DYNAMIC CERVICAL DISC PROSTHESIS FOR INTERVERTEBRAL DISC REPLACEMENT WITH PRESERVATION AND / OR RESTORATION OF CERVICAL DYNAMICS

Abstract

A dynamic cervical intervertebral disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics has a superior plate that has a rough or serrated appearance on its upper surface, which anchors it to a superior vertebra and on its lower inner surface has two concave surfaces, an anterior and a posterior, separated by a pronounced edge; these articular surfaces have a V-shaped excavated notch respectively.A lower plate has a rough or serrated underside that anchors to the inferior vertebra. On its inner upper surface are two convex spherical surfaces, anterior and posterior, separated by a pronounced rim. These articular surfaces have an anterior and a posterior post, respectively. The inner surfaces of both plates are sliding surfaces that interlock, allowing gliding movement against each other. Stops and V-shaped notches on their surfaces allow limited sliding. In a way, the post functions partially as a guide for movement between the upper and lower plates and simultaneously limits flexion, extension, lateral, and rotational movements.

Description

DYNAMIC CERVICAL DISC PROSTHESIS FOR INTERVERTEBRAL DISC REPLACEMENT WITH PRESERVATION AND / OR RESTORATION OF CERVICAL DYNAMICS. FIELD OF INVENTION This patent relates to a dynamic intervertebral cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics. Specifically, this invention relates to a two-part intervertebral disc prosthesis for the total replacement of an intervertebral disc in the cervical spine. It belongs to the segment of medical science, specifically to the surgical field for the treatment of bones or joints and devices specially adapted to them. OBJECT OF THE INVENTION The objective of this development is to assist in the rehabilitation of the cervical spine in cases of traumatic injuries, fractures, vertebral deformities, degenerative diseases, among other typical problems, allowing the patient to maintain physiological movements in the cervical spine. It is therefore a prosthesis intended for the cervical segment of the spine, specifically to occupy the intervertebral space between adjacent vertebrae. BACKGROUND The two techniques currently used are anterior cervical discectomy with fusion and arthroplasty. Anterior cervical discectomy with fusion involves removing the intervertebral disc and replacing it with bone grafts or interbody cages, which can be simple cages or anchored cages. Simple cages and bone grafts require the additional placement of a plate bonded to the anterior surface of the adjacent vertebral bodies and fixed to the spine with screws to prevent displacement. Anchored cages include mechanisms that allow them to be anchored to the adjacent vertebral bodies. In all cases, the goal is to fuse the vertebrae adjacent to the discectomy site, creating a block formed by two vertebrae, thus causing the loss of pre-existing physiological mobility between these vertebrae.Drawbacks of this technique: The first drawback is the loss of joint mobility between the fused vertebrae. The second drawback is that the vertebrae adjacent to the fusion, both the superior and inferior vertebrae that retain mobility, are overloaded, which predisposes them to disc disease adjacent to the fusion. This leads to degeneration of the intervertebral disc and facet joints, causing early-onset osteoarthritis and pain. The second current technique is arthroplasty. Spinal arthroplasty is a rapidly growing field. It's a treatment that aims to preserve functional spinal movement while maintaining stability, thereby potentially preventing or reducing the development of adjacent disc disease. Several decades of work have been underway to develop clinically relevant devices that mimic the kinematics of the intervertebral disc. The configuration and design of artificial cervical prostheses aim to functionally mimic the kinematics of a normal intervertebral disc. A consensus on the design of currently available prostheses has not yet been established. The main drawbacks of most prostheses currently used are the development of a complication called hyperostotic ossification, which leads to loss of prosthesis mobility and degeneration of the articular facets. An intervertebral disc prosthesis consists of at least a lower plate and a upper plate. The surfaces of these plates have anchoring formations intended for the adjacent vertebral bodies, to prevent them from losing their anchoring point in the spine and losing their position in the intervertebral space. A three-part prosthesis, in addition to its upper and lower plates, consists of an intermediate or central plate. Three-part prostheses are articulated by contact surfaces that allow them to slide against each other, causing the intermediate plate to behave as a sliding plate between the upper and lower sliding plates. BRIEF DESCRIPTION OF THE FIGURES The objectives, characteristics, advantages and other qualities are detailed more clearly through the following description, without being limited to the achievements revealed, providing further details by reference to the attached drawings in the following figures. Figure 1: shows a perspective view of the invention corresponding to a two-part intervertebral disc prosthesis. Figure 2: is a front view of the intervertebral disc prosthesis. 