RU2712131C1 - Carbon plate for osteosynthesis of long bones fractures - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention refers to medicine, particularly to traumatology and orthopedics. Disclosed is a carbon plate for osteosynthesis of long bones fractures, characterized by that the plate is made of carbon nanostructured composite material; length of the plate varies from 120 to 240 mm, and width is 15–18 mm; plate has two end sections equal to one-third of the plate length each, with thickness of 2 mm at the end with a cone-shaped increase in thickness of up to 5 mm at the border with a middle third and a middle third with thickness of 5 mm, overlapping the fracture line; has holes in one or two rows for plate fixation to bone; plate is made with possibility to insert clips through holes in plate into holes of adjoining cortical plate of bone, and with possibility of screwing in lengthwise conical channel of core clips having thread in head area, as a result of which clip end tabs diverge.EFFECT: invention provides osteosynthesis of fractures of long bones using non-metallic material, having mechanical strength, bio-inertia and biocompatibility with surrounding tissues, high plasticity, and also reduces length of rehabilitation.1 cl, 6 dwg

Description

The inventive device relates to medicine, in particular to traumatology and orthopedics, and can be used in the surgical treatment of bone fractures, including those with a multi-fragmented nature.

Known plate Lena, one of the first plates used in traumatology and orthopedics for osteosynthesis. It is made of steel. The main disadvantage of this plate is its size and small thickness. Due to frequent fractures of the plate at the level of a bone fracture, it is currently practically not used.

Over the past 40-50 years, a large number of metal plates have been proposed (Kaplan A.V., Antonova A.I., Tkachenko S.S., Sivasha K.M., Demyanova V.M., Kalnberza V.K.) the form and material from which they are made. The first plates were made of stainless steel, in recent years - from titanium.

Currently used perforated mounting plates, dynamic compression ones - DCP, LC-DCP, L, V, T - shaped, with limited contact and others (N.V. Kornilov, E.G. Gryaznukhin, “Traumatology and Orthopedics. Guide for Doctors, Volume 1, pp. 324-325, Hippocrates. 2004; Müller M., Allgover M., Schneider R., Willinegger X. Guide to Internal Osteosynthesis, 1996 - p. 241; plates for osteosynthesis, lower leg osteosynthesis plates - wwwcito.pro/ru/index?option=com_content/&view-article&id=184). Offering new designs of plates, the authors pursued the goal - to minimize damage to the periosteum and create conditions for the formation of bone bridges under the plate itself near the fracture line.

The main disadvantage of the metal plates used is the introduction of a large number of through screws into the bone fragments. This creates the prerequisites for weakening the mechanical strength of the bone and its additional fracture at the level of one of the screws. The second disadvantage is the instability of the plates to alternating loads with functional loads on the limb, which leads to fatigue fractures of the plates at the level of contact of bone fragments. To exclude such a complication, plates began to be produced in the form of a gutter and thicker (up to 5-6 mm or more). This has led to a decrease in their elastic properties, which has recently been the main reason for tearing screws out of the bone and violating stability in the fracture zone.

A large number of inserted screws, an increase in plate thickness is the cause of the development of infectious complications, impaired periosteal circulation, the development of bone necrosis and widespread osteoporosis. This is the natural biological response of the bone. (VV Klyuchevsky. Surgery for injuries. - Yaroslavl - Rybinsk. - 2004, p. 261)

It should be added that after the consolidation of bone fragments is achieved, the metal plates must be removed, often with great difficulty. Therefore, there is a constant search for new materials and methods of fixing plates to bone fragments.

So, in the USA in 2008 L.D. Efskind and T.E. Idsoe received US20090263458A1 patent for the development of a composite material for surgical use in bone fractures. This material consists of two parts: the first one consists of a biocompatible polymer matrix capable of transforming under natural conditions into a substantially liquid phase by energy release, and the second component is able to solidify the biocompatible polymer matrix with energy absorption. The authors themselves believe that the proposed composite material refers to a temporary biocompatible structure to enhance osteosynthesis in bone fractures.

