RU2629777C2 - Device for fixation of head of laboratory animals - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: device contains an ear locator, a snap lock, and a micromanipulator. The ear clip consists of the micrometric mechanisms of the ear locks, the tips of the ear locks, the safety balls of the ear locks of the ear locks and the support of the ear locks. The muzzle fixator consists of lambs for fastening the incisors of the upper jaw, fixator of the upper mandibles, nasal lock and mandible bushing, muzzle snap ring, springs, muzzle retainer frame, and micromanipulator - from vertical and horizontal micrometric mechanisms with manual feed and wheels of vertical and Horizontal feed.

EFFECT: use of the invention makes it possible to quickly and quickly provide access to any part of the body of a laboratory animal and conduct a large list of surgical manipulations.

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Description

The invention relates to medicine, namely to experimental medicine, physiology, pathological physiology and pharmacology, and can be used for careful fixation of small laboratory animals, mainly rats, during scientific experiments.

The common problem of fixing small animals in research institutes during medical and physiological experiments is, on the one hand, the unreliability of fixation, and on the other hand, the invasiveness of known methods, which negatively affects the quality and purity of the experiment.

A device for gentle fixation in a stationary state of small laboratory animals, allowing manipulations with a selected area of the body surface (RF patent No. 2524251, MCP A61D 3/00, 2014). The device allows to achieve the degree of complete immobilization of laboratory animals, mainly rats, contains a “stenoflex” case with a loading opening and is equipped with a tripod, while the device uses a piece of cylindrical soft elastic tube with two stainless steel tape clamps with a screw transmitting force on the worm type.

However, the disadvantage of the known device for gentle fixation is the excessive rigidity of the materials used, namely metal crimp clamps and the housing of the "stenoflex", which make it difficult to control the position of the body of the laboratory animal during fixation. At the same time, metal clamps require a tool to work with them (a screwdriver or a wrench) and do not allow fast fixation, and a tripod made of wood cannot be fully sterilized with chemicals used in the operating room. In addition, the material from which the device body is made does not allow air to pass through and is not able to absorb liquid, which can lead to undesirable consequences in laboratory animals during prolonged manipulations (asphyxiation, contamination of the surgical field with biological fluids, etc.).

A known method of fixing small laboratory animals with adhesive tape to the limbs, trunk and head in a supine position on the operating table, which consists in placing an anesthetized small laboratory animal on a device containing a base with support stops and guides that follow the contours of a rat placed on its back, with the front and hind legs spread out to the sides (RF patent No. 2303421, IPC A61D 3/00, 2007).

The disadvantage of this method of fixation is that it requires pre-anesthesia biomodels (rats), which is unacceptable with simple manipulations that do not require general analgesia. In addition, this method is quite time-consuming and difficult to perform by one person. In the absence of an assistant, these shortcomings significantly increase the time of manipulation, which, in turn, requires large doses of narcotic drugs. In addition, the presented method cannot be used to fix laboratory mice and does not allow changing the position of the animal, which makes it difficult (puncture of the lateral caudal vein) or impossible (manipulation of the dorsal surface of the body, eyes) using a number of widely used techniques.

An object of the invention is to develop an effective method of fixation of small laboratory animals, the use of which does not require special skills, makes it easy and quick (without the help of assistants) to provide quick access to any part of the body of the laboratory animal and to carry out a large list of surgical procedures under conditions that maximize the level of negative factors of prolonged immobilization.

The technical result is achieved through the use of mechanical fixators: the ear and muzzle (nose and lower jaw, upper jaw incisors), which increases the reliability of fixation of the head, while reducing the risk of trauma to the oral cavity.

To solve this problem, a device is proposed for fixing the head of laboratory animals, containing a base with stand supports and guides that repeat the contours of the experimental animal, characterized in that an ear clip, a muzzle clip, which in turn contains: a nose clip, is inserted into it fixator of the maxillary incisors, fixator of the lower jaw, with the following connections: the animal’s head behind the ear holes are located between the right and left conical nozzles of the ear fixer, the lower jaw is bare you are lying on the retainer of the lower jaw, on the upper part of the muzzle - the nose and upper jaws are the nose retainer, the upper incisors are hooked on the retainer of the upper jaw incisors; the lower jaw retainer and the nose retainer are pressed against the retainer of the upper jaw incisors.

