RU202290U1 - Endoprosthesis of the glenoid fossa and condylar process of the temporomandibular joint, providing a synchronous excursion of the mandible - Google Patents

Abstract

The utility model describes an endoprosthesis for total replacement of the temporomandibular joint. Endoprosthetics of one or both temporomandibular joints, in itself, is a rather complex surgical intervention. At the same time, one of the most common complications is the dislocation of the lower jaw, associated with the disproportionate movements of the intact and operated joints and the imperfection of the designs of endoprostheses. The proposed endoprosthesis is characterized by a planting socket of a special shape, which allows natural circular movement of the operated lower jaw of a person without the risk of its dislocation.

Description

The field of technology.

The utility model relates to the field of medical technology, or rather to endoprostheses for total replacement of the temporomandibular joint.

State of the art.

The temporomandibular joint is the only paired movable joint in the body that performs symmetrical movements. The load on it is quite high and reaches 27 kg.

Significant physical activity in combination with a high frequency of movements is an aggravating factor in the development of a number of pathologies leading to ankylosis and significant limitation of movements in the joint. These pathologies include osteoarthritis, rheumatoid arthritis, benign tumors, congenital malformations, consequences after unsuccessful complete temporomandibular arthroplasty, etc. At the same time, both the mandibular fossa and the mandibular condyle can undergo pathological destruction.

The solution to the problem is total or unipolar arthroplasty of one or both temporomandibular joints, which in itself is a fairly common surgical intervention.

A distant analogue of the utility model is titanium unipolar endoprostheses manufactured by Konmet LLC described by U.T. Tairov and from titanium nickelide described in the invention 2478341 RU, which are a design that repeats the anatomical shape of the condyle of the lower jaw. Their disadvantage lies in the fact that the difference in the sliding friction coefficients of the temporomandibular joint cavity and the metal endoprosthesis, which leads to abrasion of the articular surface, dislocation of the condyle endoprosthesis, displacement of the articular head of the lower jaw in the glenoid fossa, the appearance of a significant difference in the size of the articular spaces in anterior, upper and posterior sections of the glenoid fossa. In addition, with unipolar prosthetics, the head can even destroy the articular surface, up to its prolapse with a condyle endoprosthesis. Additionally, abrasion of the material leads to the appearance of products of tissue destruction and rubbing material - the so-called debris - which cause aseptic inflammation around the joint. An improved option used for endoprosthetics is a total endoprosthesis, where both the articular surface and the condyle of the lower jaw are replaced. In this case, both components consist of titanium {Temporomandibular joint replacement. Epifanov S.A., Polyakov A.P., Bulletin of the National Medical and Surgical Center named after N.I. Pirogov 2014. Vol. 9, no. 4, from 1722).

However, in modern concepts, this option also does not meet the requirements due to high wear. Rubbing titanium components lead to scuffing and scratching of the surface, increasing the amount of debris and maintaining the activity of aseptic inflammation.

The most progressive is the use of endoprostheses, where the condyle is made of titanium, and the articular surface is made of high molecular weight polyethylene (hirulen). The results show the high efficiency of this combination (Prosthetics of the temporomandibular joint. Epifanov SA, Polyakov AP, Bulletin of the National Medical and Surgical Center named after NI Pirogov 2014. Vol. 9, No. 4, from 1722). The disadvantage of the proposed devices was that the implantable components of the temporomandibular joint allow only a limited circular rotary movement, similar to the natural movement of the human jaw. And in the case of implantation on one side of the jaw, the range of motion of the joint cannot correspond to the range of motion of the opposite healthy jaw, since the range of motion of the operated side is less than that of the natural joint. As a result, this fact leads to dislocation of the condylar component from the glenoid cavity.

Disclosure of the essence of the utility model.

The presented technical solution consists in creating a total endoprosthesis for complete replacement of the temporomandibular joint, consisting of two main parts: the glenoid fossa and the condylar component. The glenoid fossa is made of hirulen in the form of a seat with upper and lower apertures. At the same time, through the lateral larger aperture, the head of the condylar component is inserted into the socket and suspended in a narrower lower aperture. And the body of the condylar component moves freely in the space of the lower aperture, allowing wide movements in the joint without the risk of dislocation of the condylar part of the endoprosthesis.

Brief description of the drawings.

FIG. 1. General view of the glenoid fossa with the designation of the narrowing passage between the apertures (5).

FIG. 2 View of the glenoid fossa in the frontal plane with the designation of the upper (1) and lower (2) apertures.

FIG. 3 Placement of the condylar component of the endoprosthesis in the glenoid fossa: (4) - the body of the condylar component, (3) - the head of the condylar component.

Implementation of the utility model.

The articular fossa of the temporomandibular joint endoprosthesis is a landing socket and has an upper and lower aperture. In this case, the upper aperture 1 (Fig. 2) is located in the sagittal plane and its diameter is less than the head of the condylar component by 1-2 mm; the lower aperture 2 (Fig. 2) is in the horizontal plane. Its diameter is 3-6 mm less than the head of the condylar component of the endoprosthesis. The articular fossa of the endoprosthesis is made of chirulen.

The condylar component of the endoprosthesis follows the shape of the condyle of the lower jaw and has a body 4 and a head 3 of the endoprosthesis (Fig. 3).

Between themselves, the apertures have a narrowing passage 5 (Fig. 1), the smallest size of which is 0.1-0.5 mm less than the diameter of the body of the condylar part of the endoprosthesis. The functional purpose of the apertures is as follows: the upper aperture is intended for the introduction of the condyle head, and in the lower It is suspended in the aperture so that it allows free movement of the body of the condyle part in it, but delays the head of the condyle from falling out of the joint during any physiological movements, which excludes dislocation of the endoprosthesis. Considering that the size of the upper aperture is 1-2 mm less than the size of the head of the condylar component, the latter is blocked in the anti-dislocation socket after insertion.

The proposed design allows for the natural circular movement of the human jaw without the risk of its dislocation. An additional advantage of this design is its quick and easy installation.

Claims (1)

Endoprosthesis for total replacement of the temporomandibular joint, in which the condylar component is made of titanium, and the component replacing the glenoid fossa consists of hirulen, characterized in that the component replacing the glenoid fossa has the shape of a seat with an upper aperture intended for the introduction of the head a condyle located in the sagittal plane, and a smaller diameter than the head of the condylar component by 1-2 mm, and a lower aperture that allows movement of the body of the condyle in it and retards the head of the condyle from prolapse, smaller in diameter than the head of the condylar component by 3-6 mm, connected with each other by a narrowing passage, the smallest size of which is 0.1-0.5 mm less than the diameter of the body of the condylar part of the endoprosthesis.

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