GB2465560A

GB2465560A - Absorbable veterinary sterilisation clamp

Info

Publication number: GB2465560A
Application number: GB0821147A
Authority: GB
Inventors: Frank Vinzenz Benedikt
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-11-19
Filing date: 2008-11-19
Publication date: 2010-05-26
Also published as: GB0821147D0

Abstract

A veterinary clamp (200) for the ligation of a bundle of soft tissue in the ovariohysterectomy of a canine or feline animal comprises two opposed resilient members (210, 200), and a locking mechanism (230, 240). The two opposed resilient members and/or the locking mechanism comprise a material that degrades in the body of a canine or feline animal. The veterinary clamp (200) may be adapted for manual closing, without the use of an applicator. The veterinary clamp of the present invention reduces the problem of bleeding during ovariohysterectomy in a cat or dog, and hence may reduce the risk of the death of the animal. With the veterinary clamp of the invention, the ovariohysterectomy may be accomplished more rapidly, with a smaller incision, and may enable a more rapid recovery.

Description

Veterinary clamp

Field of the Invention

The invention relates to a veterinary clamp for ovariohysterectomy in a canine or feline animal.

Background of the Invention

The operation of ovariohysterectomy' in a cat or dog involves removing the uterus and the ovaries.

Ovariohysterectomy is commonly called speying'. One key side-effect of this operation is that it may result in significant bleeding.

The bleeding has several adverse consequences for the cat or dog. These consequences include: (i) Reduction in the blood volume available in the animal's circulatory system. This adds to the stress on the animal's heart and may cause death of the animal.

(ii) The build up of clotting blood inside the animal's abdominal cavity, during and after closing of the incision necessary for the operation.

The accepted current method of achieving haemostasis, i.e. stopping the bleeding, involves ligating sutures.

These sutures are used on the ovarian and uterine stumps.

They may be applied either during or after the ovariohysterectomy.

I

The ligating sutures used in ovariohysterectomy are made from materials such as polydioxanone, chromic catgut or polyglactin 910. Polydioxanone sutures are usually monofilarnents, which are produced by extrusion.

During the ovariohysterectomy, metal surgical clamps are usually used to crush soft tissue, prior to applyThg the ligature. Once the ligating suture has been applied, the clamps are then removed.

Figure 1 illustrates the relevant parts of the anatomy, and the locations of surgical intervention, in a prior art approach to ovariohysterectomy in a cat or dog.

Figure 1 shows the kidney 110, an ovary 120 and the uterus 130. The organs shown in dashed lines are to be removed during the ovariohysterectomy.

The soft tissue linking the kidney and ovary is shown as 140. The soft tissue linking the ovary and uterus is shown as 150. The extension of the uterus into the vagina is shown as 170.

Lines Xl, X2, X3 and X4 indicate points where a veterinary surgeon carries out actions as part of the hysterectomy.

There is a second ovary and a second kidney in the animal. Soft tissue 180 links uterus 130 to the second ovary, and lies symmetrically opposite soft tissue 150.

Although they have not been included in figure 1, the second ovary and second kidney would lie towards the upper right of figure 1, in a generally symmetrical relationship with ovary 120 and kidney 110.

In conventional ovariohysterectomy, the following steps are carried out by a veterinary surgeon: 1. Make a large incision in the abdominal wall. As a first stage, ovary 120 and uterus 130 may be pulled outside the body of the cat or dog, through the incision made to carry out the ovariohysterectomy. However, the ovarian ligament in the soft tissue 140 may be broken by the action of pulling these organs outside the body.

Taking these organs outside the body early in the operation allows the veterinary surgeon better access, in particular for tying sutures.

2. Apply clamps at points Xl, X2, X3, which crush soft tissue 140 at these points.

3. Remove the clamp at point Xl. The clamp has crushed soft tissue 140 at point Xl. Tie soft tissue 140 with a suture loop, as a ligature, at point Xl.

4. Cut through the soft tissue 140 between the clamps fitted at points X2 and X3.

5. Remove the clamp from point X2. The clamp fitted at point X3 can remain attached to soft tissue 140, and can be detached after uterus 130 and ovary 120 have been cut away from the cat or dog.

