, in vitro, the connector 108 (see FIG. 2) provided in the connector region 103 is connected to a measurement system, and the operation of the subdural sensor 10 is confirmed, and then the scalp 201 is sutured around the wiring region 102.

[0045] Here, there are two methods for placing a sensor under the dura: one is to open the head, incise the dura, expose the brain, and place the sensor therein; and the other is to make a small incision in the dura through a burr hole in the skull, and insert the sensor into the subdural space along the brain surface through this small incision in the dura, as described with reference to Fig. 4. The latter method has an advantage over the former in terms of the risk of infection and stable retention of the sensor, since the incision is small. The latter method is also preferable when the sensor is to be placed in the brain for a certain period of time (for example, about two weeks) to monitor biological information.

[0046] On the other hand, when inserting a subdural sensor through a small incision in the dura, it is necessary to push the subdural sensor to the target area on the brain surface. In order to perform this operation smoothly, it is preferable to use a material that has flexibility but some elasticity as the material of the substrate. Specifically, as described above, a substrate made of a resin material such as polyimide coated with Parylene (registered trademark) can be used. However, the surgeon must push such a subdural sensor into the subdural space based on the feel of the brain surface, not by visual inspection, so that the tip of the subdural sensor does not hit the brain surface. Therefore, in order to safely place the subdural sensor in the target area, the surgeon is required to have advanced techniques.

[0047] Therefore, in the subdural sensor 10 according to this embodiment, the planar shape of the tip 10a is curved convexly outward, and the side shape of the tip 10a is curved toward the surface 104. This makes it possible to safely and easily insert the subdural sensor 10 into the subdural space 205 through a small incision in the dura 204.

[0048] In detail, since the tip 10a is curved toward the surface 104, even when the subdural sensor 10 is pushed along the brain surface 206 in the subdural space 205, the tip 10a is unlikely to come into contact with the brain surface 206. Therefore, it is possible to prevent the end of the subdural sensor 10 from hitting the brain surface 206. Even if biological tissue exists in the same direction as the moving direction of the subdural sensor 10, the subdural sensor 10 contacts the biological tissue at the belly of the tip 10a (the back surface 105 of the curved tip 10a), so it is possible to prevent the end from hitting the brain surface 206. Furthermore, since the planar shape of the tip 10a is curved in a convex shape and has no corners, it is possible to reduce the impact of the end of the sensor region 101 contacting the surrounding biological tissue.

[0049] Further advantages of the subdural sensor 10 according to this embodiment will be described below. In general, when a sensor is placed in a living body, the wiring is drawn from the sensor placed in the subdural space to the outside of the skull, and the scalp is sutured. In this regard, in the subdural sensor 10, at least a part of the wiring area 102 of the substrate 100 is wound so as to have a cylindrical outer peripheral shape as a whole, so that the scalp 201 can be safely sutured around the wound part. In addition, the scalp 201 can be easily sutured using a general-purpose suturing technique such as purse string suture.

[0050] Furthermore, in the subdural sensor 10 according to this embodiment, it is also possible to improve the S / N ratio of a signal acquired in blood flow measurement using near-infrared light. Here, in blood flow measurement using near-infrared light, a technology is known in which a reflector is placed between the light-emitting element and the light-receiving element to reduce the near-infrared light that escapes outside the brain and improve the sensitivity of the gray matter (see, for example, Patent No. 6296606).

[0051] In contrast, in this embodiment, a light reflecting portion 113 having a shape (for example, a dome shape) in which the periphery rises toward the inner circumference is provided between the light emitting element 111 and the light receiving element 112. This allows the near infrared light emitted from the light emitting element 111 to be reflected toward the inside of the brain, and the near infrared light escaping to the outside of the brain to be reduced. In addition, this light reflecting portion 113 allows the near infrared light emitted from the light emitting element 111 to be prevented from directly entering the light receiving element 112. In other words, the near infrared light that does not pass through the brain and enters the light receiving element 112 can be reduced. Therefore, in blood flow measurement using near infrared light, it is possible to improve the sensitivity to the gray matter portion and improve the S / N ratio of the acquired signal.