Given the experience gained, the author of this invention proposed a non-metallic plate, namely from a carbon nanostructured composite material.

The prototype for creating the carbon composite material was the human bone structure, which is a kind of composite material, the ossein being the reinforcing base, and calcium salts being the matrix.

Xinfeng Shi, Balaji Sitharaman at all (Biomaterials. 2007 Oct; 28 (28): 4078-4090) carried out laboratory studies of the porosity of carbon composite materials on their mechanical stability and the possibility of bone growth in the pores of the material. As a result of their studies, they found that with an increase in pore size, bone growth in them is more active, but the mechanical strength of the composite decreases. Therefore, it is necessary to select the composite in such a way as to preserve the basic properties when used as implants. These studies overlap with studies conducted by a group of our experts [Gordeev S.K. et al. (2007. 2014)].

Known works of Gordeev S.K. [(Gordeev S.K. Carbon nanocomposite materials from nanodiamond: preparation and properties // Superhard materials, - 2002. - No. 6. - P. 60-67), Gordeeva S.L. et al. (Gordeev S.K., Belov I.M., Korchagina S.B. Material Science Aspects of Carbon Nanostructured Implants. // Mat. Second Scientific and Practical Conf. “Introduction of Clinical Practice of Carbon Nanostructured Implants: Preliminary. results and prospects. ”SPb., 2014)], which established that in its properties (density, compressive strength, flexural strength, compressive modulus) carbon is close to the properties of human bones.

From this point of view, back in the 60s, specialists began to use carbon in medicine as an implantable material. Its main advantage is inertness towards living tissues. However, the mechanical properties of ordinary carbon did not allow its use in conditions of significant and even moderate mechanical loads. The increased interest in carbon is due to the creation of a new generation of carbon materials, the mechanical properties of which can be set and regulated to a considerable extent. The ability to simulate the properties of carbon materials according to the parameters of native bone tissue, its germination in the pores available in the implants made it possible to consider the biomechanical system of the bone - carbon implant as a whole

Sinani I.L. et al. (2012) in the laboratory conducted studies of carbon composite materials on mechanical strength and other chemical-physical properties. They found the lack of response when implanting them into a living organism. Based on the conducted experimental studies, figured plates were developed for osteosynthesis of fractures of the lower jaw, replacement of defects of the flat bones of the skull after injury. To fix a fracture of the lower jaw, a cortical plate was removed to a depth of 2 mm in the shape of the plate. The fixation of the latter was carried out by kapron thread, metal screws or titanium brackets. Plates for replacing defects in the bones of the skull had an ellipsoid or round shape, bending along the plane in the shape of the skull. Their fixation was carried out with titanium brackets. An attempt was made to produce a hip joint prosthesis (I. L. Sinani, A. G. Schurik et al. Carbon - carbon materials for orthopedics and traumatology. Russian Journal of Biomechanics, 2012, V. 16, No. 2 (56): 74-82) .

The use of carbon fixators in dentistry to replace defects in the lower jaw bone is the subject of dissertation research by Rapekta S.I (2008), Astashina NB (2009) [Rapekta S.I. Plastic surgery of defects of the lower jaw with carbon implants “Uglekon-M”. Dcc. Candidate of Medical Science, Perm, 2008, 117 pp. Astashina N.B. Comprehensive treatment and rehabilitation of patients with acquired defects of the jaw (experimental clinical study). Diss. Doctor of Medical Sciences, Perm, - 2009. - 272 pages].

Along with dentists, carbon implants began to be used in traumatology and orthopedics. So, Zaratsyan A.K. (1990), Scriabin V.L. (2010) reported the use of carbon implants to replace bone defects resulting from the removal of benign tumors, when replacing defects of the integumentary bones of the skull and fractures of long bones (Zaratsyan AK, Submersible osteosynthesis with carbon structures. Abstract. Diss ... MD ., M., 1990; Scriabin VL New carbon implants in reconstructive surgery of bones and joints. Abstract of thesis ... Doctor of Medical Sciences. - Perm.-2010. -199 p.).

