Cervical Disc Prosthesis with Movable Blade Technical Field

The invention relates to a cervical disc prosthesis suitable for use in cervical vertebral hernias in field of medicine. The invention especially relates to a cervical disc prosthesis which comprises a movable blade and which provides a more stable structure by sticking into the bone thanks to this feature.

State of the Art

In cervical (neck) hernias (rupture), simple discectomy is the first surgical intervention method. As time passed by and the technology used in medicine improved, bone wedges suitable for the region extracted from the body were started to be used for the disc parts removed in cervical hernias. Later, synthetic structures (cage) started to be placed in the space of the removed disc. Today, with the improvement of the technology, cervical disc prostheses consisting of single or double movable parts are started to be placed in place of the removed disc.

In cervical disc prosthesis surgery, there is not an integration in the movable middle section. However, as the bottom and top surface sections of the prosthesis integrate with the bone, the neck movement of the patient are not restricted. As the disc length of the top and bottom segments in cervical disc prosthesis are not disrupted, quality of life of the patient increases.

The most important complication of cervical prosthesis surgery is the detachment of the cervical disc prosthesis from disc length after the surgery due to being movable and thus, damaging the anatomical structure of the bone in accordance with the applied prosthesis. Moreover, by harming the carotid artery, esophagus and trachea, which are the vital structures in said region, it constitutes life-threatening damages. When existing prostheses are placed inside the disc length after the cervical disc is removed, there is a possibtiity for them to detach from this length. Some prostheses detach due to the inadequacy of prosthesis surfaces to hold onto the bone at the top and bottom when lowered to the disc length. Some prostheses, on the other hand, comprise big lugs on the prosthesis surfaces that will hold onto the bone at the top and bottom when lowered to the disc length. These lugs form a track from the top to the bottom inside the bone. As they form a track on the bone, it is highly possible for them to detach from said track.

Some prostheses comprise big, blunt or ragged protrusions on the middle section of the prosthesis surfaces that will hold onto the bone at the top and bottom when lowered to the disc length. These protrusions damage the bone structure while being placed in the prosthesis disc length and form tracks on the bone. This causes the prosthesis to detach from the disc length. In some cases, due to the damage to the bone and the formed tracks, the prosthesis causes the bone to crack from the middle line.

In some prostheses used in the state of art, there is a big round structure in the middle section of the prosthesis surfaces. Due to said structure, the bone structure must be drilled from the inner section in order to place the prosthesis. These prostheses damage the anatomical structure of the cervical bone. Incorrect drilling may cause permanent damages on the health of the patient.

Some of the existing prostheses comprise some mechanisms which are stuck into the bone as additional protrusion on the surface of the prosthesis. As these mechanisms take a large space on the surface of the prosthesis, in order to fit them into the disc length, a part of the bone structure must be removed. This causes the disruption of existing anatomical structure and the disruption of cervical balance dynamic. In some existing prostheses, after the prosthesis is placed, the top and bottom surfaces are fixed to the surface of the bone with screws. These prostheses not only are hard to apply, but also require extra process. As there are extra foreign objects on the body when this prosthesis is applied, the risk of infection increases. One of the patents related to the subject in the literature is the patent application No. CN1457750A. The exterior surfaces of the cervical cage disclosed in said application have a ragged structure. While being placed between two bones, the cervical cage leaves a track on the bone as it moves inside. The tracks formed on the bone may later cause the prosthesis to detach when it is required to retract. The top and bottom cage provide back and forth movement. Another invention is disclosed in the patent application No. TR200804254B. Said application comprises a circular upper body and a lower body used in the neck section, which operate together and which provide turning of the neck. Moreover, it is a cervical disc prosthesis which comprises a connection end that connects said bodies to each other; and an at least one movement gap that is formed in the middle section of the upper body and the lower body.

As a result, due to the drawbacks in the state of the art and mentioned above and the inadequacy of the existing solutions regarding the subject matter, it is required to make a development in the related technical field.

Object of the Invention

The invention relates to a cervical disc prosthesis with movable blade which meets the requirements stated above, eliminates ail the disadvantages and brings forth some additional advantages.

The main object of the invention is to prevent the detachment of the prosthesis from the disc length thanks to the movable blade which is formed on the exterior surfaces and as impacted in the exterior surfaces in which the bottom and top surfaces of the cervical disc prostheses contact the bone. Thus, with the preservation of neck movement after surgery, quality of life the patient is increased. Moreover, the fact that the prosthesis does not detach from the disc length, the period for the patient to stay in the hospital and the use of cervical collar after the surgery are reduced.

