WO2020036325A1

WO2020036325A1 - Surgical ligation clip made of polymer material and having highly uniform ligation force

Info

Publication number: WO2020036325A1
Application number: PCT/KR2019/008989
Authority: WO
Inventors: 강성욱; 한성호; 신현석; 최복록; 박한솔; 이예철; 박재형
Original assignee: (주)유원메디텍; 강릉원주대학교산학협력단
Priority date: 2018-08-14
Filing date: 2019-07-19
Publication date: 2020-02-20
Also published as: KR102031783B1

Abstract

The present invention relates to the ligation performance that accompanies the structure of a surgical ligation clip for temporarily or permanently ligating tissue, such as blood vessels, during a surgical operation, thereby preventing bodily fluids such as blood from leaking, wherein the ligation clip uses the intentional deforming property of a polymer material. The ligation clip is a polymer ligation clip in which a female leg protrudes upward, and a male leg protrudes upward to correspond to the female leg, wherein the respective rear ends of the female and male legs are connected by a hinge. A blood vessel placed between the female leg and the male leg is ligated as a female head and a male head provided on the tips of the legs, respectively, are fastened by elasticity and recovery. The hinge is composed of an inner hinge part and an outer hinge part with a slit therebetween. A protrusion part on the outer hinge part serves as a pressing means for deformation folding when the inner hinge part collinear with an inner blood vessel contact surface of the ligation clip deforms in the slit space during ligation.

Description

Surgical Ligation Clip Made of Polymer with High Ligation Uniformity

The present invention relates to a clip for ligation of tissues such as blood vessels or other conduits, and more specifically, to bleed tissues such as blood vessels temporarily or permanently during surgical operation, so that fluids such as blood are not leaked. The present invention relates to a structure of a surgical surgical ligation clip made of a polymer for preventing detachment from a blood vessel or a conduit during a postoperative recovery.

In many cases during surgery, the vessels should be ligated to prevent excessive bleeding of the patient to maintain the surgical field and to reduce the incidence of other complications. In addition, when the tumor is to be removed or an area of an organ is to be separated and removed, specific blood vessels must be ligated before separating the tissue.

As a means for ligation of blood vessels, there is a method of suturing the vessels with a suture or ligation with a clip. However, in the case of suturing blood vessels with a classic vascular ligation suture, there is a problem that a sufficient space for the affected area is required for the operation, the operation time is long, detailed work is required, and the suture thread may be released. Recently, ligation methods using clips of various materials have been widely used, and surgical ligation clips for this purpose have been variously proposed.

Conventionally used ligation clips, there is a metal hemostatic clip formed in a narrow U-shaped or V-shaped made of tantalum (titanium) or titanium (titanium) material. The metallic hemostatic clip remains in the human body after ligation of blood vessels, and has been widely used because it does no harm to biological tissues, but the material itself is used as a metallic ligation cream by deforming (process hardening) the bar. The metallic hemostatic clip of which the inlet is open is limited in ligation force by one deformation, so that the tension cannot be maintained continuously, and there is a problem that the metallic hemostatic clip can be released from the blood vessel during surgery and recovery.

Recently, in order to solve the above problems of the metallic hemostatic clip, a polymer ligation clip using an oil-modifying property (restoreability), which is an appropriate modification of a polymer resin, has been proposed, and FIG. 1 is one example of the present invention. Is a perspective view of a surgical clip disclosed by -0115163.

As shown in FIG. 1, the polymer ligation clip corresponds to the first leg member 100 to be folded about the first leg member 100 and the hinge part 300 having a gentle inner surface. The second leg member 200 having a shape to be formed, the first locking member 140 formed at the end of the first leg member 100, and the second locking member 240 formed at the end of the second leg member 200. And the hinge part 300 includes an inner connection part having slits 33 and 300 therebetween so that the clip action of the first leg member 100 and the second leg member 200 can be flexibly performed. 310 and the outer connection portion 320. In addition,

protrusions

410 and 420 are provided on the

inner surfaces

110 and 210 of the first leg member 100 and the second leg member 200 to prevent the ligated blood vessel from sliding.

The polymer ligation clip is used to be mounted on a dedicated tool called an applier, and when ligation of blood vessels, the first leg member 100 and the second locking member 240 having a male and female structure are locked while the first leg member 100 is locked. And the second leg member 200 pressurizes the blood vessel to prevent leakage of body fluid therein.