[0052] Furthermore, when the light reflecting portion 113 is made of platinum, by mounting the light reflecting portion 113 so as to encase the electrode 114 for measuring electrocortical electroencephalograms, it is possible to improve safety to the living body and to reliably ensure electrical connection between the electrode 114 and the brain surface. Furthermore, according to this embodiment, it is possible to measure both cerebral blood flow and electroencephalograms in a common region in the brain.

[0053] (Subdural Sensor Variations) Fig. 5A is a plan view showing a first modified example of the tip portion 10a of the substrate 100. Fig. 5B is a side view showing the same modified example. The subdural sensor according to this modified example further has a cover 140 that covers the tip portion 10a of the substrate 100. As shown in Fig. 5B, the cover 140 and the substrate 100 may be integrally covered with a coating 107, or the substrate 100 covered with the coating 107 may be covered with the cover 140.

[0054] The cover 140 is preferably made of a flexible and biocompatible material such as silicone rubber. The cover 140 may have a shape that curves toward the surface 104. In this case, the tip 10a of the planar substrate 100 may be deformed by covering the tip 10a with the cover 140. Alternatively, the tip 10a of the substrate 100 that curves toward the surface 104 may be covered with a flexible cover 140 so that the cover 140 conforms to the shape of the tip 10a.

[0055] By providing such a cover 140, the end of the subdural sensor comes into soft contact with the biological tissue, further improving safety when inserting the subdural sensor into the subdural space. In addition, by providing the cover 140, a load is applied to the tip 10a, so that the substrate 100 can be prevented from floating up. This allows the various sensor parts to be in close contact with the brain surface, improving the accuracy of the acquired biological information.

[0056] Fig. 6 is a plan view showing a second modified example of the tip portion 10a of the substrate 100. The side shape of this modified example is the same as that of Fig. 5B. As shown in Fig. 6, the cover 141 that covers only the end of the tip portion 10a of the substrate 100 can also increase safety when inserting the subdural sensor into the subdural space.

[0057] When the tip of the substrate 100 is covered with a cover, the tip may not be curved convexly toward the outer periphery. Although it depends on the thickness and material of the cover, providing a cover allows the end to come into soft contact with the biological tissue, improving safety compared to the case without a cover.

[0058] 7 is a plan view showing a schematic diagram of a first modified example of the wiring region 102 of the substrate 100. The subdural sensor according to this modified example further includes a tube 150 that houses at least a portion of the wiring region 102 of the substrate 100.

[0059] The tube 150 is made of a flexible material such as silicone rubber. By accommodating at least a portion of the wiring region 102 (specifically, the portion that will be near the scalp when the subdural sensor is inserted into the subdural space) in such a tube 150, it becomes possible to easily and safely suture the scalp around the tube 150. In addition, the tube 150 can also provide an effect of protecting the wiring region 102.

[0060] 8 is a plan view showing a second modified example of the wiring region 102 of the substrate 100. In this modified example, the wiring region 102 is wound in a coil shape around a core wire 151. The core wire 151 is formed of a flexible material such as silicone rubber. The core wire 151 and the wiring region 102 wound around it may be integrally covered with a biocompatible material such as Parylene (registered trademark) or silicone rubber. By using such a core wire 151, it is possible to increase the strength of the wiring region 102 while maintaining its flexibility.

[0061] 9A to 9C are plan views showing a third modified example of the wiring region 102 of the substrate 100. Of these, Fig. 9A shows the sensor region side, and Figs. 9B and 9C show the connector region side. In this modified example, at least a portion of the wiring region 102 is divided into a plurality of strip-shaped regions along the longitudinal direction, and each of the plurality of strip-shaped regions is wound around the core wire 155.