6. Steps 2-5 above are now repeated for the other ovary, which is not shown on figure 1.

7. Apply a clamp at point X4, at the lower end of the uterine body, to crush the soft tissue there.

8. Remove the clamp at point X4. Then apply one or two suture loops as a ligature.

9. Cut through the soft tissue immediately above point X4.

10. Uterus 130 and both ovaries are now no longer attached to the body, and can be disposed of. Sutures at points Xl, X4 and below the second kidney should stem blood flow. If these sutures are made of absorbable matter, then they will eventually be absorbed by the body of the cat or dog.

The above operation may last 40 minutes in the hands of an experienced veterinary surgeon. It requires a relatively large incision in relation to the size of the cat or dog. Negative aspects of this procedure for animals and their owners are: (i) The requirement to anaesthetise the cat or dog for more than 40 minutes, which carries particular risks for older animals and is expensive.

(ii) The size of the incision. Closure of this incision requires further sutures. Cats and dogs also tend to scratch or bite scars that are healing, and it may be a major problem to dissuade them from doing so.

(iii) The problem of bleeding, and the risk of the death of the animal, discussed earlier.

One variant of the above process is to perform the operation inside the body by endoscopy. This results in a smaller incision. However, it requires a veterinary surgeon who is trained in endoscopy. The additional equipment and the time required both add considerably to the cost of the operation.

Various approaches to surgery are known in other fields, outside the field of ovariohysterectomy in a canine or feline animal.

European patent application EP-A-0 454 553 shows a ligating clip for use in the field of uterine veterinary surgery on cows. The clip is applied using a complex applicator, and appears to consist of plastic.

Looking to even more distant technical fields, there are a wide variety of other prior art approaches to surgery in general, including human surgery. In such approaches, there is commonly a need to achieve haemostasis in blood vessels. There are several ways to achieve this: (i) Metal clips are in common use in human surgery.

Occasionally, such clips may be used in veterinary surgery. These clips tend to be made from titanium or stainless steel. They may, for example, be used following removal of an animal's spleen, and may be left in the animal. These clips tend to be visible in X-Rays taken after an operation, due to their metal construction.

(ii) Non-metal clips used in human surgery include the Ligaclip' and the Absolok'. These clips are used to ligate individual blood vessels. As a consequence, the clips are sufficiently small that they can close around a blood vessel, but not take up unnecessary space inside the body. The Ligaclip is typically available in sizes between approximately 4mm and 11mm. The opposing faces of the clip may be flat, or may have small teeth that are sufficient to grip the blood vessel between them. In addition, the hinge mechanism on the clips has an appropriate strength for a clip closing off a blood vessel. These clips may be made of material that can be absorbed by the human body. Typically, the Absolok clip requires an applicator.

Statement of Invention

The invention comprises a veterinary clamp for the ligation of a bundle of soft tissue in the ovariohysterectomy of a canine or feline animal, with the features of appended claim 1.

The dependent claims provide further features of preferred embodiments of the invention.

The veterinary clamp of the present invention may reduce the problem of bleeding during and/or after ovariohysterectomy, and hence may reduce the risk of the death of the canine or feline animal. With the veterinary clamp of the invention, the ovariohysterectomy may be accomplished more rapidly, with a smaller incision, and may enable a more rapid recovery.

Brief Description of the Drawings

Fig. 1 illustrates the relevant parts of the anatomy, and the locations of surgical intervention, in a prior art approach to ovariohysterectomy in a cat or dog.

Fig. 2 shows a perspective view of an example of a veterinary clamp in accordance with the invention.

Fig. 3 illustrates the relevant parts of the anatomy, and the locations of surgical intervention, in an ovariohysterectomy in a cat or dog, using the veterinary clamp of the present invention.

Fig. 4 shows a side elevation view of the veterinary clamp of figure 2.

Fig. 5 shows a perspective view of another embodiment of a veterinary clamp in accordance with the invention.

Description of Preferred Embodiments

Figure 2 shows a veterinary clamp 200 for ovariohysterectomy in a canine or feline animal.

Veterinary clamp 200 is suitable for the ligation of a bundle of soft tissue in the ovariohysterectomy of a canine or feline animal. Veterinary clamp 200 might alternatively be termed a ligating clamp'.

