Liquid administration device

Abstract

To contribute to provision of a practical liquid object administration device by improving a required property such as tip part sealing property in a liquid object administration device that is used for administration of a liquid object into a brain tissue.SOLUTION: In a liquid object administration device 10, a seal member 42 is fitted to a projection tip projecting from a tip opening of a protective tube 26 in an inner tube 12 inserted into a brain tissue, and a gap seal part 44 entering a gap between the inner tube 12 and the protective tube 26 and a coating seal part 46 expanding over an outer peripheral surface of the protective tube 26 are formed integrally with the seal member 42.SELECTED DRAWING: Figure 3

Description

【Technical Field】 【0001】 The present invention relates to a liquid administration device provided with a cannula whose tip portion is inserted into brain tissue and used for administering a liquid substance such as a chemical solution into brain tissue. 【Background Art】 【0002】 In recent years, research and development of devices for directly administering a liquid substance such as a chemical solution into brain tissue for purposes such as disease treatment have been carried out. For example, as one of the treatment methods for neurological diseases such as Alzheimer's disease and AADC deficiency, injecting drugs, gene therapy viral vectors, transplanted cells, etc. into the target site in the brain by stereotactic brain surgery has been studied, and for such an operation, it has been studied to use a specific device and directly administer a liquid substance such as a drug into brain tissue through a cannula that can be inserted into the brain percutaneously from the outside. 【0003】 By the way, special functions, characteristics, etc. are required for a liquid administration device used for administering a liquid substance into brain tissue. Specifically, it is necessary to have a sufficiently small diameter in order to suppress the burden on the brain and the risk of damage, and to have sufficient strength during insertion and the like. Also, when injecting and administering a liquid substance into the brain, it is necessary to prevent backflow into the cannula and surely administer a minute specified amount of a chemical solution or the like into the brain. Also, sufficient attention must be paid to biotoxicity in order to avoid adverse effects on the brain. Also, since the administered chemical solution or the like is precious, etc., it is necessary to suppress the residual amount of the chemical solution or the like in the device after the operation and make it loaded. Also, it is important to ensure the workability of the operation and the ease of manufacture while satisfying the required characteristics. 【0004】 However, in fact, a device that can sufficiently achieve the required characteristics for a liquid administration device used for administering a liquid substance into brain tissue has not yet been developed. 【0005】 For example, Japanese Patent Publication No. 2015-173972 (Patent Document 1) discloses a cannula with a double-tube structure in which an ultrafine tube is covered with a protective tube or a tube of different diameters on the outside. However, this is still only in the conceptual stage and does not disclose a structure specific enough to solve the practical problems mentioned above. [Prior art documents] [Patent Documents] 【0006】 [Patent Document 1] Japanese Patent Publication No. 2015-173972 [Overview of the project] [Problems that the invention aims to solve] 【0007】 In this context, the object of the present invention is to provide a liquid substance administration device having a novel configuration that can contribute to the realization of a practical liquid substance administration device by improving at least one of the characteristics required for a liquid substance administration device used for administering liquid substances into brain tissue. [Means for solving the problem] 【0008】 The following describes embodiments of the present invention made to solve these problems. The components used in each embodiment described below can be used in any combination as much as possible. 【0009】 One aspect of the present invention is as follows: A liquid administration device equipped with a cannula whose tip is inserted into brain tissue, used for administering liquid substances into brain tissue, The tip portion of the cannula is composed of a resin inner tube having a lumen for the flow of the liquid, and a rigid protective tube that is fitted onto the inner tube. A liquid dispensing device in which the tip of the inner tube protrudes from the tip of the protective tube, and a sealing member fixed to the outer circumferential surface of the protruding tip of the inner tube integrally forms a gap sealing portion that fits into the gap between the inner tube and the protective tube, and a covering sealing portion that extends to the outer circumferential surface of the protective tube. 【0010】 According to this embodiment, by externally attaching the sealing member using the protruding tip of the inner tube that extends from the tip of the protective tube, the sealing member can be attached while avoiding adverse effects on the passage of liquid through the inner tube. Moreover, the gap sealing portion and the covering sealing portion integrally formed on the sealing member allow the sealing member to be stably attached even if the protruding tip of the inner tube is short. In addition, by sandwiching the protective tube radially between the gap sealing portion and the covering sealing portion, the adhesion force of the sealing member to the inner tube and protective tube can be advantageously secured, and the stability of the attached state of the sealing member can be improved. Furthermore, since the gap sealing portion is double-covered on its outer circumference by the protective tube and the covering sealing portion and is positioned radially sandwiched between the inner tube and the protective tube, it exhibits good fluid tightness to the gap between the inner tube and the protective tube, making it possible to effectively prevent backflow of liquid administered into the brain through the inner tube from entering the gap. 