[0062] The wiring region 102 is preferably divided into a region (signal region 153) in which a signal line pattern is formed, and a region (power region 154) in which a power line pattern is formed. In this case, the signal region 153 and the power region 154 are preferably wound in opposite directions, and more preferably wound so as to be substantially perpendicular to each other. In this modification, the wound signal region 153 and power region 154 may also be covered with a biocompatible material such as Parylene (registered trademark) or silicone rubber.

[0063] In this way, by dividing the wiring area 102 into the signal area 153 and the power area 154 and winding them around the core wire 155, the scalp can be easily and safely sutured around the wound portion. Also, by winding the signal area 153 and the power area 154 in opposite directions, it is possible to prevent electromagnetic noise generated in the power line from being induced into the signal line and being superimposed on the signal, and it is also possible to reduce the effect of noise on the signal.

[0064] In this case, connector region 156 on the signal region 153 side and connector region 157 on the power region 154 side may be left separate as shown in FIG. 9B, or may be attached back to back as shown in FIG. 9C.

[0065] 10A to 10C are diagrams showing typical implementations of brain pressure sensor 130. Of these, Fig. 10A is a plan view showing front surface 104 of substrate 100, Fig. 10B is a side view, and Fig. 10C is a plan view showing back surface 105 of substrate 100. Brain pressure sensor 130 may be implemented near the tip of substrate 100, in which case it is preferable to provide reinforcing cover 142 surrounding brain pressure sensor 130. Reinforcing cover 142 may also be integrally covered with substrate 100 by coating 107.

[0066] As shown in Fig. 10A and Fig. 10C, the tip of the reinforcing cover 142 has a shape that is curved convexly toward the outer periphery. Also, as shown in Fig. 10B, the tip of the reinforcing cover 142 is curved toward the front surface 104. The reinforcing cover 142 is made of a flexible and biocompatible material such as silicone rubber, and may have a certain amount of weight in order to apply a load to the area near the brain pressure sensor 130. As shown in Fig. 10C, a U-shaped window 143 is formed on the back side of the reinforcing cover 142, and the reinforcing cover 142 is fitted into the substrate 100 so that the brain pressure sensor 130 is exposed through this window 143. The brain pressure sensor 130 is covered with an insulating part 106 as in the above embodiment (see Fig. 1B).

[0067] According to this modification, the brain pressure sensor 130 is disposed deep inside the subdural space, and the reinforcing cover 142 prevents the brain pressure sensor 130 from floating up, so that the brain pressure can be measured more accurately. In addition, the weight of the brain pressure sensor 130 and the reinforcing cover 142 prevents the entire substrate 100 from floating up, so that the accuracy of the biological information acquired by the other sensor units can be improved.

[0068] Fig. 11 is a plan view showing a schematic diagram of another mounting example of brain pressure sensor 130, showing back surface 105 side of substrate 100. A square-shaped window 145 is formed on the back surface of reinforcing cover 144 shown in Fig. 11, exposing brain pressure sensor 130. In this way, by surrounding the entire periphery of brain pressure sensor 130 with reinforcing cover 144, a load can be applied in a well-balanced manner to the area where brain pressure sensor 130 is arranged.

[0069] 12 is a partial cross-sectional view showing a modified example of the light reflecting part. In this modified example, a temperature measuring element 120 is disposed inside a dome-shaped light reflecting part 113. The temperature measuring element 120 is surrounded by an insulating material 115 such as polydimethylsiloxane (PDMS).

[0070] In this way, by disposing the temperature measuring element 120 inside the light reflecting part 113, the temperature measuring element 120 can be reliably brought into contact with the biological tissue via the light reflecting part 113, and the efficiency of thermal conduction between the temperature measuring element 120 and the biological tissue can be improved. Therefore, the measurement accuracy of the brain temperature can be improved. In addition, since the measurement centers of the brain wave and the brain temperature are aligned, it becomes possible to measure the cerebral blood flow, the brain wave, and the brain temperature in a common area in the brain.

