RU2526242C1 - Intramedullary blocking device for osteosynthesis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: device contains an elongated body in the form of a triangular rod with sharpened ribs, proximal and sharpened distal ends, a longitudinal axial through channel with a possibility of passing a guide through it. From the butt end side of the proximal end of the body a detachable lid is fastened. The rod is made extending from the central axis outwards towards the side of the proximal end. From the side of the distal end of the rod on its ribs made are areas with rasp-like notches to provide a possibility of extension of the intramedullary canal diameter in the cortical layer in the process of the device introduction. In not less than one rib from the distal end side of the rod made is a groove for introduction of a blocking screw.

EFFECT: invention makes it possible to ensure stable fixation of fragments of tubular bones fragments taking into account configuration of the medullary canal and reduce trauma of the performed surgical operation.

14 cl, 1 ex, 4 dwg

Description

The invention relates to medical equipment used in traumatology, and is intended for the treatment of fractures of the tubular bones, in particular the femur, by conducting intramedullary osteosynthesis.

There are various designs of intramedullary blocking devices [SU copyright certificates for inventions No. 1454430, No. 1787020, RU patents for inventions No. 2102027, No. 2120790, RU patents for utility models No. 47658, No. 61542]. All of them have an extended body in the form of a rod with a rectangular cross section.

Also known is the “Rod for fixing the position and shape of the tubular bones” [RU patent for utility model No. 100717]. It contains an expansion element located along the longitudinal axis of the rod, which is made in the form of a hollow tube with ribs made of biocompatible materials. In the initial state, the expansion element has a cross section close to a triangular profile. The expansion element is configured to fill its inner cavity and increase its cross section in the radial direction. The rod also contains a head and an end nozzle located respectively at its proximal and distal ends. The interface between the end nozzle and the head with the expansion element has a shape close to triangular, the same as the expansion element in the initial state.

However, this device is designed to fix bone fragments with filling the entire space of its bone marrow canal. When the rod is stabilized in the medullary canal due to its expansion by increasing pressure in the rod cavity, an increase in pressure in the medullary canal is also observed. This fact can lead to the development of thrombo- or fat embolism both in the microcirculation pool (Haversian system) and in the macroorganism (pulmonary artery system, brain, etc.), which contributes to the development of complications of varying severity (from bone regeneration disorders to death). Ensuring a tight fit of the rod to the walls of the medullary canal leads to compression of large intraosseous vessels and a violation of the blood supply to the bone, which negatively affects its fusion. Any use of complex systems (valves) is fraught with the risk of their failure both at the stage of pressurization (stabilization by expansion of the rod) and its alignment with the environment (compression of the rod), which causes difficulties in removing the metal structure expanded in the form of the medullary canal.

The closest analogue to the claimed invention is a "Fixator for the treatment of fractures of the tubular bones" [SU copyright certificate for invention No. 992041], made in the form of a three-blade rod. In order to increase the rigidity of fixation of bone fragments on the blades of the shaft, grooves are made.

However, with the introduction of this fixative, the elastic blades of the rod, deforming, fill the medullary canal along the entire length, taking the shape of the canal and providing close spring-loaded contact with its walls. This fact negatively affects the integrity of the intraosseous vessels that affect bone fusion.

The magnitude of the spring-loaded effect is difficult to calculate taking into account different anthropometric characteristics of people, which can negatively affect the initial stiffness of fixation of bone fragments. Ensuring constant close contact of the fixative with the walls of the bone marrow canal leads to necrotization of the tissues of its adjacent surface, being a focus of aseptic inflammation, and in the presence of pathological microorganisms, it is possible to go into the phase of septic inflammation, which will require a change in treatment tactics.

The task of the invention is to ensure stable fixation of fragments of the tubular bones, taking into account the configuration of the medullary canal while reducing the morbidity of the surgical intervention.

The essence of the claimed invention is characterized in that the intramedullary blocking device for osteosynthesis comprises an extended body in the form of a trihedral rod with pointed ribs, a proximal and pointed distal ends, a longitudinal axial through channel with the possibility of a guide through it, while a removable is fixed from the end side of the proximal end of the body cap; the rod is made expanding outward from the central axis toward the proximal end, from the side of the distal end of the rod, sections with notches of the rasp type are made on its ribs to allow expansion of the diameter of the medullary canal in the cortical layer when the device is inserted; at least one of the ribs from the side of the distal end of the rod has a recess for introducing a locking screw. A device is also disclosed with the above-described features, in which at least one of the ribs from both the proximal end and the distal end of the rod has a recess for introducing a locking screw, in particular cases, at least two recesses spaced apart along the rod. In this case, the recesses for the locking screws have a rectangular shape with a length along the body larger than the diameter of the locking screw. In addition, a device with the above features is also claimed, in which the length of the sections with notches along the body is 30-60 mm, and the extension length of the rod along one of the ribs exceeds the extension length along the other two. A device with the above-described features is also claimed in which a slot is made at the proximal end of the lid, in the center of which there is a hole with a diameter equal to the diameter of the through channel of the rod.

