RU2496452C2 - Device for stabilisation of spine segments - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to field of medicine, namely to traumatology and orthopedics, and is intended for fixation and stabilisation of spine segments in case of its injury, trauma and diseases. Device is made in form of volume body, which has flat surfaces in places of contact with spine segments, which are made non-smooth and is totally produced from biocompatible composite ceramic material, which has porous-permeable structure. Larger part of said material volume has smaller input size of pores than their internal size. On flat surfaces of device impressed relief image of geometrical character is made. Calcium-phosphate compound is applied on flat surfaces of device in places of contact with spine segments. Pores of ceramic material are filled with substances of medical target.

EFFECT: application of claimed device ensures considerable acceleration of osteointegration, reliable initial device fixation, reduction of trauma in carrying out implantation operation.

3 cl, 3 dwg

Description

The invention relates to medicine, namely to traumatology and orthopedics, and is intended to fix and stabilize segments of the spine with its lesions, injuries and diseases.

To fix and stabilize segments of the spine, a significant number of implants have been proposed.

Known implants in the form of a parallelepiped with flat surfaces at the points of contact with segments of the spine, made of porous titanium nickelide (B. Silberstein, Treatment of injuries and diseases of the spine with functional materials and structures with shape memory: Abstract ... Dr. med. Sciences. - C. -Pb., 1993, 49 p.).

Their disadvantage is insufficient biocompatibility, which can lead to the development of instability in the places of support and secondary complications.

The most famous bone grafts with flat surfaces in places of contact with segments of the spine, made of autobone in size, determined by the place of its installation (Tsivyan Y. L. Spinal Surgery. - M .: Medicine, 1966 - 312 p., Yumashev G.S. , Furman M.E. Osteochondrosis of the spine.- M .: Medicine, 1984 - 384 p.).

The main disadvantages of such transplants include:

- a decrease in strength characteristics during reconstruction, accompanied by crushing of the graft and the occurrence of secondary deformations with partial loss of correction in the operated segment, the projection subsidence is 10-12% higher compared to a ceramic implant, and the loss of angular correction is 5% higher on average;

- the need for additional surgical intervention for graft collection;

- low radiological visibility relative to adjacent bone structures.

The closest to the claimed device for stabilizing segments of the spine, the prototype, the device for fixing the segments of the spine according to the patent of the Russian Federation No. 2177463, priority from 08.20.1998, the device is made in the form of a truncated segment having flat surfaces in places of contact with the body of the spine. The device is made of a biocompatible dense ceramic material containing alumina. On flat surfaces, a porous coating of the same material is applied, due to which they become rough.

The device is made of a biocompatible dense ceramic material, which completely eliminates the likelihood of secondary deformations in the operated segment, the appearance of an immunological conflict, and the risk of transmission of blood transfusion infections.

The disadvantages of this device include the risk of the formation of wear products of the porous coating that arise from the application of load during the functioning of the vertebrae.

Another disadvantage of the device is that it is made of dense ceramic, the strength of which is much higher than the strength of adjacent bone tissues, thereby causing resorption and subsequent lysis at the contact site.

The objective of the invention is to provide a device for stabilizing segments of the spine, which allows for reliable primary fixation and significantly improves osseointegration while increasing manufacturability and improving biomimetic characteristics, as well as reducing trauma during implantation.

The problem is solved due to the fact that in the known device for fixing segments of the spine, made of biocompatible ceramic material and made in the form of a volumetric body having flat surfaces in contact with segments of the spine, which are not smooth, the composite material is used as material, having a porous-permeable structure, and on flat surfaces of the device, a depressed relief pattern of a geometric nature is made. In addition, a calcium phosphate compound can be applied to flat surfaces in contact with spinal segments. The device can be made in the form of a rectangular parallelepiped with rounded ribs and a rounded hole in the center. The pores of the ceramic material can be filled with medical substances.

The proposed device is presented in FIG. 1 (top view) and FIG. 2 (side view). In FIG. Figure 3a presents scanning electron microscopy of a ceramic implant cleavage, illustrating the germination of bone plates in the deep pore of an implant coated with a calcium-phosphate compound. On figb presents the surface of the transverse cleavage of the implant, illustrating the germination of bone plates in the communicating pores of the implant.