The drawing shows a diagram of a device in isometry. which shows:

1. Lamb for fixing the retainer of the maxillary incisors (2 pcs.)

2. Vertical micrometer mechanism with manual feed

3. Horizontal micrometric mechanism with manual feed

4. The sleeve retainer nose and lower jaw

5. Wheel lock muzzle

6. Micrometric mechanism of ear fixation (2 pcs.)

7. The tip of the ear clip (2 pcs.)

8. A support of an ear fixer

9. Safety ball of a tip of an ear clamp (2 pcs.)

10. Upper and lower spring

11. Frame support retainer muzzle

12. Roller ftoroplast

13. The clamp of the lower jaw

14. The nose lock

15. The clamp of the maxillary incisors

16. Stud retainer pin

17. Head

18. Vertical feed wheel

19. Horizontal feed wheel

The composition of the device

The device consists of three blocks: ear clip, muzzle clip, micromanipulator.

The ear clip consists of: micrometric mechanisms of the ear clip 6 (2 pcs.), Tip of the ear clip 7 (2 pcs.), Support of the ear clip 8, safety balls of the tip of the ear clip 9 (2 pcs.).

The muzzle retainer consists of: wing fasteners for the upper jaw incisor retainer (2 pcs.) 1, the nose and lower jaw retainer bushing 4, the muzzle retainer wheel 5, the upper and lower springs 10, the support frame of the muzzle retainer 11, the fluoroplastic roller 12, the lower jaw retainer 13, nose lock 14, fixator of maxillary incisors 15, muzzle retainer pin 16.

In the muzzle retainer, a clamping device should be allocated consisting of: studs 16, bushings 4, springs 10, roller 12, wheel 5.

The micromanipulator consists of: a vertical micrometer mechanism with manual feed 2, a horizontal micrometer mechanism with manual feed 3, a vertical feed wheel 18, a horizontal feed wheel 19.

Novelty and advantage

The novelty is that this device

- Allows you to fix the lower jaw, which increases the reliability of fixation of the head, while reducing the risk of trauma to the oral cavity, by transferring the fixation point from the bones of the hard palate to the branches of the lower jaw. Thus, the pressure of the fixative is carried out not on the mucous membrane, but on the skin that is more resistant to mechanical damage.

- In order to secure first the upper part of the muzzle, then the lower one, springs of different stiffness are provided in the design.

- The device of the earplug.

- Micrometric mechanisms 2 and 3 (feed) are used with an adjustable slipping mechanism, which allows you to simultaneously securely and carefully fix the head 17 by the ear holes. The negative effect of the rotation of the rod of the micrometric mechanism is eliminated by, for example, a fluoroplastic conical nozzle 7 and a ball-shaped bearing 9. The nozzle is inserted into a special hole at the end of the rod. Cone nozzle and stem are coaxial. The hole in the rod is made to the depth of the nozzle sleeve. Friction between the end face of the nozzle sleeve and the bottom of the stem bore is leveled by the bearing in the form of a ball 9.

The use of removable cone nozzles for ear fixation gives:

possibility of changing nozzles

the ability to choose the nozzle of the desired anatomical shape, by changing the angle of the vertex of the cone

possibility of sterilization of nozzles

- the use of micrometric mechanisms (feeds) for positioning the head along two axes (vertical and horizontal), which ensures simplicity and accuracy of positioning the animal’s head with one hand. The horizontal feed allows you to adjust the distance between the axis passing through the ear holes and the maxillary incisors (adjusting the length of the skull), the vertical feed allows you to adjust the tilt of the head relative to the plane of the supporting platform.

- The use of fluoroplastic (synthetic polymer) parts in the design of the device has the following advantages:

cheaper construction costs

the material is easy to process

the material is used in knots with rubbing surfaces and does not require lubrication

- The ability to flip the muzzle retainer 180 °.