2a is a partially sectioned sagittal view of the disc prosthesis. Figure 3: : is a side view of the intervertebral disc prosthesis. Figure 4: This is a side view of the lower plate of the disc prosthesis. 4a is an anterior view of the lower plate. 4b is a perspective view of the lower plate. Figure 5: is a side view of the upper plate of the disc prosthesis. 5a anterior view of the upper plate. 5b perspective view of the upper plate, 5c is an inferior view of the upper plate. DETAILED DESCRIPTION OF THE INVENTION This disclosure 1 presents the innovation of a dynamic intervertebral disc prosthesis for intervertebral disc replacement, with preservation and / or restoration of cervical dynamics. The prosthesis consists of two components that allow sliding against each other, preserving and restoring the physiological movements of the cervical spine in the intervertebral spaces where it is placed, thus allowing all the natural physiological movements of a healthy cervical spine. cocenn / zznz / E / YiAi This prosthesis consists of two components or parts: an upper component (upper plate) and a lower component (lower plate). Once the intervertebral disc is surgically removed from the intervertebral space, the prosthesis is fitted into that space. The upper surface of the prosthesis's upper plate makes contact with the articular surface or lower surface of the adjacent cervical vertebral body, fitting anatomically between these two surfaces. Similarly, the lower surface of the prosthesis's lower plate makes contact with the articular surface or upper surface of the adjacent vertebral body, fitting their surfaces anatomically. Both parts are internally designed with an articulating face that firstly allows contact between them and secondly allows a sliding movement between them, that is, one slides over the other. The lower plate, on its upper or middle surface, is composed of two overlapping articular surfaces, an anterior and a posterior, separated by a pronounced groove. These surfaces have a spherical rolling principle, with the anterior surface positioned lower and the posterior surface higher. Both surfaces are convex, and each articular surface has a small post-like protuberance, one anterior and one posterior, which limits the movement of the upper plate of the prosthesis, allowing only sufficient gliding movement between the two components to mimic the physiological movement of the cervical spine. The upper plate of the prosthesis will have two concave, overlapping articular surfaces, which will fit perfectly into the convex spherical surfaces of the lower plate. These articular surfaces of the upper plate will have two V-shaped notches, where the protuberances or posts of the upper articular surface of the lower plate will fit, limiting the sliding movement between both parts, allowing only enough sliding movement to mimic the physiological movement of the cervical spine. The upper surface of the prosthesis's upper plate will have a rough, scaly, or serrated surface to facilitate its fit with the bony surface of the adjacent vertebral body's underside. Similarly, the lower surface of the prosthesis's lower plate will have a rough, scaly, or serrated surface to facilitate its fit with the upper surface of the adjacent vertebral body. This is intended to prevent the prosthesis from slipping out of the intervertebral space, thus avoiding a complication known as dislocation. As can be seen in Figure 1, the cervical disc prosthesis is shown in a perspective view, with the two plates attached. Figures 2 and 2a show the anterior view of the attached prosthesis, revealing the anterior post on the upper surface of the lower plate and the notch on the lower surface of the upper plate. A line is visible in the middle, tracing a cut shown in Figure 2a, which corresponds to a sagittal section revealing details of its internal structure. Figure 3 shows a lateral view of the attached prosthesis, with the upper plate attached to the lower plate. Figures 4, 4a, and 4b show a lateral, frontal, and perspective view of the inferior plate respectively, where 1 represents the posterior border of the inferior plate, curved and convex, the posterior stop 2 is observed on the posterior convex surface which is in turn limited by a posterior rim, the posterior convex surface 3 is one of the spherical articular surfaces as is the anterior surface, both surfaces are separated by a pronounced intermediate rim, on the anterior surface the anterior stop 5 is observed, the inferior face 6 will fit to the superior surface of the inferior vertebra, which is limited anteriorly by the anterior border and posteriorly by the posterior border. Figures 5, 5a, 5b, and 5c show a lateral