Cerebrospinal fluid pulsation buffering device

Abstract

To provide a cerebrospinal fluid pulsation buffering device which is capable of relaxing the occurrence of an overdrainage and buffers the pulsation of a cerebrospinal fluid in a cerebral ventricle, which allows for expecting for suppression of the onset and progress of a hydrocephalus.SOLUTION: A cerebrospinal fluid pulsation buffering device 10 comprises a buffer 20 which is connected to one end C12 of a cerebral ventricle catheter C1 whose the other end C11 is detained in a cerebral ventricle BV, and which internally has a storage part S for storing a cerebrospinal fluid coming by flowing inside of the cerebral ventricle catheter C1 from the cerebral ventricle BV. The buffer 20 expands when the cerebrospinal fluid moves from the inside of the cerebral ventricle catheter C1 to the storage part S by the pulsation of the cerebrospinal fluid moving in the cerebral ventricle BV with the pulsation of the heart, and contracts when the cerebrospinal fluid moves from the storage part S to the inside of the cerebral ventricle catheter C1.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a cerebrospinal fluid pulsation damping device for mitigating the impact on the brain caused by cerebrospinal fluid pulsation and inhibiting the onset and progression of hydrocephalus. [Background technology]

[0002] The brain and spinal cord are suspended in cerebrospinal fluid (CSF), which fills the subarachnoid space inside the skull and spine. Inside the brain are cavities called ventricles. CSF is produced by the choroid plexus in the ventricles.

[0003] CSF produced by the choroid plexus flows out of the ventricles into the subarachnoid space. CSF in the subarachnoid space is absorbed by the arachnoid granules into the venous sinuses. In this way, CSF circulates, constantly filling the ventricles and the subarachnoid space.

[0004] Hydrocephalus is a disease that develops when there is an abnormality in the circulation of cerebrospinal fluid. Hydrocephalus is a disease in which excess cerebrospinal fluid in the ventricles puts pressure on the brain, impairing brain function. In hydrocephalus, the ventricles are enlarged and the brain's morphology is altered. Patients with hydrocephalus may experience symptoms such as walking difficulties, dementia, urinary incontinence, headaches, vomiting, and impaired consciousness.

[0005] Shunt surgery is a common method for treating hydrocephalus. As disclosed in Patent Document 1, shunt surgery is a surgical method for connecting the ventricles or the subarachnoid space on the spinal cord side, where cerebrospinal fluid accumulates, with the atrium or abdominal cavity, which are body parts capable of absorbing cerebrospinal fluid, using a catheter. With shunt surgery, excess cerebrospinal fluid in the ventricles or subarachnoid space is drained into the abdominal cavity or right atrium through the catheter. As a result, the brain is not compressed by cerebrospinal fluid, and improvement of symptoms can be expected.

[0006] However, the shunt procedure has a problem of frequent over-drainage, in which excessive cerebrospinal fluid is discharged after surgery. Over-drainage causes a decrease in cerebrospinal fluid in the ventricles and hypotension due to a drop in intracranial pressure. As a result, there is a concern that the patient may develop complications such as sudden headache, loss of consciousness, subdural hematoma, and subdural edema. In order to prevent this over-drainage, the general catheter disclosed in Patent Document 1 has a flow control valve in the middle of the catheter to adjust the amount of cerebrospinal fluid discharged.

[0007] On the other hand, researchers have found through research analysis that hydrocephalus can also develop due to excessive pressure caused by pulsation of cerebrospinal fluid. The brain pulsates with the heartbeat. In detail, the brain expands when blood is sent from the heart, and contracts when blood returns to the heart. This expansion and contraction of the brain causes pulsation of cerebrospinal fluid, which moves the cerebrospinal fluid. The spinal cord is located inside the spinal canal of the spine, together with the spinal dural sac on the outside, floating in the cerebrospinal fluid that fills the spinal subarachnoid space. There is a gap called the spinal epidural space between this spinal dural sac and the spinal canal. The spinal epidural space contains fatty tissue and a network of veins called the Batson venous plexus.

[0008] As disclosed in Non-Patent Documents 1 and 2, the inventors have confirmed through research and analysis that the adipose tissue and Batson venous plexus in the spinal epidural space function as a buffer to absorb the pulsation of cerebrospinal fluid and the sudden change in intracranial pressure. In detail, in the early stage of cerebrospinal fluid reduction due to cerebrospinal fluid hypovolemia and overdrainage, when the spinal dural sac contracts, the Basto venous plexus expands, causing the entire spinal epidural space to expand. It has been reported that the intracranial pressure at that time was normal and brain deformation was suppressed.

[0009] From the results of these research analyses, the inventors have found that the mechanism of hydrocephalus development is as follows: Cerebrospinal fluid is naturally discharged by being slowly absorbed by body tissues. When the movement of cerebrospinal fluid between the brain side and the spinal cord side in the subarachnoid space is restricted, the pulsation of cerebrospinal fluid is no longer buffered by the fatty tissue in the spinal epidural space and the Batson venous plexus. If this condition continues, the brain is repeatedly compressed every time the cerebrospinal fluid in the skull pulsates. As a result, the ventricles expand and the brain shape is deformed, leading to the onset and progression of hydrocephalus. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2023-29964 A [Non-patent literature]

[0011] [Non-Patent Document 1] Takashi Kawahara, Ryosuke Hanaya et al, Dural sac shrinkage signs on magnetic resonance imaging at the thoracic level in spontaneous intracranial hypotension - its clinical significance, Acta Neurochirurgica, 163(10) 2685-2694(2021) [Non-Patent Document 2] Takashi Kawahara, Ryosuke Hanaya et al, Dural sac shrinkage signs on spinal magnetic resonance imaging indicate overdrainage after lumboperitoneal shunt for idiopathic normal pressure hydrocephalus, Surgical Neurology International 13 269-269(2022) Summary of the Invention [Problem to be solved by the invention]

[0012] The catheter disclosed in the above-mentioned Patent Document 1 is used in a shunt procedure that assumes the drainage of cerebrospinal fluid from the ventricles. Therefore, even if the catheter has a valve for regulating the flow rate of cerebrospinal fluid, it is difficult to reliably prevent the occurrence of overdrainage.

[0013] On the other hand, according to the mechanism of hydrocephalus discovered through the inventors' research and analysis described above, it is expected that the onset and progression of hydrocephalus can be suppressed by buffering the pulsation of cerebrospinal fluid that occurs within the skull without discharging cerebrospinal fluid.