[0071] 13 is a partial cross-sectional view showing another modified example of the light reflecting part. In this modified example, the electrode 116 for detecting an electrocortical electroencephalogram is formed in a circular ring shape, and the light reflecting part 117 is formed in a doughnut shape so as to enclose the electrode 116. A temperature measuring element 120 is mounted on the substrate at the center of the light reflecting part 117.

[0072] As shown in Fig. 13, if at least the peripheral portion of the light reflecting portion 117 is shaped to rise toward the inner circumference, the near-infrared light can be reflected at this peripheral portion to prevent the near-infrared light from being directly incident on the light receiving element 112 from the light emitting element 111. Of course, by reflecting the near-infrared light from the entire surface of the light reflecting portion 117, the near-infrared light escaping to the outside of the brain can be reduced, and the sensitivity of the gray matter portion can be improved. Furthermore, since the measurement centers of the brain wave and the brain temperature are aligned, it becomes possible to measure the cerebral blood flow, the brain wave, and the brain temperature in a common area of ​​the brain.

[0073] Alternatively, the shape of the light reflecting portion may be, for example, a truncated cone whose periphery rises linearly toward the inner circumference, or the portion in contact with the brain surface may be flat. In either case, however, it is preferable to determine the shape of the light reflecting portion so that the edge is not exposed.

[0074] In the above embodiment and modified example, the light emitting element 111 and the light receiving element 112 for measuring blood flow using near-infrared light are mounted on the back surface 105 side of the substrate 100, but the light emitting element 111 and the light receiving element 112 may be provided on the front surface 104 side. In this case, it is preferable to form the substrate 100 from a material having high optical transparency at least to near-infrared light.

[0075] Fig. 14 is a plan view showing a modified example of the substrate shape. As shown in Fig. 14, in the subdural sensor 10A, the width of the wiring region 102a in the short side direction is smaller than the width of the sensor region 101a in the short side direction. The sensor region 101a and the wiring region 102a are connected in a gentle tapered shape. In this modified example, the wiring region 102a is not wound, and the scalp is sutured around the planar wiring region 102a.

[0076] Here, when attempting to remove the subdural sensor from the sutured site on the scalp after the sensor region of the subdural sensor has been left in the subdural space for a predetermined period of time, a large force may be applied to the connection region between the sensor region and the wiring region.

[0077] Therefore, by making the connection region M between the sensor region 101a and the wiring region 102a tapered as shown in FIG. 14, it is possible to prevent force from being applied to a specific point of the substrate when pulling out the subdural sensor 10A, and to make it possible to pull out the sensor smoothly.

[0078] As yet another modification, the widths of the sensor region and the wiring region in the short direction may be made uniform, which also allows the subdural sensor to be smoothly removed.

[0079] Fig. 15 is a plan view showing another modified example of the substrate shape. Fig. 15 shows a state in which a plurality of sensor units are arranged in the sensor area 101b of the subdural sensor 10B along the longitudinal direction of the substrate 100b. The width W2 of the wiring area 102b in the lateral direction is equal to or greater than the maximum width W1 of the substrate 100b of these sensor units in the lateral direction. In this modified example, the wiring area 102b is not wound, and the scalp is sutured around the planar wiring area 102b.

[0080] Here, when attempting to remove the subdural sensor from the sutured site on the scalp after the sensor area of ​​the subdural sensor has been left in the subdural space for a predetermined period of time, a large force may be applied to the end of the sensor area, which is wider than the wiring area.

[0081] Therefore, as shown in FIG. 15, by making the width W2 of the wiring region 102b greater than or equal to the maximum width W1 of the sensor portion, even when the subdural sensor 10B is pulled out from the sutured portion of the scalp, deformation of the sensor region 101a can be limited to the end region where the sensor portion is not located.

[0082] Fig. 16 is a plan view illustrating wiring in the connector region. As shown in Fig. 16, a signal line pattern 300 is formed in the wiring region of the subdural sensor 10C, transmitting signals output from each sensor unit arranged in the sensor region 101. Each signal line 301 included in the signal line pattern 300 is connected to a pin provided on the connector 108 mounted in the connector region 103c.

