FR2851158A1 - Inter-vertebral prosthesis for replacing inter-vertebral disc, has two elastic plates, each including perpendicular extension to fix plate to vertebral, and two stainless steel plates to push extensions to vertebra - Google Patents

Abstract

The prosthesis has two compressible and elastic plates (1a, 1b), each of which has a perpendicular extension (2a, 2b) to fix the plate to a vertebral. Two stainless steel plates (4a, 4b) are intended to push the extensions to the vertebra. Screws (6a-6d) are arranged to assemble the elastic and stainless steel plates with the vertebra.

Description

The present invention relates to a device which makes it possible to remedy

  serious intervertebral disc problems requiring surgery.

  In general, intervention on severely damaged discs consisted in blocking the vertebrae adjoining these discs by means of two metal plates screwed in parallel face to face on the two sides of these vertebrae making them integral, leaving sufficient intervertebral space to remove compressions of nerves and ligaments. This type of intervention had considerable consequences since it reduced the length of flexibility of the spine. The vertebra superior to the blocked vertebrae became a pivot and the disc which supported it in turn deteriorated very quickly. The handicap was important, especially irreversible under these conditions. The patient was condemned to an increasingly restricted mobility. Given the importance of the after-effects, the specialists now choose to intervene as soon as the symptoms of denervation are limited to releasing the compressed nerves by removing the overhang of the disc. This process relieves the patient temporarily but limits it in their daily life and the handicap remains because efforts are prohibited and movements must be made very carefully. Despite this, over time the recurrence is felt.

  The device of the invention makes it possible to avoid all of these drawbacks. It allows you to operate on one or more very damaged discs which generate significant denervation resulting in paralysis, causing suffering, difficulty and often the impossibility of moving. It keeps the initial mobility of the spine over its entire length. It removes all 25 risks of paralysis by restoring the intervertebral space. It removes pain, causes no sequelae and allows the operated patient to move completely normally without any risk. With the device of the invention, recidivism is excluded.

  The device of the invention consists in replacing all or part of the damaged intervertebral discs with prostheses. These prostheses have the same properties as the original discs. The manufacturing is done by molding in a material which presents no risk of rejection, intoxication or deterioration of its environment and for an unlimited period. The invention therefore consists of an intervertebral prosthesis improving the mobility of the spine in that it comprises two compressible and elastic plates each comprising a perpendicular extension serving to fix the plates to a vertebra and forming only a mass and material with these plates, two stainless steel plates 10 intended to plate the extensions perpendicular to the vertebra, and screws allowing the assembly of all of said previous parts. These prostheses are composed of several parts which will be illustrated in the attached drawings as a non-limiting example.

  According to a first embodiment with the aim of completely replacing a damaged disc.

  Figure 1. shows the prosthesis in place viewed from the side.

  Figure 2. shows the prosthesis in place seen from the back.

  Figure 3. shows all parts of the prosthesis.

  Figure 4. shows the prosthesis in place in section seen from the back. 20 According to a first alternative embodiment.

  - Two elastic and compressible plates (la-lb) of parallel thickness each of which could resemble a half-moon having by their contours the shape of the base of a vertebra when they are assembled face to face strongly resembling a real intervertebral disc. They have a sense of placement.

  According to a second embodiment with the aim of partially replacing a damaged disc.

  Figure 2a. represents the prosthesis in place seen from the side.

  Figure 2a. represents the prosthesis in place seen from the back.

  Figure 3a. represents all parts of the prosthesis.

  Figure 4a. represents 1 prosthesis in place in cross section seen from the back.

  According to a second alternative embodiment.

  Two elastic and compressible plates (la-lb) of parallel thickness in the shape of an arc of a circle which could resemble a half crescent. The internal contour of this arc corresponds to the curve of the lumbar canal. These plates have a sense of positioning.

  For the two variant embodiments, each plate includes its fixing (2a-2b) which is nothing other than an extension perpendicular to the surface of this plate molded in the mass from a single material. These fasteners are rectangular by way of nonlimiting example and vary in their thickness. They are flat on their external face and convex on their internal face because they follow the shape of the vertebra on which they are pressed and fixed. Each fixing is pierced with two holes (3a-3b-3c-3d).

  - Two rectangular stainless steel plates (4a-4b) for example.

  These plates are pre-drilled (5a-5b-5c-5d) they undergo no effort, they serve to press and stiffen the fasteners over their entire length and allow reliable screwing.

  - Four stainless steel screws (6a-6b-6c-6d) to screw the entire prosthesis into the vertebra. The four holes of the steel plates are found opposite the four holes of the fasteners during assembly.

  With the device of the invention, the surgical procedure takes place under general anesthesia. An opening is made along the spine at the level of the region concerned to reach the disc damaged by both sides. These are the two easiest passages and cause the least damage.

  In the first embodiment, the defective disc is entirely removed by the accesses on the sides, in order to put in place on each side a plate which is passed obliquely and which is positioned once inside in rotating it because the passage is narrow.

  - In the second embodiment, only the crushed part is removed on the rear of the disc, over a width of about 1 cm and over the entire periphery of the lumbar canal to put in place on each side a plate serving as a wedge .

  This device makes it possible to keep most of the disc if it is satisfactory.

  - In the two embodiments, the two plates are found face to face in the intervertebral space, they are complementary and on which the spinal column will rest. On each fixation we affix the stainless steel plate which will press it against the vertebra. To fix everything, pass the 10 two screws through the holes provided on the steel plate, crossing the pre-drilled fixing in passing. We tighten everything while screwing into the vertebra.

  Regarding the fixings, there are two options: you can use the upper vertebra or the lower vertebra as needed. The two processes are similar; they allow an additional chance in the event that one of the two adjoining vertebrae is unusable. The prostheses are fixed on a single vertebra thus leaving it completely independent and mobile. This device makes it possible to treat several discs on the same spine. - 5

Claims (3)

  1) Intervertebral prosthesis improving the mobility of the spine characterized in that it comprises two compressible and elastic plates (la-lb) each comprising a perpendicular extension (2a-2b) serving to fix the plates (la-lb) to a vertebra and forming only one mass and material with these said plates, two stainless steel plates (4a-4b) intended to press the perpendicular extensions (2a-2b) to the vertebra and screws (6a to 6d) allowing the assembly of all of said previous parts.   2) Prosthesis according to claim 1 characterized in that the extension (2a-2b) perpendicular to the surface of each plate used for fixing is molded in the mass in one and the same material, said fastenings being pierced with two holes (3a -3b-3c-3d).   3) Prosthesis according to claim 1 or 2 characterized in that the perpendicular extensions (2a-2b) and the stainless steel plates (4a-4b) are each provided with two corresponding orifices (3a to 3d; 5a to 5d) allowing the passage of the screws (6a to 6d).