RU6696U1 - LOCK FOR COMPRESSION OSTEOSYNTHESIS - Google Patents

Abstract

1. A clamp for compression osteosynthesis, comprising a bracket covering a bone made of material with thermomechanical shape memory, characterized in that the bracket made of a plate with a width of 3-7 mm has a curved convex section, closing two located at an acute angle with a radius mate the rectilinear sides of the bracket, one of which is formed by counter-curved short legs of the bracket, and on the side surface of the bracket there is at least one through hole for installing a wave-like loin ostnogo abutment made of a material with thermomechanical memory formy.2. The latch according to claim 1, characterized in that the legs of the bracket are located with a gap of 3 to 6 mm. The latch according to claim 1, characterized in that the transverse emphasis is made of wire with a cross section of 1 to 2 mm

Description

FRGSATOR FOR COMPRESSION OSTEOSYNTHESIS

The utility model relates to surgical devices for osteosynthesis and can be used to treat oblique and comminuted fractures of long tubular bones, mainly of the tibia.

In accordance with 1, the modern concept of surgical treatment of fractures of long tubular bones is based on achieving stable fixation of bone fragments, which allows relieving pain and ensuring complete mobility of adjacent joints.

At the same time, the structures used for osteosynthesis must have sufficient mechanical strength and provide constant compression of the fracture in order to achieve primary fusion without the formation of bone marrow.

At the same time, along with the mechanical aspect of stable fixation, preservation of the natural biological conditions of blood supply to the bone and adjacent soft tissues is no less important for the effective restoration of limb functions.

Known device 2 for stabilizing a fracture of a long bone on the basis of a rigid plate with tightening bracelets and intraosseous fixing screws and device 3 made of a polymer material compatible with coA61B 17/58

A strap containing bone bracelets, tires of various lengths and lock bolts.

A common disadvantage of these devices is the extensive contact surface with the bone, which impedes the normal blood supply to the bone and tissues.

A device for osteosynthesis 4 is also known, containing transosseous rods with locking heads, in which through holes for strings are made, through which longitudinal compression of bone fragments is carried out.

The disadvantage of this device is the high invasiveness of the operation associated with drilling holes in the bone directly near the fracture site, and an insufficient level of compression due to the stretching of thin strings within the framework of severe deformation of the material.

A new direction in the design of devices for osteosynthesis, which have sufficient mechanical strength and provide a constant level of compression during the treatment of fracture with limited contact with the bone, is associated with the widespread use of materials with thermomechanical memory form 5.

So, in the treatment of simple fractures, to ensure longitudinal compression, staples with inclined legs inserted into the bone and wire 5, s. 21.6 or lamellar 7 osseous extensions.

However, in the treatment of oblique and comminuted fractures, the use of these devices is not effective, since they do not provide anti-lateral compression

bone necessary for stable fixation of the fracture.

Known transosseous retainer 8, made of a material with a shape memory effect. The fixator, designed for osteosynthesis of oblique fractures, is made in the form of a longitudinal rod, split with the formation of arched legs curved in opposite directions, fixed on the bone surface with lock washers. At the diametrically opposite end of the rod there is a compression section in the form of z-shaped bone stops.

The disadvantage of device 8 is the uneven effect of the compressive load distributed on the surface of only one of the bone fragments and concentrated on the surface of the opposite. In addition, the installation of the latch is associated with the drilling of holes that further weaken the bone.

Known two- and four-jaw wire ring-shaped clamps 5, p. 22, fig. 10, providing an external entanglement of the bone with the distribution of the covering branches along the length of the bone fracture. Due to the elastic properties of the shape restoration of the material with shape memory, the device provides uniform compression over the fracture surface with limited contact with the bone.

The disadvantage of the device with respect to the tibia is the inadequacy of the shape of the round branches of the shape of the anatomical section of the bone.