But for osteosynthesis of fractures of long bones, plates were made like metal, their thickness did not exceed 2 mm. (Zaratsyan A.K. Surgical treatment of fractures using carbon structures / A.K. Zaratsyan, S.D. Tumyan // Orthopedist. Traumatol. And prosthetics. - 1988. - No. 7. - C 29-32). The plate was fixed to the bone fragments by carbon screws. When using carbon plates, the authors note a large number of complications associated with the insufficient mechanical strength of carbon structures. The plates broke at the level of the bone fracture, the screws were cut off at the screws or the heads twisted. In such situations, it was necessary to drill a screw and cut new threads into the bones.

Known plate M.Yu. Kollerova et al. (Patent RU2488361C1) for the correction of funnel chest deformity. But this plate is significantly different from the proposed author of this invention.

1. The plate according to patent ru2488361С1 differs from that proposed by the author in terms of its functionality. The metal plate according to the patent is intended for the correction of the funnel-shaped deformation of the chest without violating the integrity of the bone skeleton, the carbon plate proposed by the author is for fixing bone fragments in case of bone diaphysis fractures.

2. The plate according to patent RU2488361C1 in the description is depicted rectilinear, which is not true, since it is not possible to correct the existing deformation of the chest with a straight plate.

To correct the existing deformation of the chest when installing the plate, it is given a working position - an arched shape. Then the arch is introduced into the cavity of the chest, the top of the arch of the plate is brought under the sternum pulled inwardly and the pressure of the sternum from the front in front is brought out to normal position. The plate proposed by the author has a working rectilinear shape and does not exert pressure on the bone underneath.

3. The plate according to patent RU2488361C1 has a different thickness of the Central part and the end departments. The thicker central part passes into the end sections through a short bevel. The end sections have a greater length than the central part, throughout the entire length they have the same thickness. In the plate claimed by the author, the central part and the end sections have the same length, the end sections have a conical shape, their height gradually decreases from the central part to the ends of the plate.

4. Plate according to patent RU2488361C1 - on its body there are no holes for fixing screws. The inventive plate has one or two rows of fixation holes.

5. For fixing the plate according to patent RU2488361C1, there are two additional plates with eyes. After installing the arcuate curved plate at the workplace, eyes of additional plates are put on its ends, mounted perpendicular to the longitudinal axis of the main plate. Through the openings in the additional plates, the latter are fixed with sutures to the chest wall. The inventive plate does not have additional mounting nodes.

Thus, the carbon plate proposed by the author differs significantly from the plate according to patent RU2488361C1 by the material from which it is made, the working form and functionality. Therefore, it meets the criterion of "novelty."

The present invention is to develop a device for osteosynthesis of fractures of long bones in order to improve the fixation of bone fragments, reduce the number of complications and increase the effectiveness of treatment.

The technical result is the creation of a device for osteosynthesis of fractures of long bones from a new material with mechanical strength, bioinertness and biocompatibility with surrounding tissues, high plasticity, the absence of fatigue inherent in metal products, which reduces the rehabilitation time of patients.

As a result, over time, the fixation of bone fragments does not weaken, as is observed during osteosynthesis with metal fixatives, but increases. Not only is the consolidation of bone fragments achieved, but the plate is firmly fused with the bone, forming a bone-carbon conglomerate, as reported by other authors. Therefore, plate removal is not required.

To exclude destructive effects on the plate, its configuration was changed. The total length of the plate is divided into three parts: the end parts have a gradually increasing thickness from the periphery to the center - from 2 mm to 5 mm. The middle third of the plate has a constant thickness of 5 mm. It overlaps the fracture line. The plates are made in two versions. In one embodiment, the holes for fixing the plate to the bone are applied in one row, in the other in two rows (Fig. 1,2). The length of the plates ranges from 120 to 240 mm. Fixation of the plates to the bone is carried out not with screws passing through both cortical plates, but with clips. Clips insertion holes are drilled in only one cortical bone plate adjacent to the carbon plate. This configuration and fixation of the plate eliminates the destructive effect of alternating forces in the fracture zone, which prevents the destruction (possibility of fracture) of the plate after osteosynthesis. The exhausted ends of the carbon plate increase its elasticity, which eliminates the possibility of tearing clips from the bone under functional load.