Veterinary clamp 200 comprises two opposed resilient members, first member 210 and second member 220.

Portion 230 of first member 210 and portion 240 of second member 220 provide a locking mechanism.

The two opposed resilient members 210, 220 and/or the locking mechanism 230, 240 are made of a solid material that degrades in the body of a canine or feline animal.

The two opposed resilient members 210 and 220, and the locking mechanism 230, 240 are adapted to clamp a bundle of at least two types of soft tissue forming part of the ovarian pedicle or the uterine body of the cat or dog.

Importantly, the veterinary clamp 200 of the present invention is suitable for the ligation of a whole bundle of soft tissue. The soft tissue may comprise at least two of the following types of tissue: blood vessels, fat, nerves, muscle, ligaments and other connective tissue.

These tissues are typical constituents of the ovarian pedicle of a dog.

The two opposed resilient members 210, 220 have lengths in the range of 15-70mm. The width would be expected to be in the range of 5-15mm. The thickness of each of opposed resilient members 210 and 220 would be around 5mm. However, the thickness might vary along the length of one or both members 210 and 220, see the discussion of figure 4 for more details. The veterinary clamp 200 is therefore available in sizes that are big enough to clamp the ovarian pedicle even in large canine breeds.

The intrusion into the body of the dog or cat may preferably be minimised by the two opposed resilient members have lengths in the range of 20-60 mm. Usually, larger clamp sizes are more appropriate for larger animals, such as large dogs. Smaller clamp sizes are more appropriate for smaller animals, such as kittens, cats, smaller breeds of dog, and dogs that have not reached their full size.

The opposing faces of the two opposed resilient members 210, 220 may be adapted to crush the soft tissue clamped between them, thereby promoting clotting within the soft tissue. In order to do this, the opposing faces of the two opposed resilient members may carry teeth 250 running in a transverse direction to the longest dimension of the resilient members 210, 220.

The degradable solid material, of which the two opposed resilient members 210, 220 and/or the locking mechanism 230, 240 are made, may exhibit low tissue reaction and predictable absorption into the body. An example of a suitable material is polydioxanone. Polydioxanone is reasonably stiff. The present invention may also take advantage of shape memory properties of polydioxanone, which are undesirable characteristics in a suture but not in a veterinary clamp in accordance with the present invention.

Looking once again at figure 2, the two opposed resilient members comprise first 210 and second 220 longitudinal members. The first ends 230, 240 of the first and second longitudinal members 210, 220 together form the locking mechanism. The first 210 and second 220 longitudinal members form a common joint 260 at their second ends.

Veterinary clamp 200 may be adapted for manual closing, without the use of an applicator. Locking mechanism 230, 240 shown in figure 2 allows a veterinary surgeon to close the locking mechanism using his fingers.

Locking mechanism 230, 240 shown in figure 2 shows a single protrusion 230 on first longitudinal member 210.

Protrusion 230 is inserted into a rectangular hole in portion 240 of second longitudinal member 220.

Figure 3 illustrates the relevant parts of the anatomy, and the locations of surgical intervention, in an ovariohysterectomy in a cat or dog, using the veterinary clamp of the present invention.

In figure 3, kidney 310, ovary 320, and uterus 330 correspond to the similarly numbered items in figure 1.

Using a veterinary clamp 200 in accordance with the invention to carry out ovariohysterectomy, the veterinary surgeon may carry out the following steps: 1. Make a small incision in the abdominal wall.

2. Apply a veterinary clamp 200 in accordance with the invention at point Yl. The veterinary clamp crushes the soft tissue 340 at point Yl. Veterinary clamp 200 prevents haemorrhage from the ovarian stump, i.e. the upper part of soft tissue 340 that will remain in the animal.

3. Apply another clamp, which may be a conventional metal clamp, at point P. This crushes the soft tissue 350 at point P, and prevents the flow of blood to ovary 320 and soft tissue 340.

4. Cut the through the soft tissue 340 between point Yl and ovary 320. The veterinary clamp in accordance with the invention, at point Yl, remains in the body.

5. The clamp fitted at point P can remain attached to soft tissue 350, and can be detached after uterus 330 and ovary 320 have been cut away from the cat or dog.

