The present invention relates to a microsyringe unit including a microsyringe and a needle guide.
There has been proposed a microsyringe for injecting a liquid such as a drug or a tissue piece or therapeutic cell preparation composition into a target area of a patient's brain (refer to Patent Literature 1). With the tip of a cylindrical needle in the liquid such as a drug, the plunger that is passed through the inside of the needle moves backward from the tip of the needle, by which the liquid is inhaled inside the needle. With the needle that is passed through the needle guide constituting the needle guide whose tip is inserted into the patient's brain, the plunger passed through the needle moves forward, by which the liquid is ejected from the tip of the needle.
Patent Literature 1: Japanese Utility Model Application Laid-Open No. S51-44389
If, however, the liquid ejected from the tip of the needle comes into contact with the tip of the needle guide, the liquid is more likely to spread outward in the radial direction of the needle accordingly, by which it may be difficult to accurately eject the liquid in front of the needle and thus to accurately inject the liquid into the target area in the brain.
Therefore, it is an object of the present invention to provide a microsyringe unit capable of improving the accuracy of the injection position of liquid in a brain.
The present invention relates to a microsyringe unit composed of a microsyringe that includes a cylindrical needle and a plunger that is passed through the needle, and a cylindrical needle guide.
According to an aspect of the present invention, there is provided a microsyringe unit wherein the base portion of the needle abuts on a guide base portion that supports the needle guide, thereby causing the tip of the needle to protrude from the tip of the needle guide in a first specified state in which forward movement of the needle passed through the needle guide is stopped.
According to the microsyringe unit having the above configuration, the tip of the needle is separated from the tip of the needle guide in the first specified state, thereby ensuring that the liquid such as a drug ejected from the tip of the needle does not come into contact with the tip of the needle guide to spread in the radial direction of the needle. This allows the liquid ejected from the tip of the needle to be accurately ejected in front of the needle and thus the liquid to be accurately injected into a target area in a brain.
In the microsyringe unit of the present invention, preferably the tip of the needle has a convex curved surface whose outer diameter gradually decreases toward the tip.
According to the microsyringe unit having the above configuration, a gap is secured between the convex curved surface at the tip of the needle and a tissue of the brain, thereby enabling the liquid ejected from the tip of the needle to be retained in the gap to suppress the radial spread of the liquid. This further ensures that the liquid does not come into contact with the tip of the needle guide to spread in the radial direction of the needle.
In the microsyringe unit of the present invention, preferably the surface roughness of the convex curved surface of the tip of the needle is greater than the surface roughness of the outer side surface of the needle.
According to the microsyringe unit having the above configuration, the tip of the needle is hydrophilic, thereby enabling the wetness of the outer side surface of the tip to be lower than the wetness of the convex curved surface, the liquid ejected from the tip of the needle to be retained in the gap between the convex curved surface of the tip of the needle and the tissue of the brain, and the liquid to be prevented from spreading radially along the outer side surface of the needle. This more reliably prevents the liquid from coming into contact with the tip of the needle guide and spreading in the radial direction of the needle.
In the microsyringe unit of the present invention, preferably the tip of the needle guide has a convex curved surface whose outer diameter gradually decreases toward the tip, and the radius of curvature of the convex curved surface of the tip of the needle is greater than the radius of curvature of the convex curved surface of the tip of the needle guide.
According to the microsyringe unit having the above configuration, a large gap is secured between the convex curved surface of the tip of the needle and the tissue of the brain due to the radius of curvature of the convex curved surface of the tip of the needle greater than the radius of curvature of the convex curved surface of the tip of the needle guide accordingly, thereby enabling more liquid to be retained in the gap to prevent radial spread of the liquid. Moreover, the radius of curvature of the convex curved surface of the tip of the needle guide is smaller than the radius of curvature of the convex curved surface of the tip of the needle, thereby reliably preventing the tip of the needle guide from damaging the brain tissue accordingly.
In the microsyringe unit of the present invention, preferably the microsyringe unit further includes a stylet that is passed through the needle guide and is columnar at least in the tip, wherein the base portion of the stylet abuts on the guide base portion that supports the needle guide, thereby causing the tip of the stylet to protrude from the tip of the needle guide in a second specified state in which forward movement of the stylet passed through the needle guide is stopped.