Let us explain what was said by the figure. The figure shows the longitudinal profile of the plate. The A-thickness of the middle third of the plate is 5 mm, the B-terminal third with a cone-shaped thickness from 5 mm in the center to 2 mm at the end. On the centerline of the plate, holes for carbon clips were drilled in one row, holes in two rows in the other plate (Fig. 1, 2). The distance between the centers of the holes is 20 mm. The width of the plates is 15-18 mm; they have a grooved shape on the cross section.

When the plate is applied to bone fragments, the plate fits snugly to the bone and holes 6 mm in diameter are drilled through the holes in the plate in the underlying cortical bone plate. The opposite cortical plate remains intact. Metal clips with a diameter of 5.5 mm are inserted into the holes. The clip has a head, a body and a shank, in which 4 petals. On the head there is a thread for a screwdriver.

The body of the clip has a conical hole into which the core is inserted. The core has a head with a recess under the hexagon and a body, in the underside of which there is a thread. During osteosynthesis, a core is introduced into the longitudinal channel of the conical shape in the clips (Fig. 4).

When screwing the core, the petals of the shank of the clip fan-like diverge to the sides (Fig. 3). In this case, the plate is pressed closer to the bone. Due to the divergence of the shank petals, the adherence density of the carbon plate is constantly maintained in the postoperative period. This creates the necessary biomechanical conditions for the consolidation of a bone fracture. In FIG. 5 shows the position of the plate on the bone after fixing it with clips. A tight fit of the plate to the bone is noted. In Fig 6. X-ray image of a bone fracture after fixing it with a carbon plate with metal clips.

An analysis by the applicant of an existing device for osteosynthesis of long bone fractures, including a search by patent and scientific and technical sources of information, and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find an analogue characterized by identical (identical) signs of all essential features of the claimed invention.

The definition from the list of identified analogues of the prototype made it possible to identify a set of essential distinguishing features with respect to the technical result in the inventive device for osteosynthesis of long bone fractures set forth in the claims. Therefore, the application meets the criterion of "novelty."

To verify the compliance of the claimed invention with the condition "inventive step", the applicant conducted an additional search for known solutions to identify signs that match the distinctive features of the prototype of the features of the claimed invention.

The search results showed that the claimed invention does not derive explicitly from the prior art determined by the applicant for the specialist, the influence of the transformations provided for by the essential features of the claimed invention on the achievement of the technical result is not revealed. Therefore, the claimed invention "Carbon plate for osteosynthesis of fractures of long bones" meets the criterion of "inventive step".

The criterion of "industrial applicability" is confirmed by the fact that the proposed invention can be successfully used in medical institutions of the Russian Federation and CIS countries.

Claims (2)

1. Carbon plate for osteosynthesis of fractures of long bones, characterized in that the plate is made of carbon nanostructured composite material; the length of the plate varies from 120 to 240 mm, and the width is 15-18 mm; the plate has two end sections equal to one third of the plate length each, with a thickness of 2 mm or more at the end with a cone-shaped increase in thickness to 5 mm at the boundary with the middle third and the middle third, 5 mm thick, overlapping the fracture line; contains holes in one or two rows for fixing the plate to the bone; the plate is made with the possibility of introducing clips through the holes in the plate into the holes of the adjacent cortical plate of the bone, and with the possibility of screwing into the longitudinal conical channel of the clip of a core having a thread in the sub-half region, as a result of which the end petals of the clip fan-like diverge. 2. The plate according to claim 1, characterized in that the changing profile of the plate increases its plasticity, which eliminates the effect of tearing clips from the bone during the functional load of the limb.

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