Cannula holder

Abstract

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.

Claims

1. A cannula holder used in ophthalmic operations, the cannula holder comprising: a cannula; a piercing needle configured to pierce an eyeball upon attachment of the cannula to the eyeball, whereupon the piercing needle is removed from the cannula together with the holder; the cannula including a resin cap with a slit through which the piercing needle passes at a back end of the cannula; and claw portions that are formed on a front end of the cannula holder and which clamp sides of the cannula at positions where said claw portions face each other, wherein the piercing needle is manufactured to have an approximately oblong cross-section that fits together with a form of the slit at a position that allows the piercing needle to pass through the slit, and the claw portions are provided at positions to apply clamping forces perpendicularly toward opposed long sides of the approximately oblong cross-section of the piercing needle via pressing on the cannula so as to suppress bending of the piercing needle, the claw portions extending toward a front end of the needle beyond where the needle pierces the slit, the cannula holder further comprising a sloped front end face of gradually narrowing circumference toward a tip thereof for accommodating the cannula therein, the tip having a circumference smaller than a circumference of the back end of the cannula holder, the cannula holder further including multiple elongated depressions, tapered so as to narrow toward the front end of the cannula holder, disposed between the claw portions at regular radial intervals around lateral sides of the front end of the cannula holder.

Description

BRIEF DESCRIPTION OF DRAWINGS

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

(2) FIG. 2 is an oblique view of a different holder of the present invention, wherein FIG. 2(a) illustrates only the holder, and FIG. 2(b) illustrates a state where a piercing needle is attached to the holder;

(3) FIG. 3 is a cross-section cut along a line A-A of FIG. 1(c);

(4) FIG. 4 is a cross-section of the piercing needle and the cannula attached to the holder;

(5) FIG. 5 is a cross-section of a conventional cannula;

(6) FIG. 6 is diagram illustrating how an ophthalmic operation is performed; and

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

DESCRIPTION OF EMBODIMENTS

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

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

(10) A cannula holder 10 of the present invention, to which a piercing needle 30 and a cannula 20 for piercing an eyeball during an ophthalmic operation are attached, is used when attaching the cannula 20 to the eyeball.

(11) The cannula 20 is configured in the same manner as the conventional cannula by fitting a metal pipe 21 into a base 22 made of resin, and covering and enveloping a cylindrical side surface of the base 22 and the base end of the pipe 21 by a cap 23 made of silicone rubber. Since such a cannula 20 is small, it is difficult to pinch with fingers, and is thus attached to the holder 10 so as to facilitate attachment to the eyeball.

(12) Moreover, the piercing needle 30 is used for piercing the eyeball. The base end side of the piercing needle 30 is secured to the holder 10 with the point of the needle protruding from the pipe 21 of the cannula 20. It then pierces the eyeball with the piercing needle 30 and the pipe 21 united as one body. Therefore, during the piercing work, the piercing needle 30 and the cannula 20 need to be tightly secured to the holder 10.

(13) As a result, claw portions 11 for securing the cannula 20 are provided on a front end of the holder 10. The claw portions 11 of FIG. 1 are configured so as to press the sides of the cannula 20 at positions where the claw portions face each other. In other words, the claw portions 11 are made to clamp sides of the cap 23 of the cannula 20.

(14) There may be two pairs or more of the claw portions 11, and increasing the number of pairs thereof allows further tightly securing of the cannula 20 to the holder 10. However, if the cannula 20 is secured too tightly, there is concern that the cannula 20 will detach from the eyeball when removing the cannula 20 from the holder 10. Therefore, since removal of the cannula 20 becomes difficult when there are too many pairs of the claw portions 11, one pair is preferable, and up to two pairs may be used. There is an advantage particularly with one pair of the claw portions 11 in that the cap 23 of the cannula 20 is easily clamped using tweezers or the like when removing the cannula 20 from the holder 10.

(15) FIG. 2 is an oblique view of a different holder of the present invention, wherein FIG. 2(a) illustrates only the holder, and FIG. 2(b) illustrates a state where a piercing needle is attached to the holder. There are three of the claw portions 11 in this working example. With such a configuration, the claw portions 11 are not at positions facing each other, but they may press and secure the cannula 20 from the sides in a well-balanced manner. Note that the number of the claw portions 11 is not limited to three. That is, as long as the cannula 20 can be secured to the holder, the number of the claw portions 11 pressing from multiple directions is not necessarily limited. However, as described above, since removal of the cannula 20 becomes difficult when there are too many of the claw portions 11, around three are appropriate.

(16) A depression 12 is formed in a side of the front end of the holder 10 illustrated in FIG. 1 and FIG. 2. The depression 12 is provided for facilitating removal of the cannula 20 from the holder 10 using tweezers or the like.

(17) FIG. 3 is a cross-section cut along a line A-A of FIG. 1(c). As can be confirmed from the drawings, it is configured such that a part of a back end surface of the cannula 20 is visible from the position of the depression 12. That is, since tweezers or the like may be positioned on the depression 12, pressing the cap 23 of the cannula 20 from the back end is possible, thereby making it easy to remove the cannula 20 from the holder 10. Note that while the number of the depression 12 is not limited, if the depression 12 is, for example, in two places, it becomes possible to push the back end of the cannula 20 from two places using two front ends of the tweezers. Therefore, multiple depressions are preferable.

(18) FIG. 4 is a cross-section of the piercing needle and the cannula attached to the holder. The cannula 20 here has a resin cap 23 including a slit 23a through which the piercing needle 30 passes at the back end of the cannula 20. Moreover, the piercing needle 30 has a thin, approximately oblong cross-section fitted together with the form of the slit 23a at a position for passing therethrough. Such a structure allows control of deformation of the slit 23a to a minimum, and even after the piercing needle 30 is pulled out, the slit 23a is hardly spread open at all, making it possible to control leakage of vitreous humor, etc., from the eyeball.

(19) In the case of the piercing needle 30 made to have a small cross-section at the position of the slit 23a in 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 needle 30 moves when piercing, making it difficult to pierce at a precise position. However, provision of the claw portions 11 at positions to apply pressing forces perpendicularly toward the long sides facing each other of the approximately oblong cross-section of the piercing needle 30 can suppresses bending of the piercing needle 30.

(20) The cross-sectional form of the piercing needle 30 at the position that allows the piercing needle to pass through the slit 23a may have a different shape than a thin, approximately oblong shape. For example, it may be a circular cross-section with a reduced diameter (see FIG. 2(b)). In such a case, since the piercing needle 30 is weakened with bending in any direction, the claw portions 11 should be provided at positions to apply pressing forces from multiple directions toward the sides of the circular cross-section with the reduced diameter.

(21) 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

(22) 10: Cannula holder 11: Claw portion 12: Depression 20: Cannula 21: Pipe 22: Base 22a: Groove 23: Cap 23a: Slit 30: Piercing needle 40: Surgical tool E: Eyeball