[0014] The objective of the present invention is to provide a cerebrospinal fluid pulsation cushioning device that can mitigate the occurrence of over-drainage and is expected to suppress the onset and progression of hydrocephalus by cushioning the pulsation of cerebrospinal fluid in the ventricles. [Means for solving the problem]

[0015] The cerebrospinal fluid pulsation damping device according to the present invention comprises: a buffer body having one end connected to the other end of a ventricular catheter placed in a ventricle and having a reservoir therein for storing cerebrospinal fluid flowing from the ventricle through the ventricular catheter; The buffer body is The pulsation of the cerebrospinal fluid causes the cerebrospinal fluid to move in the ventricles as the heart beats, The catheter expands when the cerebrospinal fluid moves from inside the ventricular catheter to the reservoir, and contracts when the cerebrospinal fluid moves from the reservoir to inside the ventricular catheter.

[0016] The volume of the reservoir of the buffer is 10 to 60 mL. This may also be the case.

[0017] Further comprising a base plate to which the buffer body is fixed on a plate surface. This may also be the case.

[0018] As the buffer, a first buffer body connected to the other end of the ventricular catheter and having a first reservoir therein; a second buffer body connected to the first buffer body and having a second reservoir therein; having When the first buffer body and the second buffer body are connected to each other, the first storage portion and the second storage portion communicate with each other. This may also be the case.

[0019] a cerebrospinal fluid regulating valve located between the ventricular catheter and the buffer for regulating movement of the cerebrospinal fluid between the ventricle and the reservoir without being affected by pulsation of the cerebrospinal fluid; The cerebrospinal fluid regulating valve is a housing having a first opening connected to the other end of the ventricular catheter and a second opening connected to the buffer body, the housing having a flow path therein communicating with the first opening and the second opening, respectively, through which the cerebrospinal fluid passes; a valve body movably housed in the flow path portion of the housing, The valve body is When the cerebrospinal fluid pressure in the ventricle becomes lower than the cerebrospinal fluid pressure in the reservoir, the cerebrospinal fluid flows from the ventricular catheter into the flow path, and moves toward the second opening side to narrow the width of the flow path. When the cerebrospinal fluid pressure in the reservoir becomes higher than the cerebrospinal fluid pressure in the ventricle, the cerebrospinal fluid flows from the reservoir into the flow path, and moves toward the first opening side to narrow the width of the flow path. This may also be the case. Effect of the Invention

[0020] According to the present invention, it is possible to alleviate the occurrence of over-drainage, and it is expected that the onset and progression of hydrocephalus can be inhibited by buffering the pulsation of cerebrospinal fluid in the ventricles. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of the human body showing how cerebrospinal fluid pulsations during brain expansion are buffered by the spinal epidural space. [Diagram 2] FIG. 1 is a schematic diagram of the human body showing how cerebrospinal fluid pulsation during cerebral contraction is buffered by the spinal epidural space. [Diagram 3] FIG. 1 is a model diagram showing how cerebrospinal fluid pulsation is buffered by the spinal epidural space. [Figure 4] (a) and (b) are model diagrams showing the mechanism by which hydrocephalus develops when the ventricles expand due to an inability to buffer cerebrospinal fluid pulsation. [Diagram 5] 1 is a schematic diagram showing a state in which a cerebrospinal fluid pulsation damping device according to a first embodiment is embedded in a patient's body. [Figure 6] 1A is a front view showing the configuration of the cerebrospinal fluid pulsation damping device according to the first embodiment, and FIG.1B is a plan view showing the configuration of the cerebrospinal fluid pulsation damping device according to the first embodiment. [Figure 7] 1A is a side view showing the cerebrospinal fluid pulsation damping device according to the first embodiment in an expanded state, and FIG. [Figure 8] 11 is a schematic diagram showing a state in which a cerebrospinal fluid pulsation damping device according to a second embodiment is embedded in a patient's body. FIG. [Figure 9] 11 is a plan view showing a configuration of a portion of a cerebrospinal fluid pulsation damping device according to a second embodiment. FIG. [Figure 10] 11 is a schematic diagram showing a state in which a cerebrospinal fluid pulsation damping device according to a third embodiment is embedded in a patient's body. FIG. [Figure 11] FIG. 11 is a plan view showing the configuration of a cerebrospinal fluid regulating valve according to a third embodiment. [Figure 12] 13A is a front view showing a state in which the cerebrospinal fluid regulation valve according to the third embodiment is moved by cerebrospinal fluid to close the first opening, and FIG. 13B is a front view showing a state in which the cerebrospinal fluid regulation valve according to the third embodiment is moved by cerebrospinal fluid to close the second opening. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a cerebrospinal fluid pulsation damping device according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are given the same reference numerals. Note that the present invention is not limited to the following embodiment and drawings. Note that in the following embodiment, the expressions "have", "include" and "contain" also include the meaning of "consisting of" or "consisting of".

[0023] First, the details of how the inventors have completed the cerebrospinal fluid pulsation damping device according to the present invention will be described. Shunt surgery, which is a common method for treating hydrocephalus, includes VPS (Ventriculo peritoneal shunt) that connects the ventricles and the abdominal cavity, VAS (Ventriculo atrial shunt) that connects the ventricles and the right atrium of the heart, and LPS (Lumbo peritoneal shunt) that connects the subarachnoid space inside the lumbar spine and the abdominal cavity.

[0024] VAS cannot be used in patients with heart failure, as it may prevent cerebrospinal fluid from draining. In addition, VAS requires the insertion of a catheter into the heart, which carries the risk of bleeding, air clots, and sepsis during surgery. VPS and LPS cannot be used in patients with obesity, for example, when the abdominal cavity is compressed by fat, or when there is a malignant tumor in the abdominal wall.

[0025] Thus, in addition to the problem of over-drainage mentioned above, there are cases in which shunt surgery cannot be performed because there is an abnormality in the organ that absorbs the cerebrospinal fluid, and because the surgery to place the catheter is difficult and dangerous.

[0026] In response to these problems with shunt surgery, the inventors focused on idiopathic normal pressure hydrocephalus, which is common among the elderly, and continued to research the causes of hydrocephalus, exploring methods of treating hydrocephalus using an approach other than shunt surgery.

[0027] Idiopathic normal pressure hydrocephalus is a type of hydrocephalus in which the ventricles are enlarged and the brain is deformed, even though the intracranial pressure (the pressure of the cerebrospinal fluid inside the skull) is normal. Until now, it has been thought that the cause of the onset of idiopathic normal pressure hydrocephalus is poor absorption of cerebrospinal fluid. Normal intracranial pressure is 6 to 18 cmH2O.

