Cannula holder

A cannula holder capable of securing a cannula to the holder at the time of piercing work, and easily removing the cannula from the holder using tweezers or the like. The cannula holder, to which a piercing needle for piercing an eyeball and a cannula are attached when attaching the cannula used in ophthalmic operations to the eyeball, includes claw portions that are formed on a front end of the cannula holder and which press sides of the cannula either at positions where said claw portions face each other or from multiple directions. A depression may be provided in a side of the front end of the cannula holder, allowing visibility of a part of a back end of the cannula from the depression.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/JP2018/028232, filed on Jul. 27, 2018, which claims priority from Japanese Application No. 2017-147886, filed on Jul. 31, 2017, the entire disclosures of which are hereby incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a cannula holder (hereafter referred to as ‘holder’) used when attaching a cannula used in ophthalmic operations to an eyeball.

BACKGROUND ART

The cannula is attached to an eyeball, and a surgical tool or the like is passed through the cannula when using a surgical tool or the like within an eyeball during an ophthalmic operation (e.g., Patent Document 1).FIG.5is a cross-section of a conventional cannula, andFIG.6is diagram illustrating how an ophthalmic operation is performed. A cannula20is configured by fitting a metal pipe21into a base22made of resin, and covering and enveloping a cylindrical side surface of the base22and the base end of the pipe21by a cap23made of silicone rubber.

The base22has a function of a stopper by touching the surface of an eyeball E when the pipe21is pierced in the eyeball E, and the cap23has a function of controlling leakage of vitreous humor, etc., from the inside of the eyeball E. The base22has a nearly cylindrical shape and a groove22aformed along the circumference near the middle position of its side surface. The groove22ais used to hold the cannula20with tweezers, and to fit in a locking part23bof the cap23when covering the base22with the cap23.

The cap23has a slit23a, which connects the inner side of the pipe21and the outer side of the cap23, provided in a portion that covers a base end of the pipe21, and may be provided with a piercing needle used for piercing the eyeball E by passing through the slit23a, or otherwise various surgical tools40, optical instruments for monitoring, etc., may be inserted in the eyeball E through the slit23a.

FIG.7is a diagram describing a method of attaching the cannula to an eyeball, whereinFIG.7(a)illustrates a state before piercing,FIG.7(b)illustrates a state after piercing, andFIG.7(c)illustrates a state of cannula attachment completion.

Since the cannula20is a very small tool, it is attached to a front end of the holder100so as to carry out attachment when being attached to the eyeball E. At this time, a piercing needle30for piercing the eyeball E is also attached to the holder100with the piercing needle passing through the pipe21of the cannula20(state ofFIG.7(a)). The piercing needle30and the pipe21of the cannula20as one body pierce the eyeball E (state ofFIG.7(b)). The holder100and the piercing needle30are then removed from the cannula20, leaving only the cannula20piercing the eyeball E (state ofFIG.7(c)).

PRIOR ART DOCUMENTS

Patent Documents

DISCLOSURE OF THE INVENTION

Problem to be Solved by the Invention

Here, the cannula needs to be secured to the front end of the holder during the attachment since the cannula is attached to the eyeball with both of the cannula and the piercing needle attached to the holder. However, since the cannula needs to be removed from the holder while the cannula is piercing the eyeball, there is fear that if it is secured too firmly, a problem that the cannula will detach from the eyeball when removing the holder will occur.

In light of this problem, the present invention aims to provide a cannula holder allowing stable attachment of securely attaching a cannula to a holder front end, and also allowing easy removal of the cannula from the holder after the cannula is attached to an eyeball.

Solution to the Problem

A cannula holder is characterized by having a cannula and a piercing needle for piercing an eyeball attached thereto when attaching the cannula used in ophthalmic operations to the eyeball. It includes claw portions that are formed on a front end of the cannula holder and press sides of the cannula either at positions where said claw portions face each other or from multiple directions.

It may have a configuration including a depression in a side of the front end of the cannula holder, allowing visibility of a part of a back end of the cannula from the depression.

Moreover, the cannula should include a resin cap including a slit through which the piercing needle passes at a back end of the cannula, and when the piercing needle has a thin, approximately oblong cross-section that fits together with the form of the slit at a position that allows the piercing needle to pass through the slit, the claw portions are provided at positions to apply pressing forces perpendicularly toward the long sides facing each other of the approximately oblong cross-section of the piercing needle, or similarly, the claw portions are provided at positions to apply pressing forces from multiple directions toward the sides of the circular cross-section with the reduced diameter of the piercing needle.

Advantageous Effect of the Invention

According to the present invention, the beneficial results are that the cannula may be secured to the holder at the time of piercing, and yet the cannula may also be easily removed from the holder using tweezers or the like.

Moreover, the claw portions pressing in directions that allow easy bending of the piercing needle allow stable attachment.

