There is provided a piercing needle-equipped cannula that has a pre-attached piercing needle, and no deformation of the slit portion due to the piercing needle is left after the piercing needle is pulled out. A piercing needle-equipped cannula (100) includes: a cannula (10) pierced in an eyeball and used in ophthalmic operations; a resin cap (13) having a slit (13a) opened in the cannula (10); and a piercing needle (15) attached to the cannula (10). The piercing needle (15) includes a needle main body (15c) on a front end side, a base (15d) on a base end side, and a slit piercing part (15s) piercing the slit (13a) in a state where the needle main body (15c) and the base (15d) are connected, and the cross-sectional area of the slit piercing part (15s) is smaller than that of the thickest part of the needle main body (15c).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/JP2016/085359, filed Nov. 29, 2016, which in turn claims priority from Japanese Patent Application No. 2015-234105 filed Nov. 30, 2015, the entire disclosures of which are hereby incorporated by reference herein.

BACKGROUND

Technical Field

The present invention relates to a piercing needle-equipped cannula having a piercing needle pre-attached to a cannula used in ophthalmic operations.

Background Art

The cannula is attached to an eyeball, and a surgical tool or the like is passed through the cannula and used in an ophthalmic operation (e.g., Patent Document 1).FIG. 5is a cross-section of a typical cannula. A cannula110is configured by fitting the base end part of a metal pipe111into a base112made of resin, and covering and enveloping a side surface of the base112and the base end of the pipe111by a cap113made of resin such as silicone rubber.

The base112has a function of a stopper by touching the surface of an eyeball when the pipe111is pierced in, and the cap113has a function of controlling leakage of vitreous humor etc. from the inside of the eyeball via the pipe111.

The cap113has a slit113a, which connects the inner side of the pipe111and the outer side of the cap113, provided in a portion that covers a base end of the pipe111, and various surgical tools, optical instruments for monitoring etc. are then inserted in the eyeball through the slit113a. Therefore, it is preferable that there is no space between the slit and the surgical tool etc. so that vitreous humor etc. does not leak when using the surgical tool etc.

On the other hand, when attaching such a cannula to an eyeball, a piercing needle is attached to the cannula and set in a holder that acts as a handle.FIG. 6is diagram illustrating a state where a piercing needle and a cannula are pierced into an eyeball. The cannula110is attached to an eyeball A in the steps of attaching the point of the piercing needle115so as to protrude from the pipe111of the cannula110, piercing the eyeball A with the piercing needle115and the pipe111in one united body, and pulling out only the piercing needle115, leaving only the cannula110in the eyeball A. At this time, while the piercing needle115should be attached to the cannula110in advance to save time, this results in deformation of the slit113adue to the piercing needle115when pulling it out. That is, problems may occur where once the piercing needle115is pulled out, the slit113ais not closed tightly, and a gap generates between the slit113aand the surgical tool etc. at the time of inserting the surgical tool etc., thereby making it easy for the vitreous humor etc. to leak.

PRIOR ART DOCUMENTS

Patent Documents

BRIEF SUMMARY

Problem to be Solved

In light of the problem, the present invention aims to provide a piercing needle-equipped cannula that has a piercing needle pre-attached to the cannula, wherein no deformation of the slit portion due to the piercing needle is left after the piercing needle is pulled out.

Solution to the Problem

A piercing needle-equipped cannula according to the present invention is characterized by including; a cannula pierced in an eyeball and used in ophthalmic operations; a resin cap having a slit opened in the cannula; and a piercing needle attached to the cannula. The piercing needle includes a needle main body on a front end side, a base on a base end side, and a slit piercing part piercing the slit in a state where the needle main body and the base are connected, and the cross-sectional area of the slit piercing part is smaller than that of the thickest part of the needle main body.

Here, the material of the slit piercing part may be different from that of the needle main body, or the slit piercing part may be made of a flexible, extremely thin material. Moreover, the cross-sectional shape of the slit piercing part may be a circle or a flat rectangle. Alternatively, the slit piercing part and the base may have the same cross-sectional shape. Further alternatively, the slit may have a linear shape when viewed from the direction of inserting the piercing needle, a curved shape including a crescent, or a shape made up of multiple lines.