【0011】 Aspect 2 of the present invention is as follows: The liquid administration device according to embodiment 1, wherein the sealing member at the tip of the cannula achieves the required fixing force between the inner tube and the protective tube without the use of adhesive. 【0012】 According to this embodiment, the need to use adhesives is eliminated, thus avoiding the cytotoxicity issues associated with adhesives, and the troublesome task of selecting adhesives is also eliminated. 【0013】 A third aspect of the present invention is as follows: The liquid dispensing device according to embodiment 1 or 2, wherein the length of the protruding tip of the inner tube protruding from the protective tube is less than 1 mm. 【0014】 According to this embodiment, by shortening the length of the protruding tip portion of the inner tube that is not covered and reinforced by the protective tube, the risk of damage to the inner tube, which is made of a small diameter and thin wall, and the sealing member fitted thereon can be reduced. While it is acceptable for the tip of the inner tube to protrude even slightly from the protective tube, if the protrusion of the inner tube tip is excessively small, there is a concern that it may negatively affect the durability and reliability of the sealing component that is extrapolated there. Therefore, it is desirable that the length of the protruding tip of the inner tube be 0.1 mm or more. 【0015】 Aspect 4 of the present invention is as follows: A liquid administration device equipped with a cannula whose tip is inserted into brain tissue, used for administering liquid substances into brain tissue, The tip portion of the cannula is composed of a resin inner tube having a lumen for the flow of the liquid, and a rigid protective tube that is fitted onto the inner tube. The protective tube is provided with tapered sections at multiple points along its length, where the inner and outer diameters gradually increase from the tip to the base. The tapered portion located at the very tip is provided in the tip region of the protective tube, A liquid dispensing device in which the tapered portion located at the most proximal end extends beyond the tip region of the protective tube. 【0016】 According to this embodiment, in a protective tube, for example, the outer diameter of the tip portion inserted into the brain is reduced to minimize damage to the brain, while the outer diameter of the proximal portion, especially the part not inserted into the brain, is increased to efficiently ensure strength (including a reinforcing effect on the inner tube). Moreover, since the portion where the outer diameter changes is a tapered portion that gradually changes in the longitudinal direction, damage during insertion into the brain can be further reduced. 【0017】 Aspect 5 of the present invention is as follows: The liquid dispensing device according to embodiment 4, wherein the protective tube is a single, integrally formed product consisting of a continuous metal member over its entire length. 【0018】 According to this embodiment, compared to a protective tube consisting of multiple connecting members in the longitudinal direction formed by welding or the like to join multiple metal pipes, it is possible to make the outer surface smoother, and variations in surface properties from product to product can be suppressed, thereby improving and stabilizing quality. 【0019】 Aspect 6 of the present invention is as follows: A liquid substance administration device used for administering liquid substances into brain tissue, comprising a cannula whose tip is inserted into brain tissue, and a connector provided at the proximal end of the cannula for connection to a liquid substance administration device, The connector has a protruding boss portion that projects from the bottom wall on the tip side toward the base end into a connection space surrounded by a peripheral wall, and a liquid through-hole that communicates with the lumen for the flow of the liquid in the cannula is provided passing through the protruding boss portion, in the liquid administration device. 【0020】 According to this aspect, since the substantial volume inside the connector is reduced by the protruding boss portion, for example, in a procedure of administering a liquid substance, the volume of the liquid substance remaining in the liquid substance passage after the procedure can be reduced. Particularly, since a chemical solution or the like administered into the brain is very precious and expensive, in a device used for administering a liquid substance into the brain tissue targeted by the present invention, a low dead space characteristic for suppressing the dead space where a chemical solution or the like remains after the procedure is considered important. 【0021】 Aspect 7 of the present invention is as follows. The liquid substance administration device according to Aspect 6, wherein a space between the peripheral wall and the protruding boss portion in the connector is an annular space into which a male tip of a syringe in the liquid substance administration device is inserted. 【0022】 According to this aspect, an adverse effect on the connection characteristics of the syringe caused by providing the protruding boss portion is avoided, and by inserting the male tip into the annular space around the protruding boss portion, the substantial residual volume of the liquid substance in the connector can be further reduced. 