As a prototype of the proposed utility model, a clamp for compression osteosynthesis 9, made of a material with a thermomechanical shape memory, is adopted. The device consists of an arcuate curved staples of circular cross section, covering the bone, and a support plate of porous material, along the edges of which there are holes for the introduction of the legs of the symmetrical branches of the bracket bent into the legs.

The disadvantage of the prototype device is the low reliability of fixation due to the inadequacy of the rounded shape of the staples to the shape of the anatomical section of the tibia. This leads to overload of the bone at the contact points of the transmission of the compressive effect of the fixative on the bone and can lead to its eruption.

The objective of the utility model is to provide reliable stable fixation of oblique and comminuted fractures of the tibia.

To solve this problem, in the fixative for compression osteosynthesis of the predominantly tibia, made of a material with thermomechanical shape memory in the form of braces covering the bone, the stained brace is made of a plate 3-7 mm wide, which has a curved convex section that closes two located under the sharp angle with radius mating, rectilinear sides, one of which is formed by counter-curved legs of the bracket, on the side surface of which at least one through a hole for installing a wave-like transverse stop made of wire with a cross section of 1-2 mm with thermomechanical shape memory, and the legs of the bracket are located with a gap of 36 mm.

The essence of the utility model is illustrated by drawings, on which are presented;

FIG. 1 - retainer, general view;

FIG. 2 - transcutaneous emphasis to the latch;

FIG. 3 is a diagram of the coverage of the tibial staple in various sections of the anatomical section.

As shown in FIG. 1, the latch comprises a brace 1 surrounding a bone, made of a curved plate with a width A and thickness k, with through holes 2 on the side surface, and a transosseous wire stop 3 (see Fig. 2), the first end 4 of which is installed in one of the holes 2 staples 1, and the second end 5 is inserted through the medullary canal until it stops in the opposite inner wall of the bone. The width L 3-7 mm and the thickness k 1.5-2 mm of the bracket 1 are selected from the condition of optimizing the contact area of the transmission of the compressive load on the bone and ensuring the mechanical strength of the structure. The diameter / 1-2 mm of the cross section of the wire transosseous emphasis 3 is selected from the condition of obtaining sufficient compressive force with a slight injury to the bone.

The shape of the bracket 1 (see Fig. 3) was selected taking into account the maximum approximation to the shape of the anatomical structure of the tibia, which throughout the length has a pronounced sharp protrusion formed by the lateral sides of the bone, and in the section from the middle third downwards has a section close to triangular form. In accordance with the indicated bracket 1 has two straight sides A and B located at an acute angle with a radius mate of the sides. In this case, one of the sides A (B) of the bracket 1 is formed by counter-curved short legs 6 and 7 located with a certain gap / in the middle of this side. The clearance mm is adjustable

depending on the anatomical features of a particular bone compared with the average parameters. The third side C, closing the angular sector of the bracket 1, when using the retainer in the upper third of the tibia, is figured-convex, and in the retainers intended for the underlying sections of the bone, it has a rectilinear section conjugated by smooth fillets with the lateral sides A and B of the bracket 1.

To form a set of retainers used on any tibia section, 12 sizes of staples are proposed, the geometric proportions of which are given in the table

Details 1 and 3 of the retainer are made of a material with a thermomechanical shape memory, for example, titanium nickelide of the ТН-10, ТН-20 or ТН-1ХЭ grades.

For the manufacture of staples 1 and transverse emphasis 3 of the retainer use templates. The staple templates of the corresponding size according to table 1 are made according to the cross-sectional shape of the anatomical section of the tibia, provided that the perimeter of the template (staple length) is 10-20% less than the perimeter of the real bone section. The blanks of titanium nickelide plates with a width of 3-7 mm and a thickness of 1.5-2 mm are heated

to a temperature above 400 C and bend according to the template, shaping the brackets, rounding the corners and placing counter-curved legs 6 and 7 of brackets in a line with a small gap of 3-6 mm between them. The formed brackets are cooled, and then through holes 2 are drilled, distributing them evenly along the length of the bracket 1. The hole size is selected depending on the diameter d of the cross-section of the transverse stop wire 3. The stop 3 is made of 30-35 mm wire. They are formed in a preheated state according to the template, giving the emphasis a wavy shape with a slight horizontal straightening of one end 4 and a hook-like bend down the second end 5. The blanks 1 and 3 of the clamp are sterilized and hermetically packaged.