Allows quick access to the ventral surface of the neck.

Materials used

- aluminum

- ftoroplast

- surgical steel

The peculiarity of working with the device, unlike analogues.

In order to fix the animal’s head 17 in the device, the animal is pre-anesthetized, then the animal’s head fixation begins with fixation at the ear holes, while the head 17 should be fixed in the center, between the right and left conical nozzles of the ear fixative 7. Next, the upper part of the muzzle is fixed - the upper the cutters are inserted into a special hole in the retainer of the maxilla incisors 15. Then, while tightening the muzzle retainer wheel 5, the nose lock 14 is pressed first, then the lower jaw lock 13.

Thus, it turns out that the lower jaw of the head 17 lies on the fixator of the lower jaw 13, on the upper part of the muzzle (nose, upper jaw) of the head 17 lies the nasal retainer 14, the upper incisors are latched onto the retainer of the maxillary incisors 15. The ear canals are clamped between the tips of the fixative earplug 7.

The clamp of the lower jaw 13 and the retainer of the nose 14 are pulled together (pressed against the clamp of the incisors of the upper jaw 15) with the help of a pin 16, a wheel 5 and a roller 12.

The pin 16 is threaded through the holes in the nose lock 14 and the upper jaw cutter lock, and the lower end is fixed in the lower jaw lock 13 using the sleeve 4. The fluoroplastic pressure roller is put on top of the pin 12; the roller with its lower rounded end is immersed in a special groove in the nose lock 14. A wheel 5 is screwed onto the pin above the roller, the wheel has an internal thread with the same pitch as the pin. The rotation of the wheel around the axis presses or weakens the retainers of the nose 14 and lower jaw 13 in the direction of the retainer of the incisors of the upper jaw 15.

Springs 10 of different stiffness are dressed on the pin 16, the upper between the nose lock 14 and the upper jaw cutter 15 and the lower between the upper jaw cutter 15 and the lower jaw 13. The springs of different stiffness are necessary for the correct order to tighten the muzzle lock, first it is pressed against the head 17 the nasal retainer 14, then the lower jaw retainer 13, and also to return the nose and lower jaw retainers to their original position when the wheel 5 is loosened.

The tips of the earloop 7 are inserted into the holes of the rods of the micrometric mechanisms 6. A safety ball 9 is inserted between the bottom of the rod hole and the tip 7.

If it is necessary to fix the head 17 in an inverted position (the animal lies on its back, lower jaws at the top), it is necessary:

- unscrew the flaps 1 of the fastener of the upper jaw incisors 15

- at the muzzle retainer, turn over the lingering device:

- twist the muzzle retainer wheel 5 and remove the muzzle retainer stud fastening sleeve in the lower jaw retainer

- fasten the pin 16 with the sleeve 4 in the nose lock

- leave springs 10 in the same order

- put on the muzzle retainer pin 16 a PTFE roller 12 and screw on the muzzle retainer wheel 5

- fasten the assembled muzzle retainer to the horizontal micrometric feed 3 in an inverted position (lower jaw retainer from above) by means of two winglets 1.

When working with animals of different sizes, there is a need to adjust the distance between the earloop and the muzzle retainer, this is achieved using micrometric mechanisms to which the muzzle retainer is attached.

Applicability

The device can be used for operations on the head, neck, brain of laboratory animals, including as part of a stereotactic installation.

Claims (1)

A device for fixing the head of a pre-anesthetized laboratory animal, characterized in that it contains an ear fixer, a muzzle fixator and a micromanipulator, while the ear fixator consists of micrometric mechanisms of ear fixators, ear fixer tips, ear balls and ear fixer supports; muzzle retainer - from lambs for fastening the maxillary incisors, maxillary incisor retainer, nose and lower jaw retainer bush, muzzle retainer wheel, springs, muzzle support retainer frame, and micromanipulator - from vertical and horizontal micrometric mechanisms with manual feed and vertical and horizontal feed.

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