[0083] 16 is made of, for example, a flexible substrate, and relays between an external device such as a control device and the subdural sensor 10C. A relay connector 410 (for example, a female connector for board-to-board connection) is mounted on the cable 400, and a signal line pattern 420 corresponding to the signal line pattern 300 of the subdural sensor 10C is formed. During use of the subdural sensor 10C, the connector 108 is fitted into the relay connector 410 and electrically connected. Signals output from each sensor unit are input to an external device such as a control device via the signal line pattern 300, the connector 108, the relay connector 410, and the signal line pattern 420.

[0084] 16, in this modification, each signal line 301 included in the signal line pattern 300 is branched into two in the connector region 103b, and each is connected to two different pins provided on the connector 108. On the other hand, each signal line 421 included in the signal line pattern 420 on the cable 400 side is also branched into two near the relay connector 410, and each is connected to two different pins provided on the relay connector 410. In other words, a signal output from each sensor unit of the subdural sensor 10C is transmitted to the connector region 103c by one signal line 301, passes through the two branched signal lines 301a and 301b in the connector region 103c, and is transmitted to the signal lines 421a and 421b on the cable 400 side via the connector 108 and the relay connector 410, and is then integrated into one signal line 421.

[0085] In this way, a backup of the signal transmission route can be secured by transmitting signals from the same source that pass through signal lines 301a and 301b to relay connector 410 via two pins. That is, even if a connection failure occurs in one of the pins between connector 108 and relay connector 410, the signal can be reliably transmitted to an external device via the other pin.

[0086] Although the positions of the two pins connecting the branched signal lines 301a and 301b are not particularly limited, it is preferable to select two pins that belong to opposing rows as shown in Fig. 16. This ensures the connection state of at least one of the pins even if the connector 108 and the relay connector 410 are connected at a slight angle.

[0087] 17 is a plan view showing a modified example of the wiring pattern in the wiring region. In this modified example, in the wiring region 102d, a signal line pattern 510 of the wiring pattern is formed on one surface 511 of the substrate 100d, and a power line pattern 520 is formed on the other surface 521 of the substrate 100d. The signal line pattern 510 and the power line pattern 520 are formed to have a wave shape with alternating peaks and valleys, and the peaks and valleys are formed alternately between the signal line pattern 510 and the power line pattern 520.

[0088] 17, may be a triangular wave (zigzag) or a sine curve. Alternatively, the shape may be a triangular wave with curved peaks and valleys, or a shape with connected arcs. The distance between the peaks and valleys in each pattern may be adjusted appropriately according to the width of the wiring area 102d in the short direction and the number of signal lines and power lines (in other words, the width of each pattern).

[0089] In this way, by forming the signal line pattern 510 and the power line pattern 520 alternately and reducing the area over which these patterns run in parallel, it is possible to reduce the effect that electromagnetic noise generated in the power line has on the signal.

[0090] The signal line pattern 510 and the power line pattern 520 may be formed in different layers on the same surface, rather than on both sides of the substrate 100d. In short, the signal line pattern 510 and the power line pattern 520 should be formed so that they do not run parallel to each other as much as possible.

[0091] FIG. 18 is a partial cross-sectional view for explaining an example of mounting the element. When the element 531 included in the sensor unit is mounted on the substrate 100 by wire bonding, it is preferable to form an insulating section 106 made of a flexible resin material such as silicone so as to cover the entire element 531 and the wire 532. This ensures that the periphery of the element 531 can be insulated, and the element 531 adheres closely to the substrate 100, so that the element 531 can be prevented from falling off even more. In addition, by forming a coating 107 on the upper layer, the flexibility of the mold 533 is restricted, so that the wire 532 can be prevented from breaking. As a modified example, two wires may be bonded to one element 531. In this case, the risk of breaking can be reduced.