The device is used as follows.

During the operation, the fracture site is exposed, blood clots and small bone fragments are removed. Fragments of the bone are repaired and held by the bone holder. An appropriate size bracket 1 is selected, which is cooled with chloroethyl or in a tray with a cold (below + 10 ° C) sterile liquid, legs 6 and 7 of the structure are partially straightened and the bracket is shaped to fit on the bone. After 15-20 seconds, as the contact is heated, the latch exhibits the effect of thermomechanical memory and tends to take its original shape. Due to the elasticity of the structure, uniform circular compression and fixation of bone fragments is achieved. To create additional compressive force in a plane perpendicular to the line of the inclined (comminuted) fracture, use the transcutaneous abutment 3. For this, a bone is drilled through one of the holes 2 of the brackets 1 and a pre-straightened abutment wire 3 is inserted inside, positioning it obliquely in the medullary canal and, if possible perpendicular to the line of bone fracture. After heating, the wire is compressed, taking the form of a wave-like spring, providing an additional compressive effect on the bone. After this, the surgical wound is sutured in layers tightly. For the period of wound healing, before removal of the sutures, external immobilization is applied, for example, with a plaster cast.

In the case of a significant fracture, several fixators of the appropriate size are installed. Installation is carried out alternately in the same sequence of operations.

The advantage of the proposed utility model in comparison with the known structures is the combination of simplicity and high reliability of fixation while minimizing the contact surface of the fixator with the bone. The design allows you to restore the integrity of the bone with minor trauma to the intraosseous element and allows you to maximize preserve the natural conditions of blood supply to the bone and adjacent soft tissues.

The industrial applicability of the utility model is determined by the fact that, using the above description and drawings, the latch can be made of materials known in the practice of orthopedics using known technology and used for its intended purpose for compression osteosynthesis of the tibia.

LIST OF REFERENCES

1. J. Schatker. Osteosynthesis Results of the XX century. - Herald. - 1996, No. 5. - S. 3-6. 2. Germany, application No. 3933217, IPC АВВ 17/58, publication 11.04.91. 3. EPO, application No. 462493, IPC A61B 17/58, publication 12/27/91. 4 . USSR, auth. testimonial. No. 1648428, IPC А61В 17/58, publication 05/15/91.

5. Guide to osteosynthesis with fixators with thermomechanical shape memory. Volume 1. Compressing brackets and ring-shaped clamps .: Novokuznetsk. - 1996.

6.SSSR, ed. testimonial. No. 1657172, IPC A61B 17/58, publication June 23, 91.

7. France, application No. 2668361, IPC A61B 17/58, publication 04/30/92.

8. USSR, ed. testimonial. No. 1621904, IPC A61B 17/58, publication 01/23/91.

9. USSR, ed. testimonial. No. 1676607, IPC АВВ 17/58, publication September 15, 91, (prototype).

Claims (3)

1. A clamp for compression osteosynthesis, comprising a bracket covering a bone made of material with thermomechanical shape memory, characterized in that the bracket made of a plate with a width of 3-7 mm has a curved convex section, closing two located at an acute angle with a radius mate the rectilinear sides of the bracket, one of which is formed by counter-curved short legs of the bracket, and on the side surface of the bracket there is at least one through hole for installing a wave-like loin ostnogo abutment made of a material with thermomechanical shape-memory.  2. The latch according to claim 1, characterized in that the legs of the bracket are located with a gap of 3 to 6 mm 3. The latch according to claim 1, characterized in that the transverse emphasis is made of wire with a cross section of 1 to 2 mm