In other words, the ligation clip is inserted into the applier to access the blood vessel between the first and

second leg members

100 and 200 of the clip, and then the ligation is performed by pulling the applier, wherein the polymer ligation clip is hinged. Deformation starts at 300 and the blood vessel is pressed between the first and

second leg members

100 and 200 and elastically locked by the male and female structures of the first and

second locking members

140 and 240.

As described above, the deformation start point of the polymer ligation clip starts at the Hanji portion 300, but more specifically, at the inner connection portion 310 and the deformation is led to each leg member 100,200, and then the first and second locking members 140,240. Is locked by). However, when the inner connecting portion 310 is deformed at the same time as the ligation by the structural characteristics of each of the

leg members

100 and 200 having a curved shape, the deformation direction of the inner connecting portion 310 sags downward.

Since the polymer clip uses the physical properties of plastics by injection molding, since the hinge structure is formed at the end of the bow shape, when the pressure is applied from the outside, the deformation direction of the inner hinge proceeds downward. That is, since the deformation of the inner connection portion proceeds between the slits by the thickness and stops, the circumference of the hinge portion causes unstable ligation compared to the male and female head portions.

As a result, gaps are generated between the two

leg members

100 and 200 of the portion adjacent to the hinge part 300, as shown in FIG. do.

On the other hand, although the

protrusions

410 and 420 are provided so that the blood vessels ligated between the first and

second leg members

100 and 200 are not slid, the end sides of the

protrusions

410 and 420 constraining the left and right directions of the blood vessels are formed vertically. When the blood vessel is pulled in any one direction, the restraint is easily released and the ligation force is weakened.

The present invention can improve the ligation force by inducing a uniform force distribution over the entire inside of the leg so that when the legs of the ligation clip is locked, the part that does not sufficiently bleed blood vessels between the legs does not occur, ensuring the stability of the ligation In addition, the purpose is to provide a surgical clip ligation clip excellent in manufacturability while having a structure that does not slip in the horizontal direction.

According to the most preferred embodiment of the present invention for solving the above problems, the female head and the male head provided at each end of the upwardly convex female legs and the upwardly convex male legs corresponding to each rear end is connected by the hinge is elastically fastened In the polymer ligation clip for ligating the blood vessel placed between the arm and the male leg, the hinge is the inner hinge portion and the outer hinge portion between the slit, and the folding surface of the inner hinge portion is the pressing means of the outer hinge portion ( There is provided a surgical ligation clip having a uniformity of high ligation force, characterized in that it consists of deformation-induced and additional deformation-proof protrusion structure.

At this time, the folding surface pressing means may be composed of a pressing projection protruding toward the slit from the outer hinge portion, the pressing projection should be located on the side of the cart with respect to the longitudinal center line of the hinge, most preferably the terminal center line and the slit Position it below the center between the carteg's ends of it.

According to another embodiment of the present invention, each inner surface of the female leg and the male leg of the ligation clip is provided with a pair of ligation protrusions are formed to protrude in the width direction, the pair of ligation protrusions of the inner surface of each leg There is provided a surgical ligation clip having uniformity of high ligation force, characterized in that the ligation protrusion of the female leg and the ligation protrusion of the male leg is positioned to be offset to the left and right with respect to the longitudinal center virtual line.

At this time, the outer end surface of the ligation protrusion may be configured as a history surface to exhibit a higher ligation force.

In the present invention, since the pressure applied to the blood vessel by the ligation clip is uniformly made when ligation of the blood vessel, the uniform ligation force is achieved regardless of the position of the blood vessel placed inside the ligation clip. As it can proceed, the operation time can be shortened, and by exerting a high binding force, the ligation state can be stably maintained without the blood vessel slipping in the horizontal direction, thereby reducing side effects of the surgery.

1 is a perspective view of a ligation clip according to the prior art.

2 is a photograph showing a state in which malocclusion (GAP) occurs in the ligation clip and a comparative example of the ligation clip of the present invention.

3 is a perspective view of the ligation clip according to an embodiment of the present invention.

Figure 4 is an enlarged cross-sectional view of the hinge portion of the ligation clip of the present invention.

5 is an enlarged plan view and a cross-sectional view of the ligation protrusion part of the ligation clip of the present invention.

