Intervertebral Prosthesis or Disk Prosthesis

Abstract

An intervertebral prosthesis or disk prosthesis comprising a front side, a rear side, an upper side which can be placed on the base plate of vertebral body, a lower side which can be placed on the base plate of a vertebral body, a right side, a left side, a cavity which can receive a fluid hydraulic osteocementum, an opening in the cavity and several outlets out from the cavity. The total of the transversal surfaces of the outlets S.sub.V on the front side, the total of the transversal surfaces of the outlets S.sub.H on the rear side, the total of the transversal surfaces of the outlets S.sub.R on the right side and the total of the transversal surfaces of the outlets on the left side satisfy the following conditions: S.sub.L>S.sub.R or S.sub.R>S.sub.L or S.sub.H>S.sub.V or S.sub.V>S.sub.H.

Claims

1. Intervertebral prosthesis or disk prosthesis (1) in the form of a rectangular hollow body with a front side (2), a rear side (3), an upper side (4) suitable for resting against the base plate of a vertebral body, a lower side (5) suitable for resting against the base plate of a vertebral body, a right side (6), a left side (7), a cavity (8) suitable for accommodating flowable osteocementum (20), an inlet opening (9) into the cavity (8) and several outlet openings (10; 11; 12; 13) for the flowable osteocementum from the cavity (8), the sum of the cross-sectional surfaces of the outlet openings (10) emerging from the front side (2) being S.sub.V, the sum of the cross-sectional surfaces of the outlet openings (11) emerging on the rear side (3) being S.sub.H, the sum of the cross-sectional surfaces of the outlet openings (12) emerging from the right side (3) being S.sub.R, and the sum of the cross-sectional surfaces of the outlet openings (13) emerging from the left side (7) being S.sub.L, characterized in that the outlet openings (10; 11; 12; 13) are dimensioned so that, when a flowable osteocementum (20) is supplied through the inlet opening (9) into the cavity (8) either: A) the amount of osteocementum K.sub.L, emerging through S.sub.L is larger or smaller than the amount of osteocementum K.sub.R emerging through S.sub.R or B) the amount of osteocementum K.sub.H, emerging through S.sub.H is larger or smaller than the amount of osteocementum K.sub.V emerging through S.sub.V.

2. The intervertebral prosthesis or disk prosthesis (1) of claim 1, characterized in that one of the following conditions applies: S.sub.L>S.sub.R or S.sub.R>S.sub.L or S.sub.H>S.sub.V or S.sub.V>S.sub.H.

3. The intervertebral prosthesis or disk prosthesis (1) of claim 1 or 2, characterized in that the inlet opening (9) is provided in the front side (2) and the cavity (8) extends from the inlet opening (9) in the direction of the rear side (3).

4. The intervertebral prosthesis or disk prosthesis (1) of claim 1 or 2, characterized in that the inlet opening (9) is provided in the left or right side (6, 7) and the cavity (8) extends from the inlet opening (9) in the direction of the opposite right or left side (7, 6).

5. The intervertebral prosthesis or disk prosthesis (1) of claim 3 or 4, characterized in that cross section of the cavity (8) decreases at least on a partial section as the distance from the inlet opening (9) increases.

6. The intervertebral prosthesis or disk prosthesis (1) of claims 6, characterized in that the cavity (8) decreases in wedge-shaped or conical fashion at least on a partial section.

7. The intervertebral prosthesis or disk prosthesis (1) of one of the claims 1 to 6, characterized in that the upper side (4) and lower side (5) converge toward the front side (2) at least on a partial section.

8. The intervertebral prosthesis or disk prosthesis (1) of one of the claims 1 to 7, characterized in that it is filled at least partly with a cured, hydraulic osteocementum (20), which extends at least partly beyond the outlet openings (10; 11; 12; 13).

9. Implant material consisting of intervertebral prostheses or disk prostheses (1) of one of the claims 1 to 8, which are disposed next to one another, characterized in that: A) the right side (6) of the intervertebral prosthesis (1) disposed on the left is oriented towards the left side (7) of the intervertebral prosthesis (1) disposed on the right and B) for the intervertebral prosthesis (1), disposed on the left, the condition S.sub.L>S.sub.R applies and for the intervertebral prosthesis (1) disposed on the right, the condition S.sub.R>S.sub.L applies.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The invention and further development of the invention are described in even greater detail by means of several examples and partially diagrammatic drawings, in which

[0018] FIG. 1 shows a perspective view of an inventive, lens-shaped intervertebral implant,