【Effects of the Invention】 【0023】 According to the present invention, at least one of the characteristics required for a liquid substance administration device used for administering a liquid substance into the brain tissue is improved, and for example, a more practical liquid substance administration device can be provided as compared with those described in Patent Document 1. 【Brief Description of the Drawings】 【0024】 [Figure 1] It is an overall explanatory view showing a liquid substance administration device as an embodiment of the present invention, where (a) is a front explanatory view, (b) is a plan explanatory view, and (c) is a C-C cross-sectional explanatory view in (b). [Figure 2] It is a longitudinal sectional view showing an enlarged tip side portion of a catheter in the liquid substance administration device shown in FIG. 1, where (a) is a view showing the tip side of the protection tube, and (b) is a view showing the base end side of the protection tube. [Figure 3] Figure 1 is a magnified longitudinal cross-sectional view showing the proximal end portion of the catheter in the liquid administration device shown. [Figure 4] This is a longitudinal cross-sectional view illustrating another form of connector that may be used in the liquid dispensing device of the embodiment shown in Figure 1. [Modes for carrying out the invention] 【0025】 The present invention will now be described in more detail based on embodiments with reference to the drawings. 【0026】 First, Figure 1 shows the entire liquid substance administration device 10, which is an exemplary embodiment of the present invention. Figure 2 shows an enlarged view of the tip portion of the liquid substance administration device 10, and Figure 3 shows an enlarged view of the base portion. The liquid substance administration device 10 is used in a procedure to inject a liquid substance, such as a drug solution, into a target area in the brain, and the cannula, which is inserted percutaneously into the brain from the outside, is composed of a double tubular structure consisting of an inner tube 12 and an outer covering tube 14. 【0027】 The inner tube 12 is a resin tube with a lumen for the flow of drug solution, and is composed of a single continuous tube from the tip to the proximal end of the cannula. The material of the inner tube 12 is not particularly limited, but in addition to the required non-toxicity, flexibility, and strength against bending and kinking, it is preferable to have an extremely small diameter and a smooth inner surface of a constant diameter along its entire length so as to deliver a minute, specified amount of drug solution and achieve loading. 【0028】 Specifically, the inner tube 12 can preferably be a polyimide resin tube with an inner diameter of about 0.1 to 0.5 mm and a wall thickness of about 0.01 to 0.1 mm. Furthermore, the length of the inner tube 12 should preferably be about 1 to 2 m, taking into consideration the ease of the procedure. 【0029】 Furthermore, an external conduit is connected to the base end of the inner tube 12, and a liquid substance such as a drug solution is supplied from the external conduit to the lumen of the inner tube 12. In this embodiment, a connector 16 is attached to the base end of the inner tube 12, and the external conduit is connected via the connector 16. 【0030】 The structure of the connector 16 is not particularly limited, but assuming that a drug supply device such as the one described in Patent Document 1 is used, a cap-shaped connector 16 to which a male Luer of a syringe for supplying drug solution can be connected may be adopted. In this embodiment, the connector 16 has a threaded portion for Luer locking formed on the peripheral wall 18, and a blunt needle (non-bevel needle) 24 is inserted into and fixed to a slender cylindrical port portion 22 that protrudes outward from the bottom wall 20. 【0031】 Then, the base end of the inner tube 12 is inserted into and fitted onto the blunt needle 24 of the connector 16, thereby connecting the internal space of the connector 16 to the lumen of the inner tube 12. The attachment of the blunt needle 24 to the port portion 22 of the connector 16, the attachment of the inner tube 12 to the blunt needle 24, and the sealing to the external space may be achieved by press-fitting, or by using an adhesive as needed. 【0032】 The outer covering tube 14 is entirely hollow and cylindrical in shape, covering and protecting the inner tube 12 over its entire length. In this embodiment, the outer covering tube 14 is a connected or composite structure composed of a hollow cylindrical protective tube 26 that forms the tip end and a hollow cylindrical outer tube 28 that forms the base end. 【0033】 The protective tube 26 is made of a rigid material with sufficient strength and rigidity to not deform substantially under the degree of manipulative force applied during the procedure. Furthermore, considering the use of MRI, for example, non-magnetic materials such as non-magnetic metals, ceramics, or synthetic resins are preferable. If the use of X-rays is also considered, it may be made of a rigid resin with high X-ray transparency. However, from the viewpoint of further reducing the outer diameter, metal is preferable, and in this embodiment, stainless steel (SUS) is used. 【0034】 The metal protective tube 26 of this embodiment is formed as a continuous cylindrical object along its entire length and circumference by plastic deformation such as extrusion, drawing, or progressive press. A protective tube 26 made of such a plastically formed object preferably has a smooth inner and outer surface without welding marks in the axial middle portion, compared to a connected object formed by, for example, welding together divided cylindrical materials of different diameters. Furthermore, a smooth inner and outer surface can be achieved compared to a tubular body formed by rolling a longitudinal flat plate and then welding the butt joints together in a continuous manner along the length. 