An object of the invention is to prevent formation of tracks on the bone structures during the implantation of the prosthesis due to the impacted structure comprised by the movable blade on the surfaces. By this means, the damage to occur on the anatomy of the bone during the implantation of the prosthesis is minimized. Moreover, without the formation of tracks, the detachment of the prosthesis from the disc length is prevented.

Another object of the invention is to provide opening and closing of the movable blade, which is impacted thanks to the slot comprised by the exterior surfaces of the prosthesis, with a movement member. Thus, the movable blade is stuck and fixed into the bone structure when it is opened. By this means, its detachment from the disc length is prevented. Moreover, thanks to the folding feature thereof, it can be removed and reinstalled when intended or required. During the application of the prosthesis, if the prosthesis placed in the space created by the removal of the disc is not in the suitable location, it can be easily removed by closing into the slot in which said blade was previously impacted. Later, it can be re-installed into the same place optionally. Also, as the sticking process is conducted through the middle of the bone structure, end plates of the top and bottom vertebra are not damaged.

Another object of the invention is to provide a stable structure thanks to sticking of the blade into the bone by being opened. By this way, as a section of the prosthesis blade is left inside the slot, prosthesis does not move back and forth on the bone surface. However, with the movement of bottom and top surfaces of the prosthesis on each other, the neck movement of the patient is easily ensured. Moreover, after the sticking process is conducted, the slot in which the blade was previously impacted is left empty. This situation ensures an easier fusion of the bone structure by moving towards said slot and more durable adhesion of the prosthesis surface to the bone. A similar object of the invention is to provide the use of the prosthesis according to the invention in two length cervical hernias. As there are not any additional lengths and additional parts on the top and bottom surfaces while said prosthesis is applied to the length, it is not necessary to conduct bone rounding with high speed drill in cervical vertebra bones. Thus, ease of application is achieved and the normal anatomy of the bone structure is preserved.

The invention aims to reduce the complication risks thanks to the easy applicability of said prosthesis and the stable structure it has after the application. By this way, it is ensured that the surgeon conducting the surgical intervention feels safe.

A similar object of the invention is to provide acquiring various versions of the movable fixing arm located on the prosthesis according to the invention.

In order to realize the objects stated above, it is a cervical disc prosthesis suitable for use in cervical vertebral hernias, comprising a bottom part and a top part, which are configured monolithically or separately, and the exterior surfaces of which are in contact with the bone; at least one slot formed on said bottom part or top part; at least one movable blade which is located inside said slot as closed and which is fixed inside the bone after exiting the slot and being opened; at least one movement member embedded inside the bottom part or the top part transmitting movement to the blade it is connected to; at least one movement member slot in which said movement member is embedded; and a turning member which provides movement to the blade via said movement member. The structural and characteristic features and all the advantages of the present invention will be more clearly understood thanks to the figures below and the detailed description written with reference to those figures, therefore, the evaluation needs to be done by taking said figures and the detailed description into consideration.

Figures for a Better Understanding of the Invention

Figure 1 is a general perspective view of the blade, which is formed on the surface of the prosthesis according to the invention, as impacted (closed).

Figure 2 is a general perspective view of the blade, which is formed on the surface of the prosthesis according to the invention, as open. Figure 3a is a perspective view of the surface of the prosthesis according to the invention.

Figure 3b is a view of the blade of the prosthesis according to the invention.

Figure 3c is a perspective view of the movement member of the prosthesis according to the invention.

Figure 4 is the impacted and front view of an alternative embodiment of the prosthesis according to the invention. Figure 5 is the open and front view of an alternative embodiment of the prosthesis according to the invention.

Figure 6 is the open and front view of an alternative embodiment of the prosthesis according to the invention.

Figure 7 is the open and front view of an alternative embodiment of the prosthesis according to the invention.

Figure 8 is the open and front view of an alternative embodiment of the prosthesis according to the invention. Figure 9 is the top view of the surface of the prosthesis according to the invention as the blade is open.

Figure 10 is the view of the monolithic movement arm located on the prosthesis according to the invention.

Figure 11a is the perspective view of an alternative embodiment of the top part of the prosthesis according to the invention. Figure 11b is the perspective view of an alternative embodiment of the bottom part of the prosthesis according to the invention.

Figure 11c is the perspective view of an alternative embodiment of the bottom part of the prosthesis according to the invention.

Figure 1d is the side view of an alternative embodiment of the prosthesis according to the invention.

The drawings do not need to be scaled and the details that are not necessary for understanding the present invention may have been ignored. In addition, the members that are at least identical to a great extent or at least have identical functions to a great extent are referred with the same number.