According to the microsyringe unit having the above configuration, the tip of the stylet protruding from the needle guide that is fixed while entering the patient's brain deviates the tissue of the brain in the second specified state, thereby enabling formation of a space for the tip of the needle protruding from the needle guide to enter in the first specified state that is implemented after the second specified state.
In the microsyringe unit of the present invention, preferably the tip of the stylet has a convex curved surface whose outer diameter gradually decreases toward the tip and the radius of curvature of the convex curved surface of the tip of the stylet is greater than the radius of curvature of the convex curved surface of the tip of the needle guide.
According to the microsyringe unit having the above configuration, the radius of curvature of the convex curved surface of the tip of the stylet is greater than the radius of curvature of the convex curved surface of the tip of the needle guide, thereby preventing the tissue of the brain from being damaged accordingly with the brain deviated by the tip of the stylet protruding from the needle guide that is fixed while entering the patient's brain in the second specified state.
In the microsyringe unit of the present invention, preferably the protruding length of the stylet from the tip of the needle guide in the second specified state is equal to or greater than the protruding length of the needle from the tip of the needle guide in the first specified state. Thereby, a cell injection space can be secured since a space is formed in the brain for the volume caused by a difference in protruding length between the stylet and the needle.
According to the microsyringe unit having the above configuration, the tip of the stylet deviates the brain's tissue as described above, thereby enabling a sufficient space for the tip of the needle to be formed.
In the microsyringe unit of the present invention, preferably the tip of the plunger has a convex curved surface whose outer diameter gradually decreases toward the tip and the radius of curvature of the convex curved surface of the tip of the plunger is smaller than the radius of curvature of the convex curved surface of the tip of the needle.
According to the microsyringe unit having the above configuration, the radius of curvature of the convex curved surface of the tip of the plunger is smaller than the radius of curvature of the convex curved surface of the tip of the needle, thereby enabling a gap between the tip of the plunger and the inner side surface of the needle to be reduced accordingly with the tip position of the plunger matching the tip position of the needle. Therefore, when the plunger is pushed in until the tip position of the plunger matches the tip position of the needle, the amount of liquid that stays in the gap is reduced and thus the amount of liquid ejected from the tip of the needle can be accurately adjusted.
In the microsyringe unit of the present invention, preferably at least a part of the needle is composed of a transparent member.
According to the microsyringe unit having the above configuration, when the plunger passed through the needle whose tip is in contact with the liquid moves backward, whether the liquid has been properly contained in the internal space of the needle can be seen from the part composed of a transparent member of the needle.
In the microsyringe unit of the present invention, preferably the microsyringe unit further includes a cylindrical packing that is arranged so as to abut on the side wall of a through hole penetrating the base portion of the needle and having a narrow portion that narrows toward the tip inside the through hole and so as to abut on the narrow portion at the tip and that the plunger is passed through.
According to the microsyringe unit having the above configuration, the liquid can be prevented from entering the space on the rear side of the packing in the internal space of the needle.
In the microsyringe unit of the present invention, preferably the needle guide has at least one stepped portion where its outer diameter decreases discontinuously from the rear end side to the tip side.
Thereby, in the needle guide, the outer diameter of the tip side part that is thinner than the rear end side part across the stepped portion and is continuous with the tip can be designed within an appropriate numerical range from the viewpoint of being inserted into the brain.