【0035】 Furthermore, the protective tube 26 is designed so that during the procedure, the tip is inserted into the brain, while the base remains exposed to the outside of the body without being inserted into the brain. In the area covered by the protective tube 26, the bending of the cannula is substantially inhibited, and if the protective tube 26 is too long, there are concerns about adverse effects on the ease of the procedure. Therefore, it is desirable to set the total length of the protective tube 26 within the range of 10 to 30 cm. 【0036】 Furthermore, the protective tube 26 has different diameters (inner and outer diameters) at its tip and base. The tip, which is inserted into the brain, has a smaller diameter to reduce brain damage, while the base, which is exposed to the outside of the body, has a larger diameter to ensure strength. In particular, the protective tube 26 of this embodiment has a shape in which multiple straight sections 30, 32, and 34 with different inner and outer diameters are connected via tapered sections 36 and 38 that widen from the tip to the base. The number, position, and length of the straight sections and tapered sections are not limited. 【0037】 For example, the protective tube 26 of this embodiment has a total of two tapered portions, a first tapered portion 36 and a second tapered portion 38, which are spaced apart in the longitudinal direction, and a total of three straight portions, a tip straight portion 30 located at the tip, an intermediate straight portion 32 located in the middle, and a base straight portion 34 located at the base, which are each provided in the longitudinal direction, flanking the tapered portion. 【0038】 The straight tip portion 30 is the part that is expected to be inserted into the brain during the procedure. Considering the burden on the brain and the reduction of risks, it is desirable that the straight tip portion 30 be sufficiently small in diameter while still allowing for insertion of the inner tube 12. Specifically, it is desirable that the outer diameter dimension Da of the straight tip portion 30 be 1 mm or less. 【0039】 Furthermore, considering the need to keep the outer diameter of the straight tip portion 30 sufficiently small while ensuring strength and reducing the burden on the brain, it is preferable to set the length of the straight tip portion 30 to 20 mm or less. For example, the length La from the tip to the first tapered portion 36 (length of the straight tip portion 30) should be set within the range of 3 to 20 mm. 【0040】 The intermediate straight section 32 is made larger in diameter than the tip straight section 30 to ensure strength, but it is desirable that it be formed with an outer diameter that is small enough to be inserted into the brain during surgery, for example, it is desirable that the outer diameter Db be 1.5 mm or less. 【0041】 Furthermore, it is desirable that the length of the intermediate straight portion 32 be set such that at least its proximal end is not inserted into the brain. For example, if the length expected to be inserted into the brain during the procedure is 60 mm from the tip of the inner tube 12, it is desirable that the proximal end of the intermediate straight portion 32 be set at a position of 80 mm or more from the tip of the inner tube 12, and that the length Lb of the intermediate straight portion 32 be set within the range of 50 to 150 mm. 【0042】 The proximal straight portion 34 is located outside the body and is not inserted into the brain during the procedure. It is designed to have sufficient thickness and length to not interfere with the procedure while ensuring sufficient strength. For example, it is desirable that the tip of the proximal straight portion 34 be set at a position more than 80 mm from the tip of the protective tube 26, and that the proximal end of the proximal straight portion 34 be set at a position of 150 mm or more from the tip of the protective tube 26. Furthermore, it is desirable that the proximal straight portion 34 has a larger diameter than the intermediate straight portion 32, with an outer diameter Dc in the range of 1.0 to 3.0 mm and a length Lc in the range of 50 to 150 mm. 【0043】 It is desirable to set the inclination angles θa and θb of the first and second tapered portions 36 and 38 with respect to the central axis within the range of 3 to 30 degrees. This reduces the burden on and risk of damage to biological tissue, and also allows for smoother insertion of the cannula into the body during the procedure. 【0044】 The lengths of the first and second tapered portions 36 and 38 are determined by the set value of the taper inclination angle and the diameter of the adjacent straight portion, and are not limited, but it is desirable that they be shorter than the length of either straight portion. Furthermore, it is desirable that the first tapered portion 36 is located in the area 10 to 60 mm from the tip of the protective tube 26 (tip region), and the second tapered portion 38 is located in the area beyond 60 mm from the tip of the protective tube 26. 【0045】 As described above, the protective tube 26, which extends axially and includes multiple straight sections 30, 32, 34 and multiple tapered sections 36, 38, has a total length L set to achieve a tip position that reaches the target location in the brain during the procedure and a proximal end position that remains outside the body and provides the operating part. This total length L varies depending on the expected procedure, but it is generally desirable to set it within the range of 150 to 300 mm. 【0046】 Furthermore, in a protective tube 26 formed with the above-described suitable dimensions and shape, such as multiple straight sections 30, 32, 34 and multiple tapered sections 36, 38, the outer diameter of the protective tube can be kept small in areas that are likely to be inserted into the brain during a typical procedure (for example, a 6 cm length from the tip) to suppress damage to the brain. In particular, the leading straight section inserted to the deepest part can be made sufficiently small in diameter, while the proximal end of the area where insertion into the brain is still possible can be made slightly larger in diameter, thereby achieving both avoidance of brain damage and ensuring strength. Moreover, in the proximal end where there is no risk of insertion into the brain, an even more appropriate shape can be realized to achieve both sufficient strength and the ability to ensure the operator's field of view. 