DESCRIPTION OF EMBODIMENTS

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

FIG.1is an oblique view of a holder of the present invention, whereinFIG.1(a)illustrates only the holder,FIG.1(b)illustrates a state where a piercing needle is attached to the holder, andFIG.1(c)illustrates a state where a piercing needle and a cannula are attached to the holder.

A cannula holder10of the present invention, to which a piercing needle30and a cannula20for piercing an eyeball during an ophthalmic operation are attached, is used when attaching the cannula20to the eyeball.

The cannula20is configured in the same manner as the conventional cannula by fitting a metal pipe21into a base22made of resin, and covering and enveloping a cylindrical side surface of the base22and the base end of the pipe21by a cap23made of silicone rubber. Since such a cannula20is small, it is difficult to pinch with fingers, and is thus attached to the holder10so as to facilitate attachment to the eyeball.

Moreover, the piercing needle30is used for piercing the eyeball. The base end side of the piercing needle30is secured to the holder10with the point of the needle protruding from the pipe21of the cannula20. It then pierces the eyeball with the piercing needle30and the pipe21united as one body. Therefore, during the piercing work, the piercing needle30and the cannula20need to be tightly secured to the holder10.

As a result, claw portions11for securing the cannula20are provided on a front end of the holder10. The claw portions11ofFIG.1are configured so as to press the sides of the cannula20at positions where the claw portions face each other. In other words, the claw portions11are made to clamp sides of the cap23of the cannula20.

There may be two pairs or more of the claw portions11, and increasing the number of pairs thereof allows further tightly securing of the cannula20to the holder10. However, if the cannula20is secured too tightly, there is concern that the cannula20will detach from the eyeball when removing the cannula20from the holder10. Therefore, since removal of the cannula20becomes difficult when there are too many pairs of the claw portions11, one pair is preferable, and up to two pairs may be used. There is an advantage particularly with one pair of the claw portions11in that the cap23of the cannula20is easily clamped using tweezers or the like when removing the cannula20from the holder10.

FIG.2is an oblique view of a different holder of the present invention, whereinFIG.2(a)illustrates only the holder, andFIG.2(b)illustrates a state where a piercing needle is attached to the holder. There are three of the claw portions11in this working example. With such a configuration, the claw portions11are not at positions facing each other, but they may press and secure the cannula20from the sides in a well-balanced manner. Note that the number of the claw portions11is not limited to three. That is, as long as the cannula20can be secured to the holder, the number of the claw portions11pressing from multiple directions is not necessarily limited. However, as described above, since removal of the cannula20becomes difficult when there are too many of the claw portions11, around three are appropriate.

A depression12is formed in a side of the front end of the holder10illustrated inFIG.1andFIG.2. The depression12is provided for facilitating removal of the cannula20from the holder10using tweezers or the like.

FIG.3is a cross-section cut along a line A-A ofFIG.1(c). As can be confirmed from the drawings, it is configured such that a part of a back end surface of the cannula20is visible from the position of the depression12. That is, since tweezers or the like may be positioned on the depression12, pressing the cap23of the cannula20from the back end is possible, thereby making it easy to remove the cannula20from the holder10. Note that while the number of the depression12is not limited, if the depression12is, for example, in two places, it becomes possible to push the back end of the cannula20from two places using two front ends of the tweezers. Therefore, multiple depressions are preferable.

FIG.4is a cross-section of the piercing needle and the cannula attached to the holder. The cannula20here has a resin cap23including a slit23athrough which the piercing needle30passes at the back end of the cannula20. Moreover, the piercing needle30has a thin, approximately oblong cross-section fitted together with the form of the slit23aat a position for passing therethrough. Such a structure allows control of deformation of the slit23ato a minimum, and even after the piercing needle30is pulled out, the slit23ais hardly spread open at all, making it possible to control leakage of vitreous humor, etc., from the eyeball.

In the case of the piercing needle30made to have a small cross-section at the position of the slit23ain this manner, it is weak when bent with a thin approximately oblong cross-section, and thus there is concern that the point of the piercing needle30moves when piercing, making it difficult to pierce at a precise position. However, provision of the claw portions11at positions to apply pressing forces perpendicularly toward the long sides facing each other of the approximately oblong cross-section of the piercing needle30can suppresses bending of the piercing needle30.

The cross-sectional form of the piercing needle30at the position that allows the piercing needle to pass through the slit23amay have a different shape than a thin, approximately oblong shape. For example, it may be a circular cross-section with a reduced diameter (seeFIG.2(b)). In such a case, since the piercing needle30is weakened with bending in any direction, the claw portions11should be provided at positions to apply pressing forces from multiple directions toward the sides of the circular cross-section with the reduced diameter.

Use of such a cannula holder allows sufficient securing of a cannula to the holder at the time of piercing work, and allows easy removal of the cannula from the holder using tweezers or the like. Moreover, the claw portions pressing in directions that otherwise allow easy bending of the piercing needle enable secure attachment.

EXPLANATION OF REFERENCE NUMERALS