RU2757153C1 - Intramedullary rod for external and transosseous osteosynthesis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to traumatology and orthopedics, and discloses an intramedullary rod for external and transosseous osteosynthesis. The intramedullary rod is characterised by being made of medical polymer materials, containing an internal thread located on the proximal section, and containing an internal metal insert located in the central part of the rod.

EFFECT: invention can be used in osteosynthesis of long bones in mammals.

8 cl, 11 dwg

Description

The invention relates to medicine, namely to traumatology and orthopedics and can be used for osteosynthesis of tubular bones in mammals.

Improvement of structures for osteosynthesis, the use of minimally invasive techniques, reduction of the operation time due to the simplification and reduction of its stages, is an urgent task of osteosynthesis. For the treatment of fractures, especially fractures of long tubular bones, in surgical orthopedics, intramedullary rods are used, inserted into the broken bone after drilling the medullary canal (US Pat. 2252723, RU, US Pat. 2339325, US Pat. 2714441 RU). In order to exclude rotational displacement of fragments and their shortening in case of multifragmental fractures, the rod is fixed on the support of the external fixation apparatus or on the extraspinal plate using locking screws, which are passed through the corresponding holes in the rod.

Known polymer pins for osteosynthesis (pat. For utility model 47656, 47657, 47657, IPC A61B 17/58, RU, 2004) made of vinylpyrrolidone copolymer with methyl methacrylate grade PPM-1, modified nylon fiber, terlon aramid fiber and with various additives for medicinal purposes. The known rods are of limited use, because due to their excessive fragility, they are effective only for medicinal purposes, but not for osteosynthesis tasks.

A device for surgical intramedullary treatment of tubular bone fractures is known (patent for invention 2358681, RU, IPC A61B 17/72, 2007), containing an intramedullary titanium rod coated with a bioactive coating. The rod has holes for locking screws. The disadvantages of the known device are that the insertion of the rod and, mainly, fixation of the distal part of the rod itself in the fragments of the broken bone are rather complicated operations due to the fact that it is often difficult to center the screws inserted into the holes of the rods. The disadvantages include the high cost of titanium rods. The disadvantage is that the installation completely destroys the structures located in the medullary canal, in particular the bone marrow, blood vessels. During operation, the rod micro-loosening occurs, it does not grow together with the bone and does not stimulate reparative processes. Titanium rods are potentially traumatic due to the fact that the mechanical strength of the titanium rod is higher than the mechanical strength of the injured bone, which provides little resistance to sudden mechanical stress, which leads to its mechanical destruction.

Known Intramedullary nail for osteosynthesis (Pat. For the invention 2239382, RU, IPC A61B 17/72, 2000), in the form of an elongated hollow rod, which is attached to the bone fragments with locking screws. The shaft and locking screws are made of absorbable material. In order to increase its strength, a reinforcing mesh is made in the wall of the rod, which is attached to a sleeve installed at the end of the rod. The sleeve is provided with a thread for a guide for inserting the rod into the medullary canal and under an extractor for removing the reinforcing mesh. The bushing is equipped with a screw plug. The disadvantage of the known rod is the complexity of installation, as well as the fact that it can be used for osteosynthesis of fragments and fragments of cancellous bone that are not subjected to stress.

The objective of the invention Intramedullary nail for immersion and transosseous osteosynthesis is to provide stable fixation of any types of fractures by improving the designs of intramedullary nails for osteosynthesis.

The technical result of solving the problem is to reduce the operation time by simplifying and reducing its stages and using minimally invasive techniques, reducing the cost of the operation.

The claimed technical result is achieved by the fact that the invention is proposed Intramedullary nail for immersion and transosseous osteosynthesis. The rod for immersion and transosseous osteosynthesis is made of a polymeric material for medical purposes (polyethylene, polypropylene, polystyrene, polyamide, silicone, fluoroplastic, etc.) and is supplemented to increase the strength with an internal metal insert, for example, titanium, which is located in the central part of the rod. In addition, polymer rods are made in cross-section as solid, round, triangular, tetrahedral, in the form of a clover leaf.

