FR2877833A1 - Prosthesis for correction of lordosis to improve the mobility of the spinal column, comprises titanium rigid plates, incompressible brace, biocompatible silicone intermediate and rigid emergences - Google Patents

Abstract

The plates (1,2) with the emergences (5) appearing on their external surface in conical/ pyramidal form. The plate (1) is equipped with the brace (3), which is resistant to crushing. The brace is parallelepiped, oval shape to camber and fold, and hard semicircular shape is obtained by molding. The intermediate (4) is not parallel in its thickness.

Description

The present invention relates to a device for correcting

  completely severe lordosis.

  To date, there is no effective way to completely correct severe lordosis. Mergers do not solve the problem. Only a very limited improvement can be achieved by moderately relieving pain. With permanent support on the back of the vertebrae, the lordosis is accentuated irreparably, and the articular and spinal joints of the two adjacent vertebrae approach each other to the point of touching each other. With osteoarthritis and rheumatism the two vertebrae eventually become welded.

  The device of the invention makes it possible to avoid all these drawbacks. It is designed to rectify a severe lordosis without technical risk and without sequelae. It allows an intervention on several vertebrae at the same time. In many cases, we have to intervene on the last three. It raises the back of the very inclined vertebrae, compensates the inclination of these vertebrae and restores the spine a normal curve. It definitely resists crushing while leaving a perfect mobility to these vertebrae. The procedure can be performed anteriorly but also posteriorly. In both cases, because of its size and shape, the device will be placed on the side of the vertebrae. Do not touch the anterior surface of the vertebrae to be treated so as to eliminate the risk of sequelae. The recurrence of a lordosis treated by placing the device of the invention on one or even several vertebrae is excluded.

  The device of the invention aims essentially to correct the lordosis by interposing between two vertebrae a prosthesis for straightening the very inclined rear of the upper vertebra in order to prevent the articular and thorny of the two adjacent vertebrae to meet and to remove the consequences that follow.

  The invention therefore consists of a prosthesis in that it comprises an upper rigid plate (1), a lower rigid plate (2), a hard shim (3), a flexible intermediate (4) and rigid emergences (5). .

  Rigid plates (1 2): they look like a half-moon with a convex peripheral part but with the slightly concave opposite peripheral part. They may be of variable thickness but preferably about 5 / 10ths of a millimeter, they must be as close as possible to a true intervertebral disc both in the shape of their contour and in their size. They are preferably of pure titanium metal, but can also be other rigid materials compatible and assembled with silicone. They serve as a template, a guide, to maintain the entire prosthesis between two vertebrae. They can be obtained from a sheet or by machining in the mass.

  The wedge (3) lasts: it is incomprehensible, it can be of variable dimensions and of different forms. Its height varies and determines the desired space on the back of the prosthesis according to the angle of inclination of the lordosis to be corrected. It keeps the back of the vertebra raised. It is made of metal preferably of pure titanium, but may be other hard materials compatible and assembled to the plate (1) or to the two plates (1-2) as appropriate. It is positioned at the rear of the upper plate (1) juxtaposed on its inner face and perpendicular to its surface. It is located in the center of the concave part of this plate, parallel and in the extension of its peripheral surface, it is integral and descends in contact with the plate (2) to rely on it. Its function is to prevent crushing of the prosthesis on the back and maintain the desired space between the two plates (1-2). It can be a parallelepiped machined with the plate (1) in a mass and material or a parallelepiped reported to be welded to its upper base against the inner face of the plate (1) by means of a laser weld or a argon welding. The three inner edges of the lower base bearing on the lower plate are rounded to allow the movements a harmonious curve. It may have approximately non-limiting dimensions of the order of 5 mm thick 10 mm wide and 8 mm in height. It may also be a portion of horizontal oval with two flattened and parallel faces from which only the lower half machined with the plate (1) remains in a mass and material or an oval portion added to be welded to its base upper right against the inner face of the plate (1) by means of a laser weld or an argon weld. The oval lower part is supported on the lower plate (2). The oval allows the movements a harmonious curve. The diameter of the oval represents about 30% of the concave portion of the prosthesis. It can also be made from a developed plate (1). This developed length corresponding to the necessary height is arched and folded inward of said plate perpendicular to its shaped surface with the curved lower base and slightly rounded. A height of approximately 8 mm is folded over a width of approximately 10 mm, the rounded return of the base approximately 2 mm. These dimensions are nonlimital: ives. With another technology, it can be obtained with a biocompatible silicone hard core of semi-circular shape with the slightly concave rear part so as to follow the curve of the plates (1-2) between which it is inserted. The diameter of the hard core is about 30% of the concave periphery of the prosthesis. Not having a specific color, he does not disagree with the rest of the intermediary. The assembly of titanium and silicone consists in this case in what is called a flash, which implies the need to mold the entire intermediate part at the same time in a chronological order. Titanium plates (1-2) are mounted at a temperature of 1000, the hard core is molded between the two plates by compressing the 4770 silicone heated to about 400 at 75 bar. Immediately afterwards, the remaining total is molded by compressing to 60 shores the 4755 silicone heated to nearly 400 also. The expansion of titanium caused by the high temperature, allows the fluidized silicone also by its high temperature to impregnate superficially in the titanium. A phenomenon of superficial interpenetration occurs which excludes all risks of separation of the two materials. It cools quickly because the operation can not last more than two minutes. Once cooled, the 4770 silicone compressed to 75 shores becomes very hard and almost incomprehensible.