【0047】 For reference, in one exemplary embodiment, within the range of suitable dimensions and shapes as described above, the outer diameter Da of the straight portion 30 at the tip of the protective tube 26 is 1.0 mm or less, the outer diameter Db at a position 6 cm from the tip of the protective tube 26 is greater than Da and 1.5 mm or less, and the outer diameter Dc of the straight portion at the base end of the protective tube 26 is greater than Db and 3.0 mm or less. 【0048】 Furthermore, in the protective tube 26 of this embodiment, the wall thickness of the tip straight portion 30 is thinner than that of at least the proximal straight portion 34. This makes it possible to keep the outer diameter small while ensuring an inner diameter that allows the inner tube 12 to pass through the tip portion that is inserted into the brain. On the other hand, it is easier to ensure the strength and rigidity of the protective tube 26 at the proximal portion that is located outside the body. 【0049】 The protective tube 26 is attached to the tip of the inner tube 12 in an externally fitted state, and in this fitted state, the tip of the inner tube 12 protrudes slightly from the tip opening of the protective tube 26. A sealing member 42 is attached to the protruding tip 40 of the inner tube 12 in an externally fitted state, without blocking the tip opening of the inner tube 12. 【0050】 The sealing member 42 has an annular portion with an axial length that covers substantially the entire protruding tip 40 of the inner tube 12 that protrudes from the protective tube 26, and the inner circumferential surface of the sealing member 42 is in close contact with the outer circumferential surface of the inner tube 12. In addition, the outer diameter of the sealing member 42 is approximately the same as or slightly larger than the outer diameter of the protective tube 26. 【0051】 Furthermore, the sealing member 42 has a substantially cylindrical gap sealing portion 44 that extends axially toward the base end on its inner circumference and a substantially cylindrical covering sealing portion 46 that extends axially toward the base end on its outer circumference integrally formed thereon. The gap sealing portion 44 expands to fit into the radial gap between the inner tube 12 and the protective tube 26, filling and sealing the gap. On the other hand, the covering sealing portion 46 is superimposed on the outer surface of the protective tube 26 in close contact and extends toward the base end. 【0052】 The sealing member 42 having a gap sealing portion 44 and a covering sealing portion 46 is preferably made of, for example, a thermoplastic resin or elastomer. For example, the gap sealing portion 44 can be formed by filling the radial gap between the inner tube 12 and the protective tube 26 with the material in a heated and molten state. This makes it easier to install the sealing member 42 than, for example, forming the gap sealing portion 44 of the sealing member 42 and then pushing it into the radial gap between the inner tube 12 and the protective tube 26. When forming the gap sealing portion 44 by filling the radial gap between the inner tube 12 and the protective tube 26 with a thermoplastic resin in a heated and molten state, it is preferable that the inner tube 12 be made of a thermoplastic resin or thermosetting resin with a higher melting point than at least the sealing member 42. The sealing member 42 having a gap sealing portion 44 and a covering sealing portion 46 may also be formed by integrating multiple divided parts by heat welding or the like. 【0053】 In particular, in this embodiment, the gap sealing portion 44 of the sealing member 42 is attached to both members in a tight-fitting state so as to fill the radial gap between the inner tube 12 and the protective tube 26, so that the inner tube 12 and the protective tube 26 are fixed to each other at the tip of the cannula without using an adhesive. Furthermore, in this embodiment, the inner surface of the sealing member 42 is attached in a tight-fitting state to the outer surface of the protruding tip 40 of the inner tube 12, and the covering sealing portion 46 and the gap sealing portion 44 are in tight-fitting state to the inner and outer surfaces of the protective tube 26, respectively, so that the protective tube 26 is sandwiched between the covering sealing portion 46 and the gap sealing portion 44, the mutual fixing force between the inner tube 12 and the protective tube 26 by the sealing member 42 can be exerted more effectively. 【0054】 Furthermore, the length of the protruding tip 40 of the inner tube 12 from the protective tube 26 should preferably be less than 1 mm, as excessive length would make it difficult to ensure the deformation strength of the inner tube 12. On the other hand, if the protruding tip 40 is too short, it would be difficult to ensure the thickness dimension of the sealing member 42 and the mounting stability, so it is preferable that it be 0.1 mm or longer. 【0055】 On the other hand, the outer tube 28, which is connected to the proximal end of the aforementioned protective tube 26 and works in cooperation with the protective tube 26 to form the outer covering tube 14, is not inserted into the body during the procedure. However, it is required to be soft enough to allow for bending and deformation so as not to hinder the ease of the procedure, and to have properties such as flexibility and strength so as to prevent and protect the inner tube 12 from bending or kinking. 