6 is a front view showing the operating relationship of the present invention folded surface pressing means.

7 is a result of the structural analysis of the surface pressure distribution of the inner hinge portion with or without the folded surface pressing means.

8 to 11 are the results of the structural analysis of the surface pressure of the blood vessel according to the shape of the ligation protrusion of the invention.

Figure 12 is a photograph of each of the initial setting step and the step of calculating the measurement of the final result during the experiment of the test subject of the present invention.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described in detail. However, in describing the present invention, when the technical concept of the present invention is obscured or obscured by describing the known configuration in detail, the description of the known configuration will be omitted.

Figure 3 is a perspective view showing the overall shape of the ligation clip according to an embodiment of the present invention, Figure 4 is an enlarged cross-sectional view of the hinge 30 portion of the ligation clip, Figure 5 is the ligation projection 50 of the ligation clip Each is an enlarged plan view and an AA cross section for the part.

As shown in FIG. 3, the ligation clip of the present invention is made of a polymer material, and each end of the female leg 11 and the male leg 21 and the female leg 11 and the female leg 21 for ligation of blood vessels. The arm head 12 and the male head 22 and the rear end of the female leg 11 and the male leg 21 which lock the female leg 11 and the male leg 21 in a state in which the blood vessels are ligated. It consists of a hinge 30 to enable relative rotation of these arm legs 11 and the male leg 21 while connecting integrally.

The arm leg 11 is formed in an upwardly convex shape, and the male leg 21 is also formed in an upwardly convex shape corresponding to the shape of the arm leg 11 to form a blood vessel placed between these arm legs 11 and the male leg 21. Ligation with elastic force.

Each inner surface of the arm leg 11 and the male leg 21 is ligated by preventing the outer wall of the blood vessel from slipping in the forward direction during ligation and preventing the ligation clip from slipping down in the horizontal direction from the ligation vessel. Is provided with a ligation protrusion (50) for maintaining a stable.

The hinge 30 connecting the female legs 11 and the male legs 21 has an inner hinge portion 31 and an outer hinge portion 32 so that the female legs 11 and the male legs 21 can be easily rotated. It is similar to the prior art in that it consists of a slit 33 therebetween, but in the present invention, in addition to the folded surface pressing means of the inner hinge portion 31, for example, the projected structure for the intended deformation induction and further prevention of further deformation There is a significant technical difference in that the means are further provided.

Herein, the folded surface 34 of the inner hinge portion 31 means a portion to which the inner legs of the female legs 11 and the male legs 21 opposite to the slits 33 of the inner hinge portion 31 are connected. .

When the arm legs 11 and the wagons 21 are locked in the state of ligation of blood vessels, the inner hinge portion 31 sags downward, and an abnormal large gap (gap) in the folded surface 34 of the inner hinge portion 31 is observed. ) Is formed, and this causes the malocclusion between the female legs 11 and the male legs 21 around the entire hinge portion 30, and the folding surface pressing means sags downward as shown in FIG. By pressing the lower side of the inner hinge portion 31 upward to increase the surface pressure so that the above-mentioned voids to have a malocclusion on the folded surface 34 is not formed.

FIG. 7 shows the results of structural analysis regarding the surface pressure distribution of the inner hinge portion 31 comparing the case where the folded surface pressing means is not provided with the case where the folding surface pressing means is provided. (B) shows the latter surface pressure distribution.

As shown in FIG. 7, in the case of (a) where the folding surface pressing means is not provided, the surface pressure distributed by the inner hinge portion 31 is 1.621e-01, and the folding surface pressing means is provided (b). ) Indicates that the surface pressure distributed to the inner hinge portion 31 is increased by about 13.57% to 1.841e-01.

The folding surface pressing means is sufficient as long as the female legs 11 and the male legs 21 can be precisely engaged at the folding surface 34 while preventing the inner hinge portion 31 from sagging downward. In the embodiment, the pressing protrusion 40 protrudes from the outer hinge portion 32 toward the slit 33. The folding surface pressing means consisting of the pressing projection 40 is simple in its configuration to facilitate the production of the ligation clip and to have an accurate pressing force.