[0092] FIG. 19 is a plan view showing a schematic diagram of yet another modified example of the subdural sensor. The subdural sensor 10E shown in FIG. 19 includes two sensor regions 101e and a wiring region 102e continuous with the sensor regions 101e. The configuration of the sensor unit provided in each sensor region 101e is the same as that shown in FIG. 1A. In this way, by branching the tip side of one substrate 100e to form a plurality of sensor regions, the number of measurable sensor channels can be increased, and bioinformation relating to a greater number of regions can be obtained. In addition, by widening the distance between the tips of the two sensor regions 101e, it is possible to obtain bioinformation over a wider range.

[0093] FIG. 20 is a plan view showing a schematic diagram of yet another modified example of the subdural sensor. In the subdural sensor 10F shown in FIG. 20, a notch is made on the tip side of the strip-shaped substrate 100f, and the substrate 100f is separated along the longitudinal direction to form two sensor regions 101f. The wiring region 102f of the substrate 100f is folded along the longitudinal direction, so that when the two sensor regions 101e are arranged on the same surface, the distance between the tips of the two sensor regions 101e is naturally widened. The configuration of the sensor unit provided in each sensor region 101f is the same as that shown in FIG. 1A. According to this modified example, the processing of the shape of the substrate 100f can be simplified.

[0094] The present invention is not limited to the above-described embodiment and modified examples, and may be embodied in various other forms without departing from the scope of the present invention. For example, some components may be removed from all the components shown in the above embodiment and modified examples, or the components shown in the above embodiment and modified examples may be appropriately combined to form the present invention. [Explanation of symbols]

[0095] 10, 10A, 10B, 10C, 10E, 10F...subdural sensor, 10a...tip portion, 10b...distal portion, 100, 100a, 100b, 100d, 100e, 100f...substrate, 101, 101a, 101e, 101f...sensor area, 102, 102a, 102b, 102d, 102e, 102f...wiring area, 103, 103b, 103c...connector area, 104...surface, 105...back side, 106...insulating portion, 107...coating, 108...connector, 110...blood flow measuring portion, 111...light emitting element, 112...light receiving element, 113...light reflecting portion, 114, 116...electrode, 115...insulating material, 117...light reflecting portion, 120...temperature measuring element, 130...brain pressure sensor, 140 and 141...cover, 142 and 144...reinforcement cover, 143 and 145...window, 150...tube, 151 and 155...core wire, 153...signal area, 154...power area, 156 and 157...connector area, 201...scalp, 202...skull, 204...dura, 205...subdural space, 206...brain surface, 300 and 420...signal line pattern, 301, 301a, 301b, 421, 421a, 421b...signal line, 400...cable, 410...relay connector, 510...signal line pattern, 511 and 521...surface, 520...power line pattern, 531...element, 532...wire

Claims

1. A subdural sensor for obtaining biological information related to a brain, the subdural sensor being disposed in a subdural space, A substrate formed of a flexible material; At least one type of sensor unit mounted on the substrate; Equipped with the at least one type of sensor unit includes a blood flow measuring unit having a light emitting element capable of emitting near-infrared light, a light receiving element capable of receiving near-infrared light, and a light reflecting unit disposed between the light emitting element and the light receiving element; The light reflecting portion has a shape such that at least a peripheral portion thereof rises toward an inner circumference.

2. The subdural sensor according to claim 1 , wherein the light reflecting portion also serves as an electrode for measuring an electrocortical electroencephalogram.

3. The subdural sensor according to claim 1 or 2, wherein the at least one type of sensor portion includes a temperature measuring element disposed inside the light reflecting portion.

4. The substrate is It has an elongated shape overall, a sensor region in which the at least one type of sensor unit is mounted and in which a wiring pattern connected to the at least one type of sensor unit is formed; a wiring region that is continuous with the sensor region at one end side and through which the wiring pattern extends; a connector region continuous with the other end side of the wiring region, in which a connector is mounted to be connected to the wiring pattern extending from the wiring region; The subdural sensor of any one of claims 1 to 3, comprising:

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