【0056】 Therefore, a resin tube is preferably used as the outer tube 28. However, since the tip end of the outer tube 28 is fixed to the protective tube 26 and the base end end is fixed to the connector 16, ease of fixing to these other components by adhesive or other means is also required. Furthermore, since the inner tube 12, which is extremely thin and has low strength, needs to be inserted into the outer tube 28 during assembly, ease of insertion of the inner tube 12 should also be considered. 【0057】 Considering these required characteristics, in this embodiment, a tube having a multilayer composite structure in the radial direction is used as the outer tube 28. Specifically, for the innermost layer 48, a transparent, low-friction resin layer, such as a Teflon-based resin material, is preferably used. For the outermost layer 50, in addition to appropriate flexibility and strength, a colored resin layer with a wide range of adhesive applicability and high protective performance for the inner tube 12 is preferably used, such as a relatively inexpensive, well-moldable polyamide-based resin material. In this embodiment, the outer tube 28 has a two-layer structure consisting of an inner layer 48 and an outer layer 50, but a further layer of a different material or a braided layer may be provided as an intermediate layer to create a laminated tube with three or more layers. 【0058】 Furthermore, while the length and inner and outer diameter dimensions of the outer tube 28 are not particularly limited, it is desirable that the length be in the range of 1 to 2 m and the outer diameter be in the range of 0.5 to 3 mm, taking into consideration the insertion of the inner tube 12 and the ease of the procedure. Preferably, the outer tube 28 is composed of a single, bendable straight tube with a substantially constant diameter along its entire length. 【0059】 In this embodiment, the tip of the outer tube 28 is inserted to a predetermined length through the base end opening of the protective tube 26, and the two are fixed together in an inner and outer layer state. While the inner and outer layers may be fixed by press-fitting, in this embodiment, the tip of the outer tube 28 is inserted into the base end of the protective tube 26, and the outer surface of the outer tube 28 and the inner surface of the protective tube 26 are fixed together using an adhesive. 【0060】 In particular, since the outer layer 50 that constitutes the adhesive surface to the protective tube 26 in the outer tube 28 is made of a polyamide resin, an adhesive can be appropriately selected from known adhesives. Even if the protective tube 26 is made of metal, known adhesives such as two-component acrylic adhesives, epoxy adhesives, or hot-melt adhesives that do not contain organic solvents can be appropriately used. 【0061】 On the other hand, the base end portion of the outer tube 28 is externally fitted onto the blunt pin 24 of the connector 16, and the base end surface of the outer tube 28 is fixed to the tip surface of the port portion 22 of the connector 16. The outer tube 28 and the blunt pin 24 may be fitted and fixed by press-fitting, but they can be bonded together if necessary. In this embodiment, a light-curing adhesive is used to shorten the bonding process time. 【0062】 Specifically, for example, known UV-curing acrylic or epoxy adhesives can be used. In this embodiment, the colored outer layer 50 with low light transmittance is removed from the base end portion of the outer tube 28, exposing the inner layer 48 with high light transmittance to the outer surface. This allows light irradiated from the outside during the curing process to be efficiently directed to the bonding area. However, even when using a light-curing adhesive, it is sufficient that the base end portion of the outer tube 28 is light-transmitting. For example, it is possible to form a colorless (including uncolored transparent) outer layer 50 only on the base end portion of the outer tube 28, or to use a colorless outer layer 50 along the entire length of the outer tube 28 and form a coating on the surface of the area excluding the base end portion as needed. 【0063】 By employing an outer covering tube 14 composed of a protective tube 26 and an outer tube 28, the required strength and rigidity are ensured at the tip of the cannula by the protective tube 26, while the required flexibility is ensured from the middle to the proximal end of the cannula by the outer tube 28, thereby achieving protection for the inner tube 12. 【0064】 Furthermore, the outer covering tube 14 is substantially fixed to the inner tube 12 at its tip and base, but in its intermediate length, it is not fixed to the inner tube and is arranged with a small gap in the radial direction. This effectively avoids or reduces external forces acting on the inner tube 12 during procedures, thereby reducing the risk of damage to the inner tube 12 and achieving good flexibility even during bending deformation. 【0065】 In this embodiment, thin-walled cylindrical connection cover tubes 52 are fitted externally to the protective tube 26 and the connection points to the connector 16 at both ends of the outer tube 28 in the longitudinal direction. These connection cover tubes 52 cover any steps or gaps at the connection points, thereby improving the strength and stability of the connection. Furthermore, by reinforcing the protective tube 26 and the connection points to the connector 16 at both ends of the outer tube 28, local bending or kinking of the cannula at connection points where the material and rigidity change is also prevented. Additionally, by using heat-shrinkable tubing or the like as the connection cover tube 52, the strength and reliability of the connection points can be further improved. 