[0028] However, the inventors believe that the cause of the onset of idiopathic normal pressure hydrocephalus is not malabsorption of cerebrospinal fluid but something else. When malabsorption of cerebrospinal fluid occurs, the amount of cerebrospinal fluid in the ventricles increases, and intracranial pressure should rise. However, in idiopathic normal pressure hydrocephalus, intracranial pressure is normal. From this, the inventors speculate that in idiopathic normal pressure hydrocephalus, excess cerebrospinal fluid is naturally discharged by being absorbed by the body's tissues.

[0029] In Non-Patent Document 1 by the inventors, it is reported that in patients with cerebrospinal fluid hypovolemia in which cerebrospinal fluid leaks from the dural sac, DSSS (dural sac shrinkage signs) in which the spinal dural sac shrinks with a decrease in cerebrospinal fluid can be confirmed. DSSS is a finding in which the spinal cord is displaced toward the vertebral body, the dorsal dura of the dural sac is displaced forward, and the spinal epidural space and Batson's venous plexus are expanded.

[0030] In the early stage of CSF depletion, the Batson venous plexus in the spinal epidural space expands during DSSS, causing the entire spinal epidural space to expand. At that time, intracranial pressure is normal, and brain deformation is suppressed. It has been confirmed that if CSF depletion continues in the DSSS state, intracranial pressure decreases, causing hypointracranial hypertension, resulting in brain ptosis and subdural hematoma.

[0031] In addition, the inventors reported in Non-Patent Document 2 that the suppression of the decrease in DSSS and intracranial pressure was confirmed even in hydrocephalus patients who had overdrainage immediately after shunt surgery. It has been confirmed that, similar to cerebrospinal fluid hypovolemia, if overdrainage continues in the DSSS state, low intracranial pressure occurs, causing brain ptosis and subdural hematoma.

[0032] Based on these research analyses, the inventors speculate that the cause of hydrocephalus is insufficient buffering of cerebrospinal fluid pulsation by the fatty tissue in the spinal epidural space and the Batson venous plexus. The mechanism by which hydrocephalus develops due to insufficient buffering of cerebrospinal fluid pulsation is as follows.

[0033] As shown in Figures 1 and 3, in a healthy human, when the brain expands due to heartbeat, a flow of cerebrospinal fluid occurs, moving the cerebrospinal fluid from the ventricle side to the spinal canal side. As the cerebrospinal fluid moves to the spinal canal side, the spinal dural sac expands. The expanded spinal dural sac is received by the adipose tissue of the spinal epidural space and the Batson venous plexus.

[0034] As shown in Figure 2, when the brain contracts due to heartbeat, a flow of cerebrospinal fluid occurs, moving the cerebrospinal fluid from the spinal canal side to the ventricle side. As the cerebrospinal fluid moves toward the ventricle side, the spinal dural sac contracts, and the adipose tissue and Batson's venous plexus in the spinal epidural space expand. The contracted spinal dural sac is supported by the expanded adipose tissue and Batson's venous plexus in the spinal epidural space. In this way, the pressure caused by the pulsation of the cerebrospinal fluid is buffered by the adipose tissue and Batson's venous plexus in the spinal epidural space.

[0035] On the other hand, as people age, they may develop diseases such as spinal canal stenosis, scoliosis, multi-intervertebral lesions, and intervertebral disc disease. These symptoms narrow the width of the cerebrospinal fluid passage between the skull, where the brain is located, and the spinal canal, where the spinal cord is located, as shown in Figure 4(a), and the permeability of cerebrospinal fluid deteriorates. Therefore, the pressure caused by the pulsation of cerebrospinal fluid is not buffered by the fatty tissue in the spinal epidural space and the Batson venous plexus. As a result, as shown in Figure 4(b), excessive pressure caused by the pulsation of cerebrospinal fluid is repeatedly applied to the brain, causing the ventricles to expand and the morphology of the brain to change, resulting in the onset and progression of hydrocephalus.

[0036] From the above consideration of the mechanism of hydrocephalus, the inventors have found that if a measure can be taken to cushion the pulsation of cerebrospinal fluid in the skull, it is possible to alleviate the occurrence of overdrainage without being affected by the problems of the organs that receive the cerebrospinal fluid, as in the case of shunt surgery, and it is expected that the onset and progression of hydrocephalus can be suppressed. As a result, they have developed a cerebrospinal fluid pulsation cushioning device that replaces the spinal arachnoid membrane, spinal dural sac, spinal subarachnoid space, adipose tissue, and Batson's venous plexus, which cushion the pulsation of cerebrospinal fluid. The configuration of this device is described below.

[0037] [Embodiment 1] As shown in Fig. 5, the cerebrospinal fluid pulsation damping device 10 according to this embodiment is embedded in the body tissue of a patient P in a state where it is connected to a ventricular catheter C1 extending from a ventricle BV of a brain B. The ventricular catheter C1 is a member that substitutes for a flow path through which cerebrospinal fluid flows between the ventricle BV and the spinal subarachnoid space. The ventricular catheter C1 is a silicon tube. Inside the body of the patient P, the ventricular catheter C1 extends from the ventricle BV to the anterior chest via the outer surface of the skull.

[0038] One end C11 of the ventricular catheter C1 is placed in the ventricle BV. The one end C11 of the ventricular catheter C1 can be placed in the ventricle BV by burr hole surgery, similar to the shunt procedure. A cerebrospinal fluid pulsation damping device 10 is connected to the ventricular catheter C1. The cerebrospinal fluid pulsation damping device 10 includes a damping body 20 and a base plate 30.

[0039] The buffer 20 is connected to the other end C12 of the ventricular catheter C1 located in the anterior chest. The buffer 20 is a member that substitutes for the spinal arachnoid membrane, the spinal dural sac, the fat tissue of the spinal epidural space, and the Batson venous plexus. The buffer 20 is made of elastic silicone resin and is hollow inside. The buffer 20 has an elastic modulus that expands when cerebrospinal fluid of at least 6 cmH2O, which is the lower limit of normal cerebrospinal fluid pressure, flows into the reservoir S and contracts when it flows out of the reservoir S. In other words, if the buffer 20 has an elastic modulus that does not expand or contract even when cerebrospinal fluid of a pressure of 6 cmH2O or more flows into or out of the reservoir S, the pulsation of the cerebrospinal fluid in the ventricle BV is not buffered. As shown in FIG. 6(a) viewed from the front and FIG. 6(b) viewed from the top, the buffer 20 is formed into a semi-cylindrical body that is rounded as a whole. As a result, the buffer 20 deforms in the radial direction of the semicircle with the bottom of the semicylinder (the cut surface of the cylinder) as the reference, and therefore the buffer 20 can expand and contract in a stable state.