[0019] FIG. 2 shows a longitudinal section through the intervertebral implant of FIG. 1 along the central plane VIII-VIII,

[0020] FIG. 3 shows a side view from the right of the intervertebral implant of FIG. 1,

[0021] FIG. 4 shows a side view from the left of the intervertebral implant of FIG. 1,

[0022] FIG. 5 shows a perspective view of an inventive intervertebral prosthesis, which is secured by means of cured osteocementum,

[0023] FIG. 6 shows a plan view of the intervertebral prosthesis of FIG. 5,

[0024] FIG. 7 shows a perspective view of a variation of the embodiment, using two intervertebral implants, the osteocementum securing the implant in their position relative to one another as well as to prevent migrating apart,

[0025] FIG. 8 shows a plan view of the two intervertebral implants of FIG. 7,

[0026] FIG. 9 shows a front view of a variation of the embodiments, in which the perforated intervertebral implant has a rectangular cross section and

[0027] FIG. 10 shows a front view of a variation of the embodiment, in which the perforated intervertebral implant has a circular ring-shaped cross section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The intervertebral prosthesis 1, shown in FIGS. 1 and 2, consists of a rectangular hollow body and has a front side 2, a rear side 3, an upper side 4 suitable for positioning against the baseplate of a vertebral body, a lower side 5 suitable for positioning against the baseplate of a vertebral body, a right side 6, a left side 7, a cavity 8 suitable for accommodating a flowable, hydraulic osteocementum, an inlet opening 9 into the cavity 8 and several outlet openings 10; 11; 12; 13 from the cavity 8. The upper side 4 and the lower side 5 converge toward the front side 2 as well as toward the rear side 3, so that a lens-like configuration of the intervertebral prosthesis results.

[0029] As can be seen from FIG. 2, the cross section of the cavity 8 decreases in the shape of a cone as the distance from the inlet opening 9 increases.

[0030] As shown in FIG. 3, there are three outlet openings 12 with areas F.sub.1, F.sub.2 and F.sub.3 in the right side 6 of the intervertebral prosthesis 1, so that the sum S.sub.R of the cross sectional surfaces of the outlet openings emerging the right side 6 is S.sub.R=F.sub.1+F.sub.2+F.sub.3.

[0031] As shown in FIG. 4, there are two outlet openings 13 with the areas F.sub.4 and F.sub.5 in the left side 7 of the intervertebral prosthesis 1, so that the sum S.sub.L of the cross-sectional surfaces of the outlet openings emerging for the left side 7 is S.sub.L=F.sub.4+F.sub.5.

[0032] It is important that the sum S.sub.L>S.sub.R, so that more osteocementum can emerge on the left side 7 of the intervertebral prosthesis 1 from the cavity 8 through the outlet opening 13 into the intervertebral space than from the right side 6.

[0033] FIGS. 5 and 6 show how the osteocementum 20, emerging from the right side 6 and the left side 7 of the intervertebral prosthesis 1, is distributed. Because the sum S.sub.L of the cross sectional areas of the outlet openings 13 emerging on the left side 7 is larger, the amount of osteocementum 20, emerging on the left side 7 and curing, is also larger than that emerging on the right side 6 and curing.

[0034] FIGS. 7 and 8 show a further embodiment, which consists of two inventive intervertebral prosthesis 1, which are disposed next to one another. The two intervertebral prostheses are positioned in such a manner, that the right side 6 of the intervertebral prosthesis 1, which is disposed on the left, is oriented in the direction of the left side 7 of the intervertebral prosthesis 1, which is disposed on the right. For the intervertebral prosthesis 1, disposed on the left, the condition S.sub.L>S.sub.R applies, whereas, for the intervertebral prosthesis 1, which is disposed on the right, the reverse applies, namely S.sub.R>S.sub.L. Due to this measure, less osteocementum 20 emerges in the space between the two intervertebral prostheses 1 than emerges to the right side of the intervertebral prosthesis 1 disposed on the right and to the left side 7 of the intervertebral prosthesis 1 disposed on the left.

[0035] FIG. 9 shows a variation of the embodiment of an inventive intervertebral implant 1, which has a rectangular cross section and from which a larger amount of osteocementum 40 has emerged on the right side than on the left side.

[0036] FIG. 10 shows a further variation of an embodiment of an intervertebral prosthesis 1, which has a circular cross section and for which the amount of osteocementum 40 emerging on the right side through the outlet openings 12 is larger than that emerging on the left side through outlet openings 13.