【0066】 Incidentally, since the liquid substances such as medications used during the procedure are often precious and expensive, it is desirable to minimize the amount of liquid remaining in the device after the procedure. In the liquid substance administration device 10 described above, it is important to reduce the inner diameter of the inner tube 12 that constitutes the liquid substance flow path, but it is also desirable to pay attention to the connector 16, which is the connection point to the external flow path. 【0067】 Figure 4 shows an example of a different form of connector 54 in view of the above points. Since this connector 54 can be used in place of the connector 16 exemplified in the liquid dispensing device 10 of the above embodiment, only the connector itself will be described. Furthermore, the same reference numerals are used for members and parts that have the same structure as the connector 16 exemplified in the above embodiment. 【0068】 In other words, the connector 54 illustrated in Figure 4 has a protruding boss portion 56 that protrudes axially inward from the center of the bottom wall 20 toward the base end. This protruding boss portion 56 protrudes into the connection space surrounded by the peripheral wall 18 in the connector 54. A through hole 58 for the flow of liquid through which the blunt needle 24 is inserted penetrates the bottom wall 20 and extends linearly toward the base end, passing through the protruding boss portion 56 and opening on the protruding tip surface of the protruding boss portion 56. 【0069】 In such a connector 54, the annular space between the protruding boss portion 56 and the peripheral wall 18 is designated as the insertion area 64 into which the male tip 62 of the syringe 60 in the aforementioned liquid administration device is inserted during connection. In this connected state, the protruding boss portion 56 is inserted into the male tip 62 of the syringe 60. 【0070】 Therefore, when a procedure is performed in which a syringe 60 is connected to the connector 54 to establish an external flow path to the lumen of the inner tube 12 and administer a drug solution into the brain, the flow path volume of the drug solution within the connector 54 is reduced by the volume of the protruding boss portion 56. As a result, the amount of drug solution remaining in the device is reduced by this volume, and loading can be achieved. 【0071】 The specific shape of the protruding boss portion 56, such as its protruding height and outer circumference, can be appropriately adjusted according to the shape of the male tip of the syringe or the like to be connected, and is not limited to these dimensions. Furthermore, it is desirable that the protruding boss portion 56 makes close contact with the outer circumference of the male tip 62 on its outer surface, thereby preventing leakage of the drug solution from the male tip 62 into the space inside the connector 54. In addition, sealing members may be placed on the outer surface of the protruding boss portion 56 or on the inner surface of the bottom wall 20 of the connector 54 to prevent leakage of the drug solution from the male tip 62 into the space inside the connector 54. 【0072】 Although embodiments of the present invention have been illustrated above, the present invention is not intended to be limited by such description. For example, in the above embodiment, the protruding tip 40 of the inner tube 12 was covered by the sealing member 42 over substantially its entire axial length, but the tip of the inner tube 12 may protrude further from the tip of the sealing member 42. It is also possible to reduce the area of ​​the tip surface of the sealing member 42 by making the outer circumferential surface shape of the sealing member 42 a tapered shape. 【0073】 Furthermore, in the above embodiment, an example of a liquid administration device was provided in which the inner tube is made of polyimide, the protective tube is made of stainless steel, and the sealing member is made of thermoplastic resin, but the specific materials of each member are not limited. However, depending on the selection of materials for each member as exemplified above, by adopting an inner tube made of a polyimide-based resin material, it becomes advantageous to realize a passage for a minute amount of liquid administered into the brain. Specifically, for example, it becomes possible to easily put into practical use an ultra-fine tube having an inner diameter of 0.2 mm or less, with thin walls and small tolerances in diameter. Also, by adopting a protective tube made of a stainless steel-based metal material, it becomes advantageous to achieve thin walls and protection and reinforcement of the inner tube. In addition, by adopting a sealing member made of thermoplastic resin, for example, it is possible to fill the gap between the inner tube and the protective tube with heated and molten thermoplastic resin to form a gap seal, thereby improving the sealing performance of the sealing member and simplifying manufacturing. 【0074】 Furthermore, the specific shapes of the gap sealing portion 44 and the covering sealing portion 46 in the sealing member 42, such as their length dimensions, are not limited. In the above embodiment, the covering sealing portion 46 extends toward the base end to the first tapered portion 36 of the protective tube 26, thereby avoiding a step on the outer circumferential surface caused by the formation of the covering sealing portion 46. However, it is also possible to form the covering sealing portion 46 with an axial length that does not reach the first tapered portion 36. The outer circumferential surface of the covering sealing portion 46 may also be provided with a tapered surface that decreases in diameter toward the tip. In addition, the outer diameter dimension of the covering sealing portion 46 is not limited, but it is desirable that it be smaller than the maximum outer diameter dimension of the first tapered portion 36, as in the above embodiment. The covering sealing portion 46 may be provided only partially in the circumferential direction, and the covering sealing portion 46 is not essential for the sealing member 42, with only the gap sealing portion 44 being provided. 