[0040] The buffer 20 has a reservoir S therein for storing cerebrospinal fluid flowing from the ventricle BV through the inside of the ventricular catheter C1. The reservoir S is a space that substitutes for the spinal subarachnoid space. The reservoir S is watertightly closed by the peripheral wall of the buffer 20. The reservoir S is formed with a volume equal to the amount of cerebrospinal fluid that moves between the ventricle BV and the subarachnoid space with each beat of the heart during cerebrospinal fluid pulsation, and the volume is specifically 40 mL.

[0041] The base plate 30 is formed of a flexible silicon resin plate. The base plate 30 is provided integrally with the buffer body 20 by arranging a plate surface on the bottom (cut surface of a cylinder) of a semicircular shape perpendicular to the extending direction of the buffer body 20. The base plate 30 is formed in a rectangular shape with an outer periphery located slightly outward from the outer periphery of the buffer body 20 when viewed in a plan view. The base plate 30 extends in the longitudinal direction toward the axial direction of the buffer body 20. The plate thickness of the base plate 30 is greater than the thickness of the peripheral wall of the buffer body 20. The base plate 30 maintains the shape of the cerebrospinal fluid pulsation damping device 10, and improves operability when a doctor uses the cerebrospinal fluid pulsation damping device 10 for surgery and installation inside the body of the patient P.

[0042] The buffer 20 has a cylindrical first connector 41 at one axial end (front) thereof, which is connected to the other end C12 of the ventricular catheter C1. The first connector 41 is inserted into the other end C12 of the ventricular catheter C1 and connected thereto.

[0043] The first connector 41 extends in the axial direction of the buffer body 20 and penetrates one end wall 21 of the buffer body 20. The first connector 41 is disposed at a position where its axis overlaps with the axis X1 of the buffer body 20. The first connector 41 has a first cylindrical portion 411 and a first engagement portion 412.

[0044] The first cylindrical portion 411 is formed of an elongated pipe member. The first cylindrical portion 411 penetrates one end wall 21 of the buffer body 20, with the base end being disposed in the storage portion S and the tip being disposed outside the buffer body 20.

[0045] The first engagement part 412 is provided at a tip of the first cylindrical part 411 located outside the buffer 20. The first engagement part 412 is formed in a shape tapering toward the axial tip of the first connector 41. The first engagement part 412 engages with the inner wall of the ventricular catheter C1 in a state in which the first connector 41 is inserted into the ventricular catheter C1.

[0046] When the cerebrospinal fluid pulsation damping device 10 having such a configuration is placed inside the body of a patient P, the reservoir S of the buffer 20 is filled in advance with a certain amount of artificial cerebrospinal fluid. The artificial cerebrospinal fluid filling the reservoir S is physiological saline that has been adjusted to be isotonic with human body fluids. The volume of the artificial cerebrospinal fluid is half the capacity of the reservoir S, specifically 20 mL.

[0047] The cerebrospinal fluid pulsation damping device 10, whose storage section S is filled with a certain amount of artificial cerebrospinal fluid, is connected to a ventricular catheter C1 after air has been removed. The cerebrospinal fluid pulsation damping device 10 is then inserted into a subcutaneous pocket SP (see FIG. 5) formed in the anterior chest of the patient P and is left in the subcutaneous tissue of the anterior chest. The subcutaneous pocket SP can be formed in the anterior chest by a surgical method similar to that used for general shunt surgery.

[0048] When the cerebrospinal fluid pulsation damping device 10 is connected to the ventricular catheter C1, the ventricle BV, the inside of the ventricular catheter C1, and the reservoir S of the buffer 20 communicate with each other in this order to form a closed flow path for the cerebrospinal fluid filled with cerebrospinal fluid. In other words, excess cerebrospinal fluid is absorbed by the extraarachnoid tissue inside the skull and spinal canal and naturally discharged, and is not discharged by the cerebrospinal fluid pulsation damping device 10.

[0049] In such a closed cerebrospinal fluid flow path, the cerebrospinal fluid pressures in the ventricle BV, inside the ventricular catheter C1, and in the reservoir S of the buffer 20 are all equal and maintained at normal human intracranial pressure of 6 to 18 cmH2O. The cerebrospinal fluid pulsation damping device 10 thus implanted in the body of the patient P to form a closed cerebrospinal fluid flow path dampens the pulsation of cerebrospinal fluid occurring in the ventricle BV in the following manner.

[0050] As shown in FIG. 7(a), the cushioning body 20 of the cerebrospinal fluid pulsation damping device 10 expands when cerebrospinal fluid flows from inside the ventricular catheter C1 into the reservoir S due to pulsation of the cerebrospinal fluid generated in the ventricle BV accompanying heartbeat.

[0051] In detail, when the brain B expands due to heartbeat, the cerebrospinal fluid pressure in the ventricle BV temporarily becomes positive. As a result, the cerebrospinal fluid flows from the ventricle BV into the inside of the ventricular catheter C1 and also flows from the inside of the ventricular catheter C1 into the reservoir S. Then, the buffer 20 expands. In this way, the cerebrospinal fluid moves from the ventricle BV to the reservoir S of the buffer 20 with pulsation, and the buffer 20 of the cerebrospinal fluid pulsation damping device 10 expands, thereby buffering the positive pressure caused by the pulsation of the cerebrospinal fluid in the ventricle BV.

[0052] On the other hand, as shown in FIG. 7(b), the buffer 20 contracts when cerebrospinal fluid flows out from the reservoir S into the inside of the ventricular catheter C1 due to pulsation.

[0053] In detail, when the brain contracts due to heartbeat, the cerebrospinal fluid pressure in the ventricle BV temporarily becomes negative. As a result, cerebrospinal fluid flows from the reservoir S into the inside of the ventricular catheter C1 and flows from the inside of the ventricular catheter C1 to the ventricle BV. The buffer 20 then contracts. In this way, the cerebrospinal fluid moves from the reservoir S of the buffer 20 to the ventricle BV with pulsation, and the buffer 20 contracts, thereby buffering the negative pressure caused by the pulsation of the cerebrospinal fluid in the ventricle BV.

[0054] Therefore, excessive pressure due to pulsation of cerebrospinal fluid in the ventricle BV is not applied to the brain B. Therefore, the ventricle BV does not expand and the shape of the brain B does not change. As a result, hydrocephalus does not develop or progress.

[0055] Also, unlike conventional catheter-based shunt procedures, over-drainage does not occur because cerebrospinal fluid is not discharged. Therefore, complications such as low intracranial pressure, cerebral ptosis, and subdural hematoma do not occur after surgery. In addition, no organ is required to absorb the cerebrospinal fluid discharged from the ventricles. Furthermore, compared to shunt procedures, the difficulty of the surgery to install the cerebrospinal fluid pulsation dampening device 10 is low, and the risk of the surgery is low.