The differences between the claimed invention and the prototype are that

what:

- intramedullary rods are made of polymeric materials for medical and technical purposes, for example, polyethylene, polypropylene, polystyrene, polyamide, silicone, fluoroplastic, etc., which, in terms of their physical qualities (mechanical strength, hardness, elasticity), can be an alternative to metal products. The elasticity of rods made of polymer materials is higher than that of rods made of titanium alloys;

- intramedullary rods made of polymeric materials for medical and technical purposes are made without holes for locking screws, so the surgeon does not need to aim at a specific hole, he chooses the place of screw insertion, effortlessly drills the bone and the rod in the most convenient place, in terms of fixation rigidity and less traumatization. This simplifies the operation and reduces its duration, and at the same time allows the surgeon to rigidly fix bone fragments with an intramedullary nail in combination with an extramedullary plate or an external fixation device;

- the intramedullary nail made of polymeric materials, due to its elasticity and elasticity, takes the anatomical shape of a pre-drilled medullary canal, reaching full contact with the walls of the canal along its entire length, and maintains bone fragments in combination with an extramedullary plate or an external fixation device in the achieved consolidated position along length with a simultaneous anti-rotation effect until the appearance of primary calluses;

- intramedullary rods made of polymeric materials for medical and technical purposes are made with an internal metal insert, for example, titanium, located in the center of the rod, and are used for installation in a bone in a state of osteoporosis for the necessary reinforcement of the fracture area that can withstand the maximum load;

- polymer rods with a variety of cross-sectional shapes allow the surgeon to choose the most effective means for treating a bone defect;

- when carrying out an X-ray examination, the rods are not radiopaque and do not interfere with the review and assessment of the condition of the fracture area or the osteotomy area;

- intramedullary rods made of polymer high-tech polymer materials for medical and technical purposes have advantages over titanium ones both in terms of cost reduction and in terms of technological processes of their manufacture.

The set of distinctive features of the described device ensures the achievement of the task. These distinctive features allow us to conclude that there is novelty in the proposed technical solution, and their implementation ensures the achievement of a result in solving the problem. The conducted patent search did not reveal solutions having characteristics similar to the claimed invention, which indicates an inventive step. The description and drawings demonstrate the possibilities of implementing the inventions, which gives the right to conclude that the criterion of "industrial applicability" is met.

The claimed invention is illustrated by description and illustrations:

FIG. 1 - polymer intramedullary nail;

FIG. 2 - polymer intramedullary nail with titanium insert;

FIG. 3 - polymeric intramedullary nail with a through groove;

FIG. 4 is a cross-section of a round polymer rod;

FIG. 5 - cross-section of a trihedral polymer rod;

FIG. 6 - cross-section of a tetrahedral polymer rod;

FIG. 7 is a cross-sectional view of a clover leaf-shaped polymer rod;

FIG. 8 - a diagram of the use of an intramedullary polymer nail with an extramedullary plate

FIG. 9 - X-ray image after plate installation and fracture consolidation;

FIG. 10 is a diagram of the use of a polymer intramedullary nail with an external fixation device;

FIG. 11 is a diagram of the use of two polymer rods for fracture consolidation.

Group of inventions An intramedullary nail for immersion and transosseous osteosynthesis is represented by a polymer rod 1 (Fig. 1) and a polymer rod with a titanium insert 2 (Fig. 2) and a polymer rod 3 (Fig. 3) with a through groove.

Polymer rod 1 (Fig. 1) is a rod made of polymeric material for medical purposes (polyethylene, polypropylene, polystyrene, polyamide, silicone, fluoroplastic, etc.) with a solid section. The proximal end of the rod contains a section 3 with an internal thread for easy extraction from the bone. Polymer rod 1 is intended for osteosynthesis in the physiological state of the bone. Polymer rods are able to reduce the shock load on the bone, evenly distribute the bones along the shaft, keep the locking screw or transosseous wire as stable as possible in their thickness, have stabilizing properties, and are also easily inserted into the bone at different angles.

Polymer rod 2 (Fig. 2), made of polymeric material for medical purposes (polyethylene, polypropylene, polystyrene polyamide, silicone, fluoroplastic, etc.), is intended for installation in bone in a state of osteoporosis. The proximal end of the rod contains a section 3 with an internal thread for easy extraction from the bone. To enhance the rigidity of the rod, an internal titanium insert 4 is provided, made integral with the rod 2, located in its central part. When installing the rod 2, one end of the rod is inserted into the distal bone fragment, the other end of the rod 2 is inserted into the proximal portion of the bone, and the portion of the rod with an internal titanium insert 4 is placed in the fracture zone. Locking screws are installed perpendicular to the axis of the intramedullary rod 2, positioning above and below the titanium insert 4, and combined with an extramedullary plate or with an external fixation device (Fig. 8, 10).