A device with the above-described features is also claimed, in which, from the end side of the proximal end of the rod, the faces are beveled 3-7 mm along the outer edge and are pointed. In addition, a device with the above-described features is also claimed, which is made of a solid bioinert material with the possibility of applying polymer materials or metals to its outer surface.

A device with the above-described features is also claimed in which the rod has a bend, and its outer diameter in the middle part is 1-2 mm larger than the diameter of the medullary canal of the damaged bone.

The technical result of the claimed invention.

 The implementation of the rod with an extended through channel allows you to enter the device into the damaged bone along the guide by the type of spokes installed less traumatic under x-ray control. The insertion of the rod begins with its pointed distal end, in the area of which rasp incisions are made on the ribs, which make it possible to cut the cortical layer of the apophysis of the hip (the site of insertion of the rod in the greater trochanter) and the medullary canal, including the cortical layer of anatomical narrowing in the middle third of the femur, on the trihedral shape of the rod, which greatly facilitates its installation with minimal trauma.

The trihedral shape of the rod eliminates damage to the intraosseous vessels adjacent to the cortical layer of the bone. The trihedral shape of the rod expanding from the central axis outward toward the proximal end with pointed ribs allows the rod to be inserted with increasing force, filling the anatomical expansion of the medullary canal in the upper third of the diaphysis and firmly fixing the structure in the spongy structure of the trochanteric bone region. The design features of the device make it possible to ensure a tight insertion of the trihedral shape of the rod into the medullary canal, to cut the cortical layer in the middle third and the proximal metaphysis of the femur, and therefore to obtain stable fixation of fragments and completely eliminate rotational overloads.

The implementation of the recesses for the locking screws allows, after introducing the rod into the medullary canal to prevent displacement along the axis, to block the position of the claimed structure in the distal, and, if necessary, also proximal area of the rod. Moreover, this type of blocking allows the rod to be fixed eccentrically to the bone axis, which reduces the distance from the cortical bone plates, and this increases the stability of the bone-fixer system. The large length along the rectangular-shaped body of the recess in the edge of the rod, namely more than the diameter of the locking screw, makes it easier to get the latter into its corresponding recess.

The presence of at least two recesses on the ribs of the rod, remote from each other along the rod, allows, if necessary, the blocking of the rod at different levels and in different planes, which during multi-fragmented fractures will create high-quality fixation of fragments.

The presence of pointed beveled faces along the outer edge by 3-7 mm from the end side of the proximal end of the rod allows them to cut the newly formed spongy bone in the region of the greater trochanter (injection site) while removing the metal structure, reducing the morbidity of the manipulation.

The presence on the end of the core of the removable cover with a slot, in the center of which a hole is made with a diameter equal to the diameter of the through channel of the rod, allows you to install the cover in the direction without expanding the operational access.

The manufacture of the inventive device from a solid bioinert material with the possibility of applying various polymer materials to its surface allows you to directly affect the pathological focus, prevent infectious complications, reduce the time of bone fusion and increase the effectiveness of treatment.

The invention is illustrated using Fig.1-3, which depict: Fig.1 is a General view of the device, Fig.2 is a view from the proximal end of the rod, Fig.3 is a view from the side of the distal end of the rod, Fig .4 - device cover. In figure 1-4, positions 1-12 are indicated:

1 - rod;

2 - ribs;

3 - proximal end of the rod;

4 - the distal end of the rod;

5 - through channel;

6 - a cover;

7 - slot;

8 - hole cover;

9 - plot extension rod;

10 - section with notches;

11 - recesses for locking screws at the distal end;

12 - recesses for locking screws at the proximal end.

The intramedullary blocking device for osteosynthesis contains an extended body in the form of a trihedral rod 1 with pointed ribs 2, proximal 3 and pointed distal 4 ends, a longitudinal axial through channel 5 with the possibility of passing a guide through it like a spoke. The device is made of a solid bioinert material with the possibility of applying polymeric materials, for example, carbon or bioceramic coatings, as well as antiseptic and antimicrobial coatings, including various metals, in particular gold, to its outer surface. The outer diameter of the rod 1 in its middle part is 1-2 mm larger than the diameter of the medullary canal of the damaged bone. Rod 1 has, depending on the anatomical segment, a bend with a radius of about 1500 mm.

A removable cover 6 is fixed on the end side of the proximal end 3 of the rod 6. A slot 7 is made on the proximal end of the cover 6, in the center of which there is an opening 8 with a diameter equal to the diameter of the through channel 5 of the rod 1. The rod 1 is made expanding 9 from the central axis outward to the proximal end 3.

The length of the expansion section 9 of the rod 1 along one of the ribs 2 exceeds the extension length along the other two. For osteosynthesis of the femur, for example, the length of the extension along two of the ribs 2 is about 1/8, along the third - 1/4 the length of the entire device. From the side of the distal end 4 of the rod on its ribs 2 there are sections with incisions 10 of the type of rasp to enable expansion of the diameter of the medullary canal in the cortical layer with the introduction of the device. The length of the sections with notches 10 along the rod 1 is 30-60 mm Not less than in one of the ribs 2 from the side of the distal 4 and proximal 3 ends of the rod 1 can be made recesses 11, 12 for the introduction of locking screws. In individual cases, both from the side of the proximal end 3 and the distal end 4 of the rod 1, at least two recesses 11, 12 can be made, spaced from each other along the rod 1.