【0075】 Furthermore, at the attachment site of the sealing member 42 at the tip of the cannula, an adhesive may be used between the sealing member 42 and the inner tube 12 and / or protective tube 26 for purposes such as further increasing the sealing strength of the sealing member. 【0076】 Furthermore, in the above embodiment, a liquid substance administration device was disclosed that includes a cannula whose tip portion is inserted into brain tissue, and is used for administering a liquid substance into brain tissue, wherein the tip portion of the cannula is composed of a resin inner tube having a lumen for the flow of the liquid substance and a rigid protective tube that is fitted onto the inner tube, a connector is connected to the proximal end of the inner tube extending from the proximal end of the protective tube, an outer tube is disposed between the protective tube and the connector and the outer tube is fitted onto the inner tube, and the outer tube is made of a laminated resin having an inner layer of fluororesin and an outer layer of polyamide resin, but the disclosure is not limited to this scope. 【0077】 However, according to the embodiments of the liquid dispensing device within the scope of this disclosure, a laminated structure can be adopted for the outer tube that is fitted onto and protects the inner tube, thereby achieving different special properties required for the inner and outer surfaces. Specifically, by using a fluororesin inner layer on the inner surface of the outer tube to suppress frictional resistance, the ease of inserting the inner tube can be improved, and the sliding between the inner and outer tubes that occurs when bending deformation occurs during procedures can be improved, thereby achieving flexible bending characteristics overall. Furthermore, by using a polyamide resin outer layer on the outer surface of the outer tube, mechanical properties such as durability and kink resistance (bend resistance) can be easily tuned, and it is also possible to achieve a degree of freedom in setting colors that take visibility into consideration, for example, and ease of adhesion to the protective tube. 【0078】 Furthermore, in the embodiments of the liquid administration device described above, at least one of the following can be adopted: for example, "an embodiment in which the tip portion of the outer tube is inserted into and bonded to the base portion of the protective tube, while the base portion of the outer tube is externally fitted onto a hollow needle provided on the connector, and the base portion of the outer tube is made light-transmitting and bonded to the hollow needle with a photocurable adhesive" or "an embodiment in which a connection cover tube is fitted onto the connection portion between the tip portion of the outer tube and the protective tube, and the connection portion between the base portion of the outer tube and the connector, respectively." By adopting the former embodiment, the tip side of the outer tube can be easily bonded to the protective tube using various known adhesives that exhibit sufficient adhesion to the polyamide resin constituting the outer layer, for example, while the base side of the outer tube can be quickly and firmly bonded to the hollow needle using a photocurable adhesive. By adopting the latter configuration, the adhesive portions at both ends of the outer tube in the longitudinal direction are covered with a connecting cover tube, thereby protecting each adhesive portion and stabilizing the adhesive strength. Furthermore, by reinforcing the protective tube of the outer tube and the connection portion to the connector, effects such as preventing kinking (breakage) of the connection portion when external forces are applied can be expected. 【0079】 Furthermore, although not listed individually, the present invention can be implemented in various forms based on the knowledge of those skilled in the art, and it should be understood that such embodiments, as long as they do not depart from the spirit of the present invention, are all included within the scope of the present invention. [Explanation of symbols] 【0080】 10 Liquid administration devices 12 inner tubes 14 Outer covering tube 16 connectors 18 Peripheral wall 20 Bottom wall 22-port section 24 Blunt needles 26 Protective Tubes 28 Outer tubes 30. Straight tip 32. Middle straight section 34. Base end straight section 36 First tapered portion 38 Second tapered section 40 Protruding tip 42 sealing member 44 Gap sealing section 46 Covering seal portion 48 Innermost layer 50 outermost layer 52 Connection Cover Tube 54 Connectors 56 Protruding boss section 58 Through hole 60 syringes 62 Male Tips 64 Area for bringing in gifts

Claims

[Claim 1] A liquid administration device equipped with a cannula whose tip is inserted into brain tissue, used for administering liquid substances into brain tissue, The tip portion of the cannula is composed of a resin inner tube having a lumen for the flow of the liquid, and a rigid protective tube that is fitted onto the inner tube. A liquid dispensing device in which the tip of the inner tube protrudes from the tip of the protective tube, and a sealing member fixed to the outer circumferential surface of the protruding tip of the inner tube integrally forms a gap sealing portion that fits into the gap between the inner tube and the protective tube, and a covering sealing portion that extends to the outer circumferential surface of the protective tube. [Claim 2] The liquid administration device according to claim 1, wherein the sealing member at the tip portion of the cannula achieves the required fixing force between the inner tube and the protective tube without using an adhesive. [Claim 3] The liquid dispensing device according to claim 1 or 2, wherein the length of the protruding tip of the inner tube protruding from the protective tube is less than 1 mm.

Images