The pressing protrusion 40 provided on the outer hinge part 32 is to pressurize the lower side of the inner hinge part 31 upwards, and the position thereof is lower based on the terminal center line OO of the hinge 30. That is, it should be located on the side of the cart 21, most preferably located below the center between the terminal center line (OO) and the end of the cart 21 side of the slit (33).

In addition, the pressing projection 40 may have a variety of shapes, but preferably configured in a semi-circular shape when the degree of pressing against the inner hinge portion 31 gradually increases, the inner hinge portion 31 is in the central axis direction To induce deformation and to prevent further deformation downwards.

When the arm leg 11 and the male leg 21 are folded for vascular attachment, the width of the slit 33 toward the inner hinge portion 31 is reduced by about 70 to 80%. Therefore, the semicircular midpoint Q of the pressing protrusion 40 is positioned on the line of the arc h formed by the inner surface of the outer hinge portion 32, and the radius R thereof is the slit located at the midpoint Q. It is preferable to configure 0.3 to 0.6 times the initial width of (33). For example, when the radius is less than 0.3 times, the pressing on the inner hinge portion 31 may not be performed at all or the degree of the pressing may be insignificant. When it exceeds 0.6 times, there exists a possibility that the deformation which is not required for the hinge 30 may generate | occur | produce, such as a pressurization degree too large and the inner hinge part 31 twists to a side.

As described above, the pressing protrusion 40 of the present invention directly increases the surface pressure at the folding surface 34 at the rear end of the

legs

11 and 21 by pressing the inner hinge portion 31 upwardly. The pressing force exerts an additional effect of increasing the ligation force of the ligation clip by affecting the arm legs 11 and the entire leg 21 and has a complementary relationship to the shape of the teeth described later. This will be described later through an experimental example.

As described above, each inner surface of the arm leg 11 and the male leg 21 is provided with a ligation protrusion 50 to prevent slipping in the horizontal direction in the ligated blood vessel to have a high ligation force.

The ligation protrusion 50 is formed to protrude in the horizontal direction from each of the inner surface of the female leg 11 and the male leg 21, as shown in Figure 5 (a) of the inner surface of each leg (11, 21) The pair of protrusions 50 of the female leg 11 and the ligation protrusion 50 of the male leg 21 are installed to be engaged with each other while the pair is positioned to the left and right on the basis of the longitudinal center virtual line K.

The ligation protrusion 50 may have a higher anti-slip force by configuring the outer end surface as the inverse surface 51 as shown in FIG.

8 to 11 shows the surface pressure of blood vessels located at the engaging portion with the outer end surface of the ligation protrusion 50 when the ligated blood vessel is contracted during the postoperative recovery period or the ligation force of the ligation clip is reduced and pulled in the horizontal direction. As a result of the structural analysis compared according to the angle of (51), FIG. 8 shows the virtual vertical plane length L1 of the outer end face and the length of the inner end face from the lower face when the inverse surface 51 is not formed. In the case where the ratio L2 is 20: 3, FIG. 10 shows the virtual vertical plane length L1 of the outer end face and the length L2 entered inwardly from the lower face 20: 4. The case where the ratio of the vertical surface length L1 and the length L2 which went inwardly from the lower surface is 20: 5 is shown, respectively.

According to FIG. 8, the stress generated in the blood vessel is 6.351e-01, but in FIG. 9, 6.657e-01, FIG. 10, 6.701-e01, and FIG. 11, 6.884e-01 are shown. It can be seen that the angle α of the inverse surface 51 increases as the angle increases.

As described above, when the outer end surface of the ligation protrusion 50 is constituted by the history surface 51, and the larger the angle α of the history surface 51, the ability of the blood vessel to resist slip increases. However, if the angle α of the inclined surface 51 is too large, the stress generated in the blood vessel exceeds the allowable stress, so that the blood vessel may be torn. Therefore, it is preferable to set the angle (alpha) of the inversion surface 51 so that the ratio of the virtual vertical surface length L1 of an outer end surface and the length L2 which went inwardly from the lower surface may not exceed 20: 5.

The ligation clip of the present invention has an overall uniform and high ligation force by the shape of the folding surface pressing means formed on the hinge 30 and the binding protrusions formed on the inner surfaces of the

legs

11 and 21. In addition, as described above, the folding surface pressurizing means increases the ligation force of the ligation clip by affecting the entirety of the arm leg 11 and the male leg 21.