(Configuration)
A microsyringe unit as an embodiment of the present invention, which is illustrated in its entirety in
As illustrated in
As illustrated in
As illustrated in
The surface roughness of the convex curved surface of the tip of the needle 110 may be designed to be greater than the surface roughness of the outer side surface of the needle 110. For example, the surface roughness Ra of the convex curved surface of the tip of the needle 110 is designed to be within the range of 1.0 to 6.0 μm, preferably 1.0 to 4.0 μm, and more preferably 1.0 to 2.0 μm, while the surface roughness Ra of the outer side surface of the tip of the needle 110 is designed to be within the range of 0.04 to 1.0 μm, preferably 0.04 to 0.50 μm, and more preferably 0.04 to 0.10 μm. In this case, it is preferable to make the tip of the needle 110 hydrophilic. For example, the tip of the needle 110 can be made hydrophilic by imparting a hydrophilic functional group to the needle 110 made of SUS or of synthetic resin by plasma treatment or the like.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
The syringe inner cylinder 152 is formed in a substantially cylindrical shape having an inner diameter that is substantially equal to or slightly greater than the diameter of the plunger 120 and having an outer diameter that is substantially equal to the through hole of the plunger guide 142 (and smaller than the outer diameter of the outer cylinder 151). As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
There may be a magnitude relation between the radius of curvature R110 of the convex curved surface of the tip of the needle 110, the radius of curvature R120 of the convex curved surface of the tip of the plunger 120, and the radius of curvature R210 of the convex curved surface of the tip of the inner needle guide 210 as represented by the relational expression (1).
R120<R210<R110 (1)
As illustrated in
Each of the inner needle guide 210 and the outer needle guide 220 has a wall thickness that ensures enough strength to prevent bending thereof as it is longer in the axial direction. In the case where each of the inner needle guide 210 and the outer needle guide 220 is made of, for example, stainless steel, its wall thickness is designed to be, for example, within the range of 0.1 to 1.0 mm, preferably 0.1 to 0.5 mm, and more preferably 0.2 to 0.5 mm.
As illustrated in
The microsyringe unit as an embodiment of the present invention may further include a stylet 400 illustrated in
As illustrated in
R210<R410 (2)
(Functions)
At the time of brain surgery, the needle guide 200 in the second specified state is inserted into a brain, first. At this time, the tip position and posture of the needle guide 200 are determined by the needle guide 200 supported by a support mechanism (not illustrated). In the “second specified state,” the substantially columnar stylet 400 is passed through the internal space of the needle guide 200 (that is, the inner needle guide 210), and the base portion 420 of the stylet 400 abuts on the guide base portion 230, by which forward movement of the stylet 400 is stopped (see
Subsequently, the needle 110 of the microsyringe 100 with a liquid containing a therapeutic composition inhaled at the tip in advance is passed through the needle guide 200 supported by the support mechanism. The substantially truncated cone-like lateral inner side surface that defines the internal space on the rear side of the guide base portion 230 constitutes a tapered surface that approaches the central axis line of the guide base portion 230 as it goes forward in the longitudinal section (See
The needle base portion 130 and the guide base portion 230 are moved relative to each other so that they are closer to each other with the needle 110 passed through the needle guide 200, by which the tip of the second base element 132 of the needle base portion 130 abuts on the rear end of the guide base portion 230 (see
In the first specified state, a part of the needle 110 protrudes from the tip of the needle guide 200 (that is, the inner needle guide 210) (see
The protruding length q of the needle 110 is equal to or similar to the protruding length p of the shaft 410 of the stylet 400. The protruding length q of the needle 110 is within the range of 1d to 30d, for example, with respect to the maximum wall thickness d of the inner needle guide 210, and when d=0.15 mm, q=0.15 to 4.5 mm. The protruding length q of the needle 110 is preferably within the range of 2d to 15d, more preferably 5 to 10d. The protruding length p of the shaft 410 of the stylet 400 is within the range of 1d to 30d, for example, with respect to the maximum wall thickness d of the inner needle guide 210, and when d=0.15 mm, q=0.15 to 4.5 mm. The protruding length p of the stylet 400 is preferably within the range of 3d to 16d, more preferably 6 to 11d.
When the plunger holder 122 moves forward relative to the syringe outer cylinder 140 in this state, the plunger 120 moves forward and a liquid such as a cell preparation composition is injected into the minute space in the brain from the opening at the tip of the needle 110 (see
(Other Embodiments of the Present Invention)
At least a part of the needle 110, especially the tip thereof, may be formed of an acrylic or other transparent member. Thereby, when the plunger 120 inserted into the needle 110 whose tip is in contact with the liquid moves backward, whether the liquid has been properly contained in the internal space of the needle 110 can be seen from the part composed of the transparent member of the needle 110.
Number | Date | Country | Kind |
---|---|---|---|
2018-142134 | Jul 2018 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2019/029532 | 7/26/2019 | WO | 00 |