[0056] Thus, according to the cerebrospinal fluid pulsation damping device 10 of the present embodiment, unlike conventional shunt surgery, it is possible to mitigate the occurrence of over-drainage, and to cushion the cerebrospinal fluid pulsation by replacing the tissues and organs of the human body that are responsible for cushioning the cerebrospinal fluid pulsation, which is expected to suppress the onset and progression of hydrocephalus.

[0057] [Embodiment 2] As shown in FIG. 5, the cerebrospinal fluid pulsation damping device 10 according to the first embodiment has one buffer 20, but is not limited thereto. In a patient in whom the width of the cerebrospinal fluid flow passage between the skull in which the brain is located and the spinal canal in which the spinal cord is located is extremely narrow, the amount of cerebrospinal fluid pulsating in the ventricle BV flowing to the spinal canal side is reduced. Therefore, the amount of cerebrospinal fluid moving between the ventricle BV and the storage section S per beat increases. In that case, if there is only one buffer 20 as in the cerebrospinal fluid pulsation damping device 10 according to the first embodiment, the amount of cerebrospinal fluid entering and leaving the storage section S may exceed the volume of the storage section S. As a result, there is a risk that the cerebrospinal fluid pulsation in the ventricle BV will not be damped by the cerebrospinal fluid pulsation damping device 10. Therefore, the cerebrospinal fluid pulsation damping device 10 of the present embodiment has a configuration that can damp the cerebrospinal fluid pulsation of a patient in whom a large amount of cerebrospinal fluid moves between the ventricle BV and the storage section S per beat. The configuration will be described below.

[0058] As shown in Figure 8, the cushioning body 20 of the cerebrospinal fluid pulsation damping device 10 of this embodiment has a first cushioning body 201 having a first storage portion S1 therein, and a second cushioning body 202 that is provided continuously with the first cushioning body 201 and has a second storage portion S2 therein.

[0059] The first storage section S1 and the second storage section S2 are formed to have the same volume, specifically, 40 mL. A relay catheter C2 that connects the first buffer body 201 and the second buffer body 202 extends between the first buffer body 201 and the second buffer body 202. The relay catheter C2 is a silicon tube.

[0060] The first buffer body 201 and the second buffer body 202 each have a cylindrical first connector 41 and a cylindrical second connector 42 at both axial ends. The second connector 42 of the first buffer body 201 is inserted into one end C21 of the relay catheter C2 and connected thereto. The first connector 41 of the second buffer body 202 is inserted into the other end C22 of the relay catheter C2 and connected thereto.

[0061] 9, the second connector 42 is provided at the other axial end of the buffer body 20. The second connector 42 extends in the axial direction of the buffer body 20 and penetrates the other end wall 22 of the buffer body 20. The second connector 42 is disposed at a position where its axis overlaps with the axis X1 of the buffer body 20 and the axis of the first connector 41.

[0062] The second connector 42 has a second cylindrical portion 421 and a second engagement portion 422 provided at the tip of the second cylindrical portion 421. The second cylindrical portion 421 penetrates the other end wall 22 of the buffer body 20, with the base end disposed in the storage portion S and the second engagement portion 422 at the tip disposed outside the buffer body 20.

[0063] In addition, the second buffer body 202 has a cap body 50 that is detachable from the second connector 42 at the other end. The cap body 50 is attached to the second connector 42 when the second connector 42 is not in use, and closes the tip opening watertightly.

[0064] The first reservoir S1 and the second reservoir S2 are in communication with each other in such a state that the first buffer 201 and the second buffer 202 are connected to each other. In detail, with the cerebrospinal fluid pulsation damping device 10 connected to the ventricular catheter C1, the ventricle BV, the inside of the ventricular catheter C1, the first reservoir S1 of the first buffer 201, the inside of the relay catheter C2, and the second reservoir S2 of the second buffer 202 are in communication with each other in this order to form a closed flow path of cerebrospinal fluid filled with cerebrospinal fluid.

[0065] In a closed cerebrospinal fluid flow path, the cerebrospinal fluid pressure, which is the internal pressure in the ventricle BV, inside the ventricular catheter C1, the first reservoir S1, inside the relay catheter C2, and the second reservoir S2, is equal during cerebrospinal fluid pulsation.

[0066] In this embodiment, the two first buffers 201 and the second buffers 202 of the cerebrospinal fluid pulsation damping device 10 installed in the body of the patient P also dampen the pulsation of the cerebrospinal fluid. Therefore, the pressure caused by the pulsation of the cerebrospinal fluid in the ventricle BV is not applied to the brain. Therefore, the ventricle BV does not expand, and the shape of the brain B does not change. As a result, it is expected that the onset and progression of hydrocephalus can be suppressed. In particular, in the cerebrospinal fluid pulsation damping device 10 of this embodiment, the two first buffers 201 and the second buffers 202 are expected to dampen the pulsation of the cerebrospinal fluid of the patient P in which the width of the cerebrospinal fluid flow path between the skull in which the brain is located and the spinal canal in which the spinal cord is located is extremely narrow.

[0067] [Embodiment 3] In the above-mentioned first and second embodiments, there is no particular mention of the posture of the patient P. However, the patient P implanted with the cerebrospinal fluid pulsation damping device 10 includes not only bedridden people, but also people who live an ordinary life by repeatedly lying down and standing up.

[0068] When the patient P suddenly sits up from a lying position, gravity and the inertial force caused by the change in the patient's posture act suddenly on the cerebrospinal fluid in the ventricle BV. As a result, the cerebrospinal fluid may flow out through the ventricular catheter C1 into the reservoir S of the buffer 20, causing a sudden decrease in the amount of cerebrospinal fluid in the ventricle BV.

[0069] Furthermore, when the patient P turns over and lies face down, the patient P's weight acts as an external force on the cerebrospinal fluid pulsation damping device 10 embedded in the anterior chest, causing the damping body 20 to suddenly contract. As a result, the cerebrospinal fluid in the reservoir S flows into the ventricle BV through the ventricular catheter C1, and the amount of cerebrospinal fluid in the ventricle BV may suddenly increase.

[0070] In this way, regardless of the pulsation of the cerebrospinal fluid, the cerebrospinal fluid may move suddenly between the ventricle BV and the reservoir S, causing a sudden change in the cerebrospinal fluid pressure in the ventricle BV, which may cause the patient P to suffer a headache or loss of consciousness.

[0071] Therefore, the cerebrospinal fluid pulsation damping device 10 of this embodiment is provided with a cerebrospinal fluid regulating valve 60 that regulates the sudden movement of cerebrospinal fluid between the ventricle BV and the reservoir S. The configuration of the cerebrospinal fluid pulsation damping device 10 of this embodiment will be described below.