Advantageous Effect

According to the present invention, as a result of making the opening of the slit small when attaching the piercing needle to the cannula, there are beneficial effects of no remaining deformation of the slit portion due to the piercing needle after the piercing needle is pulled out, and thus the slit may be closed tightly.

DESCRIPTION OF EMBODIMENTS

An embodiment according to the present invention is described below with reference to accompanying drawings.

FIG. 1illustrates four types of piercing needles used for a piercing needle-equipped cannula of the present invention. Here, a pointed end part of a piercing needle15is a front end15a, and a pointed end part on the opposite side is a base end15b.

The basic form of the piercing needle15includes a needle main body15c, which is made from the front end15apointed to pierce an eyeball and a cylindrical portion connecting to the front end15a, a slit piercing part15s, which is a portion passing through the slit when the cannula is attached and connecting to the needle main body15c, and a base15d, which is further on the base end15bside than the slit piercing part15s. That is, the slit piercing part15sis a portion connecting the needle main body15cand the base15d.

FIG. 1(a)illustrates a needle having a flatter rectangular cross-sectional shape on the base end15bside than the slit piercing part15s, andFIG. 1(b)illustrates a needle having a flat rectangular cross-sectional shape only near the slit piercing part15s.FIG. 1(c)illustrates a needle having a round cross-sectional shape smaller in diameter on the base end15bside from the slit piercing part15sthan the diameter of the thickest part of the needle main body15c, andFIG. 1(d)illustrates a needle having a round cross-sectional shape smaller in diameter only near the slit piercing part15sthan the diameter of the thickest part of the needle main body15c. In other words, the cross-sectional shapes of the slit piercing part15sand the base end15dinFIG. 1(a)andFIG. 1(c)are the same.

If the cross-sectional shape of the slit piercing part15sis a flat rectangle as inFIGS. 1(a) and 1(b), the opening of the slit can be kept small when the piercing needle15is attached to the cannula. Moreover, since deformation of the slit can be kept to a minimum even if the shape is a circle with a small diameter as inFIGS. 1(c) and 1(d), there is hardly any deformation of the slit left after the piercing needle15is pulled out.

Note that the cross-sectional shape of the slit piercing part15sis not limited to a flat rectangle or small circle as illustrated inFIG. 1, basically as long as the cross-sectional area is smaller than the thickest part or columnar portion of the needle main body15cof the piercing needle15. This is because if the cross-sectional area is made small, regardless of cross-sectional shape, there is a specific angle at which the height of the cross-sectional area is lower than at least the diameter of the columnar portion of the needle main body15c, and thus if the piercing needle15pierces at such an angle that the opening of the slit is small, there can at least be little deformation of the slit. The slit13amay have a linear shape when viewed from the direction of inserting the piercing needle, a curved shape including an arc, or a shape made up of multiple lines.

FIG. 2shows illustrations of the piercing needle-equipped cannula/device, whereinFIG. 2(a)is a cross-section of the piercing needle,FIG. 2(b)is a cross-section of the piercing needle-equipped cannula, andFIG. 2(c)is a cross-section of the cannula set in a holder.FIG. 3shows illustrations of a different piercing needle-equipped cannula, whereinFIG. 3(a)is a cross-section of the piercing needle,FIG. 3(b)is a cross-section of the piercing needle-equipped cannula, andFIG. 3(c)is a cross-section of the cannula set in a holder.FIG. 2shows where the cross-sectional shape further on the base end15bside than the slit piercing part15sis made smaller in accordance with the cross-sectional shape of the slit piercing part15s, andFIG. 3shows where the cross-sectional shape only in the vicinity of the slit piercing part15sis made smaller. Note thatFIGS. 1(a) and 1(c), and FIGS.1(b) and1(d) have nearly the same shapes when comparing only the respective cross-sectional shapes along the axis of the piercing needle15, whereFIGS. 1(a) and 1(c)are considered to correspond toFIG. 2, andFIGS. 1(b) and 1(d)are considered to correspond toFIG. 3.