In order to confirm this, the Korea Institute of Construction and Environmental Testing (KCL) conducted a slim pull-off test (Lateral Pull-off Test).

Experiment 1: Ligation clip of US W company recognized as having the world's best slip resistance (more than 21N) (formation of ligation protrusion 50, which is not provided with pressurization means and history surface 51 in XL type)

Test Subjects 2 to 5: In each embodiment of the present invention, the pressing projection 40 is formed in the outer hinge portion 32, the position of the center line (OO) of the hinge 30 and the male legs of the slit 33 The pressing protrusion 40 is formed in the center between the end portions 21, and the radius of the pressing protrusion 40 is 0.45 mm and 0.40 mm in consideration of the fact that the initial width of the slit 33 is usually 0.7 to 0.8 mm. , 0,35mm and 0.3mm, respectively, and the inclined surface 51 of the binding protrusion has no inclination angle and the ratio of L1: L2 of 20: 3, 20: 4, and 20: 5 is sequentially applied to the pressing protrusion 40 ) To correspond to the scale.

The test method was: ① Fix the top of the 5cm PVC tube to the upper jig of the PUSH-PULL gauge (IMADA, JAPEN) → ② Ligation the ligation clip to about 5mm at the bottom of the PVC tube → ③ PVC ligation at the speed of 2000pps (1mm / s) Pull out the PUSH-PULL gauge until it is completely removed from the tube → ④ Insert the ligation ligation clip into the bottom of the jig so that the armleg (11) and the wagon (21) parts are caught by the jig (the lower jig is made of PVC) Slip enough to take only the leg part of the ligation clip without applying force to the tube.) ⑤ After the ligation clip is completely removed from the PVC tube, the slip resistance of each specimen is measured by measuring the peak value of the PUSH-PULL gauge. Was measured, and the results are shown in Table 1 below. 12 is a photograph of each of the initial setting step and the step of calculating the measurement of the final result during the experiment process.

구분division	실험체 1(대조군 W사)Test Subject 1 (Control W Company)	실험체 2(R 0.45, 20:0)) Subject 2 (R 0.45, 20: 0))	실험체 3(R 0.40, 20:3)Test Subject 3 (R 0.40, 20: 3)	실험체 4(R 0.35, 20:4)Test Subject 4 (R 0.35, 20: 4)	실험체 5(R 0.30, 20:5)Test Subject 5 (R 0.30, 20: 5)
1One	16.7 16.7	29.8 29.8	33.9 33.9	26.0 26.0	23.7 23.7
22	23.3 23.3	38.7 38.7	23.5 23.5	37.3 37.3	22.5 22.5
33	22.4 22.4	26.7 26.7	36.0 36.0	27.1 27.1	25.8 25.8
44	24.4 24.4	24.9 24.9	28.3 28.3	28.9 28.9	30.1 30.1
55	24.0 24.0	22.4 22.4	35.2 35.2	42.5 42.5	24.0 24.0
66	24.2 24.2	43.8 43.8	33.8 33.8	32.0 32.0	24.7 24.7
77	21.8 21.8	41.0 41.0	31.3 31.3	40.9 40.9	22.4 22.4
88	24.7 24.7	43.9 43.9	27.6 27.6	27.3 27.3	31.0 31.0
99	23.6 23.6	42.1 42.1	26.9 26.9	37.0 37.0	39.1 39.1
1010	24.9 24.9	34.4 34.4	29.7 29.7	22.1 22.1	39.9 39.9
AvgAvg	23.0 23.0	34.8 34.8	30.6 30.6	32.1 32.1	28.3 28.3

(Unit N)

As a result of the above experiment, all of the ligation clips according to the present invention exhibit higher slip resistance than the US W ligation clip. In particular, the size of the slip resistance is inclined angle α of the history surface 51 of the ligation protrusion 50. It is shown that it is controlled by the standard of the pressurization protrusion 40 rather. That is, the larger radius of the pressing protrusion 40 has a larger ligation force than the larger angle of the inlet surface 51 of the ligation protrusion 50.

This experimental result confirms that the pressing protrusion 40 increases the ligation force not only on the folding surface 34 located at the rear end of each

leg

11, 21, but also on the

entire leg

11, 21. have. Of course, the larger the angle (α) of the history surface 51 of the ligation protrusion 50, the larger the ligation force has been confirmed through the previous structural analysis.