[0072] 10, the cerebrospinal fluid control valve 60 is located between the ventricular catheter C1 and the buffer body 20. Between the cerebrospinal fluid control valve 60 and the buffer body 20, a relay catheter C2 that connects the cerebrospinal fluid control valve 60 and the buffer body 20 is inserted.

[0073] As shown in FIG. 11, the cerebrospinal fluid regulating valve 60 includes a housing 61 having a flow path portion S3 therein through which cerebrospinal fluid passes, and a valve body 62 housed in the flow path portion S3.

[0074] The housing 61 is an elongated cylindrical member having a first opening 63 and a second opening 64 at both ends in the axial direction, and a cylindrical hole corresponding to the flow path section S3 inside. An inner peripheral surface 61a of the housing 61 has a cross section perpendicular to the axial direction formed as an inclined surface that inclines inward from the center in the axial direction toward the first opening 63 and the second opening 64 at both ends. In other words, the width of the flow path section S3 narrows from the center in the axial direction toward the first opening 63 and the second opening 64 at both ends.

[0075] The housing 61 also has a first groove 63a and a second groove 64a on the inner circumferential surface 61a. The first groove 63a and the second groove 64a extend from the center in the axial direction toward the first opening 63 and the second opening 64 at both ends. The first groove 63a and the second groove 64a are included in the flow path section S3, and are portions through which cerebrospinal fluid flows when a valve body 62 (described later) is in contact with the inner circumferential surface 61a.

[0076] The housing 61 also has a cylindrical third connector 43 and a cylindrical fourth connector 44 at both ends in the axial direction.

[0077] The third connector 43 and the fourth connector 44 are connected to the first opening 63 and the second opening 64, respectively, and extend axially outward from both ends of the housing 61. The third connector 43 and the fourth connector 44 are disposed at positions where their respective axes overlap the axis X2 of the housing 61. The cylindrical holes of the third connector 43 and the fourth connector 44 communicate with the flow path portion S3.

[0078] The third connector 43 has a third cylindrical portion 431 and a third engagement portion 432, and is connected to the other end C12 of the ventricular catheter C1. The fourth connector 44 has a fourth cylindrical portion 441 and a fourth engagement portion 442, and is connected to one end C21 of the relay catheter C2.

[0079] The valve body 62 is a spherical gravity valve, and moves in the flow path section S3 of the housing 61. The diameter O of the valve body 62 is smaller than the width D1 of the flow path section S3 at the center of the axial direction of the housing 61, and is larger than the width D2 of the first opening 63 and the width D3 of the second opening 64 at both ends of the axial direction of the housing 61. The diameter O of the valve body 62 is also larger than the groove widths of the first groove 63a and the second groove 64a.

[0080] When such a cerebrospinal fluid regulating valve 60 is disposed between the ventricular catheter C1 and the buffer 20, the ventricle BV, the inside of the ventricular catheter C1, the flow path section S3 of the cerebrospinal fluid regulating valve 60, the inside of the relay catheter C2, and the reservoir section S of the buffer 20 are connected in this order to form a closed flow path for cerebrospinal fluid filled with cerebrospinal fluid.

[0081] In a closed cerebrospinal fluid flow path, when the cerebrospinal fluid pulsates, the internal pressures of the ventricle BV, the inside of the ventricular catheter C1, the first reservoir S1, the flow path S3 of the cerebrospinal fluid regulating valve 60, the inside of the relay catheter C2, and the reservoir S of the buffer 20, i.e., the cerebrospinal fluid pressure, are equal.

[0082] The cerebrospinal fluid regulating valve 60 configured as above regulates the sudden movement of cerebrospinal fluid between the ventricle BV and the reservoir S in the following manner.

[0083] During normal pulsation of cerebrospinal fluid, the valve body 62 of the cerebrospinal fluid regulating valve 60 does not hinder the movement of cerebrospinal fluid in the flow path portion S3 of the housing 61. During normal pulsation of cerebrospinal fluid, the valve body 62 forms a gap with the inner peripheral surface 61a to open the flow path portion S3. This maintains the movement of cerebrospinal fluid between the ventricle BV and the reservoir portion S.

[0084] On the other hand, as cerebrospinal fluid moves due to gravity or external forces accompanying a sudden change in the patient's posture, not due to normal cerebrospinal fluid pulsation, the valve body 62 moves to either the first opening 63 side or the second opening 64 side at both axial ends of the housing 61, narrowing the gap between the inner surface 61a, i.e., the width of the flow path section S3, and regulating the movement of cerebrospinal fluid in the flow path section S3.

[0085] In detail, when a patient suddenly sits up from a lying down state, gravity and inertial forces act on the cerebrospinal fluid in the ventricle BV. Then, the cerebrospinal fluid in the ventricle BV flows into the ventricular catheter C1 from one end C11. As a result, the cerebrospinal fluid flows into the flow path section S3 from the other end C12 of the ventricular catheter C1 through the third connector 43. In the closed flow path of the cerebrospinal fluid, the cerebrospinal fluid pressure in the ventricle BV at this time is lower than the cerebrospinal fluid pressure in the reservoir S.

[0086] As shown in FIG. 12(a), the cerebrospinal fluid that has flowed suddenly from the ventricle BV into the flow path portion S3 moves the valve body 62 through the flow path portion S3 toward the second opening 64 and contacts the inner peripheral surface 61a. In this state, the second groove 64a, which is the flow path portion S3, is located on the outside of the valve body 62. In other words, the valve body 62 does not completely block the flow path portion S3, i.e., the second opening 64. Therefore, a small amount of cerebrospinal fluid flows through the second groove 64a. This movement of the valve body 62 limits the excessive outflow of cerebrospinal fluid from the ventricle BV through the second opening 64. As a result, the cerebrospinal fluid pressure in the ventricle BV does not suddenly decrease, and the ventricle BV does not contract.

[0087] Furthermore, when the patient P turns over and applies his / her weight to the anterior chest, the patient P's weight acts as an external force on the buffer 20, causing the buffer 20 to contract. Then, the cerebrospinal fluid in the reservoir S flows rapidly into the relay catheter C2 from the other end C22. As a result, the cerebrospinal fluid flows rapidly from the one end C21 of the relay catheter C2 through the fourth connector 44 into the flow path S3. In the closed flow path of the cerebrospinal fluid, the cerebrospinal fluid pressure in the reservoir S at this time is higher than the cerebrospinal fluid pressure in the ventricle BV.

