RU2570168C1 - Device for bone fragment approximation and fixation - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: device for bone fragment approximation and fixation comprises movably jointed branches with a ratchet, and handles. The branches have end threaded pins and two removable adapters configured as a regular quadrangular prism with through holes in mutually perpendicular planes, and two removable jaws having two conical pins and one threaded pin opposing the conical ones.

EFFECT: smooth coaxial approximation and gradual compression of bone fragments with minimum bone injuries and preserved bone blood supply.

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Description

The present invention relates to medicine, in particular to surgical instruments, and can be used to approximate and fix bone fragments.

A device is known consisting of a working part, represented by elastic curved jaws with a thickness of 2 mm and a width of 30 mm, having a crescent shape with two diverging spikes, with mutual concavity, smooth bending and with teeth on the concave side, and jaws with a rack and five teeth, allowing vary the distance between the jaws and measure the grip strength of bone fragments in the range from one to five (see RF patent No. 2410054, 2011).

However, this device has the following disadvantages: 1) the large size of the working part of the instrument necessitates the skeletonization of bone fragments over a large extent for their capture, which affects the blood supply to the fragments; 2) the device increases the risk of crushing or cracking of bone fragments, especially with osteoporosis, as well as trauma to the periosteum due to the large contact area of the working part of the instrument with tissues; 3) the use of the device is possible only on tubular bones, the cross section of which corresponds to the concavity of the working jaws of the tool; 4) the device does not provide a smooth axial approach of bone fragments and their necessary compression.

Known devices containing one pin with a rigid fixation to the instrument or monolithic with the instrument (see Osteosynthesis. Guide for doctors under the editorship of the member of the Academy of Medical Sciences of the USSR, Prof. SS Tkachenko, 1987, pp. 39-40).

However, they do not allow to achieve coaxiality of bone fragments during their rapprochement, connection and their uniform end pressure. In addition, they do not allow to control (manipulate) the position of fragments in different planes and at the required angle.

A pointed reposition clamp is also known, including a working part with pins and providing minimal contact of the working part of the instrument with tissues, since the pins are inserted into the holes formed in the cortical plate (see M.E. Muller, M. Allgover, R. Schneider, X Willinegger, Guide to Internal Osteosynthesis, Recommended Practice by AO Group (Springer-Verlag, 1996, pp. 514-515).

However, when using the device, there is an angular displacement of fragments of tubular bones when they approach each other to achieve end stop due to traction of the muscles attached to the bones, which is especially pronounced when the bone fragments are standing at a considerable distance. This drawback requires the use of additional tools, often with additional tissue injury. In addition, this device allows you to control the position of the fragments and fix them in the required position in only one plane. When using them, it is not possible to adjust the angle of fixation of bone fragments. Under the conditions of use of the device, adequate reposition and stable fixation of bone fragments of tubular bones is not provided.

As a prototype, a device containing arms and jaws with spikes was selected, the jaws are equipped with U-shaped legs, at the ends of which cylindrical thickenings are made, ending with supporting platforms, in the center of which there are spikes located and oriented towards each other, while the distance between the spikes of one pair of legs less than the second opposite pair of legs, and in the closed position, all four bearing pads are in the same plane and the distances between the centers of the spikes are equal (see patent 2195211, 2002).

However, the known device has disadvantages: 1) does not provide a gradual rapprochement and fixation of bone fragments with the necessary end compression; 2) does not allow reliable fixation of fragments at the required angle after corrective osteotomy; 3) fixed distances between the spikes do not allow the device to be used during operations on small bones of the hand and foot; 4) the device does not provide reposition of flat bones with minimal trauma; 5) there is a need for skeletonization of fragments for a considerable extent.

The task of the invention is to improve the device.

The technical result is the provision of a gradual coaxial approximation of bone fragments with their metered compression with minimal trauma to the bone tissue and preservation of its blood supply, as well as a uniform end stop when fixing bone fragments at an angle in a different plane.

The technical result is achieved due to the fact that in the device, which includes movably connected jaws with a rack and handles, the jaws are made with end threaded pins and are equipped with two removable adapters in the form of a regular quadrangular prism with through holes in mutually perpendicular planes and two removable forks having two conical pins and one threaded pin directed oppositely conical.

A device for convergence and fixation of bone fragments is illustrated by drawings, where in FIG. 1 shows a general view of the device, FIG. 2 - adapter with through holes in mutually perpendicular planes, in FIG. 3 shows a detachable plug with tapered and threaded pins.