An intramedullary blocking device for osteosynthesis works as follows.

An x-ray study is carried out, according to which the localization of the fracture, the size and shape of the injured bone, such as the femur, are evaluated. The patient is placed on the operating table in the supine position on the healthy side, the surgical field is treated and its restriction with sterile material. Under aseptic conditions, after performing a closed reposition, for example, using the device described in RU patent for utility model No. 114601, 3-7 cm surgical access is made to the end of the greater trochanter, into which, under X-ray control, a guide is introduced in the form of a spoke along the axis of the medullary canal passing the fracture line to the middle of the distal fragment. A cannulated drill of the order of 10 mm in the cortical and metaphysical part of the greater trochanter, according to the established needle, form an opening to the medullary canal of the proximal femoral fragment. According to preliminary data from a set of sizes of intramedullary blocking devices for osteosynthesis, a device is selected with the necessary length equal to the length of the medullary canal and a diameter in the middle part exceeding the latter by 1-2 mm. Assemble the device in working condition. To do this, an adapter is fixed to the rod body from its proximal end. The pointed end of the rod is inserted along the guide in the form of a spoke into the hole formed by means of a drill in the medullary canal and by striking an adapter fixed from the side of the proximal end of the rod, providing the latter to move along the thigh axis in the forward-backward direction using rasp notches made on the ribs of the rod, a trihedral channel is formed along the entire length of the thigh, including the cortical layer at the site of the anatomical narrowing of the thigh, under the rod. Then, the rod is inserted before the end part of its proximal end is immersed in the greater trochanter, while ensuring that the distal end of the rod does not reach the articular surfaces of the bone by less than 3 cm.Anatomically, the anatomy of matching fragments, the correct insertion of the rod, and the fixation stability are checked by x-ray.

In necessary cases, for example, with multi-fragmented fractures and osteoporosis, an additional blocking of the entire device is carried out with locking screws passing through both cortical layers of the bone and the recesses in the ribs of the shaft. The number of locking screws and their location (through which edge of the rod to enter them) is determined individually depending on the clinical situation.

The adapter is removed. At the proximal end of the rod from its end side, for example, using a cannulated screwdriver, a cover with a slot is fixed, putting its hole on the guide. The latter is recovered. The wound is sutured in layers and proceed with rehabilitation measures. After consolidation of the fragments, the device is removed in the reverse order.

Example

The claimed invention is implemented in an experimental sample and is preparing for practical testing in a medical institution. Found constructive improvements are biomechanically justified and justified their constructive expediency.

Claims (14)

1. An intramedullary blocking device for osteosynthesis, characterized in that it contains an extended body in the form of a trihedral rod with pointed ribs, a proximal and pointed distal ends, a longitudinal axial through channel with the possibility of a guide through it, while fixed from the end side of the proximal end of the body removable cover; the rod is made expanding outward from the central axis toward the proximal end, from the side of the distal end of the rod, sections with notches of the rasp type are made on its ribs to allow expansion of the diameter of the medullary canal in the cortical layer when the device is inserted; at least one of the ribs from the side of the distal end of the rod has a recess for introducing a locking screw. 2. The device according to claim 1, characterized in that at least in one of the ribs from the side of the proximal end of the rod is made a recess for introducing a locking screw. 3. The device according to claim 2, characterized in that the recesses for the locking screws have a rectangular shape with a length along the housing greater than the diameter of the locking screw. 4. The device according to claim 2, characterized in that at least two recesses are made from the side of the proximal end of the rod, spaced apart from each other along the rod. 5. The device according to claim 1, characterized in that on the side of the distal end of the rod is made of at least two recesses, remote from each other along the rod. 6. The device according to claim 1, characterized in that the length of the sections with notches along the distal end of the housing is 30-60 mm 7. The device according to claim 1, characterized in that the extension length of the rod along one of the ribs exceeds the extension length along the other two. 8. The device according to claim 1, characterized in that a slot is made at the proximal end of the lid, in the center of which there is an opening with a diameter equal to the diameter of the through channel of the rod. 9. The device according to claim 1, characterized in that from the front side of the proximal end of the rod, the faces are beveled 3-7 mm along the outer edge. 10. The device according to claim 9, characterized in that the beveled edges are made pointed. 11. The device according to claim 1, characterized in that it is made of a solid bioinert material with the possibility of applying polymer materials to its external surface. 12. The device according to claim 1, characterized in that it is made of a solid bioinert material with the possibility of applying metals to its external surface. 13. The device according to claim 1, characterized in that the outer diameter of the rod in its middle part is 1-2 mm larger than the diameter of the medullary canal of the damaged bone. 14. The device according to claim 1, characterized in that the rod along its length has a gentle bend.

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