view, anterior view, perspective view, and inferior view of the upper plate, respectively. Its upper surface 14 has an anatomical design to fit the inferior surface of the superior vertebral body in the intervertebral space. It is bounded anteriorly by the anterior border 19 and posteriorly by the posterior border 10. On the upper plate, the anterior and posterior sliding contact surfaces 13 and 12, respectively, of its inferior surface are excavated surfaces perfectly designed to fit the anterior sliding surfaces 4 and 3, respectively, of the lower plate, which will allow the sliding movements of the prosthesis.The lower sliding surfaces of the upper plate feature anterior and posterior notches 18 and 17, respectively, which allow for sliding movement between the two plates. This movement is limited by anterior stops 5 and posterior stops 2, located on the anterior and posterior sliding surfaces of the lower plate, respectively, to permit only physiological movement of the cervical spine. The anterior sliding surfaces 13 and posterior sliding surfaces 12 of the upper plate engage with anterior sliding surfaces 4 and posterior sliding surfaces 3 of the lower plate. Anterior surface 13 and posterior surface 12 are separated by a pronounced rim 15. The posterior surface is limited posteriorly 16 by a lip, which continues into a small contact surface 11 that engages with the posterior rim 1 of the lower plate. The parts of the prosthesis will be manufactured from the same material or a combination of different materials, to give it the properties for which it has been designed. Other aspects, features and additional advantages of the present invention are readily apparent from the following detailed description, showing its characteristics. Variations and modalities of development The present invention also has the capacity to be modified in several obvious aspects, all without departing from the spirit and scope of the present invention. Therefore, the drawings and descriptions are to be considered illustrative, not restrictive. Additional objectives and advantages of the invention will be set forth in part in the following description, or may be learned during the exercise of the invention. The functional principle of the prosthesis lies in the arrangement of the sliding surfaces between the inner surfaces of the upper plate and the lower plate. These sliding articular surfaces comply with the specific functional principles required for the prosthesis to accurately mimic the physiological movements of the cervical spine. This design and development principle is the core of the prosthesis upon which its function is based. cocenn / zznz / E / YiAi Regarding the stops that will limit the movement between both sliding surfaces, in these drawings we decided to place them on the anterior part of the anterior surface of the lower plate of the prosthesis, and on the posterior part of the posterior surface of the lower plate of the prosthesis. However, this arrangement can be changed to a central position on both lower surfaces, modifying the position of the notches on the lower surfaces of the upper plate. Alternatively, the posts can be placed on the anterior and posterior surfaces of the upper plate at the central level or on the posterior part of these surfaces, or one post can be placed on the lower plate and one post on the upper plate. It is even possible to consider, at the time of manufacture, not placing posts but developing a rim on the lower plate that limits the movement of the upper plate.with the objective of only allowing physiological movements of the cervical spine in that segment. Also, a modality of the invention will include, extending over the anterior edges of the upper and lower plates, a vertical upper and lower plate, which will have holes for inserting screws and providing fixation support for the prosthesis to the vertebral body. Details or characteristics that will be perfected during the exercise of the invention, reiterating that the current drawings are descriptive, but not restrictive. In these drawings, the prosthesis has a virtually rectangular shape in a plan view; however, it is conceivable to incorporate a kidney shape into the prosthesis, or to imitate the shape of the vertebral body when viewed in a plan view, or some other preferred shape. Regarding its manufacture, it can be developed with 3D printing technology, with the implementation of CNC lathes, or other technologies that allow its articulated surfaces to be mirrored to limit wear and increase its lifespan, characteristics that will be perfected during the exercise of the invention. With regard to the material, bio-compatible materials are selected, such as titanium, titanium alloys or titanium carbide, chromium and cobalt alloys, suitable ceramic materials, high-density polyethylenes, diamond, carbon or composite materials. To enable visualization once implanted in the interbody space, tantalum balls can be added to facilitate visualization in X-ray images, or some other radiopaque material.