The cannula10illustrated inFIGS. 2 and 3has a typical structure in which a base end part of a metal pipe11is fit into a resin base12, covering and enveloping a side surface of the base12and the base end of the pipe11by a cap13made of silicone rubber.

When attaching the piercing needle15to the cannula10, the slit piercing part15sis attached so as to be positioned at the slit13aopened in the cap13, and at that time, a pointed front end15aof the piercing needle15protrudes out from the pipe11of the cannula10. Note that by making the outer diameter of the cylindrical portion of the needle main body15calmost the same as the inner diameter of the pipe11, rattling between the piercing needle15and a cannula100is suppressed.

Moreover, when attaching the cannula10to the eyeball, the piercing needle-equipped cannula100is secured by a holder16acting as a handle. The holder16secures the base15dand the periphery of the cap13, which is attached to the cannula10. Note that since the cross-sectional shape of the base15dis different inFIGS. 2 and 3, places near the base15dsecured by the holder16are appropriate for the cross-sectional shapes of the respective bases15d.

As shown inFIGS. 2(c) and 3(c), the piercing needle15and the pipe11of the cannula10are pierced into the eyeball with the holder16having secured them. Only the piercing needle15is pulled out while leaving the cannula10therewithin, thereby attaching the cannula10to the eyeball. If the piercing needle-equipped cannula100of the present invention is used at this time, after the piercing needle15is pulled out, no deformation of the slit13adue to the piercing needle15is left, making the slit13atightly closed. This allows suppression of vitreous humor etc. from leaking out of the eyeball, and performance of a safe ophthalmic operation.

FIG. 4shows illustrations of a different piercing needle-equipped cannula, whereinFIG. 4(a)is an oblique view of the piercing needle, andFIG. 4(b)is a cross-section of the cannula set in a holder. The piercing needle15illustrated here includes the needle main body15con the front end15aside, the base15don the base end15bside, and the slit piercing part15sconnecting the needle main body15cand the base end15b.

In this case, since the piercing needle15illustrated inFIG. 1is manufactured as one body, all parts are made from the same material (e.g., austenitic stainless steel, etc.). On the other hand, the piercing needle15illustrated inFIG. 4(a)has the slit piercing part15smade of a flexible, extremely thin material. That is, the needle main body15cis made of a different material from that of the slit piercing part15s. Moreover, if the slit piercing part15sis very thin, there is a beneficial effect of no remaining deformation of the slit portion due to the piercing needle. Note that the flexible, extremely thin material corresponds to thread, string, wire etc., but is not limited thereto.

Furthermore, the base15dmay also be made of a different material than that of the needle main body15c. This is because while the needle main body15cneeds to be made of a material (e.g., austenitic stainless steel, etc.) such as that used for a conventional piercing needle, so as for the needle main body to pierce the eyeball, securing it by the holder16is sufficient as the base15ditself does not pierce the eyeball. Note that the slit piercing part15sand the base15dare made of different materials and have different cross-sectional shapes inFIG. 4; however, alternatively, they may be made of the same material and have the same cross-sectional shape as inFIGS. 1(a) and 1(c). In this case where the base15dand the slit piercing part15sare made of the same flexible, extremely thin material, a configuration in which the end part of the base15dis secured to the inner side of the holder16is possible. However, the method of securing the base15dby the holder16is not limited.

FIG. 4(b)illustrates the cannula set in the holder16. The piercing needle-equipped cannula100should be stable when piercing the eyeball in this state. Moreover, since the piercing needle15needs to be pulled out after piercing, connections between the needle main body15cand the slit piercing part15sand between the slit piercing part15sand the base15drequire strengthening so as not to detach. As long as the above conditions are fulfilled, the piercing needle15may have the structure as inFIG. 4(a)without any problems, and there is a beneficial effect of no remaining deformation of the slit portion due to the piercing needle.

EXPLANATION OF REFERENCES