Description of Part References

10. Prosthesis

20. Part

21. Bottom part

22. Top part

30. Blade

31. Pointed end

32. Blade indent

40. Slot

50. Movement member

51. Movement member slot

52. Movement arm

53. Lug 54. Turning member

55. Indent

60. Safety protrusion

61. Protrusion

70. Mechanism

80. Groove

81. Male connection member

82. Female connection member

A: Direction

B: Direction

Detailed Description of the Invention

In this detailed description, the preferred embodiments of the cervical disc prosthesis (10) with movable blade (30) according to the present invention are described only for the subject to be understood better without any limiting effect.

The invention relates to a cervical disc prosthesis (10) comprising at least one slot (40) formed on the exterior surface of a part (20) which contacts with the bone; and a blade (30) positioned inside said slot (40) via a movement member (50). Said part (20) can be the bottom part (21) or the top part (22) of the prosthesis (10), which come into contact with the bone. Said prosthesis (10) may be formed of two separate parts consisting of bottom part (21) and top part (22). Also, the bottom part (21) and the top part (22) can be formed monoiithically as connected with a pin. Said monolithic or two-part prosthesis (10) structure can be placed in a disc length with a hand tool. The invention comprises a rotatable mechanism (70) which connects the bottom part (21) and the top part (22) together and provides movement of the bones on each other. Said slot (40) is formed on the part (20) in a size capable of housing the blade (30) inside. Said slot (40) may be in different shapes in accordance with the shape of the blade (30).

Blade (30) has a movable structure. The movement of the blade (30) is achieved via a movement member (50) embedded in the movement member slot (51). Movement member (50) is connected to the blade (30). As mentioned before, the blade (30) and the movement member (50) can either be as two parts or be formed monoiithically. Moreover, said monolithic structure can also be used in a way to comprise the movement member (50), the blade (30) and a turning member (54) (Figure 10). The monolithic structure hosting said three parts is referred to as the movement arm (52). Said movement member slot (51) can either be formed inside the part (20) and be covered or be open without being covered with the part (20). In the event that the movement member slot (51) is not covered, the part (20) comprises lugs (53) which prevent detachment of the movement member (50). Said lugs (53) are formed on the part (20).

Moreover, a turning member (54), which provides opening and closing of the blade (30) and which is either fixed on the movement member (50) or formed monoiithically with the movement member (50), is comprised. Said turning member (54) can be rotated by means of a tool externally. In order to conduct the rotating process by means of a tool, the part of the turning member (54) must have a female-male part adaptation with the part of the related tool. The turning member having the female part feature comprises an indent (55) to form a female structure compatible with the tool with male feature. When the turning member (54) is rotated, the blade (30) can be opened and closed with an angle of at least 90° or more. The end section of the blade (30) located on the prosthesis according to the invention is formed so as not to be sharp. In a preferred embodiment of the invention, the blade (30) comprises a pointed end (31) which provides sticking function. Said pointed end (31) is configured on the blade at the remotest point from the movement member (50). Figure 1 is a general perspective view of the blade (30), which is formed on the part (20) of the prosthesis (10) according to the invention, as impacted (closed). In the figure, the blade (30), while in the closed position, is provided within the slot (40) such that there cannot be a protrusion on the exterior surface of the part (20). In order to move said blade (30), the turning member (54) is rotated on the direction A. The movement member (50), which transmits the movement received from turning member (54), opens the blade (30) by moving it towards direction A.

Figure 2 is a general perspective view of the blade (30), which is formed on the part (20) of the prosthesis (10) according to the invention, as open. As it is seen, the blade (30) is positioned vertically exiting from the slot (40). The prosthesis (10), seen in the figure as open, is closed by being turned towards direction B by the turning member (54). The movement member (50), which transmits the movement received from turning member (54), closes the blade (30) by moving it towards direction B. Figure 3a is a perspective view of the part (20) of the prosthesis (10) according to the invention. On the figure, the movement member slot (51), on which the movement member (50) is placed, is shown. Figure 3b and 3c are perspective views of the blade (30) and the movement member (54) of the prosthesis (10) according to the invention. As it is seen in Figure 3c, the movement member (50) has a monolithic structure with the turning member (54). Figure 4 is the closed and front view of an alternative embodiment of the prosthesis (10) according to the invention. On said figure, the structure formed as one on the bottom part (21) and the top part (22) is shown. Said structure is formed by a movement arm (52) preferably formed by the blade (30), movement member (50) and the turning member (54). Moreover, as said movement arm (52) is embedded in the part (20) as uncovered, the part (20) comprises lugs (53). Thus, detachment of movement arm (52) from the movement member slot (51) is prevented.