The device contains two movably connected branches 1 with end threaded pins 2 with nuts, equipped with two removable adapters 3 in the form of a regular quadrangular prism with through holes made in mutually perpendicular planes perpendicular to the side faces of the prism through the axis of symmetry closer to the base of the prism, and two removable forks 4, having two conical pins 5 and one threaded pin 6 with a nut directed opposite to the conical pins 5. The angle between the jaws in the closed position is 10 °, in the open position - 130 °. The distance between the branches in the closed position is 0 mm, in the maximum open position - 120 mm. The length of the conical pin is 18 mm, and the distance between the ends of the pins is 9 mm. The diameter of the base of the pin is 2 mm. The device has handles 7 with a rack 8. The removable forks 4 have different sizes, differing in the distances between the pins. They are 9 mm, 12 mm, 14 mm, 18 mm, 20 mm.

The device is used as follows. The threaded pin 6 of the plug 4 is passed through one of the holes in the adapter 3 and fixed with a nut. Through the second hole of the adapter 3, a threaded end pin 2 of the jaw 1 is held and the adapter 3 is fixed with a nut in such a position that the conical pins 5 of the forks 4 are directed downward in one direction parallel to each other and perpendicular to the branches 1. 1.0 cm apart from the osteotomy or a fracture of the tubular bone, form two holes in the cortical plate of each fragment perpendicular to its longitudinal axis along the midline and in the same plane using a drill with a diameter of 1-2 mm or a thick Kirschner spoke, depending on the size of the braids fragments. The distance between the holes is equal to the distance between the conical pins 5 of the plug 4. Into each pair of holes, respectively, the conical pins 5 of the plug 4. Introduce the jaw 1 to come closer and compress the bone fragments. In this position, the ratchet 8 is latched. Next, fixation of the fracture using metal. After that, the device is removed.

If necessary, the connection of fragments at an angle of 180 ^{about the} adapter 3 is installed in a neutral position in the same plane with the branches and fix with a nut. The conical rods 5 of the forks 4 are parallel to each other. The second nut on the threaded pin 6 of the plug 4 remains relaxed. When the jaw is closed, the fragments come closer and come together along one common axial line, which ensures their uniform end emphasis and compression over the entire contact area. If it is necessary to connect the fragments at a given angle, the fork 4 is installed at the required angle equal to the angle at which the fragments are connected in one plane or another. If the junction of the fragments is located in a vertical plane, then loosen the nut fixing the adapter 3 to jaw 1. After installing the plug 4 in a position equal to the angle of fixation, tighten the nut. The nut securing the plug to adapter 3 remains relaxed. When the jaw is closed, the fragments come closer at the required angle and a uniform end stop is achieved. If it is necessary to connect the fragments at an angle located in the horizontal plane, then loosen the nut fixing the fork 4, which is set at the required angle, and then tighten the nut. Tighten the second nut in the neutral position of the adapter 3. Closing the jaw leads to the location of the fragments at a given angle with the necessary end stop. The achieved position is fixed using the cremallera 8. If necessary, the orientation of the bone fragments simultaneously in several planes, the angle of the forks relative to each other is regulated by loosening the nuts on the threaded pins 2 and 6 and tightening the nuts in a predetermined position.

Thus, the device allows you to smoothly control the location and connection of fragments at the required angle in several planes and makes it possible to change the angle of the pair of conical pins relative to each other in different planes depending on the angle of connection of the bone fragments after corrective osteotomy. The device allows you to orient and reliably fix bone fragments in three planes and perform stable osteosynthesis. The device provides uniform end pressure of the bone fragments while maintaining axial ratios, including at a given angle. The device provides fixation of bone fragments at the required angle, which is important when performing corrective osteotomies and osteosynthesis in the conditions of the coming shortening of the segment and the inevitable corrugation of soft tissues in such conditions. The device provides axial self-orientation of the fragments while relaxing the attachment point of the plug to the adapter and ensures coaxiality of the bone fragments in several planes due to the existing mechanism of self-orientation of the bone fragments if necessary to fix them at an angle in the frontal, sagittal or horizontal planes.

The device enables coaxial approach with reliable fixation and compression of fragments in conditions of bone tissue defects, when it becomes necessary to perform osteosynthesis with shortening, in which the oncoming corrugation of soft tissues prevents less traumatic approach and adequate comparison of bone fragments.

The device has an important advantage when connecting bones of various structures (metacarpal bones and wrist bones, metatarsal bones and tarsal bones), as well as spongy bones (wrists and tarsus).

The presence of conical pins ensures minimal contact of the instrument with bone fragments and preservation of their blood supply.

Thus, when using the instrument, minimal tissue trauma and reliable temporary fixation of bone fragments in adverse conditions are achieved. This creates optimal conditions for performing the final osteosynthesis.

The presence of forks of several sizes with conical rods makes it possible to operate on bones of various sizes and structures.

Claims (1)

A device for rapprochement and fixation of bone fragments, containing movably connected jaws with a rack and handles, characterized in that the jaws are made with end threaded pins and are equipped with two removable adapters in the form of a regular quadrangular prism with through holes in mutually perpendicular planes and two removable forks having two conical pins and one threaded pin directed oppositely conical.

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