Therefore, the present invention having a folding surface pressing means such as the pressing protrusion 40 has a uniform and high ligation force with respect to the

entire legs

11 and 21 including the hinge 30, regardless of the ligation position of the blood vessel. The ligation state can be maintained stably, and the size of the ligation force can be further increased by adjusting the angle α of the back surface 51 of the ligation protrusion 50.

The present invention has been described in detail above with reference to specific embodiments, but the above embodiments are merely examples for easy understanding of the present invention, so that those skilled in the art have the scope of the technical idea of the present invention. It will be apparent that various modifications can be made within the scope of the invention. Therefore, such modifications will be said to belong to the scope of the present invention as described in the claims.

The present invention relates to the ligation performance according to the structure of the ligation clip for surgical surgery using the intended deformation characteristics of the polymer material to prevent the leakage of body fluids such as blood by ligation of tissues such as blood vessels temporarily or permanently during surgical operation As the ligation clip is connected to each rear end by a hinge, the female head and male head provided at each end of the upwardly convex female leg and the upwardly convex male leg corresponding to each other are fastened by elasticity and eccentricity between the female leg and the male leg In the polymer ligation clip for ligation of blood vessels placed on the hinge, the hinge is deformed in the slit space when the inner hinge portion and the outer hinge portion between the slits and the inner hinge portion collinear with the inner blood vessel contact surface of the ligation clip are ligated. When it is, characterized in that the protrusion made of the outer hinge portion by the pressing means of the deformation folding.

The present invention relates to a clip for ligation of tissues such as blood vessels or other conduits, and more specifically, to bleed tissues such as blood vessels temporarily or permanently during surgical operation, so that fluids such as blood are not leaked. The invention relates to the structure of the ligation clip for surgical surgery made of a polymer material for preventing detachment from blood vessels or conduits in the postoperative recovery process.

Claims

As the rear end is connected by the hinge 30, the female head 11 and the male head 22 provided at each end of the upwardly convex female leg 11 and the upwardly convex male leg 21 corresponding thereto are elastically fastened. In the polymer ligation clip for ligation of blood vessels placed between the arm legs 11 and the male legs 21,

The hinge 30 has a high ligation force, characterized in that the inner hinge portion 31 and the outer hinge portion 32 with the slit 33 therebetween, and the folding surface pressing means of the inner hinge portion 31. Surgical ligation clip with uniformity.
The method of claim 1,

The folding surface pressing means is a surgical ligation clip having a uniformity of high ligation force, characterized in that the pressing protrusion 40 protruding toward the slit 33 from the outer hinge portion (32).
The method of claim 2,

The pressurizing protrusion 40 is a surgical ligation clip having a uniformity of high ligation force, characterized in that located on the side of the cart 21 relative to the longitudinal center line (O-O) of the hinge (30).
The method of claim 3,

The pressurizing protrusion 40 is a surgical ligation clip having uniformity of high ligation force, characterized in that located below the center between the end of the center line (OO) and the end of the leg 21 side of the slit 33. .
The method of claim 2,

The pressurizing protrusion 40 has a semicircular shape, and the midpoint Q is positioned on the line of the arc h formed by the inner surface of the outer hinge part 32, and the radius R is located at the midpoint Q. Ligation clip for surgical operation with uniformity of high ligation power, characterized in that 0.3 to 0.6 times the width of the slit (33).
The method of claim 1,

Each inner surface of the female leg 11 and the male leg 21 is provided with a pair of ligation protrusions 50 protruding in the width direction, the pair of ligation protrusions 50 are each legs 11, 21) The ligation protrusion 50 of the arm leg 11 and the ligation protrusion 50 of the male leg 21 are installed to be engaged with each other while being positioned on the left and right sides with respect to the longitudinal center virtual line K of the inner surface. Ligation clip for surgery with high ligation uniformity.
The method of claim 6,

The outer end surface of the ligation protrusion 50 is a surgical ligation clip having a uniformity of high ligation power, characterized in that consisting of the history surface (51).
The method of claim 7, wherein

The shape of the back surface 51 of the ligation protrusion 50 is a ratio of the length of the virtual vertical surface length L1 of the outer end surface and the length L2 entered into the inner side from the lower surface is 20: 3 to 20: 5. Surgical ligation clip with high ligation uniformity.