[0088] As shown in FIG. 12(b), the cerebrospinal fluid that flows suddenly from the reservoir S into the flow path S3 moves the valve body 62 toward the first opening 63 and contacts the inner circumferential surface 61a. In this state, the first groove 63a, which is the flow path S3, is located on the outside of the valve body 62. In other words, the valve body 62 does not completely block the flow path S3, i.e., the first opening 63. Therefore, a small amount of cerebrospinal fluid flows through the first groove 63a. This movement of the valve body 62 limits the excessive outflow of cerebrospinal fluid from the reservoir S through the first opening 63. As a result, the cerebrospinal fluid pressure in the ventricle BV does not rise suddenly, and the ventricle BV does not expand.

[0089] In this manner, in the cerebrospinal fluid pulsation damping device 10 of this embodiment, the cerebrospinal fluid regulating valve 60 located between the ventricular catheter C1 and the buffer 20 regulates the sudden movement of cerebrospinal fluid between the ventricle BV and the reservoir S, thereby preventing a sudden change in cerebrospinal fluid pressure in the ventricle BV. As a result, there is no concern that the patient P will suffer from a headache or impaired consciousness even if he or she changes posture.

[0090] Although the embodiment has been described above, the present invention is not limited to this, and the following modifications are possible.

[0091] FIG. 5 illustrates a configuration in which the cerebrospinal fluid pulsation damping device 10 is embedded in the anterior chest of the patient P. However, as long as the cerebrospinal fluid pulsation damping device 10 can damp the pulsation of the cerebrospinal fluid in the ventricle BV through the ventricular catheter C1, the position at which the cerebrospinal fluid pulsation damping device 10 is installed may be any configuration. For example, the cerebrospinal fluid pulsation damping device 10 may be installed under the scalp and on the surface of the skull, or may be installed in the abdominal cavity. In addition, the cerebrospinal fluid pulsation damping device 10 may be installed outside the patient P's body, for example, on the surface of the scalp or the skin of the anterior chest, and installed in a manner exposed to the outside. In this case, maintenance of the device, such as replacement and cleaning of the cerebrospinal fluid pulsation damping device 10, is facilitated. In addition, there is no need to form a place to install the cerebrospinal fluid pulsation damping device 10 in the patient P's body, and the physical burden on the patient P during surgery can be reduced.

[0092] Moreover, in the first embodiment, the buffer 20 is formed in a semi-cylindrical shape from a flexible silicone resin. However, the buffer 20 may be formed in a cylindrical or rectangular prism shape, for example, as long as it has a reservoir S therein and can expand and contract with cerebrospinal fluid that moves with pulsation. The buffer 20 may be formed in a flexible material that is safe for the human body, for example, it may be formed in a flexible resin such as polyurethane or polyethylene.

[0093] 5 also illustrates a configuration in which the buffer 20 has a first connector 41 that is connected to the other end C12 of the ventricular catheter C1. However, the first connector 41 is not essential as long as the ventricular catheter C1 and the buffer 20 are connected. For example, the ventricular catheter C1 and the buffer 20 may be integrally configured rather than being separate.

[0094] Moreover, in the first embodiment, the volume of the storage section S is 40 mL. However, the volume of the storage section S is not limited to this. The storage section S may be formed with a volume equal to the amount of cerebrospinal fluid moving between the ventricle BV and the subarachnoid space for each heart beat, depending on the individual differences of the patient, and is preferably 10 to 60 mL in detail. If the volume of the storage section S is smaller than 10 mL, the buffer 20 cannot contract and expand, and there is a risk that the pulsation of the cerebrospinal fluid is not buffered. If the volume of the storage section S is larger than 60 mL, the cerebrospinal fluid pulsation buffering device 10 becomes large, the installation in the human body becomes poor, and the buffer 20 becomes susceptible to external forces, and there is a risk that the cerebrospinal fluid may suddenly flow back from the storage section S to the ventricle BV.

[0095] Moreover, in the first embodiment, a configuration is exemplified in which the artificial cerebrospinal fluid that fills the reservoir S in advance when the doctor installs the cerebrospinal fluid pulsation damping device 10 inside the body of the patient P is physiological saline. However, the artificial cerebrospinal fluid may be, other than physiological saline, for example, Ringer's solution, or a liquid that is strictly adjusted to have the component composition of human cerebrospinal fluid, as long as it is isotonic and has the same pH as human cerebrospinal fluid and can protect the brain and spinal cord.

[0096] 6(a) and 6(b) show an example of a configuration in which the cerebrospinal fluid pulsation damping device 10 includes a base plate 30 to which the buffer 20 is fixed. However, if the cerebrospinal fluid pulsation damping device 10 can cause cerebrospinal fluid pulsation by the buffer 20, the base plate 30 is not an essential component. However, from the viewpoint of operability when a doctor uses the cerebrospinal fluid pulsation damping device 10 to perform surgery and ease of installation inside the body of the patient P, it is preferable that the buffer 20 is fixed to the base plate 30. Furthermore, the size and shape of the base plate 30 are optional.

[0097] 8 shows an example of a configuration in which the first buffer 201 and the second buffer 202 are connected to each other via a relay catheter C2, and FIG. 10 shows an example of a configuration in which the cerebrospinal fluid regulating valve 60 and the buffer 20 are connected to each other via a relay catheter C2. However, the relay catheter C2 is not an essential component. For example, the second connector 42 of the first buffer 201 and the first connector 41 of the second buffer 202 may be directly connected, or the fourth connector 44 of the cerebrospinal fluid regulating valve 60 and the first connector 41 of the buffer 20 may be directly connected.

[0098] In addition, the first connector 41 and the second connector 42 are not essential components as long as the first storage section S1 and the second storage section S2 of the first buffer 201 and the second buffer 202 are connected to each other. For example, the first buffer 201 and the second buffer 202 may be configured integrally instead of being separate. Similarly, the third connector 43 and the fourth connector 44 of the cerebrospinal fluid regulating valve 60 are not essential components as long as the flow path section S3 is connected to the inside of the ventricular catheter C1 and the storage section S. For example, the ventricular catheter C1, the cerebrospinal fluid regulating valve 60, and the buffer 20, the cerebrospinal fluid regulating valve 60 and the buffer 20, or the ventricular catheter C1 and the cerebrospinal fluid regulating valve 60 may be configured integrally.

[0099] FIG. 8 illustrates a configuration in which the buffer 20 is a first buffer 201 and a second buffer 202 that are consecutive. However, the number of buffers 20 can be appropriately changed according to the individual differences of the patient, taking into consideration the amount of cerebrospinal fluid that flows out from the ventricle BV to the reservoir S every time the heart beats. For example, a third buffer (not shown) may be connected to the second buffer 202, and a fourth buffer may be connected to the third buffer in sequence. In that case, when the buffer 20 located at the end farthest from the ventricle BV among the consecutive buffers 20 has the second connector 42, the second connector 42 closes the opening of the cap body 50. Furthermore, the volumes of the reservoirs S of the multiple buffers 20 may be different from each other.