The device shown in FIG. 1, 2, is made in the form of a rectangular parallelepiped with rounded ribs and with a rounded hole 1 in the center. The device contains above and below flat surfaces 2 on which a depressed relief pattern of a geometric nature 3 is made.

Execution on flat surfaces 2 of a depressed relief pattern of a geometric nature 3 allows to increase the area of contact with the vertebral body. Due to this implementation of a flat surface, reliable primary fixation of the vertebrae is provided, which helps to accelerate the fusion of the device with bone tissue.

This embodiment of a flat surface contributes to a more snug fit of the device to the vertebral body, and a depressed relief allows less damage to the operated bed.

The use of porous ceramic material described in application No. 20111119067 on May 12, 2011, provides a device for stabilizing spinal segments with a porous-permeable structure. Unlike the prototype, the proposed device is made entirely of porous ceramic material, due to which the biomimetic characteristics are improved. Osteointegration is also ensured over the entire volume of the device, and not only over the surface where there is a porous coating, as in the prototype.

Moreover, in most of the volume of porous-permeable material, the input pore size is smaller than their internal dimensions. This is an important circumstance, since it was found that such a porous-permeable structure of the device ensures that the newly formed osteoid tissue, growing in the inner space of the pore, cannot “slip out”, since the narrow exit from the pore “locks” it, and the pores contain osteoid tissue in the form of bone plates in its internal space. The described effect is illustrated by a photomicrograph of scanning electron microscopy (figa). Exposition 10 weeks. Osteoid tissue in the form of bone plates in the deep sections (pores) of the implant coated with calcium - phosphate compound. The germination of bone plates in the communicating pores of the implant (figb).

The implementation of the device in the form of a parallelepiped with rounded ribs and with a rounded hole in the center provides anatomy during surgery. The completed geometric shape in the form of a parallelepiped allows the preparation of the installation site in the vertebral bodies with standard surgical instruments from standard access. At the level of damage, the prevertebral fascia and the anterior longitudinal ligament are cut along the axis of the spine, and segmental vessels are coagulated if necessary. The damaged disk is dissected and completely excised together with adjacent hyaline plates of the vertebral bodies, and the fibrous ring should be dissected in an H-shape with preservation of it. The spinal canal is freed from fragments of discs, bodies, etc., by which decompression of the spinal cord and roots is achieved. The end plates of the vertebral bodies are cleaned with bone spoons until the appearance of “blood dew”, but without removing the dense cortical layer of the bone. In cases where the caudoventral angle of the overlying vertebral body covers the intervertebral space, 1-2 mm of the angle are removed with chisels to open the vertebral end plates. It is the proposed device shape that is most conveniently introduced into the space thus formed.

The rounding of the ribs of the device ensures non-invasiveness of the introduction and its subsequent location in the operated area. A round hole in the center is necessary for the introduction of special materials, for example, allostones or bone straws, which have a positive effect on the processes of osseointegration.

The use of ceramics in the manufacture of the device expands the possibilities of modeling the shape and size. The device can be manufactured by known methods used in the shaping of ceramic products.

A device for stabilizing spinal segments is manufactured industrially by uniaxial pressing from a composite ceramic powder prepared according to application No. 20111119067 (priority 05/12/2011), using the developed mold with a wide range of device sizes, from 0.5 mm to a height of the device 19 mm

Claims (3)

1. A device for stabilizing segments of the spine, made of biocompatible ceramic material, made in the form of a three-dimensional body having flat surfaces in contact with segments of the spine, which are made non-smooth, characterized in that the device is entirely made of a composite ceramic material having a porous-permeable structure, while for most of the volume of this material, the input pore size is smaller than their internal dimensions, and on the flat surfaces of the device bulged relief pattern geometric nature. 2. The device according to claim 1, characterized in that a calcium phosphate compound is applied to its flat surfaces in places of contact with segments of the spine. 3. The device according to any one of claims 1 and 2, characterized in that the pores of the ceramic material are filled with medical substances.

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