Figure 5 shows the open status of the closed alternative structure mentioned in Figure 4. The blade (30) is opened by rotating the turning arm (54). Said blades (30) are positioned in opposing directions.

Figure 6 is the open and front view of another alternative embodiment of the prosthesis (10) according to the invention. As it is seen in the related figure, a prosthesis (10) is formed by using two movement arms (52) each on the bottom part (21) and the top part (22). In said prosthesis (10), the fixing members (30) on the top part (22) are formed so as to face each other and similarly, the fixing members (30) on the bottom part (21) are formed so as to face each other.

Figure 7 is the open and front view of another alternative embodiment of the prosthesis (10) according to the invention. The top part (22) comprises two blades (30) while the bottom part (21) comprises one. Moreover, as it is seen in the figure, the turning member (54) comprises an indent (55) having a structure compatible with phillips screwdriver. By this means, rotating process can be conducted via a phillips screwdriver. Figure 8 is the open and front view of an alternative embodiment of the prosthesis (10) according to the invention. The turning members (54) seen in the related figure comprise an indent (55) having a structure compatible with flat screwdriver. By this means, rotating process can be conducted via flat screwdriver. Figure 9 is the top view of the part (20) of the prosthesis (10) according to the invention as the blade (30) is open. The part (20) seen in the figure comprises a monolithic and open movement arm (52). The part (20) preferably comprises thereon a safety protrusion (60) which ensures a more stable structure for the prosthesis (10). The part (20) can be the bottom part (21) or the top part (22).

Moreover, in a preferred embodiment of the invention, there are protrusions (61) on the part (20) for helping the prosthesis (10) to stay immobile.

Figure 11a is the perspective view of an alternative embodiment of the top part (22) of the prosthesis (10) according to the invention. As it is seen on the figure, there are oval grooves (80) on the exterior surface of the bottom part (21). When the patient gets into sitting position and stands up after the prosthesis (10) is placed, the weight of the head and the neck is loaded on the prosthesis (10). Thanks to said grooves (80), sliding of the prosthesis (10) is prevented by setting on the bone structure. Bone fills these grooves (80) in time and thus, fusion is strengthened. Moreover, there is at least one blade indent (32) which is formed on the blade (30) and which facilitates fusion after the fixation. Bone fills said blade indent (32) in time and provides a stronger fusion.

Figure 11 b is the perspective view of an alternative embodiment of the top part (22) of the prosthesis (10) according to the invention. There is a male connection member (81) providing connection with the bottom part (21) on the bottom surface of said top part (22). The male connection member (81) formed as knob provides 360° movement capability to the top part (22). Figure 11c is the perspective view of an alternative embodiment of the bottom part (21) of the prosthesis (10) according to the invention. A female connection member (82) is formed on the top surface of the bottom part (21), in which the male connection member (81) formed on the bottom surface of the top part (22) is placed. Female connection member (82) is configured in a shape (geometry) compatible with the structure of the male connection member (81) and thus, the parts (20) have the capability of moving 360° on each other. Moreover, optionally, the grooves (80) formed on the top part (22) are also formed on the bottom part (21) (Not shown in the figure). Figure 11d is the side view of an alternative embodiment of the prosthesis (10) according to the invention. In this view, the prosthesis (10) bearing the features mentioned in Figure 11a, 11b and 11c is shown.

In preferred embodiments of the invention, said blade (30) can be configured in different numbers in a way to be comprised at least one on the bottom part (21) and the top part (22). Moreover, said blade (30) can be comprised in both the top part (22) and the bottom part (21). In the event that there are more than one blades (30) on a part (20), blades can be configured as facing or opposing each other.

After the prosthesis (10) according to the invention is placed into the disc length, turning member (54) is rotated manually or via a tool. The movement transmitted from the turning member (54) is transmitted to the blade (30) via the movement member (50). By this way, the blade (30) exits from the slot (40) in which it is comprised as covered, and is opened so as to have an angle about 90° or more. The blade (30) brought into open position is stuck into the bone in said position. The blade (30) going into the bone approximates the bone and the prosthesis (10) when the retractors drawing away the two bones are removed.

The opened blade (30) sticks into the inner section of the bone and provides the prosthesis (10) a stable structure. Moreover, as a section of the fixing blade (30) is inside the slot (40), the rotation of the blade (30) on the surface of the prosthesis (10) is prevented. By means of the biade (30) stuck into the bone so as to form a right angle or a wide angle, the advancement of the prosthesis to the anterior or posterior is prevented. Removal process of the prosthesis is conducted by rotating the turning member (54) the other way around. Thus, the blade (30) goes into the slot (40) and switches to closed position.