  The flexible intermediate (4) is compressible and elastic to allow the mobility of the treated vertebrae. It is arranged between the two plates (1-2), it occupies entirely the remaining internal volume determined by the surface of said plates and the height of the shim. The surface of its periphery is an extension of the peripheral surface of said plates. The plate and intermediate assembly is not necessarily parallel. The back may be thicker than the front depending on the angle of inclination of the lordosis to catch up and determined by the height of the hold. It is obtained by molding silicone 4755 which remains compressible and elastic after cooling.

  The silicones mentioned are manufactured by the laboratories NUSIL and referenced: type A. MED 4770 and type A. MED 4755. They are biocompatible implantable long-term.

  The emergences (5) appear on the surface of the outer face of each plate perpendicular to its surface. They can be conical or pyramidal, other forms are possible. These emergences are intended to serve as inking between the two vertebrae to the entire prosthesis. They are obtained by stamping the plates (1-2) or by machining in the mass. They offer a double interest by being convex on the outer face of these plates to serve as inking against the bone and concave on the inner face of these plates to allow the silicone to soak in the cavities, thus adding security additional to the efficiency and reliability of the assembly technique of the two materials.

  It is understood that modifications of the invention described above are covered by the appended claims. 20

  The accompanying drawings illustrate the various embodiments described above.

  Figure (1) is a perspective view of the prosthesis provided with the parallelepipedal wedge.

  Figure (2) is a sectional view of the prosthesis provided with the parallelepiped wedge placed between two vertebrae.

  Figure (3) is a perspective view of the prosthesis provided with the oval wedge.

  Figure (4) is a sectional view of the prosthesis provided with the oval wedge placed between two vertebrae.

  Figure (5) is a view of the plate (1) before folding.

  Figure (6) is a sectional view of the prosthesis provided with the folded wedge placed between two vertebrae.

  Figure (7) shows the hard core by transparency.

Claims (6)

  1) Correction prosthesis for lordosis improving the mobility of the spine characterized in that it comprises: a plate (1) rigid upper, a plate (2) inferior stiff, a wedge (3) hard, an intermediate (4) flexible, emergences (5) rigid.   2) correction prosthesis according to claim 1 characterized in that the plates (1-2) are made of metal preferably of titanium.   3) correction prosthesis according to any one of claims 1 or 2 characterized in that the plates (1-2) are provided with emergences (5) rigid appearing on their outer surface conical or pyramidal.   4) Correction prosthesis according to claim 1 characterized in that the plate (1) is provided with an incompressible shim (3) resistant to crushing which can be a parallelepiped, an oval portion, the bending and folding of one, developed from said plate or a semicircular hard portion obtained by molding.   5) correction prosthesis according to claim 1 characterized in that the intermediate (4) compressible and elastic is a biocompatible silicone inserted between the plates (1-2) by molding.   6) correction prosthesis according to any one of claims 1 to 5 characterized in that the intermediate (4) is not necessarily parallel in its thickness.