[0100] 9(b) illustrates a configuration in which the positions at which the first connector 41 and the second connector 42 extend from the buffer 20 overlap with the axis X1 of the buffer 20. However, the positions of the first connector 41 and the second connector 42 may be any position as long as the interiors of the first connector 41 and the second connector 42 communicate with the reservoir S to form a flow path for cerebrospinal fluid.

[0101] 11 illustrates a configuration of the cerebrospinal fluid regulation valve 60 in which the housing 61 is an elongated cylindrical member and the valve body 62 is a spherical ball valve. However, as long as the cerebrospinal fluid regulation valve 60 can regulate the sudden movement of cerebrospinal fluid between the ventricle BV and the reservoir S due to gravity and external force, the shape and material of the housing 61 and the valve body 62 can be any configuration. For example, the housing 61 may be cubic or cylindrical as long as it has a first opening 63 and a second opening 64 that communicate with the internal flow path S3. The valve body 62 may be a swing-type or check valve body that is supported by the inner wall of the housing 61 at one end so as to be able to move due to the cerebrospinal fluid flowing through the flow path S3 due to gravity and external force not due to pulsation and automatically narrow the width of the flow path S3, i.e., the opening width of the first opening 63 and the second opening 64. In particular, the cerebrospinal fluid regulating valve 60 only needs to be configured to restrict the excessive outflow of cerebrospinal fluid from the ventricle BV due to a change in gravity caused by a change in body position, and the valve body 62 only needs to have a configuration that does not completely block the second opening 64 when it moves to the second opening side in the flow path section S3, and does not completely prevent the movement of cerebrospinal fluid. In other words, the housing 61 may not have the first groove 63a on the inner peripheral surface 61a, and the valve body 62 may completely block the flow path section S3, i.e., the first opening 63, when it moves to the first opening 63 side and abuts against the inner peripheral surface 61a. In that case, the valve body 62 only needs to be configured to move away from the inner peripheral surface 61a on the first opening 63 side by gravity when the patient P stands upright, thereby opening the first opening 63.

[0102] In the present embodiment, the cerebrospinal fluid pulsation damping device 10 is used to treat hydrocephalus, particularly idiopathic normal pressure hydrocephalus. However, the cerebrospinal fluid pulsation damping device 10 can also be used to inhibit the onset and progression of other diseases caused by cerebrospinal fluid pulsation, such as obstructive hydrocephalus and cerebral atrophy.

[0103] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. The above-described embodiments are for the purpose of explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and the scope of the invention equivalent thereto are considered to be within the scope of the present invention. [Industrial Applicability]

[0104] The cerebrospinal fluid pulsation cushioning device of the present invention is useful in treating diseases in which abnormalities in cerebrospinal fluid circulation are observed, such as hydrocephalus, obstructive hydrocephalus, and cerebral atrophy, by mitigating the impact on the brain caused by cerebrospinal fluid pulsation. [Explanation of symbols]

[0105] 10...cerebrospinal fluid pulsation damping device, 20...dampening body, 201...first damping body, 202...second damping body, 21...one end wall, 22...other end wall, 30...base plate, 41...first connector, 411...first cylindrical portion, 412...first engagement portion, 42...second connector, 421...second cylindrical portion, 422...second engagement portion, 43...third connector, 431...third cylindrical portion, 432...third engagement portion, 44...fourth connector, 441...fourth cylindrical portion, 442...fourth engagement portion, 50...cap body, 60...cerebrospinal fluid regulating valve, 61...housing , 61a...inner circumferential surface, 62...valve body, 63...first opening, 64...second opening, 63a...first groove, 64a...second groove, B...brain, BV...ventricle, C1...ventricular catheter, C11...one end, C12...other end, C2...relay catheter, C21...one end, C22...other end, O...diameter of valve body, D1...width of flow path, D2...width of first opening, D3...width of second opening, P...patient, S...storage portion, S1...first storage portion, S2...second storage portion, S3...flow path portion, SP...subcutaneous pocket, X1...axis of cushioning body, X2...axis of housing

Claims

1. a buffer body having one end connected to the other end of a ventricular catheter placed in a ventricle and having a reservoir therein for storing cerebrospinal fluid flowing from the ventricle through the ventricular catheter; The buffer body is The pulsation of the cerebrospinal fluid causes the cerebrospinal fluid to move in the ventricles as the heart beats, The catheter expands when the cerebrospinal fluid moves from the inside of the ventricular catheter to the reservoir, and contracts when the cerebrospinal fluid moves from the reservoir to the inside of the ventricular catheter. Cerebrospinal fluid pulsation dampener.

2. The volume of the reservoir of the buffer is 10 to 60 mL; 2. The cerebrospinal fluid pulsation dampening device according to claim 1.

3. Further comprising a base plate to which the buffer body is fixed on a plate surface.

3. The cerebrospinal fluid pulsation damping device according to claim 1 or 2.

4. As the buffer, a first buffer body connected to the other end of the ventricular catheter and having a first reservoir therein; a second buffer body connected to the first buffer body and having a second reservoir therein; having When the first buffer body and the second buffer body are connected to each other, the first storage portion and the second storage portion communicate with each other.

3. The cerebrospinal fluid pulsation damping device according to claim 1 or 2.

5. a cerebrospinal fluid regulating valve located between the ventricular catheter and the buffer for regulating movement of the cerebrospinal fluid between the ventricle and the reservoir without the pulsation of the cerebrospinal fluid; The cerebrospinal fluid regulating valve is a housing having a first opening connected to the other end of the ventricular catheter and a second opening connected to the buffer body, the housing having therein a flow path portion communicating with the first opening and the second opening, respectively, through which the cerebrospinal fluid passes; a valve body movably housed in the flow path portion of the housing, The valve body is When the cerebrospinal fluid pressure in the ventricle becomes lower than the cerebrospinal fluid pressure in the reservoir, the cerebrospinal fluid flows from the ventricular catheter into the flow path, and moves toward the second opening side to narrow the width of the flow path. When the cerebrospinal fluid pressure in the reservoir becomes higher than the cerebrospinal fluid pressure in the ventricle, the cerebrospinal fluid flows from the reservoir into the flow path, and moves toward the first opening side to narrow the width of the flow path.

3. The cerebrospinal fluid pulsation damping device according to claim 1 or 2.

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