Polymer rod 3 (Fig. 3), made of polymeric material for medical purposes (polyethylene, polypropylene, polystyrene polyamide, silicone, fluoroplastic, etc.), contains a through groove 6 located in the distal part of the rod. The through groove 6 provides the possibility of distraction of the tubular bone on the polymer rod using external fixation devices with the possibility of linear movement of the transosseous rods or wires.

The diameter of the rods 1,2 depends on the contours of the diaphyseal tube into which the rod is inserted, and is 2-4 mm for small bones (for example, the shaft of the phalanx of a finger or ribs); 5 mm or more - for the diaphysis of large bones, for example, the humerus, tibia and femur. Polymer rods in cross section are solid round (Fig. 4), triangular, tetrahedral (Fig. 5, 6), in the form of a clover leaf (Fig. 7), or have another polymorphic cross section. The resulting cavities between the nail and the canal can be used to inject drugs directly into the shaft of the bone. Polymer rods 1, 2, 3 have notches on the outer surface, which enhance the osseointegration processes with bone tissue. The inventive intramedullary rods are made by milling semi-finished products and blanks from polymeric materials for medical and technical purposes, as well as by hot pressing, extrusion.

Intramedullary rods in accordance with the invention are used for internal (immersion) osteosynthesis, when for the treatment of fractures, bone fragments are fixed inside the patient's body using, for example, a plate, as well as for external (transosseous) osteosynthesis, when bone fragments are connected using distraction-compression devices external fixation.

Before the operation, an X-ray examination is carried out. If a fracture is detected, a rod or several rods are selected in accordance with the diameter of the bone canal, then the rod is inserted antegrade or retrograde from the central or lateral position, depending on the task set by the surgeon. After the installation of the rod, the appropriate extraal plate is selected (Fig. 8) and the final reposition of the fragments is carried out. Above and below the fracture area, holes of the required diameter are drilled perpendicularly into the bone for locking screws to install the plate: first, the first cortical layer of the bone is drilled, then the rod is drilled, then the second cortical bone is drilled. After placing the plate, locking screws are screwed into the prepared holes, which pass through the plate, the first cortical layer of the bone, are fixed in the thickness of the polymer rod, then pass the second cortical layer, thus achieving the most reliable fixation (Fig. 9). After the bone has healed, the rod can be removed from the bone, or it can remain for life.

When using a polymer rod in combination with an external fixation device (Fig. 10), a polymer rod is installed, after making sure that the bone is repositioned as accurately as possible, blocking rods or pins are inserted transosseously, fixing them on external supports. The introduction of the rod into the canal can be carried out either with a drill or by hammering in. After healing, a thin threaded rod is inserted into the threaded section 3 of the polymer rod for subsequent extraction.

In some surgical cases, several small-diameter rods are used (the total diameter of which corresponds to the diameter of the shaft of the bone). The rods are inserted not axially, but at an angle to the shaft of the bone (Fig. 11), they are inserted into the shaft from different points of application, fixing them on the external supports of the external fixation apparatus.

Claims (8)

1. Intramedullary rod for immersion and transosseous osteosynthesis with an internal thread located in the proximal area, containing a section with a metal insert to increase the strength of the rod, characterized in that the rod is made of polymeric materials for medical purposes, which are polyethylene, polypropylene, polystyrene, polyamide, silicone or fluoroplastic, and supplemented with an internal metal insert, which is located in the central part of the rod, while the internal metal insert is made of titanium. 2. Intramedullary rod according to claim 1, characterized in that the inner metal insert is made of titanium. 3. Intramedullary nail according to PP. 1, 2, characterized in that the polymer rods are made with a through groove. 4. Intramedullary nail according to PP. 1, 3 characterized in that the polymer rods are solid in cross-section. 5. Intramedullary nail according to PP. 1, 2, 3, characterized in that the polymer rods are round in cross-section. 6. Intramedullary nail according to PP. 1, 3, characterized in that the polymer rods are triangular in cross-section. 7. Intramedullary nail according to PP. 1, 3, characterized in that the polymer rods are tetrahedral in cross-section. 8. Intramedullary nail according to PP. 1, 3, characterized in that the polymer rods in cross-section are made in the form of a clover leaf.

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