6. Repeat steps 2-5 above for the other ovary, which is not shown on figure 3.

7. Apply a veterinary clamp in accordance with the invention at point Y2, at the lower end of the uterine body, to crush the soft tissue there. The veterinary clamp prevents haemorrhage from the uterine stump, i.e. the lower part of soft tissue 370 that will remain in the animal.

8. Cut through the soft tissue immediately above point Y2.

9. Uterus 330 and both ovaries are now no longer attached to the body, and can be disposed of.

The veterinary clamps in accordance with the invention at points Yl, Y2 and below the second kidney remain n the body to stem blood flow. No sutures are required at these points. These veterinary clamps will eventually be absorbed by the body of the cat or dog. The absorption time is typically several months. However, within the order of one week after the operation, the tissue and/or blood vessels secured by the veterinary clamp will have clotted and remodeled themselves.

There are several advantages of the procedure described in connection with Figure 3, in comparison to that described in connection with Figure 1. Some of these are that: (i) The veterinary clamps of the present invention reduce the problem of bleeding, and hence may reduce the risk of the death of the animal. One reason for this is that the veterinary clamp of the invention provides a more even distribution of pressure across the pedicle than was possible with a ligating suture. The large area of the veterinary clamp in contact with tissue reduces the likelihood that it will slip off.

(ii) The above operation may last only 10-20 minutes in the hands of an experienced veterinary surgeon. The reduction in time in comparison to the procedure described in connection with figure 1 is largely clue to the elimination of the time required to tie ligatThg sutures in the prior art procedure. The requirement to anaesthetise the cat or dog for only 10-20 minutes reduces the health risks, particularly for older animals.

The fact that the operation is faster also reduces the costs for owners.

(iii) It is more likely that the operation can be performed whilst the ovaries and uterus are still within the body cavity, i.e. without pulling them out through the incision. This reduces the likelihood of damage to organs that are still needed by the animal, such as the kidneys. It also reduces the general level of trauma within the animal, such as bruising of the connective tissues, and this reduces the time and discomfort for the animal during recovery. The ovarian ligament does not need to be torn.

(iv) The operation requires a smaller incision in the abdominal wall. This reduces both the number of sutures and the time required to close the incision. A smaller wound may heal more quickly, be less prone to re-opening, and be easier to protect from scratching or biting by the cat or dog. One reason for the smaller incision is that the operation requires fewer metal clamps, so the ovarian pedicle remains more visible.

Fig. 4 shows a side elevation view of the veterinary clamp of figure 2. First longitudinal member 410, second longitudinal member 420, protrusion 430 and portion 440 correspond to the similarly numbered parts of figure 2.

However, in figure 4, first 410 and second 420 longitudinal members are bowed towards their longitudinal midpoints. In alternative arrangements that are not shown on figure 4, first 410 and second 420 longitudinal members could be thickened towards their longituthnal midpoints, or could be thickened or bowed towards their transverse midpoints.

Bowing or thickened the first 410 and second 420 longitudinal members towards their longitudinal midpoints and/or their transverse midpoints provides extra force towards the longitudinal midpoint of the veterinary clamp. Without such bowing or thickening, the crushing effect of the veterinary clamp may be less towards the midpoints than at the first and second ends. Achieving a more even distribution of the clamping force along the length of the first 410 and second 420 longitudinal members helps to ensure even clotting along the tissue that is clamped, and avoids excessive damage to tissue clamped towards the ends of the longitudinal members.

Figure 4 also shows the main points of flexion of the veterinary clamp, when it is changed from the open to the locked positions. Five points of flexion are shown on figure 4 as solid oval points. One of these has been labeled 450.

The two opposed resilient members 510 and 520 correspond generally to the similarly numbered elements in figure 2.

The first end 530 of first resilient member 510 forms one part of the locking mechanism. First end 530 comprises a pair of U-shaped fingers, which are arranged symmetrically about the centre line of first resilient member 510.

The first end 540 of second resilient member 520 forms the second part of the locking mechanism. First end 540 comprises a T-shaped portion. The upper arms of the T-shaped portion are designed to fit into the U-shaped fingers of first end 530 of first resilient member 510.