Claims

1. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, the prosthesis comprising: A superior plate whose anatomically shaped upper surface 14 has a rough or serrated appearance, which fits and anchors to the superior vertebra, on its lower or internal surface has two superimposed concave spherical surfaces, an anterior 13 and a posterior 14 separated by a pronounced edge 15, each of these anterior and posterior articular surfaces having an anterior 18 and posterior 17 notch respectively, in the shape of a V.A lower plate whose lower surface 6 has a rough or serrated appearance, which anchors it to the lower vertebra, and a superior or internal surface, which contains two convex spherical surfaces, an anterior 4 and a posterior 3, separated by a pronounced groove 9, both spherical articular surfaces have an anterior post 4 and a posterior post 2 respectively.Both plates on their inner surfaces are designed with an exceptional geometry, allowing them to fit together perfectly, creating a joint with the ability to slide against each other without loss of mutual contact. This allows for different sliding movements that mimic the physiological movements of the cervical spine. These movements are limited by the posts and V-shaped notches on their corresponding surfaces. These flexion, extension, lateral, and rotation movements are restricted, allowing only the physiological movement of a healthy cervical spine.

2. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, according to the previous clause, characterized by the lower plate having two superimposed spherical sliding surfaces 3 and 4, in different positions and of different sizes, separated by a pronounced groove, designed in such a way as to allow coupling, without dead spaces, with the two lower sliding surfaces 13 and 12 of the upper plate, which are designed in mirror image, allowing the creation of an articulation with its own limitation of the physiology of the cervical spine, which allows sliding between both.

3. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, according to the previous clause, characterized by the anterior 5 and posterior 2 posts of the articular surfaces of the lower plate, once coupled with the corresponding articular surfaces of the upper plate, between the posts and the V-shaped notches of the upper plate, there is a space that allows the different sliding movements and where the function of the posts is to limit the excessive displacement of the upper plate on the lower plate, allowing only the physiological movement of the cervical spine.

4. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, according to the preceding clause, characterized by the prosthesis defined in claim 1, wherein the upper surface 14 of the upper plate and the lower surface 6 of the lower plate have an anatomical design that allows them to be coupled to the lower and upper surfaces of the adjacent vertebrae once the prosthesis has been applied in the intervertebral space. These surfaces shall have a rough or serrated appearance to promote integration of the prosthesis with the vertebral bone.

5. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, according to the previous clause, characterized in that the upper plate and the lower plate can be made of different materials, or of the same material with different properties, biocompatible materials are selected, such as titanium, titanium alloys or titanium carbide, chromium and cobalt alloys, suitable ceramic materials, high-density polyethylenes, diamond, carbon or composite materials.

6. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, in accordance with the previous clause, characterized by the variety of diameters and / or sizes of the prosthesis, without affecting the functionality of the device, which will be selected according to the patient's need, in order to replace the intervertebral disc, thus allowing the preservation and / or restoration of cervical dynamics.

7. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, in accordance with the previous clause, characterized by the sliding articular surfaces of the upper plate and the lower plate, they will not lose their contact with each other at any time, thereby avoiding an asymmetric contact overload.

8. A dynamic cervical disc prosthesis for intervertebral disc replacement with preservation and / or restoration of cervical dynamics, in accordance with the previous clause, the prosthesis has the compatible anatomical design to occupy the interbody space, without requiring complex instruments, only a guide instrument will be used for its application in the interbody space.

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