Alternative locking arrangements to those shown in figures 2, 4 and 5 are also possible. For example, a ratchet type mechanism or a safety-pin' mechanism might be used. Alternatively, the first ends of the resilient members could take the form of rings or loops. When the rings or loops are in alignment, they could be secured together by a pin inserted into them, or a suture tied through and around them.

In figures 2, 4 and 5, the teeth on the opposed faces of the two opposed resilient members run across the opposed members. Teeth that run in the direction of the longest dimension of the resilient members could alternatively be used. Such teeth may not promote the clotting required in the soft tissue of the stumps of the ovarian or uterine pedicle as well as those shown in figures 2, 4 and 5.

However, they might give greater resilience to bending or bowing of the opposed resilient members. This would reduce the need to thicken or bow the resilient members towards their longitudinal or transverse midpoints, which would simplify construction and manufacture, and reduce the volume of material required. Ridges of varying orientation, and ridges whose spacing and/or height varied along the length or width of the resilient members may also achieve similar advantages.

Claims

Claims 1. A veterinary clamp (200) for the ligation of a bundle of soft tissue (340, 370) in the ovariohysterectomy of a canine or feline animal, comprising: two opposed resilient members (210, 220); a locking mechanism (230, 240); whereby the two opposed resilient members (210, 220) and/or the locking mechanism (230, 240) comprise a material that degrades in the body of a canine or feline animal.
2. A veterinary clamp (200) in accordance with claim 1, wherein: the opposed resilient members (210, 220) and the locking mechanism (230, 240) are adapted to clamp a bundle of at least two types of soft tissue (340, 370) forming part of the ovarian pedicle (340) or the uterine body (370) of the cat or dog.
3. A veterinary clamp (200) in accordance with claim 1 or claim 2, wherein: the veterinary clamp (200) is adapted for manual closing, without the use of an applicator.
4. A veterinary clamp (200) in accordance with any previous claim, wherein: opposing faces of the opposed resilient members (210, 220) are adapted to crush the soft tissue (340, 370) clamped between them, thereby promoting clotting within the soft tissue (340, 370)
5. A veterinary clamp (200) in accordance with claim 4, wherein: opposing faces of the opposed resilient members (210, 220) carry teeth (250) running in a transverse direction to the longest dimension of the opposed resilient members (210, 220)
6. A veterinary clamp (200) in accordance with any previous claim, wherein: the opposed resilient members (210, 220) comprise a first (210) longitudinal member and a second (220) longitudinal member; the first ends of the first (210) and second (220) longitudinal members together form the locking mechanism (230, 240); and the first (210) and second (220) longitudinal members are joined at their second ends (260)
7. A veterinary clamp (200) in accordance with claim 6, wherein: the first (410) and second (420) longitudinal members are bowed or thickened towards their longitudinal midpoints and/or their transverse midpoints.
8. A veterinary clamp (200) in accordance with any previous claim, wherein: the veterinary clamp (200) comprises a material that exhibits low tissue reaction and predictable absorption into the body.
9. A veterinary clamp (200) in accordance with claim 8, wherein the veterinary clamp (200) comprises polydioxanone.
10. A veterinary clamp (200) in accordance with any previous claim, wherein: the opposed resilient members (210, 220) have lengths in the range of 15-70mm.
11. A veterinary clamp (200) in accordance with claim 10, wherein: the opposed resilient members (210, 220) have lengths in the range of 20-60 mm.
12. A veterinary clamp (200) in accordance with any previous claim, wherein: the locking mechanism (230, 240) comprises a protrusion (230) at the first end of first longitudinal member (210), and a portion (240) with a rectangular hole at the first end of the second longitudinal member (220)
13. A veterinary clamp (200) in accordance with any of claims 1-11, wherein: the locking mechanism (230, 240) comprises a pair of U-shaped fingers at the first end (530) of first resilient member (510), and a I-shaped portion at the first end (540) of second resilient member (520), the upper arms of the I-shaped portion being designed to fit into the U-shaped fingers of first resilient member (510)
14. A veterinary clamp (200) as hereinbefore described with reference to, and/or as illustrated by, any of figures 2, 4 or 5.